282 research outputs found

    Social-Cultural Environment and Performance of Donor Funded Health Projects in Kenya

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    This study provides an empirical investigation on the effect of the social-cultural environment; local community literacy levels, support from local communities, language, and corruption levels on the performance of donor-funded health projects in Kenya. Empirical evidence indicatesthat most donor-funded health projects in Kenya experience time and cost overruns as well as quality issues. This study investigated a population of 69 donor-funded health projects that were initiated between 2008 and 2018 and were ongoing during the study period. A census study was conducted to ensure efficiency, representativeness, reliability, and flexibility since the population was small. The study adopted explanatory and descriptive research designs. Regression results indicated that language, support from the local communities, and the level of literacy in the local communities had positive relationships with the performance of donor-funded health projects in Kenya with coefficients of 0.021, 0.045, and 0.042 respectively. These factors were significant at a 5 percent significance level with p-values of 0.018, 0.019, and 0.047 respectively. Corruption levels had a negative relationship with the performance of donor-funded health projects in Kenya with a coefficient of - 0.031 that was significant at a 5 percent significance level with a p-value of 0.013. The study recommends that the government develops policies and frameworks that will help projects to minimize the negative effects of the social-cultural environment and enhance the positive effects, and that all decision-makers and other donor-funded health project stakeholders devise policies and strategies for controlling the effect of the social-cultural environment on the donor-funded health projects

    The Lunar Neon Exosphere Seen in LACE Data

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    Using the LACE data from Apollo 17 we have found measured neon densities consistent with the 20Ne surface number densities reported by Cook et al. (2013) for normal conditions, terminator surface densities of 3 (1.5) 10(exp 3) per cu.cm. These values are almost an order of magnitude less than those reported by Benna et al. (2015) for CME conditions. Using a Monte Carlo model and assuming the normal solar wind and a photoionization lifetime for Ne of 300 days, our result was more consistent with the Benna (2015) result than our measured result. Two lunations showed an increase in Ne during the night, consistent with the simulation, but two of the lunations showed a decrease in surface number density through the night. We have shown that explaining the Ne distribution is not as simple as assuming dynamic equilibrium with the solar wind and an exosphere accommodated to the local surface temperature

    Orthobunyavirus antibodies among humans in selected parts of the Rift Valley and northeastern Kenya

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    Ngari, Bunyamwera, Ilesha, and Germiston viruses are among the mosquito-borne human pathogens in the Orthobunyavirus genus, family Bunyaviridae, associated with febrile illness. Although the four orthobunyaviruses have been isolated from mosquito and/or tick vectors sampled from different geographic regions in Kenya, little is known of human exposure in such areas. We conducted a serologic investigation to determine whether orthobunyaviruses commonly infect humans in Kenya. Orthobunyavirus-specific antibodies were detected by plaque reduction neutralization tests in 89 (25.8%) of 345 persons tested. Multivariable analysis revealed age and residence in northeastern Kenya as risk factors. Implementation of acute febrile illness surveillance in northeastern Kenya will help to detect such infections.Swedish International Development Coorporation Agency (SIDA) through the African Regional Postgraduate Program in Insect Science of ICIPE.http://online.liebertpub.com/VBZhb201

    Serological evidence of chikungunya virus infection among suspected measles cases in selected regions of Kenya : 2008-2014

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    Chikungunya virus (family Togavirdae and genus Alphavirus) is an emerging and reemerging virus of public health importance both regionally and globally. In Kenya, about 50-60% of the suspected measles cases remain undiagnosed once measles and rubella is ruled out by immunoglobulin M (IgM) ELISA thus prompted the need to do differential diagnosis on the measles/rubella negative samples. Nothing is known about the role played by chikungunya infection among these suspected measles cases. Febrile rash illness is a common clinical presentation of arboviruses, including chikungunya. In this study, we conducted a serosurvey to explore the possible role of chikungunya infections among suspected measles cases in Kenya that had tested negative for measles and rubella. Sera were tested by commercially available ELISA for the presence of IgG and IgM antibodies against the chikungunya virus. All positive samples for chikungunya by ELISA were confirmed by plaque reduction neutralization test (PRNT), and to rule out cross-reactivity with other alphaviruses a panel of viruses was used, namely o' nyong' nyong, Semliki Forest, and Sindbis viruses. Of the 392 serum samples screened, 0.3% (n = 1) tested positive for IgM antibodies, while 4.6% (n = 18) tested positive for IgG antibodies against the chikungunya virus. PRNT results indicated 2 (11%) chikungunya positives and 7 (38.9%) o' nyong' nyong positives. We recommend awareness among health care providers and improved surveillance for these arboviruses by both serology and molecular testing. Testing for other pathogens should also be done to improve disease detection and diagnosis.http://online.liebertpub.com/VBZ2021-12-01hj2020Medical Virolog

    Performance of methylcellulose and Avicel overlays in plaque and focus assays of Chikungunya virus

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    Background: Chikungunya virus is a re-emerging pathogen that is responsible for Chikungunya fever periodic outbreaks along the Kenyan coast and in other African countries.  Epidemiological data from the World Health Organization show that in 2014-2015, there was a major outbreak of Chikungunya fever in the Americas and Pacific Islands.  Surveillance and correct diagnosis are therefore key in controlling the spread and management of the disease. Plaque and focus assays are key techniques in viral characterization or quantification, and both assays typically require overlay with gelling polymers to limit the spread of viruses in cell culture.  There are anecdotal reports that Avicel may be superior to methylcellulose in assay of Influenza virus. However, it is unclear whether this would apply to other viruses. Objective: The objective of this study was to determine the performance of methylcellulose and Avicel overlays in plaque and focus assays of Chikungunya virus. Methods: Confluent Vero cells were seeded in 6- or 96-well plates for plaque and focus assays respectively. Cells were inoculated with serially diluted Chikungunya virus, and incubated to allow adherence of the virus to the cells. The inoculum was removed; replaced with Avicel or methylcellulose overlay at various concentrations and stained with crystal violet or immunostained.  Statistical significance was computed using the Holm-Sidak test. Results: The size of plaques formed by Chikungunya virus was dependent on the concentration of both Avicel and methylcellulose gels used as overlays, with Avicel overlays giving consistently larger plaques than methylcellulose.  Chikungunya virus formed plaques nearly 2.5 times larger in diameter (2 vs 0.8 mm) with 1.2 % Avicel than with 1.25 % methylcellulose after 60 hr growth.  Plaques formed with Avicel were better defined and easier to count after 48 hr growth period compared to a 60 hr period. However, methycellulose overlays provided smaller, more distinct and better defined foci in focus assays. Conclusion: Both methylcellulose and Avicel are good overlay media for viral assays. Avicel is marginally better for plaque assays while methylcellulose provides more distinct and easier to count foci in focus assays. Key words: Chikungunya virus, plaque assay, focus assay, methylcellulose, Avice

    Isolation and phylogenetic characterization of arboviruses circulating among phlebotomine sandflies in parts of North Rift, Kenya

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    BackgroundUntil recently, arbovirus surveillance is mainly focused on mosquito and tick vectors, resulting in the discovery of several mosquito- and tick-borne arboviruses. However, the role of sandflies in arbovirus transmission and disease has remained largely unexplored. This study sought to isolate and characterize arboviruses from phlebotomine sandflies from selected pastoral ecozones in the North Rift region of Kenya.MethodsSandflies were collected from selected sites in North Rift Kenya between 2015 and 2018. They were sorted and pooled by sex, site, and collection date. The pools were homogenized and inoculated onto Vero cells for virus isolation. The positive pools were analyzed by polymerase chain reaction targeting different arboviruses. The isolates were further characterized by high-throughput sequencing using Illumina Miseq platform.ResultsApproximately 28,226 sandflies translating to 824 pools were sampled from the selected regions. A total of 11 showed reproducible cytopathic effects on Vero cells. We identified five arboviruses: sindbis (n = 4) from Kacheliba and Baringo, Chandipura (n = 4) from Turkana and Baringo, Koutango (n = 1) and Ntepes (n = 1) from Baringo, and Bogoria (n = 1) from Kacheliba. The percent identities of the identified viruses were approximately 80% to 98% compared to known viruses in GenBank, suggesting that some of them could be novel viruses.ConclusionThis study successfully isolated and characterized five arboviruses from sandflies. The findings suggest that sandflies are potential hosts of a wide range of arboviruses and are therefore important vectors to consider in arbovirus surveillance and evaluated for their ability to transmit them. Further studies are needed to determine the public health importance and extent of exposure of these viruses to humans and livestock populations

    Assessment of risk of dengue and yellow fever virus transmission in three major Kenyan cities based on Stegomyia indices

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    Dengue (DEN) and yellow fever (YF) are re-emerging in East Africa, with contributing drivers to this trend being unplanned urbanization and increasingly adaptable anthropophilic Aedes (Stegomyia) vectors. Entomological risk assessment of these diseases remains scarce for much of East Africa and Kenya even in the dengue fever-prone urban coastal areas. Focusing on major cities of Kenya, we compared DEN and YF risk in Kilifi County (DEN-outbreak-prone), and Kisumu and Nairobi Counties (no documented DEN outbreaks). We surveyed water-holding containers for mosquito immature (larvae/pupae) indoors and outdoors from selected houses during the long rains, short rains and dry seasons (100 houses/season) in each County from October 2014-June 2016. House index (HI), Breteau index (BI) and Container index (CI) estimates based on Aedes (Stegomyia) immature infestations were compared by city and season. Aedes aegypti and Aedes bromeliae were the main Stegomyia species with significantly more positive houses outdoors (212) than indoors (88) (n = 900) (χ2 = 60.52, P < 0.0001). Overall, Ae. aegypti estimates of HI (17.3 vs 11.3) and BI (81.6 vs 87.7) were higher in Kilifi and Kisumu, respectively, than in Nairobi (HI, 0.3; BI,13). However, CI was highest in Kisumu (33.1), followed by Kilifi (15.1) then Nairobi (5.1). Aedes bromeliae indices were highest in Kilifi, followed by Kisumu, then Nairobi with HI (4.3, 0.3, 0); BI (21.3, 7, 0.7) and CI (3.3, 3.3, 0.3), at the respective sites. HI and BI for both species were highest in the long rains, compared to the short rains and dry seasons. We found strong positive correlations between the BI and CI, and BI and HI for Ae. aegypti, with the most productive container types being jerricans, drums, used/discarded containers and tyres. On the basis of established vector index thresholds, our findings suggest low-tomedium risk levels for urban YF and high DEN risk for Kilifi and Kisumu, whereas for Nairobi YF risk was low while DEN risk levels were low-to-medium. The study provides a baseline for future vector studies needed to further characterise the observed differential risk patterns by vector potential evaluation. Identified productive containers should be made the focus of community-based targeted vector control programs.A scholarship to SBA by the German Academic Exchange Service (DAAD), National Institutes of Health (NIH), Grant No. 1R01AI099736-01A1 to RS, UK's Department for International Development (DFID), Swedish International Development Cooperation Agency (Sida), the Swiss Agency for Development and Cooperation (SDC), and the Kenyan Government.http://www.plosntds.orgam2017Zoology and Entomolog

    Development of Dromedary Antibody-based Enzyme Linked Immunosorbent Assay for Detecting Chikungunya virus Infections

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    Background: Chikungunya virus (CHIKV) is an arthropod-borne Togavirus belonging to the genus Alphavirus that is responsible for sporadic worldwide outbreaks of Chikungunya fever, an acute febrile illness often associated with severe polyarthralgia. In Kenya, Chikungunya virus is of great epidemiological concern, with the last major outbreak occurring in 2016 in North Eastern Kenya. Reliable detection of CHIKV infections is key to controlling this re-emerging pathogen, for which no cure currently exists.  Current diagnostic methods for CHIKV employ a combination of tests, particularly immunologic, serologic or virologic techniques.  However, the independent scientific reviews on the validity and sensitivity of currently available commercial assays have been conflicting. Objective: This study aimed to develop and validate a dromedary antibody-based enzyme linked immunosorbent assay for detecting Chikungunya virus infections. Methods: To produce sufficient antigen for camel immunization, Chikungunya virus (strain Lamu 33) was propagated in confluent C6-36 E2 cells using Cytodex microcarrier system. Purified and inactivated CHIKV immunogen was used to inoculate two camels reared at the University of Nairobi farm in Kibwezi, Kenya. Camel serum samples collected over the entire immunization period were assayed for the presence of anti-Chikungunya IgG by indirect ELISA. Purification of camel Heavy Chain IgG antibodies was performed by lectin affinity chromatography on protein A and protein G-Sepharose columns; then conjugated with horse radish peroxidase (HRP). The HRP-conjugated camel Heavy Chain IgG2 and IgG3 were optimized for ELISA, with optical density measured using a microplate reader set at 492nm.   A total of 188 human sera samples were assayed using the developed dromedary-based enzyme linked immunosorbent assay to determine Chikungunya virus infections. Results: The sensitivity of the dromedary HCAb IgG2 assay was 91.3% (95% CI: 0.831 - 0.994); while that for HCAb IgG3 assay was 95.7% (95% CI: 0.898 - 1.01).  The specificity of HCAb IgG2 assay was 92.3% (95% CI: 0.879 - 0.967); while the specificity of HCAb IgG3 method was 90% (95% CI: 0.851 - 0.949). For HCAb IgG2 and IgG3 based assays, the positive predictive values were 79.2% and 75.8 % respectively; while the negative predictive values were 97% and 98.4% for HCAb IgG2 and IgG3 based assays respectively. Conclusion: The camel antibody based assay was found to be reliable assay with very good sensitivity and specificity, and can be deployed for detection of Chikungunya virus infections. Key words: Chikungunya, ELISA, camel antibodies, diagnosi

    Predicting Abundances of Aedes mcintoshi, a primary Rift Valley fever virus mosquito vector

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    Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic arbovirus with important livestock and human health, and economic consequences across Africa and the Arabian Peninsula. Climate and vegetation monitoring guide RVFV forecasting models and early warning systems; however, these approaches make monthly predictions and a need exists to predict primary vector abundances at finer temporal scales. In Kenya, an important primary RVFV vector is the mosquito Aedes mcintoshi. We used a zero-inflated negative binomial regression and multimodel averaging approach with georeferenced Ae. mcintoshi mosquito counts and remotely sensed climate and topographic variables to predict where and when abundances would be high in Kenya and western Somalia. The data supported a positive effect on abundance of minimum wetness index values within 500 m of a sampling site, cumulative precipitation values 0 to 14 days prior to sampling, and elevated land surface temperature values ~3 weeks prior to sampling. The probability of structural zero counts of mosquitoes increased as percentage clay in the soil decreased. Weekly retrospective predictions for unsampled locations across the study area between 1 September and 25 January from 2002 to 2016 predicted high abundances prior to RVFV outbreaks in multiple foci during the 2006–2007 epizootic, except for two districts in Kenya. Additionally, model predictions supported the possibility of high Ae. mcintoshi abundances in Somalia, independent of Kenya. Model-predicted abundances were low during the 2015–2016 period when documented outbreaks did not occur, although several surveillance systems issued warnings. Model predictions prior to the 2018 RVFV outbreak indicated elevated abundances in Wajir County, Kenya, along the border with Somalia, but RVFV activity occurred west of the focus of predicted high Ae. mcintoshi abundances
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