The response of phytoplankton and its satellite bacteria to various concentrations(0.01%-10%v/v)of ethanol is studied.To elucidate the effect of ethanol,single-strains of phytoplankton(SSP)culture,pure strains of sate...The response of phytoplankton and its satellite bacteria to various concentrations(0.01%-10%v/v)of ethanol is studied.To elucidate the effect of ethanol,single-strains of phytoplankton(SSP)culture,pure strains of satellite bacteria isolated from nonaxenic SSP cultures,and Escherichia coli were screened.Results indicate that ethanol could promote the growth and photo synthetic efficiency(F_(v)/F_(m))of S SP at 0.01%and the growth of satellite bacteria at 0.01%-1%.Nevertheless,ethanol inhibited the growth and F_(v)/F_(m)of SSP at 0.1%-1%,and killed bacteria and SSP at 10% concentration.Further investigation on a satellite bacterium(Mameliella alba)revealed that ethanol promotes growth by serving as a growth stimulant rather than a metabolic carbon source.The 16 S rRNA gene amplicon indicated that all nonaxenic S SP cultures harbor distinct satellite bacteria communities where the SSP culture of Skeletonema costatum,Phaeodactylum tricornutum,and Dunaliella bardawil were dominated by bacteria genera of Marivita(~80%),Dinoroseobacter(~47%),and Halomonas(~87%),respectively,indicating that every SSP cultures have their own distinct satellite bacterial community.The bacteria family Rhodobacteraceae was dominant in the two marine diatoms,whereas Halomonadaceae was dominant in the saline green microalga.Compared to their respective controls,the supply of 0.5% ethanol to SSP cultures promoted the growth of the satellite bacteria but did not cause a significant difference in species composition of satellite bacteria.Therefore,a low concentration of ethanol can promote the growth of bacteria in a non-selective way.This study enriched our knowledge about the effect of ethanol on aquatic microbes and provided a baseline for basic and applied biotechnological re search in the aquatic environment in the future.展开更多
The present study evaluated the in vitro activity and in vivo efficacy of diminazene combined with chloroquine as a potential drug against Leishmania donovani. Amphotericin B was used as a positive control drug. In vi...The present study evaluated the in vitro activity and in vivo efficacy of diminazene combined with chloroquine as a potential drug against Leishmania donovani. Amphotericin B was used as a positive control drug. In vitro activity involved incubation of various drug concentrations with promastigotes or vero cells in culture before determination of parasite growth inhibition or cell death while in vivo evaluations involved infection of various mice groups with virulent L. donovani parasites and treatment with test drug compounds following disease establishment. Weight changes in experimental mice were also evaluated before infection and throughout the experiment. The results indicated that the diminazene-chloroquine combination was at least nine times more efficacious than individual drugs in killing promastigotes in culture. The diminazene-chloroquine combination was safer （Ld50=0.03±0.04） than Amphotericin B （Ld50=0.02±0.01）. Body weight in infected mice increased significantly （P=0.0007） from day 7 to day 37 following infection （P=0.026）. However, body weight remained comparable in all mice groups during treatment （P=0.16）. The diminazene-chloroquine combination significantly reduced splenic parasite numbers as compared to individual drug therapies （P=0.0001） although Amphotericin B was still more efficacious than any other treatment （P=0.0001）. Amongst the test compounds, the diminazene-chloroquine combination showed the lowest level of IgG antibody responses with results indicating significant negative correlation between antileishmanial antibody responses and protection against disease. These findings demonstrate the positive advantage and the potential use of a combined therapy of diminazene-chloroquine over the constituent drugs. Further evaluation is recommended to determine the most efficacious combination ratio of the two compounds.展开更多
Leishmaniasis is a disease that ranges in severity infection. Resistance to infection is associated with from skin lesions to serious disfigurement and fatal systemic a T-helper-1 immune response that activates macrop...Leishmaniasis is a disease that ranges in severity infection. Resistance to infection is associated with from skin lesions to serious disfigurement and fatal systemic a T-helper-1 immune response that activates macrophages to kill the intracellular parasite in a nitric oxide-dependent manner. Conversely, disease progression is generally associated with a T-helper-2 response that activates humoral immunity. Current control is based on chemothera- peutic treatments which are expensive, toxic and associated with high relapse and resistance rates. Vaccination remains the best hope for control of all forms of the disease, and the development of a safe, effective and affordable antileishmanial vaccine is a critical global public-health priority. Extensive evidence from studies in animal models indicates that solid protection can be achieved by immunization with defined subunit vaccines or live-at- tenuated strains of Leishmania. However, to date, no vaccine is available despite substantial efforts by many laboratories. Major impediments in Leishmania vaccine development include： lack of adequate funding from national and international agencies, problems related to the translation of data from animal models to human disease, and the transition from the laboratory to the field. Furthermore, a thorough understanding of protective immune responses and generation and maintenance of the immunological memory, an important but least-studied aspect of antiparasitic vaccine development, during Leishmania infection is needed. This review focuses on the progress of the search for an effective vaccine against human and canine leishmaniasis.展开更多
Diatoms and dinoflagellates are two major groups ofphytoplankton that flourish in the oceans, particularly in coastal zone and upwelling systems, and their contrasting production have been reported in several world se...Diatoms and dinoflagellates are two major groups ofphytoplankton that flourish in the oceans, particularly in coastal zone and upwelling systems, and their contrasting production have been reported in several world seas. However, this information is not available in the coastal East China Sea （ECS）. Thus, to investigate and compare the decadal trends in diatoms and dinoflagellates, a sediment core, 47-cm long, was collected from the coastal zone of the ECS. Sediment chlorophyll-a （Chl-a）, phytoplankton-group specifc pigment signatures of diatoms and dinoflagellates, and diatom valve concentrations were determined. The sediment core covered the period from 1961 to 2011 AD. The chlorophyll-a contents ranged from 2.32 to 73 gg/g dry sediment （dw） and averaged 9.81 gg/g dw. Diatom absolute abundance ranged from 29 152 to 177 501 valve/gram （v/g） dw and averaged 72 137 v/g dw. Diatom valve and diatom specific pigment marker concentrations were not significantly correlated. Peridinin increased after the 1980s in line with intensified use of fertilizer and related increases in nutrient inputs into the marine environment. The increased occurrence of dinoflagellate dominance after the 1980s can be mostly explained by the increase in nutrients. However, the contribution of dinoflagellates to total phytoplankton production （Chl-a） decreased during the final decade of this study, probably because of the overwhelming increase in diatom production that corresponded with the construction of the Three Gorges Dam （TGD） and related light availability. Similarly, the mean ratio of fucoxanthin/peridinin for the period from 1982 to 2001 was 6% less than for 1961 to 1982, while the ratio for 2001 to 2011 was 45.3% greater than for 1982 to 2001. The decadal variation in the fucoxanthirdperidinin ratio implies that dinoflagellate production had been gradually increasing until 2001. We suggest that the observed changes can be explained by anthropogenic impacts, such as nutrient loading and dam construction.展开更多
Over the last decade, there has been a flurry of research on adjuvants for vaccines, and several novel adjuvants are now licensed products or in late stage clinical development. The success of adjuvants in enhancing t...Over the last decade, there has been a flurry of research on adjuvants for vaccines, and several novel adjuvants are now licensed products or in late stage clinical development. The success of adjuvants in enhancing the immune response to antigens has led many researchers to re-focus their vaccine development programs. Although several vaccine candidates have been tested against leishmaniasis, there is yet no effective vaccine against this parasitic disease. Recent research has documented that efforts to develop effective Leishmania vaccine have been limited due to lack of an appropriate adjuvant. In view of this, this review paper outlines some of the adjuvants that have been used in Leishmania vaccine candidates and cites a few of the responses obtained from these studies. The aim of the present review is to consolidate these findings to facilitate the application of these adjuvants in general and experimental vaccinology.展开更多
Objective:To identify the sandfly fauna and analyze ecology of sandfly vector(s)of visceral leishmaniasis in three districts of Somali Regional State,southeast Ethiopia.Methods:Sandflies were collected from four sampl...Objective:To identify the sandfly fauna and analyze ecology of sandfly vector(s)of visceral leishmaniasis in three districts of Somali Regional State,southeast Ethiopia.Methods:Sandflies were collected from four sampling habitats,including indoor,peri-domestic,farm field and mixed forest using light and sticky traps in July 2016,and February and April 2017 in Liben and Dawa zones in the Somali Regional State,southeastern Ethiopia.Results:In total,4367 sandfly specimens,belonging to 12 species(three Phlebotomus spp.and nine Sergentomyia spp.)were identified.Phlebotomus(P.)heischi,P.orientalis,and P.martini constituted 45.7%,31.1%,and 23.1%of the sandfly collection,respectively.There were significant differences in the median number of P.orientalis,and P.martini captured per CDC trap/night between the three sampling districts(P<0.05).In light trap capture,collection habitats had significant effects on the abundance of P.orientalis,and P.martini(P<0.05).More median numbers of P.orientalis,and P.martini species were collected in agricultural fields followed by mixed forest and peri-domestic habitats.P.orientalis and P.martini were caught more in outdoor than indoor habitats,suggesting exophilic behaviour.Conclusions:The study demonstrated that the presence of P.orientalis and P.martini are probable vectors of visceral leishmaniasis in this new focus.The findings of our study will improve the understanding of the dynamics of visceral leishmaniasis transmission and will facilitate the implementation of integrated disease control measures based on ecological knowledge of visceral leishmaniasis vector in Liben and Dawa zones and its surrounding regions.展开更多
The implications of climate change during the second half of the 20th century have been reported throughout the world. Although marginal seas are sensitive to climate change and anthropogenic impacts, relatively littl...The implications of climate change during the second half of the 20th century have been reported throughout the world. Although marginal seas are sensitive to climate change and anthropogenic impacts, relatively little attention has been given to the South East Asian marginal seas. Thus, to bridge this gap in knowledge, a sediment core was collected from the coastal areas of the Leizhou Peninsula in the South China Sea （SCS） to study the inter-decadal climate change and its consequences using diatom species composition as a proxy record. Diatom absolute abundance varied from 2 300 to 68 000 and averaged 16 000 valves per gram of dry weight （v/gdw）. The fractional dissolution index （F~） was usually below 0.5, which indicates low to moderate preservation of diatom valves at coastal area of the SCS. At the inter-decadal time scale, total diatom abundance was high for the period after 1972, which coincided with 1） increased percentage of planktonic diatom abundance and F~; 2） emergence and dominance of high productivity indicative cosmopolitan species such as Thalassionema nitzschioides and Paralia sulcata （their relative abundance increased from 〈1.5% to 〉7% for the period before and after 1972, respectively）; 3） decreased relative abundance of the small-sized eutrophication indicative species, Cyclotella striata, from 70% to 40%. This study reveals that variations in the abundance of diatoms preserved in the sediment was a function of both production and dissolution/preservation of diatom valves, which in turn was intimately connected to the prevailing environmental/climatic conditions. In conclusion, these data reveal the existence of substantial changes in the coastal SCS in response to the 1970s climate shift that was recorded in different parts of the world.展开更多
Objective:To investigate the zoonotic visceral leishmaniasis(ZVL) by identification of the most probable reservoir hosts using parasite isolation and analysis of a possible transmission dynamics of the disease in extr...Objective:To investigate the zoonotic visceral leishmaniasis(ZVL) by identification of the most probable reservoir hosts using parasite isolation and analysis of a possible transmission dynamics of the disease in extra-domestic agricultural fields and rural villages.Methods:Rodents were collected from selected study sites in kala-azar endemic areas based on information for localities of kala-azar cases for screening of Leshmania infections using parasitological,serological and polymerase chain reaction(PCR) from March.2013 to January,2014.Ketamine(Clorketam Veterinary) was used to anaesthesize the rodents according the prescribed dosage(average 2 mg/kg for intra-venous route).The blood obtained using sterile needle was dropped into sterile filter paper and allowed to air dry before sealing in plastic bags.The tissues from liver,spleen and skin were macerated in Locke's solution before transferring them into NNN medium.Blood and touch smears of liver,spleen,skin and bone marrow were prepared for fixing using methanol and staining by Giemsa stain for microscopy.These tissues were also ascd for DNA extractions and PCR amplification of Leishmania infection.Results:A total of 335 rodents(13 species) were analyzed by sampling internal organs.The infection rate by PCR was 11.1%(6/54) for Arvicanthis nilothicas compared to 17.6%(3/17) and 12.5%(2/16) for Acomys cahirinus and Tarera(C) robustus respectively.Almost all the infections were found from bone marrow samples(8/48 or 16.7%) compared with 1/91(1.1%) liver,2/87(2.2%) spleen and 0/87(0%) skin.In all study sites with past human VL cases,rodents and proved vectors shared similar habitats.Conclusions:Leishmania donovani might circulate among different species of rodents in kala-azar endemic lowlands and valleys of Ethiopia by Phlebotamus orientalis and Phlebotomus martini.Detailed studies to substantiate the preliminary data on the possible role of these rodents arc urgently needed.展开更多
Objective： To determine the adjuvant potential of artemisinin with a soluble leishmanial antigen in vaccinating BALB/c mice. Methods： Seventy two female BALB/c mice were randomly assigned into six groups. The mice w...Objective： To determine the adjuvant potential of artemisinin with a soluble leishmanial antigen in vaccinating BALB/c mice. Methods： Seventy two female BALB/c mice were randomly assigned into six groups. The mice were vaccinated with soluble Leishmania antigens （SLA） alone, artemisinin co-administered with SLA, SLA and Bacille Calmette Gu fin （BCG） vaccine, and artemisinin and BCG alone. Unvaccinated mice formed the control group. The induction of cell-mediated immunity following vaccination was determined by measuring in vitro lymphocyte proliferation and the production of interleukin （IL）-4, IL-5 and gamma interferon （IFN-γ） determined by flow cytometry. Protection against L. major was determined by quantifying parasite burdens in L. major infected footpads using a limiting dilution assay and by measuring lesion sizes of the infected footpad compared to the contralateral uninfected footpad. Results： Mice receiving SLA plus artemisinin produced significantly high levels of IL-4 and IL-5 （P 〈 0.05） and low levels of IFN-γ, resulting in exacerbated disease. In addition, subcutaneous administration of SLA ＋ artemisinin, artemisinin alone or SLA alone resulted in the development of large footpad swellings and high parasite loads that were comparable to those of the control unvaccinated mice （P 〉 0.05）, resulting in exacerbated disease. Conclusion： These data suggest that artemisinin is not a suitable adjuvant for Leishmania vaccines. However, since artemisinin has been shown to be effective against Leishmania parasites in vitro and in vivo, further studies ought to be conducted to determine its immunochemotherapeutic potential when co-administered with Leishmania antigens.展开更多
Most intestinal parasites are cosmopolitan with the highest prevalence in the tropics and subtopics. Rural-to-urban migration rapidly increases the number of food eating places in towns and their environs. Some of the...Most intestinal parasites are cosmopolitan with the highest prevalence in the tropics and subtopics. Rural-to-urban migration rapidly increases the number of food eating places in towns and their environs. Some of these eating estabishments have poor sanitation and are overcrowded, facilitating disease transmission, especially through food-handling. Our investigations in Nairobi, therefore, were set to determine the presence of intestinal parasites in food-handlers with valid medical certificates. Direct and concentrated stool processing techniques were used. Chisquare test and ANOVA were used for data analysis. The parasites Ascaris lumbricoides, Entamoeba histolytica and Giardia lamblia were observed in certified food-handlers. Significant difference was found in parasite frequency by eating classes and gender （χ^2 = 9.49, P = 0.73）, （F = 1.495, P = 0.297）, but not in parasite occurrence between age brackets （χ^2 = 6.99, P = 0.039）. The six-month medical certificate validity period may contribute significantly to the presence of intestinal parasites in certified food-handlers.展开更多
Objective： This study compared the performance of the immunochromatographic strip （ICS） to the Venereal Disease Research Laboratory （VDRL） test and Treponema pallidum haemagglutination assay （TPHA） at a primary...Objective： This study compared the performance of the immunochromatographic strip （ICS） to the Venereal Disease Research Laboratory （VDRL） test and Treponema pallidum haemagglutination assay （TPHA） at a primary health care setting. Methods： The study group was comprised of 150 females randomly drawn from a population of pregnant women attending their first antenatal visit or follow-up visits at West Maternity Hospital in Eldoret Kenya, but without a previous syphilis test during that pregnancy. On-site VDRL, ICS and TPHA tests were performed and immediate treatment provided where appropriate. The performance of the three tests was compared, Results： The sero-prevalence of syphilis as determined by the VDRL test was 3%. There was no significant difference between the ICS and the VDRL test （P 〉 0.05）. The sensitivity and specificity of the ICS test were 80% and 98.6% respectively, while the negative predictive value （NPV） and positive predictive value （PPV） were both 100%. On the other hand, the sensitivity and specificity of the VDRL test were 66.7% and 99.3%, while the NPV and PPV were 80% and 98.6% respectively. The Treponema pallidum haemagglutination assay was used as a reference test and had sensitivity, specificity, NPV and PPV of 100%. Conclusion： The diagnostic accuracy of the ICS compared favorably with theVDRL gold standard. The use of the ICS in Kenya can improve the diagnosis of syphilis in health facilities both with and without laboratories and allow community health care workers to make a rapid diagnosis of the disease, and consequently make immediate therapeutic decisions.展开更多
Background: Due to the difficulty in implementing microscopy-based definitive diagnosis of malaria especially in resource-poor areas, rapid diagnostic test (RDT) kits as alternatives have been developed by different c...Background: Due to the difficulty in implementing microscopy-based definitive diagnosis of malaria especially in resource-poor areas, rapid diagnostic test (RDT) kits as alternatives have been developed by different companies. Kits from different companies may differ in sensitivity and specificity. It is therefore imperative to conduct field evaluation of kits from different manufacturers before they are recommended for widespread use in diagnosis of malaria. The present study sought to evaluate the performance of malaria RDT kits from two manufacturers against microscopy in detection of Plasmodium spp. infections among primary school children in Baringo County, Kenya. Methods: Two cross-sectional comparative surveys to assess three RDT kits (CareStart HRP-2, SD Bioline Ag-Pf and SD Bioline Ag-Pf/Pan) were conducted on 561 pupils from three primary schools within the Kerio Valley of Baringo County, Kenya. Results: A total of 561 blood samples were tested for Plasmodium spp. within a period of four months. SD Bioline Ag-Pf/ Pan RDT kit had a higher sensitivity (90%) compared to that of CareStart HRP-2 (70%) but this was not statistically significant (McNemar’s χ2 = 0.5, df = 1, p = 0.4795). The sensitivity of SD Bioline Ag-Pf was the same as that of Care Start HRP-2 (82.4%). The number of positive samples by microscopy was relatively lower than those detected by RDT kits. Two cases of non-P. falciparum infections were detected by RDT kits during the second survey. Conclusion: The results of the present study suggest that the performance of the three kits in the diagnosis of P. falciparum infections was better than microscopy. The sensitivity of SD Bioline Ag-Pf/Pan was slightly greater than that of Care Start HRP-2, although not statistically different.展开更多
Background: Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis. Anti-tuberculosis drug resistance is an emerging health problem in Kenya and especially in Coastal region. This...Background: Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis. Anti-tuberculosis drug resistance is an emerging health problem in Kenya and especially in Coastal region. This is a major challenge in tuberculosis control. Diagnosis is based on Ziel-Neelsen staining alone and patients are treated without information on sensitivity patterns. Aim: This study aimed to determine drug susceptibility patterns of Mycobacterium tuberculosis in Coastal Kenya. Study Design: Hospital and laboratory based cross-sectional study was carried between April 2015 and July 2016 at Coast General Referral hospital;Tudor, Port-Reitz, Likoni Sub-County hospitals;Mlaleo, Kongowea and Mikindani health centers. Methodology: Sputum samples from patients with bacteriological confirmed TB on microscopy were cultured on Lowenstein Jensen (LJ) media. Strains of MTB complex from Lowenstein Jensen (LJ) slopes were subjected to drug susceptibility testing (DST) to first-line drugs including isoniazid (H), rifampicin (R), streptomycin (S) and Ethambutol (E) using proportional method on the Mycobacterium Growth Indicator Tube (MGIT) conventional method. Participants were offered diagnostic testing and counselling for HIV testing. Results: Drug sensitivity test was performed for a total of 210 Mycobacterium tuberculosis isolates for the first line anti-TB drugs. About seventy eight percent and twenty nine percent of the strains from new patients and previously treated patients were fully sensitive to all the drugs tested respectively. Prevalence of any resistance to one drug was 102 (48.6%, 95% CI: 20.45 - 28.23). Any single drug resistance was most frequent in isoniazid 30 (16.0%), Ethambutol 20 (10.0%), Streptomycin 18 (18.3%) and Rifampicin 4 (2.1%) in newly diagnosed patients. Among previously treated patients any resistance to streptomycin, ethambutol, isoniaziad and rifampicin was 10 (58.8%), 9 (52.9%), 7 (41.2%) and 4 (23.5%) respectively. Prevalence of MDR-TB defined as resistant to at least both isoniazid and rifampicin was 10 (4.8%) among new and previously treated patients respectively. Conclusion: The current study reveals that the overall resistance to first line anti-TB drugs was high. Although the rate of MDR-TB was relatively low, this signifies that conditions favouring the spread of MDR-TB are on high rise. Therefore, it is essential to address the problems of development of drug re-sistant strains of TB by establishing good TB programmes (DOTS). Patients’ adherence to anti-TB drugs and introducing drug sensitivity testing (DST) services at County level hospitals will minimize occurrence of drug resistant.展开更多
Busia and Kisii Central districts are areas in western Kenya that have repeatedly reported high levels of stunting growth in children and an increase in hepatocellular carcinoma (HCC);an aspect often positively associ...Busia and Kisii Central districts are areas in western Kenya that have repeatedly reported high levels of stunting growth in children and an increase in hepatocellular carcinoma (HCC);an aspect often positively associated with chronic exposure to aflatoxins especially through consumption of foods such as peanuts. The objectives of the study were to determine the incidence, types and levels of aflatoxin in different varieties of peanuts produced in Busia and Kisii Central districts. One hundred and two (102) peanuts samples were collected from farmers’ in each district. Aflatoxin types and levels of aflatoxins were analyzed using high performance liquid chromatography (HPLC) technique. All the peanuts samples from Kisii Central and 97.06% samples from Busia were contaminated with aflatoxins. However, aflatoxin was not detected in 2.94% of samples from Busia district. The levels of total aflatoxin ranges were 0.1 to 268 μg/kg and 1.63 to 591.1 μg/kg in peanuts from Busia and Kisii Central respectively. Majority of peanuts samples had levels within Kenya Bureau of Standards (KEBS) and European Union (EU) regulatory limits for total aflatoxins. Improved variety (Valencia red) had significantly lower aflatoxin contamination compared to local varieties (Uganda local red, Homabay local and Local red). Aflatoxins B1, B2, G1 and G2 were found in peanuts;B1 was the most predominant in both districts (t = 12.4, df = 3, P = 0.034). The levels of aflatoxins especially in peanuts from Kisii Central district were high (591.1 μg/kg) where 44.6% of samples analyzed were unfit for even animal feed (USFDA regulatory limit). An assessment on the levels of aflatoxins should be done by the relevant stakeholders in other key foods in the areas for example maize. The most lethal aflatoxin type B1 was found to be the most predominant peanuts from both districts of study. This calls for frequent aflatoxin screening of peanuts from the districts particularly aflatoxin type B.展开更多
Taenia solium is an important food-bome pathogen worldwide and is emerging as a serious public health risk in both rural and urban communities where pigs are raised and consumed. Adult tapeworms are found in the intes...Taenia solium is an important food-bome pathogen worldwide and is emerging as a serious public health risk in both rural and urban communities where pigs are raised and consumed. Adult tapeworms are found in the intestines of humans while the developmental larval forms occur in the muscles and organs constituting cysticercosis of pigs and humans. Cysticercosis has a worldwide distribution, mainly related to poor hygiene and sanitation and consumption of infected pork. Pigs get infected through consumption of food and contaminated with human faeces containg eggs. In recent years pork consumption has increased with the opening up of pork eating centres. Porcine cysticercosis has previously been reported in Kenya, however, there are scarce data on the occurrence of the disease, as well as on the risk factors for transmission, in key production and consumption areas including Thika. The purpose of the study was to determine the seroprevalence of porcine cysticercosis in slaughtered pigs and associated risk factors for occurrence of the disease in selected abattoirs in Thika. Systematic random sampling was used to select a total of 276 pigs. The source of the slaughter pigs was derived fi＇om the movement permits, the breed, sex and estimation of age was done at ante mortem examination. The slaughter and meat inspection processes were carried out by the slaughter house personnel and the investigators only observed and received the outcome of the inspection. Blood samples were collected fi＇om each identified pig at slaughter, processed and analyzed using purified Taenia solium antigen ELISA commercial kit. The results meat inspection showed that none of the pigs in this study had any visible cysts whereas 4.35% of the pigs were seropositive which poses public health risk.展开更多
Background: HIV/AIDS is the principal pandemic in the world today.?Two viral types (HIV-1 and HIV-2), with numerous groups (M, N and O for HIV-1 and A through H for HIV-2) have emerged. These have further proliferated...Background: HIV/AIDS is the principal pandemic in the world today.?Two viral types (HIV-1 and HIV-2), with numerous groups (M, N and O for HIV-1 and A through H for HIV-2) have emerged. These have further proliferated into numerous subtypes, sub-subtypes and circulating recombinant forms (CRF) over the last 30 years.?HIV-1 variants circulate together within a geographical region providing an opportunity for recombination of viral strains within infected individuals.?In Kenya, at least nine different genetic HIV-1 subtypes and several recombinant forms have been defined within group M, which accounts for the majority of cases in the AIDS pandemic. Objective:?To determine the genetic diversity of HIV-1 in the western region of Kenya bordering Uganda. Methodology: A cross sectional study was carried out at Busia District Hospital between 2007 and 2009. A total of 75 patients were sampled randomly from a cohort of 1000 clients on antiretroviral therapy. Blood samples were analysed at the HIV Laboratory, Kenya Medical Research Institute, Nairobi, Kenya. PCR was carried out on the?Pol?region of HIV, sequenced and analysed by BLAST for subtypes. Results: BLAST analysis revealed the following circulating subtypes: 40/75 (53.30%) were HIV-1 group M subtype A1;21/75 (28.0%) were subtype D;5/75 (6.7%) were subtype G;4/75 (5.30%) were subtype C;and 2/75 (2.70%) were subtype A2. Only one isolate was identified for the other subtypes?viz: 1/75 (1.30%) resembled subtype B;1/75 (1.30%) was A1/C, and 1/75 (1.30%) was A1/D. Conclusion: The study showed increasing HIV-1 diversity along the Kenya-Uganda border with the emergence of A1/C and A1/D recombinants. Such HIV-1?diversityvis a vis?the recent expanded access to antiretroviral therapy in resource limited settings calls for continuous evaluation of anti-HIV regimens. There?is need therefore, for regular surveillance and monitoring for mutations that are likely to lead to drug resistance if we have to achieve successful treatment outcomes.展开更多
Background: Human immunodeficiency virus (HIV) is a major public health concern and cause of death globally including Kenya. HIV infection is characterised by CD4+ lymphocyte depletion manifested through the loss of t...Background: Human immunodeficiency virus (HIV) is a major public health concern and cause of death globally including Kenya. HIV infection is characterised by CD4+ lymphocyte depletion manifested through the loss of the immune response capacity. Aim: This study aimed to determine the prevalence of HIV infection and CD4+T cell counts among suspected tuberculosis (TB) cases seeking healthcare at TB clinics in Mombasa County, Kenya. Study Design: Hospital and laboratory based cross-sectional study was carried between May 2011 and November 2013 in Coast General Referral Hospital, Tudor, Port-Reitz, Mlaleo, Likoni and Mikandani districts and sub-districts hospitals. Methodology: A total of 500 suspected TB cases (271 males and 229 females) were screened for HIV infection using Trinity Biotech Uni-Gold<sup>TM</sup> test and positives confirmed with the enzyme- linked immunosorbent assay. CD4+ and CD8+T cells were analyzed using a BD FACS Count flow cytometer. A questionnaire was used to collect demographic data of the participants. Results: In total, 127 (25.4%) of the suspects were HIV infected 55.1% females and 44.9% males. Females were significantly affected than males (OR = 0.78;95% CI: 0.44 - 1.37;p = 0.042). The majority (36.2%) of the HIV cases were in the 25 - 34 years age group followed by the 35 - 44 (33.9%), 45 - 54 (16.5%) and 18 - 24 (7.1%) age groups, respectively. Widowed (AOR = 6.14;95% CI: 1.53 - 20.54;p < 0.033), alcohol (AOR = 2.83;95% CI: 1.71 - 4.87;p < 0.001) and condom use (AOR = 2.31;95% CI: 1.62 = 4.71;p < 0.002) were risk factors associated with HIV infection. The mean CD4 cell count was 333.27 ± 150.59 cells/mm3 and it was higher in males (343.05 ± 149.33 cells/mm3) than females (325.93 ± 152.92 cells). The mean values of white blood cells (5.9 ± 2.42) × 109/l), packed cell value (34.1% ± 4.3%), platelets (195.16 ± 88.7) × 109/l and erythrocyte sedimentation rate (102.0 ± 17.4 mm/hr) were significantly lower than the control group (p < 0.05). Conclusion: The prevalence of HIV infection among suspected TB cases was 25.4% which was higher than the current national average HIV prevalence of 6.9%. Lower CD4+ lymphocyte count was found to be the only predicting factor for HIV. There was a significant relationship between CD4/ESR and HIV infection.展开更多
Leishmaniasis is a zoonotic disease caused by protozoan parasites of the genus Leishmania.Conventional chemotherapy remains to be the most preferred measure against leishmaniasis despite being associated with high tox...Leishmaniasis is a zoonotic disease caused by protozoan parasites of the genus Leishmania.Conventional chemotherapy remains to be the most preferred measure against leishmaniasis despite being associated with high toxicity and relapse rates.They are also expensive and require hospitalization.Plant-based compounds provide a better treatment alternative because they are effective,cheap,and less associated with toxicity and resistance.This study examined the therapeutic potential of Warburgia ugandensis,Prunus africana,and Piliostigma thonningii against Leishmania donovani infection in BALB/c mice.Anti-promastigote and toxicity studies were evaluated by incubating the test compound with promastigotes and Vero cells,respectively.Serum was obtained from the mice for total immunoglobulin gamma(IgG)quantification.For in vivo studies,the mice were infected with virulent Leishmania donovani then treated with methanolic extracts of Warburgia ugandensis,Prunus africana,and Piliostigma thonningii and control drug,pentostam(sodium stibogluconate).Treatment with the plant extracts and standard drug resulted to significant reduction in parasite burden.Outcomes in the mice treated with plant extracts were comparable to those treated with pentostam(P≥0.05).In the promastigote assay,all the test compounds killed more than half of the promastigotes at the highest concentration(500μg/mL).Warburgia ugandensis,P.thonningii,and P.africana reduced the number of promastigotes from 2.0×10^(6) to 7.7×10^(3),72.0×10^(3),and 5.0×10^(3),respectively.Pentostam had the lowest IC50(210μg/mL),followed by Warburgia ugandensis(IC50 of 270μg/mL).Piliostigma thonningii and P.africana were less toxic with IC50 of 720μg/mL and 500μg/mL,respectively.There was low production of IgG antibodies following treatment with the plant extracts and high levels in the untreated control.展开更多
In a previous immunogenicity and efficacy study in mice, montanide ISA 720 （MISA） was indicated to be a better adjuvant than bacillus calmette guerin vaccine （BCG） for a Leishmania vaccine. In the present study, w...In a previous immunogenicity and efficacy study in mice, montanide ISA 720 （MISA） was indicated to be a better adjuvant than bacillus calmette guerin vaccine （BCG） for a Leishmania vaccine. In the present study, we report the safety, immunogenicity and efficacy of Leishmania donovani （L. donovani） sonicated antigen delivered with alum-BCG （A1BCG）, MISA or monophosphoryl lipid A （MPLA） in vervet monkeys following intradermal inoculums. Vaccinated and control animals were challenged with virulent L. donovani parasites and the parasitic burden was determined. Only animals vaccinated with alum-BCG adversely reacted to the inoculum by produc- ing ulcerative erythematous skin indurations. Non-parametric ANOVA followed by a post test showed signifi- cantly higher IgG antibodies, and revealed the presence of lymphoproliferative and interferon gamma responses in both AIBCG＋Ag and MISA＋Ag as compared to the MPLA＋Ag or other groups （P 〈 0.001）. We conclude that L. donovani sonicated antigen containing MISA is safe and is associated with protective immune response against Leishmania donovani infection in the vervet monkey model.展开更多
This review provides a summary of botanicals and plant strengtheners that have potential uses for disease and pest management in potato and tomato cultivation in African.We discuss their possible use to prevent major ...This review provides a summary of botanicals and plant strengtheners that have potential uses for disease and pest management in potato and tomato cultivation in African.We discuss their possible use to prevent major diseases and pests which infest potato and tomato,such as early and late blight,bacterial wilt,potato tuber moth,and tomato leafminer.There are several examples of the successful uses of botanicals for pathogen and pest control relevant for different African climatic conditions;however,most of these studies have been conducted in vitro and often lack field verification.Plant strengtheners(substances that induce and improve crop resistance,yield,and quality)are little studied and used in Africa in comparison to North America and Europe.The possible benefits of using botanicals and plant strengtheners instead of conventional pesticides are discussed here in relation to human health and the environment as well as their modes of action and accessibility to farmers.Lack of knowledge of the composition and active ingredients of extracts,environmental concerns,uncertainties regarding stability and formulation,lack of legislation and limited support from governments,hamper the development of botanicals and plant strengtheners for use in sustainable African agriculture.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.42076114,41876146)the China Postdoctoral Science Foundation Grant(No.2018M632580)the Special Investigation Project of Scientific and Technological Fundamental Resources(No.2018FY100202)。
文摘The response of phytoplankton and its satellite bacteria to various concentrations(0.01%-10%v/v)of ethanol is studied.To elucidate the effect of ethanol,single-strains of phytoplankton(SSP)culture,pure strains of satellite bacteria isolated from nonaxenic SSP cultures,and Escherichia coli were screened.Results indicate that ethanol could promote the growth and photo synthetic efficiency(F_(v)/F_(m))of S SP at 0.01%and the growth of satellite bacteria at 0.01%-1%.Nevertheless,ethanol inhibited the growth and F_(v)/F_(m)of SSP at 0.1%-1%,and killed bacteria and SSP at 10% concentration.Further investigation on a satellite bacterium(Mameliella alba)revealed that ethanol promotes growth by serving as a growth stimulant rather than a metabolic carbon source.The 16 S rRNA gene amplicon indicated that all nonaxenic S SP cultures harbor distinct satellite bacteria communities where the SSP culture of Skeletonema costatum,Phaeodactylum tricornutum,and Dunaliella bardawil were dominated by bacteria genera of Marivita(~80%),Dinoroseobacter(~47%),and Halomonas(~87%),respectively,indicating that every SSP cultures have their own distinct satellite bacterial community.The bacteria family Rhodobacteraceae was dominant in the two marine diatoms,whereas Halomonadaceae was dominant in the saline green microalga.Compared to their respective controls,the supply of 0.5% ethanol to SSP cultures promoted the growth of the satellite bacteria but did not cause a significant difference in species composition of satellite bacteria.Therefore,a low concentration of ethanol can promote the growth of bacteria in a non-selective way.This study enriched our knowledge about the effect of ethanol on aquatic microbes and provided a baseline for basic and applied biotechnological re search in the aquatic environment in the future.
基金partly supported by BPM Bulk Medicine and Pharmaceuticals Production,TROPMED GMbH,Neuhofer Welche 48,D-19370 Parchtm,Germany,courtesy of Dr Alain J.Bourdichon
文摘The present study evaluated the in vitro activity and in vivo efficacy of diminazene combined with chloroquine as a potential drug against Leishmania donovani. Amphotericin B was used as a positive control drug. In vitro activity involved incubation of various drug concentrations with promastigotes or vero cells in culture before determination of parasite growth inhibition or cell death while in vivo evaluations involved infection of various mice groups with virulent L. donovani parasites and treatment with test drug compounds following disease establishment. Weight changes in experimental mice were also evaluated before infection and throughout the experiment. The results indicated that the diminazene-chloroquine combination was at least nine times more efficacious than individual drugs in killing promastigotes in culture. The diminazene-chloroquine combination was safer （Ld50=0.03±0.04） than Amphotericin B （Ld50=0.02±0.01）. Body weight in infected mice increased significantly （P=0.0007） from day 7 to day 37 following infection （P=0.026）. However, body weight remained comparable in all mice groups during treatment （P=0.16）. The diminazene-chloroquine combination significantly reduced splenic parasite numbers as compared to individual drug therapies （P=0.0001） although Amphotericin B was still more efficacious than any other treatment （P=0.0001）. Amongst the test compounds, the diminazene-chloroquine combination showed the lowest level of IgG antibody responses with results indicating significant negative correlation between antileishmanial antibody responses and protection against disease. These findings demonstrate the positive advantage and the potential use of a combined therapy of diminazene-chloroquine over the constituent drugs. Further evaluation is recommended to determine the most efficacious combination ratio of the two compounds.
文摘Leishmaniasis is a disease that ranges in severity infection. Resistance to infection is associated with from skin lesions to serious disfigurement and fatal systemic a T-helper-1 immune response that activates macrophages to kill the intracellular parasite in a nitric oxide-dependent manner. Conversely, disease progression is generally associated with a T-helper-2 response that activates humoral immunity. Current control is based on chemothera- peutic treatments which are expensive, toxic and associated with high relapse and resistance rates. Vaccination remains the best hope for control of all forms of the disease, and the development of a safe, effective and affordable antileishmanial vaccine is a critical global public-health priority. Extensive evidence from studies in animal models indicates that solid protection can be achieved by immunization with defined subunit vaccines or live-at- tenuated strains of Leishmania. However, to date, no vaccine is available despite substantial efforts by many laboratories. Major impediments in Leishmania vaccine development include： lack of adequate funding from national and international agencies, problems related to the translation of data from animal models to human disease, and the transition from the laboratory to the field. Furthermore, a thorough understanding of protective immune responses and generation and maintenance of the immunological memory, an important but least-studied aspect of antiparasitic vaccine development, during Leishmania infection is needed. This review focuses on the progress of the search for an effective vaccine against human and canine leishmaniasis.
基金Supported by the National Key Research and Development Program of China(No.2016YFA0601302)the National Natural Science Foundation of China(Nos.41476116,41276128)
文摘Diatoms and dinoflagellates are two major groups ofphytoplankton that flourish in the oceans, particularly in coastal zone and upwelling systems, and their contrasting production have been reported in several world seas. However, this information is not available in the coastal East China Sea （ECS）. Thus, to investigate and compare the decadal trends in diatoms and dinoflagellates, a sediment core, 47-cm long, was collected from the coastal zone of the ECS. Sediment chlorophyll-a （Chl-a）, phytoplankton-group specifc pigment signatures of diatoms and dinoflagellates, and diatom valve concentrations were determined. The sediment core covered the period from 1961 to 2011 AD. The chlorophyll-a contents ranged from 2.32 to 73 gg/g dry sediment （dw） and averaged 9.81 gg/g dw. Diatom absolute abundance ranged from 29 152 to 177 501 valve/gram （v/g） dw and averaged 72 137 v/g dw. Diatom valve and diatom specific pigment marker concentrations were not significantly correlated. Peridinin increased after the 1980s in line with intensified use of fertilizer and related increases in nutrient inputs into the marine environment. The increased occurrence of dinoflagellate dominance after the 1980s can be mostly explained by the increase in nutrients. However, the contribution of dinoflagellates to total phytoplankton production （Chl-a） decreased during the final decade of this study, probably because of the overwhelming increase in diatom production that corresponded with the construction of the Three Gorges Dam （TGD） and related light availability. Similarly, the mean ratio of fucoxanthin/peridinin for the period from 1982 to 2001 was 6% less than for 1961 to 1982, while the ratio for 2001 to 2011 was 45.3% greater than for 1982 to 2001. The decadal variation in the fucoxanthirdperidinin ratio implies that dinoflagellate production had been gradually increasing until 2001. We suggest that the observed changes can be explained by anthropogenic impacts, such as nutrient loading and dam construction.
文摘Over the last decade, there has been a flurry of research on adjuvants for vaccines, and several novel adjuvants are now licensed products or in late stage clinical development. The success of adjuvants in enhancing the immune response to antigens has led many researchers to re-focus their vaccine development programs. Although several vaccine candidates have been tested against leishmaniasis, there is yet no effective vaccine against this parasitic disease. Recent research has documented that efforts to develop effective Leishmania vaccine have been limited due to lack of an appropriate adjuvant. In view of this, this review paper outlines some of the adjuvants that have been used in Leishmania vaccine candidates and cites a few of the responses obtained from these studies. The aim of the present review is to consolidate these findings to facilitate the application of these adjuvants in general and experimental vaccinology.
基金Jigjiga University for providing financial support to the study.
文摘Objective:To identify the sandfly fauna and analyze ecology of sandfly vector(s)of visceral leishmaniasis in three districts of Somali Regional State,southeast Ethiopia.Methods:Sandflies were collected from four sampling habitats,including indoor,peri-domestic,farm field and mixed forest using light and sticky traps in July 2016,and February and April 2017 in Liben and Dawa zones in the Somali Regional State,southeastern Ethiopia.Results:In total,4367 sandfly specimens,belonging to 12 species(three Phlebotomus spp.and nine Sergentomyia spp.)were identified.Phlebotomus(P.)heischi,P.orientalis,and P.martini constituted 45.7%,31.1%,and 23.1%of the sandfly collection,respectively.There were significant differences in the median number of P.orientalis,and P.martini captured per CDC trap/night between the three sampling districts(P<0.05).In light trap capture,collection habitats had significant effects on the abundance of P.orientalis,and P.martini(P<0.05).More median numbers of P.orientalis,and P.martini species were collected in agricultural fields followed by mixed forest and peri-domestic habitats.P.orientalis and P.martini were caught more in outdoor than indoor habitats,suggesting exophilic behaviour.Conclusions:The study demonstrated that the presence of P.orientalis and P.martini are probable vectors of visceral leishmaniasis in this new focus.The findings of our study will improve the understanding of the dynamics of visceral leishmaniasis transmission and will facilitate the implementation of integrated disease control measures based on ecological knowledge of visceral leishmaniasis vector in Liben and Dawa zones and its surrounding regions.
基金Supported by the National Natural Science Foundation of China(No.41476116)the National Key Research and Development Program of China(No.2016YFA0601302)
文摘The implications of climate change during the second half of the 20th century have been reported throughout the world. Although marginal seas are sensitive to climate change and anthropogenic impacts, relatively little attention has been given to the South East Asian marginal seas. Thus, to bridge this gap in knowledge, a sediment core was collected from the coastal areas of the Leizhou Peninsula in the South China Sea （SCS） to study the inter-decadal climate change and its consequences using diatom species composition as a proxy record. Diatom absolute abundance varied from 2 300 to 68 000 and averaged 16 000 valves per gram of dry weight （v/gdw）. The fractional dissolution index （F~） was usually below 0.5, which indicates low to moderate preservation of diatom valves at coastal area of the SCS. At the inter-decadal time scale, total diatom abundance was high for the period after 1972, which coincided with 1） increased percentage of planktonic diatom abundance and F~; 2） emergence and dominance of high productivity indicative cosmopolitan species such as Thalassionema nitzschioides and Paralia sulcata （their relative abundance increased from 〈1.5% to 〉7% for the period before and after 1972, respectively）; 3） decreased relative abundance of the small-sized eutrophication indicative species, Cyclotella striata, from 70% to 40%. This study reveals that variations in the abundance of diatoms preserved in the sediment was a function of both production and dissolution/preservation of diatom valves, which in turn was intimately connected to the prevailing environmental/climatic conditions. In conclusion, these data reveal the existence of substantial changes in the coastal SCS in response to the 1970s climate shift that was recorded in different parts of the world.
基金supported by the Bill and Melinda Gates Foundation Global Health Program(Grant number OPPGH5336)Gondar University
文摘Objective:To investigate the zoonotic visceral leishmaniasis(ZVL) by identification of the most probable reservoir hosts using parasite isolation and analysis of a possible transmission dynamics of the disease in extra-domestic agricultural fields and rural villages.Methods:Rodents were collected from selected study sites in kala-azar endemic areas based on information for localities of kala-azar cases for screening of Leshmania infections using parasitological,serological and polymerase chain reaction(PCR) from March.2013 to January,2014.Ketamine(Clorketam Veterinary) was used to anaesthesize the rodents according the prescribed dosage(average 2 mg/kg for intra-venous route).The blood obtained using sterile needle was dropped into sterile filter paper and allowed to air dry before sealing in plastic bags.The tissues from liver,spleen and skin were macerated in Locke's solution before transferring them into NNN medium.Blood and touch smears of liver,spleen,skin and bone marrow were prepared for fixing using methanol and staining by Giemsa stain for microscopy.These tissues were also ascd for DNA extractions and PCR amplification of Leishmania infection.Results:A total of 335 rodents(13 species) were analyzed by sampling internal organs.The infection rate by PCR was 11.1%(6/54) for Arvicanthis nilothicas compared to 17.6%(3/17) and 12.5%(2/16) for Acomys cahirinus and Tarera(C) robustus respectively.Almost all the infections were found from bone marrow samples(8/48 or 16.7%) compared with 1/91(1.1%) liver,2/87(2.2%) spleen and 0/87(0%) skin.In all study sites with past human VL cases,rodents and proved vectors shared similar habitats.Conclusions:Leishmania donovani might circulate among different species of rodents in kala-azar endemic lowlands and valleys of Ethiopia by Phlebotamus orientalis and Phlebotomus martini.Detailed studies to substantiate the preliminary data on the possible role of these rodents arc urgently needed.
文摘Objective： To determine the adjuvant potential of artemisinin with a soluble leishmanial antigen in vaccinating BALB/c mice. Methods： Seventy two female BALB/c mice were randomly assigned into six groups. The mice were vaccinated with soluble Leishmania antigens （SLA） alone, artemisinin co-administered with SLA, SLA and Bacille Calmette Gu fin （BCG） vaccine, and artemisinin and BCG alone. Unvaccinated mice formed the control group. The induction of cell-mediated immunity following vaccination was determined by measuring in vitro lymphocyte proliferation and the production of interleukin （IL）-4, IL-5 and gamma interferon （IFN-γ） determined by flow cytometry. Protection against L. major was determined by quantifying parasite burdens in L. major infected footpads using a limiting dilution assay and by measuring lesion sizes of the infected footpad compared to the contralateral uninfected footpad. Results： Mice receiving SLA plus artemisinin produced significantly high levels of IL-4 and IL-5 （P 〈 0.05） and low levels of IFN-γ, resulting in exacerbated disease. In addition, subcutaneous administration of SLA ＋ artemisinin, artemisinin alone or SLA alone resulted in the development of large footpad swellings and high parasite loads that were comparable to those of the control unvaccinated mice （P 〉 0.05）, resulting in exacerbated disease. Conclusion： These data suggest that artemisinin is not a suitable adjuvant for Leishmania vaccines. However, since artemisinin has been shown to be effective against Leishmania parasites in vitro and in vivo, further studies ought to be conducted to determine its immunochemotherapeutic potential when co-administered with Leishmania antigens.
文摘Most intestinal parasites are cosmopolitan with the highest prevalence in the tropics and subtopics. Rural-to-urban migration rapidly increases the number of food eating places in towns and their environs. Some of these eating estabishments have poor sanitation and are overcrowded, facilitating disease transmission, especially through food-handling. Our investigations in Nairobi, therefore, were set to determine the presence of intestinal parasites in food-handlers with valid medical certificates. Direct and concentrated stool processing techniques were used. Chisquare test and ANOVA were used for data analysis. The parasites Ascaris lumbricoides, Entamoeba histolytica and Giardia lamblia were observed in certified food-handlers. Significant difference was found in parasite frequency by eating classes and gender （χ^2 = 9.49, P = 0.73）, （F = 1.495, P = 0.297）, but not in parasite occurrence between age brackets （χ^2 = 6.99, P = 0.039）. The six-month medical certificate validity period may contribute significantly to the presence of intestinal parasites in certified food-handlers.
文摘Objective： This study compared the performance of the immunochromatographic strip （ICS） to the Venereal Disease Research Laboratory （VDRL） test and Treponema pallidum haemagglutination assay （TPHA） at a primary health care setting. Methods： The study group was comprised of 150 females randomly drawn from a population of pregnant women attending their first antenatal visit or follow-up visits at West Maternity Hospital in Eldoret Kenya, but without a previous syphilis test during that pregnancy. On-site VDRL, ICS and TPHA tests were performed and immediate treatment provided where appropriate. The performance of the three tests was compared, Results： The sero-prevalence of syphilis as determined by the VDRL test was 3%. There was no significant difference between the ICS and the VDRL test （P 〉 0.05）. The sensitivity and specificity of the ICS test were 80% and 98.6% respectively, while the negative predictive value （NPV） and positive predictive value （PPV） were both 100%. On the other hand, the sensitivity and specificity of the VDRL test were 66.7% and 99.3%, while the NPV and PPV were 80% and 98.6% respectively. The Treponema pallidum haemagglutination assay was used as a reference test and had sensitivity, specificity, NPV and PPV of 100%. Conclusion： The diagnostic accuracy of the ICS compared favorably with theVDRL gold standard. The use of the ICS in Kenya can improve the diagnosis of syphilis in health facilities both with and without laboratories and allow community health care workers to make a rapid diagnosis of the disease, and consequently make immediate therapeutic decisions.
文摘Background: Due to the difficulty in implementing microscopy-based definitive diagnosis of malaria especially in resource-poor areas, rapid diagnostic test (RDT) kits as alternatives have been developed by different companies. Kits from different companies may differ in sensitivity and specificity. It is therefore imperative to conduct field evaluation of kits from different manufacturers before they are recommended for widespread use in diagnosis of malaria. The present study sought to evaluate the performance of malaria RDT kits from two manufacturers against microscopy in detection of Plasmodium spp. infections among primary school children in Baringo County, Kenya. Methods: Two cross-sectional comparative surveys to assess three RDT kits (CareStart HRP-2, SD Bioline Ag-Pf and SD Bioline Ag-Pf/Pan) were conducted on 561 pupils from three primary schools within the Kerio Valley of Baringo County, Kenya. Results: A total of 561 blood samples were tested for Plasmodium spp. within a period of four months. SD Bioline Ag-Pf/ Pan RDT kit had a higher sensitivity (90%) compared to that of CareStart HRP-2 (70%) but this was not statistically significant (McNemar’s χ2 = 0.5, df = 1, p = 0.4795). The sensitivity of SD Bioline Ag-Pf was the same as that of Care Start HRP-2 (82.4%). The number of positive samples by microscopy was relatively lower than those detected by RDT kits. Two cases of non-P. falciparum infections were detected by RDT kits during the second survey. Conclusion: The results of the present study suggest that the performance of the three kits in the diagnosis of P. falciparum infections was better than microscopy. The sensitivity of SD Bioline Ag-Pf/Pan was slightly greater than that of Care Start HRP-2, although not statistically different.
文摘Background: Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis. Anti-tuberculosis drug resistance is an emerging health problem in Kenya and especially in Coastal region. This is a major challenge in tuberculosis control. Diagnosis is based on Ziel-Neelsen staining alone and patients are treated without information on sensitivity patterns. Aim: This study aimed to determine drug susceptibility patterns of Mycobacterium tuberculosis in Coastal Kenya. Study Design: Hospital and laboratory based cross-sectional study was carried between April 2015 and July 2016 at Coast General Referral hospital;Tudor, Port-Reitz, Likoni Sub-County hospitals;Mlaleo, Kongowea and Mikindani health centers. Methodology: Sputum samples from patients with bacteriological confirmed TB on microscopy were cultured on Lowenstein Jensen (LJ) media. Strains of MTB complex from Lowenstein Jensen (LJ) slopes were subjected to drug susceptibility testing (DST) to first-line drugs including isoniazid (H), rifampicin (R), streptomycin (S) and Ethambutol (E) using proportional method on the Mycobacterium Growth Indicator Tube (MGIT) conventional method. Participants were offered diagnostic testing and counselling for HIV testing. Results: Drug sensitivity test was performed for a total of 210 Mycobacterium tuberculosis isolates for the first line anti-TB drugs. About seventy eight percent and twenty nine percent of the strains from new patients and previously treated patients were fully sensitive to all the drugs tested respectively. Prevalence of any resistance to one drug was 102 (48.6%, 95% CI: 20.45 - 28.23). Any single drug resistance was most frequent in isoniazid 30 (16.0%), Ethambutol 20 (10.0%), Streptomycin 18 (18.3%) and Rifampicin 4 (2.1%) in newly diagnosed patients. Among previously treated patients any resistance to streptomycin, ethambutol, isoniaziad and rifampicin was 10 (58.8%), 9 (52.9%), 7 (41.2%) and 4 (23.5%) respectively. Prevalence of MDR-TB defined as resistant to at least both isoniazid and rifampicin was 10 (4.8%) among new and previously treated patients respectively. Conclusion: The current study reveals that the overall resistance to first line anti-TB drugs was high. Although the rate of MDR-TB was relatively low, this signifies that conditions favouring the spread of MDR-TB are on high rise. Therefore, it is essential to address the problems of development of drug re-sistant strains of TB by establishing good TB programmes (DOTS). Patients’ adherence to anti-TB drugs and introducing drug sensitivity testing (DST) services at County level hospitals will minimize occurrence of drug resistant.
文摘Busia and Kisii Central districts are areas in western Kenya that have repeatedly reported high levels of stunting growth in children and an increase in hepatocellular carcinoma (HCC);an aspect often positively associated with chronic exposure to aflatoxins especially through consumption of foods such as peanuts. The objectives of the study were to determine the incidence, types and levels of aflatoxin in different varieties of peanuts produced in Busia and Kisii Central districts. One hundred and two (102) peanuts samples were collected from farmers’ in each district. Aflatoxin types and levels of aflatoxins were analyzed using high performance liquid chromatography (HPLC) technique. All the peanuts samples from Kisii Central and 97.06% samples from Busia were contaminated with aflatoxins. However, aflatoxin was not detected in 2.94% of samples from Busia district. The levels of total aflatoxin ranges were 0.1 to 268 μg/kg and 1.63 to 591.1 μg/kg in peanuts from Busia and Kisii Central respectively. Majority of peanuts samples had levels within Kenya Bureau of Standards (KEBS) and European Union (EU) regulatory limits for total aflatoxins. Improved variety (Valencia red) had significantly lower aflatoxin contamination compared to local varieties (Uganda local red, Homabay local and Local red). Aflatoxins B1, B2, G1 and G2 were found in peanuts;B1 was the most predominant in both districts (t = 12.4, df = 3, P = 0.034). The levels of aflatoxins especially in peanuts from Kisii Central district were high (591.1 μg/kg) where 44.6% of samples analyzed were unfit for even animal feed (USFDA regulatory limit). An assessment on the levels of aflatoxins should be done by the relevant stakeholders in other key foods in the areas for example maize. The most lethal aflatoxin type B1 was found to be the most predominant peanuts from both districts of study. This calls for frequent aflatoxin screening of peanuts from the districts particularly aflatoxin type B.
文摘Taenia solium is an important food-bome pathogen worldwide and is emerging as a serious public health risk in both rural and urban communities where pigs are raised and consumed. Adult tapeworms are found in the intestines of humans while the developmental larval forms occur in the muscles and organs constituting cysticercosis of pigs and humans. Cysticercosis has a worldwide distribution, mainly related to poor hygiene and sanitation and consumption of infected pork. Pigs get infected through consumption of food and contaminated with human faeces containg eggs. In recent years pork consumption has increased with the opening up of pork eating centres. Porcine cysticercosis has previously been reported in Kenya, however, there are scarce data on the occurrence of the disease, as well as on the risk factors for transmission, in key production and consumption areas including Thika. The purpose of the study was to determine the seroprevalence of porcine cysticercosis in slaughtered pigs and associated risk factors for occurrence of the disease in selected abattoirs in Thika. Systematic random sampling was used to select a total of 276 pigs. The source of the slaughter pigs was derived fi＇om the movement permits, the breed, sex and estimation of age was done at ante mortem examination. The slaughter and meat inspection processes were carried out by the slaughter house personnel and the investigators only observed and received the outcome of the inspection. Blood samples were collected fi＇om each identified pig at slaughter, processed and analyzed using purified Taenia solium antigen ELISA commercial kit. The results meat inspection showed that none of the pigs in this study had any visible cysts whereas 4.35% of the pigs were seropositive which poses public health risk.
文摘Background: HIV/AIDS is the principal pandemic in the world today.?Two viral types (HIV-1 and HIV-2), with numerous groups (M, N and O for HIV-1 and A through H for HIV-2) have emerged. These have further proliferated into numerous subtypes, sub-subtypes and circulating recombinant forms (CRF) over the last 30 years.?HIV-1 variants circulate together within a geographical region providing an opportunity for recombination of viral strains within infected individuals.?In Kenya, at least nine different genetic HIV-1 subtypes and several recombinant forms have been defined within group M, which accounts for the majority of cases in the AIDS pandemic. Objective:?To determine the genetic diversity of HIV-1 in the western region of Kenya bordering Uganda. Methodology: A cross sectional study was carried out at Busia District Hospital between 2007 and 2009. A total of 75 patients were sampled randomly from a cohort of 1000 clients on antiretroviral therapy. Blood samples were analysed at the HIV Laboratory, Kenya Medical Research Institute, Nairobi, Kenya. PCR was carried out on the?Pol?region of HIV, sequenced and analysed by BLAST for subtypes. Results: BLAST analysis revealed the following circulating subtypes: 40/75 (53.30%) were HIV-1 group M subtype A1;21/75 (28.0%) were subtype D;5/75 (6.7%) were subtype G;4/75 (5.30%) were subtype C;and 2/75 (2.70%) were subtype A2. Only one isolate was identified for the other subtypes?viz: 1/75 (1.30%) resembled subtype B;1/75 (1.30%) was A1/C, and 1/75 (1.30%) was A1/D. Conclusion: The study showed increasing HIV-1 diversity along the Kenya-Uganda border with the emergence of A1/C and A1/D recombinants. Such HIV-1?diversityvis a vis?the recent expanded access to antiretroviral therapy in resource limited settings calls for continuous evaluation of anti-HIV regimens. There?is need therefore, for regular surveillance and monitoring for mutations that are likely to lead to drug resistance if we have to achieve successful treatment outcomes.
文摘Background: Human immunodeficiency virus (HIV) is a major public health concern and cause of death globally including Kenya. HIV infection is characterised by CD4+ lymphocyte depletion manifested through the loss of the immune response capacity. Aim: This study aimed to determine the prevalence of HIV infection and CD4+T cell counts among suspected tuberculosis (TB) cases seeking healthcare at TB clinics in Mombasa County, Kenya. Study Design: Hospital and laboratory based cross-sectional study was carried between May 2011 and November 2013 in Coast General Referral Hospital, Tudor, Port-Reitz, Mlaleo, Likoni and Mikandani districts and sub-districts hospitals. Methodology: A total of 500 suspected TB cases (271 males and 229 females) were screened for HIV infection using Trinity Biotech Uni-Gold<sup>TM</sup> test and positives confirmed with the enzyme- linked immunosorbent assay. CD4+ and CD8+T cells were analyzed using a BD FACS Count flow cytometer. A questionnaire was used to collect demographic data of the participants. Results: In total, 127 (25.4%) of the suspects were HIV infected 55.1% females and 44.9% males. Females were significantly affected than males (OR = 0.78;95% CI: 0.44 - 1.37;p = 0.042). The majority (36.2%) of the HIV cases were in the 25 - 34 years age group followed by the 35 - 44 (33.9%), 45 - 54 (16.5%) and 18 - 24 (7.1%) age groups, respectively. Widowed (AOR = 6.14;95% CI: 1.53 - 20.54;p < 0.033), alcohol (AOR = 2.83;95% CI: 1.71 - 4.87;p < 0.001) and condom use (AOR = 2.31;95% CI: 1.62 = 4.71;p < 0.002) were risk factors associated with HIV infection. The mean CD4 cell count was 333.27 ± 150.59 cells/mm3 and it was higher in males (343.05 ± 149.33 cells/mm3) than females (325.93 ± 152.92 cells). The mean values of white blood cells (5.9 ± 2.42) × 109/l), packed cell value (34.1% ± 4.3%), platelets (195.16 ± 88.7) × 109/l and erythrocyte sedimentation rate (102.0 ± 17.4 mm/hr) were significantly lower than the control group (p < 0.05). Conclusion: The prevalence of HIV infection among suspected TB cases was 25.4% which was higher than the current national average HIV prevalence of 6.9%. Lower CD4+ lymphocyte count was found to be the only predicting factor for HIV. There was a significant relationship between CD4/ESR and HIV infection.
文摘Leishmaniasis is a zoonotic disease caused by protozoan parasites of the genus Leishmania.Conventional chemotherapy remains to be the most preferred measure against leishmaniasis despite being associated with high toxicity and relapse rates.They are also expensive and require hospitalization.Plant-based compounds provide a better treatment alternative because they are effective,cheap,and less associated with toxicity and resistance.This study examined the therapeutic potential of Warburgia ugandensis,Prunus africana,and Piliostigma thonningii against Leishmania donovani infection in BALB/c mice.Anti-promastigote and toxicity studies were evaluated by incubating the test compound with promastigotes and Vero cells,respectively.Serum was obtained from the mice for total immunoglobulin gamma(IgG)quantification.For in vivo studies,the mice were infected with virulent Leishmania donovani then treated with methanolic extracts of Warburgia ugandensis,Prunus africana,and Piliostigma thonningii and control drug,pentostam(sodium stibogluconate).Treatment with the plant extracts and standard drug resulted to significant reduction in parasite burden.Outcomes in the mice treated with plant extracts were comparable to those treated with pentostam(P≥0.05).In the promastigote assay,all the test compounds killed more than half of the promastigotes at the highest concentration(500μg/mL).Warburgia ugandensis,P.thonningii,and P.africana reduced the number of promastigotes from 2.0×10^(6) to 7.7×10^(3),72.0×10^(3),and 5.0×10^(3),respectively.Pentostam had the lowest IC50(210μg/mL),followed by Warburgia ugandensis(IC50 of 270μg/mL).Piliostigma thonningii and P.africana were less toxic with IC50 of 720μg/mL and 500μg/mL,respectively.There was low production of IgG antibodies following treatment with the plant extracts and high levels in the untreated control.
基金supported by a grant from the National Council for Science and Technology,Government of Kenya (No.NCST 51003 CALL2 226)
文摘In a previous immunogenicity and efficacy study in mice, montanide ISA 720 （MISA） was indicated to be a better adjuvant than bacillus calmette guerin vaccine （BCG） for a Leishmania vaccine. In the present study, we report the safety, immunogenicity and efficacy of Leishmania donovani （L. donovani） sonicated antigen delivered with alum-BCG （A1BCG）, MISA or monophosphoryl lipid A （MPLA） in vervet monkeys following intradermal inoculums. Vaccinated and control animals were challenged with virulent L. donovani parasites and the parasitic burden was determined. Only animals vaccinated with alum-BCG adversely reacted to the inoculum by produc- ing ulcerative erythematous skin indurations. Non-parametric ANOVA followed by a post test showed signifi- cantly higher IgG antibodies, and revealed the presence of lymphoproliferative and interferon gamma responses in both AIBCG＋Ag and MISA＋Ag as compared to the MPLA＋Ag or other groups （P 〈 0.001）. We conclude that L. donovani sonicated antigen containing MISA is safe and is associated with protective immune response against Leishmania donovani infection in the vervet monkey model.
基金the AgriFose2030 programmethe swedish International Development Cooperation Agency (SIDA)the Swedish Foundation for International Cooperation in Research and Higher Education (STINT) for financial support
文摘This review provides a summary of botanicals and plant strengtheners that have potential uses for disease and pest management in potato and tomato cultivation in African.We discuss their possible use to prevent major diseases and pests which infest potato and tomato,such as early and late blight,bacterial wilt,potato tuber moth,and tomato leafminer.There are several examples of the successful uses of botanicals for pathogen and pest control relevant for different African climatic conditions;however,most of these studies have been conducted in vitro and often lack field verification.Plant strengtheners(substances that induce and improve crop resistance,yield,and quality)are little studied and used in Africa in comparison to North America and Europe.The possible benefits of using botanicals and plant strengtheners instead of conventional pesticides are discussed here in relation to human health and the environment as well as their modes of action and accessibility to farmers.Lack of knowledge of the composition and active ingredients of extracts,environmental concerns,uncertainties regarding stability and formulation,lack of legislation and limited support from governments,hamper the development of botanicals and plant strengtheners for use in sustainable African agriculture.
