Last data update: Apr 29, 2024. (Total: 46658 publications since 2009)
Records 1-16 (of 16 Records) |
Query Trace: Omondi M[original query] |
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Comparison of different trapping methods to collect malaria vectors indoors and outdoors in western Kenya
Kosgei J , Gimnig JE , Moshi V , Omondi S , McDermott DP , Donnelly MJ , Ouma C , Abong'o B , Ochomo E . Malar J 2024 23 (1) 81 BACKGROUND: Vector surveillance is among the World Health Organization global vector control response (2017-2030) pillars. Human landing catches are a gold standard but difficult to implement and potentially expose collectors to malaria infection. Other methods like light traps, pyrethrum spray catches and aspiration are less expensive and less risky to collectors. METHODS: Three mosquito sampling methods (UV light traps, CDC light traps and Prokopack aspiration) were evaluated against human landing catches (HLC) in two villages of Rarieda sub-county, Siaya County, Kenya. UV-LTs, CDC-LTs and HLCs were conducted hourly between 17:00 and 07:00. Aspiration was done indoors and outdoors between 07:00 and 11:00 a.m. Analyses of mosquito densities, species abundance and sporozoite infectivity were performed across all sampling methods. Species identification PCR and ELISAs were done for Anopheles gambiae and Anopheles funestus complexes and data analysis was done in R. RESULTS: Anopheles mosquitoes sampled from 608 trapping efforts were 5,370 constituting 70.3% Anopheles funestus sensu lato (s.l.), 19.7% Anopheles coustani and 7.2% An. gambiae s.l. 93.8% of An. funestus s.l. were An. funestus sensu stricto (s.s.) and 97.8% of An. gambiae s.l. were Anopheles arabiensis. Only An. funestus were sporozoite positive with 3.1% infection prevalence. Indoors, aspiration captured higher An. funestus (mean = 6.74; RR = 8.83, P < 0.001) then UV-LT (mean = 3.70; RR = 3.97, P < 0.001) and CDC-LT (mean = 1.74; RR = 1.89, P = 0.03) compared to HLC. UV-LT and CDC-LT indoors captured averagely 0.18 An. arabiensis RR = 5.75, P = 0.028 and RR = 5.87, P = 0.028 respectively. Outdoors, UV-LT collected significantly higher Anopheles mosquitoes compared to HLC (An. funestus: RR = 5.18, P < 0.001; An. arabiensis: RR = 15.64, P = 0.009; An. coustani: RR = 11.65, P < 0.001). Anopheles funestus hourly biting indoors in UV-LT and CDC-LT indicated different peaks compared to HLC. CONCLUSIONS: Anopheles funestus remains the predominant mosquito species. More mosquitoes were collected using aspiration, CDC-LTs and UV-LTs indoors and UV-LTs and CD-LTs outdoors compared to HLCs. UV-LTs collected more mosquitoes than CDC-LTs. The varied trends observed at different times of the night suggest that these methods collect mosquitoes with diverse activities and care must be taken when interpreting the results. |
Late morning biting behaviour of Anopheles funestus is a risk factor for transmission in schools in Siaya, western Kenya
Omondi S , Kosgei J , Musula G , Muchoki M , Abong'o B , Agumba S , Ogwang C , McDermott DP , Donnelly MJ , Staedke SG , Schultz J , Gutman JR , Gimnig JE , Ochomo E . Malar J 2023 22 (1) 366 BACKGROUND: Children in Kenya spend a substantial amount of time at school, including at dawn and dusk when mosquitoes are active. With changing vector behaviour towards early morning biting, it is important to determine whether there is an additional risk of transmission in schools. This study sought to understand whether late morning biting by Anopheles funestus, previously documented in households in western Kenya, was replicated in schools. METHODS: From the 4th to the 6th of August 2023, human landing collections were conducted hourly in four schools in Alego Usonga sub-County, Siaya County. The collections were conducted in and outside five classrooms in each school and ran for 17 h, starting at 18:00 until 11:00 h the next morning. RESULTS: Anopheles funestus was the predominant species collected, forming 93.2% (N = 727) of the entire collection, with peak landing between 06:00 and 07:00 h and continuing until 11:00 h. More than half of the collected An. funestus were either fed or gravid, potentially indicative of multiple bloodmeals within each gonotrophic cycle, and had a sporozoite rate of 2.05%. CONCLUSION: School children spend up to 10 h of their daytime in schools, reporting between 06:00 and 07:00 h and staying in school until as late as 17:00 h, meaning that they receive potentially infectious mosquito bites during the morning hours in these settings. There is a need to consider vector control approaches targeting schools and other peridomestic spaces in the morning hours when An. funestus is active. |
A comparison of the attractiveness of flowering plant blossoms versus attractive targeted sugar baits (ATSBs) in western Kenya
Yalla N , Polo B , McDermott DP , Kosgei J , Omondi S , Agumba S , Moshi V , Abong'o B , Gimnig JE , Harris AF , Entwistle J , Long PR , Ochomo E . PLoS One 2023 18 (6) e0286679 Attractive Targeted Sugar Baits (ATSB) have been demonstrated to result in significant reductions in malaria vector numbers in areas of scarce vegetation cover such as in Mali and Israel, but it is not clear whether such an effect can be replicated in environments where mosquitoes have a wide range of options for sugar resources. The current study evaluated the attractiveness of the predominant flowering plants of Asembo Siaya County, western Kenya in comparison to an ATSB developed by Westham Co. Sixteen of the most common flowering plants in the study area were selected and evaluated for relative attractiveness to malaria vectors in semi-field structures. Six of the most attractive flowers were compared to determine the most attractive to local Anopheles mosquitoes. The most attractive plant was then compared to different versions of ATSB. In total, 56,600 Anopheles mosquitoes were released in the semi-field structures. From these, 5150 mosquitoes (2621 males and 2529 females) of An. arabiensis, An. funestus and An. gambiae were recaptured on the attractancy traps. Mangifera indica was the most attractive sugar source for all three species while Hyptis suaveolens and Tephrosia vogelii were the least attractive plants to the mosquitoes. Overall, ATSB version 1.2 was significantly more attractive compared to both ATSB version 1.1 and Mangifera indica. Mosquitoes were differentially attracted to various natural plants in western Kenya and ATSB. The observation that ATSB v1.2 was more attractive to local Anopheles mosquitoes than the most attractive natural sugar source indicates that this product may be able to compete with natural sugar sources in western Kenya and suggests this product may have the potential to impact mosquito populations in the field. |
Natural sugar feeding rates of Anopheles mosquitoes collected by different methods in western Kenya
Omondi S , Kosgei J , Agumba S , Polo B , Yalla N , Moshi V , Abong'o B , Ombok M , McDermott DP , Entwistle J , Samuels AM , Ter Kuile FO , Gimnig JE , Ochomo E . Sci Rep 2022 12 (1) 20596 Attractive targeted sugar baits (ATSBs) are a potential vector control tool that exploits the sugar-feeding behaviour of mosquitoes. We evaluated the sugar-feeding behaviour of Anopheles mosquitoes as part of baseline studies for cluster randomised controlled trials of ATSBs. Mosquitoes were collected indoors and outdoors from two villages in western Kenya using prokopack aspirations, malaise tent traps and ultraviolet (UV) light traps. Individual mosquitoes were subjected to the cold anthrone test to assess the presence of sugar. Overall, 15.7% of collected mosquitoes had fed on natural sugar sources. By species and sex, the proportion sugar-fed was 41.3% and 27.7% in male and female Anopheles funestus, 27.2% and 12.8% in male and female An. arabiensis, and 9.7% and 8.3% in male and female An. coustani, respectively. Sugar-feeding was higher in unfed than blood-fed mosquitoes and higher in male than gravid mosquitoes. Anopheles mosquitoes obtained sugar meals from natural sources during all physiological stages, whether they rest indoors or outdoors. These findings offer a potential avenue to exploit for the control of mosquitoes, particularly with the advent of ATSBs, which have been shown to reduce mosquito densities in other regions. |
Standardizing clinical culture specimen collection in Ethiopia: a training-of-trainers
Kue J , Bersani A , Stevenson K , Yimer G , Wang SH , Gebreyes W , Hazim C , Westercamp M , Omondi M , Amare B , Alebachew G , Abubeker R , Fentaw S , Tigabu E , Kirley D , Vanderende D , Bancroft E , Gallagher KM , Kanter T , Balada-Llasat JM . BMC Med Educ 2021 21 (1) 195 BACKGROUND: Proper specimen collection is central to improving patient care by ensuring optimal yield of diagnostic tests, guiding appropriate management, and targeting treatment. The purpose of this article is to describe the development and implementation of a training-of-trainers educational program designed to improve clinical culture specimen collection among healthcare personnel (HCP) in Ethiopia. METHODS: A Clinical Specimen Collection training package was created consisting of a Trainer's Manual, Reference Manual, Assessment Tools, Step-by-Step Instruction Guides (i.e., job aides), and Core Module PowerPoint Slides. RESULTS: A two-day course was used in training 16 master trainers and 47 facility-based trainers responsible for cascading trainings on clinical specimen collection to HCP at the pre-service, in-service, or national-levels. The Clinical Specimen Collection Package is offered online via The Ohio State University's CANVAS online platform. CONCLUSIONS: The training-of-trainers approach may be an effective model for development of enhanced specimen collection practices in low-resource countries. |
Time to HIV testing of sexual contacts identified by HIV-positive index clients in Siaya County, Kenya
Wekesa P , Kataka J , Owuor K , Nyabiage L , Miruka F , Wanjohi S , Omondi S . PLoS One 2020 15 (9) e0238794 There are no studies on time to test since notification among identified sexual contacts of HIV-positive index clients using program data in Siaya County and Kenya. We sought to understand time to HIV testing by contact characteristics after identification to inform targeted testing interventions. We retrospectively analyzed data from adult (aged ≥18 years) sexual contacts identified by HIV-positive index clients from 117 health facilities in Siaya County (June 2017-August 2018). We used Chi-square tests to assess for differences in characteristics of contacts by HIV testing. We performed Cox proportional hazards analysis and time to HIV testing of contacts analysis including time-varying covariates (cluster-adjusted by facility) to assess characteristics (age, sex, and relationship to index client) associated with time to HIV-testing since notification. Sexual contacts not tested were right censored at last follow-up date. We calculated hazard ratios with 95% confidence intervals to evaluate characteristics associated with time to testing. Of the 6,845 contacts included in this analysis, 3,858 (56.4%) were men. Most were aged 25-34 years (3,209 [46.9%]). Median time to contact testing was 14.5 days (interquartile range, 2.5-62). On multivariable analysis, contacts aged 18-24 years (aHR, 1.32 [95% CI: 1.01-1.73], p = 0.040) and 25-34 years (aHR, 1.18 [95% CI: 1.01-1.39], p = 0.038) had shorter time to HIV testing than those aged 35-44 years. Married polygamous (aHR, 1.12 [95% CI: 1.01-1.25], p = 0.039) and single contacts (aHR, 1.17 [95% CI: 1.08-1.27], p <0.001) had shorter time to HIV testing than married monogamous contacts. Non-spouse sexual contacts had shorter time to HIV testing than spouses, (aHR, 1.23 [95% CI: 1.15-1.32], p <0.001). We recommend enhanced differentiated partner services targeting older adults, married monogamous, and spouse sexual contacts to facilitate early diagnosis, same day treatment, and prevention in Western Kenya and sub-Saharan Africa at large. |
Development and validation of a sociodemographic and behavioral characteristics-based risk-score algorithm for targeting HIV testing among adults in Kenya
Muttai H , Guyah B , Musingila P , Achia T , Miruka F , Wanjohi S , Dande C , Musee P , Lugalia F , Onyango D , Kinywa E , Okomo G , Moth I , Omondi S , Ayieko C , Nganga L , Joseph RH , Zielinski-Gutierrez E . AIDS Behav 2020 25 (2) 297-310 To inform targeted HIV testing, we developed and externally validated a risk-score algorithm that incorporated behavioral characteristics. Outpatient data from five health facilities in western Kenya, comprising 19,458 adults >/= 15 years tested for HIV from September 2017 to May 2018, were included in univariable and multivariable analyses used for algorithm development. Data for 11,330 adults attending one high-volume facility were used for validation. Using the final algorithm, patients were grouped into four risk-score categories: </= 9, 10-15, 16-29 and >/= 30, with increasing HIV prevalence of 0.6% [95% confidence interval (CI) 0.46-0.75], 1.35% (95% CI 0.85-1.84), 2.65% (95% CI 1.8-3.51), and 15.15% (95% CI 9.03-21.27), respectively. The algorithm's discrimination performance was modest, with an area under the receiver-operating-curve of 0.69 (95% CI 0.53-0.84). In settings where universal testing is not feasible, a risk-score algorithm can identify sub-populations with higher HIV-risk to be prioritized for HIV testing. |
Expanded eligibility for HIV testing increases HIV diagnoses - A cross-sectional study in seven health facilities in western Kenya
Joseph RH , Musingila P , Miruka F , Wanjohi S , Dande C , Musee P , Lugalia F , Onyango D , Kinywa E , Okomo G , Moth I , Omondi S , Ayieko C , Nganga L , Zielinski-Gutierrez E , Muttai H , De Cock KM . PLoS One 2019 14 (12) e0225877 Homa Bay, Siaya, and Kisumu counties in western Kenya have the highest estimated HIV prevalence (16.3-21.0%) in the country, and struggle to meet program targets for HIV testing services (HTS). The Kenya Ministry of Health (MOH) recommends annual HIV testing for the general population. We assessed the degree to which reducing the interval for retesting to less than 12 months increased diagnosis of HIV in outpatient departments (OPD) in western Kenya. We conducted a retrospective analysis of routinely collected program data from seven high-volume (>800 monthlyOPD visits) health facilities in March-December, 2017. Data from persons >/=15 years of age seeking medical care (patients) in the OPD and non-care-seekers (non-patients) accompanying patients to the OPD were included. Outcomes were meeting MOH (routine) criteria versus criteria for a reduced retesting interval (RRI) of <12 months, and HIV test result. STATA version 14.2 was used to calculate frequencies and proportions, and to test for differences using bivariate analysis. During the 9-month period, 119,950 clients were screened for HIV testing eligibility, of whom 79% (94,766) were eligible and 97% (92,153) received a test. Among 92,153 clients tested, the median age was 28 years, 57% were female and 40% (36,728) were non-patients. Overall, 20% (18,120) of clients tested met routine eligibility criteria: 4% (3,972) had never been tested, 10% (9,316) reported a negative HIV test in the past >12 months, and 5% (4,832) met other criteria. The remaining 80% (74,033) met criteria for a RRI of < 12 months. In total 1.3% (1,185) of clients had a positive test. Although the percent yield was over 2-fold higher among those meeting routine criteria (2.4% vs. 1.0%; p<0.001), 63% (750) of all HIV infections were found among clients tested less than 12 months ago, the majority (81%) of whom reported having a negative test in the past 3-12 months. Non-patients accounted for 45% (539) of all HIV-positive persons identified. Percent yield was higher among non-patients as compared to patients (1.5% vs. 1.2%; p-value = <0.001) overall and across eligibility criteria and age categories. The majority of HIV diagnoses in the OPD occurred among clients reporting a negative HIV test in the past 12 months, clients ineligible for testing under the current MOH guidelines. Nearly half of all HIV-positive individuals identified in the OPD were non-patients. Our findings suggest that in the setting of a generalized HIV epidemic, retesting persons reporting an HIV-negative test in the past 3-12 months, and routine testing of non-patients accessing the OPD are key strategies for timely diagnosis of persons living with HIV. |
Diagnostic dose determination and efficacy of chlorfenapyr and clothianidin insecticides against Anopheles malaria vector populations of western Kenya
Agumba S , Gimnig JE , Ogonda L , Ombok M , Kosgei J , Munga S , Guyah B , Omondi S , Ochomo E . Malar J 2019 18 (1) 243 BACKGROUND: Malaria vector control is dependent on chemical insecticides applied to walls by indoor residual spraying or on long-lasting insecticidal nets. The emergence and spread of insecticide resistance in major malaria vectors may compromise malaria control and elimination efforts. The aim of this study was to estimate a diagnostic dose for chlorfenapyr (class: pyrrole) and clothianidin (class: neonicotinoid) and assess the baseline susceptibility of three major Anopheles malaria vectors of western Kenya to these two insecticides. METHODS: The Centers for Disease Control and Prevention (CDC) bottle assay was used to determine the diagnostic doses of chlorfenapyr and clothianidin insecticides against the susceptible Kisumu strain of Anopheles gambiae. Probit analysis was used to determine the lethal doses at which 50% (LD50) and 99% (LD99) of the susceptible mosquitoes would be killed 24, 48 and 72 h following exposure for 1 h. Insecticidal efficacy of chlorfenapyr, clothianidin and the pyrethroid deltamethrin was then evaluated against field collected female Anopheles mosquitoes sampled from Nyando, Bumula and Ndhiwa sub-Counties in western Kenya. Members of Anopheles funestus and An. gambiae complexes were identified using polymerase chain reaction (PCR). RESULTS: The determined diagnostic doses of chlorfenapyr and clothianidin insecticides were 50 microg/bottle and 150 microg/bottle, respectively, for An. gambiae, Kisumu strain. When exposed to the diagnostic dose of each insecticide, Anopheles malaria vector populations in western Kenya were susceptible to both insecticides with 100% mortality observed after 72 h. Mortality of mosquitoes exposed to deltamethrin increased over time but did not reach 100%. Mortality of Anopheles arabiensis from Nyando exposed to deltamethrin was 83% at 24 h, 88% at 48 h and 94.5% at 72 h while An. funestus from Ndhiwa was 89% at 24 h, 91.5% at 48 h and 94.5% at 72 h. CONCLUSION: Mosquitoes of western Kenya, despite being resistant to pyrethroids, are susceptible to chlorfenapyr and clothianidin. Field evaluations of the formulated product are needed. |
Establishment of a sentinel laboratory-based antimicrobial resistance surveillance network in Ethiopia
Hazim C , Abubeker Ibrahim R , Westercamp M , Belete GA , Amare Kibret B , Kanter T , Yimer G , Adem TS , Stevenson KB , Urrego M , Kale KN , Omondi MW , VanderEnde D , Park BJ , Parsons MMB , Gallagher KM . Health Secur 2018 16 S30-s36 In 2014, as part of the Global Health Security Agenda, Ethiopia was provided the technical and financial resources needed to prioritize antimicrobial resistance (AMR) in the national public health sphere. Under the direction of a multi-stakeholder working group, AMR surveillance was launched in July 2017 at 4 sentinel sites across the country. The AMR surveillance initiative in Ethiopia represents one of the first systematic efforts to prospectively collect, analyze, and report national-level microbiology results from a network of hospitals and public health laboratories in the country. Baseline readiness assessments were conducted to identify potential challenges to implementation to be addressed through capacity-building efforts. As part of these efforts, the working group leveraged existing resources, initiated laboratory capacity building through mentorship, and established infrastructure and systems for quality assurance, data management, and improved coordination. As a result, AMR surveillance data are being reported and analyzed for use; data from more than 1,700 patients were collected between July 2017 and March 2018. The critical challenges and effective solutions identified through surveillance planning and implementation have provided lessons to help guide successful AMR surveillance in other settings. Ultimately, the surveillance infrastructure, laboratory expertise, and communication frameworks built specifically for AMR surveillance in Ethiopia can be extended for use with other infectious diseases and potential public health emergencies. Thus, building AMR surveillance in Ethiopia has illustrated how laying the foundation for a specific public health initiative can develop capacity for core public health functions with potential benefit. |
Young adults in endemic areas: An untreated group in need of school-based preventive chemotherapy for schistosomiasis control and elimination
Korir HK , Riner DK , Kavere E , Omondi A , Landry J , Kittur N , Ndombi EM , Ondigo BN , Secor WE , Karanja DMS , Colley DG . Trop Med Infect Dis 2018 3 (3) Parasitologic surveys of young adults in college and university settings are not commonly done, even in areas known to be endemic for schistosomiasis and soil-transmitted helminths. We have done a survey of 291 students and staff at the Kisumu National Polytechnic in Kisumu, Kenya, using the stool microscopy Kato-Katz (KK) method and the urine point-of-care circulating cathodic antigen (POC-CCA) test. Based on three stools/two KK slides each, in the 208 participants for whom three consecutive stools were obtained, Schistosoma mansoni prevalence was 17.8%. When all 291 individuals were analyzed based on the first stool, as done by the national neglected tropical disease (NTD) program, and one urine POC-CCA assay (n = 276), the prevalence was 13.7% by KK and 23.2% by POC-CCA. Based on three stools, 2.5% of 208 participants had heavy S. mansoni infections (>/=400 eggs/gram feces), with heavy S. mansoni infections making up 13.5% of the S. mansoni cases. The prevalence of the soil-transmitted helminths (STH: Ascaris lumbricoides, Trichuris trichiura and hookworm) by three stools was 1.4%, 3.1%, and 4.1%, respectively, and by the first stool was 1.4%, 2.4% and 1.4%, respectively. This prevalence and intensity of infection with S. mansoni in a college setting warrants mass drug administration with praziquantel. This population of young adults is 'in school' and is both approachable and worthy of inclusion in national schistosomiasis control and elimination programs. |
Environmental assessment and blood lead levels of children in Owino Uhuru and Bangladesh settlements in Kenya
Etiang NA , Arvelo W , Galgalo T , Amwayi S , Gura Z , Kioko J , Omondi G , Patta S , Lowther SA , Brown MJ . J Health Pollut 2018 8 (18) 180605 Background. Lead exposure is linked to intellectual disability and anemia in children. The United States Centers for Disease Control and Prevention (CDC) recommends biomonitoring of blood lead levels (BLLs) in children with BLL ≥5 μg/dL and chelation therapy for those with BLL ≥45 μg/dL. Objectives. This study aimed to determine blood and environmental lead levels and risk factors associated with elevated BLL among children from Owino Uhuru and Bangladesh settlements in Mombasa County, Kenya. Methods. The present study is a population-based, cross-sectional study of children aged 12-59 months randomly selected from households in two neighboring settlements, Owino Uhuru, which has a lead smelter, and Bangladesh settlement (no smelter). Structured questionnaires were administered to parents and 1-3 ml venous blood drawn from each child was tested for lead using a LeadCare ® II portable analyzer. Environmental samples collected from half of the sampled households were tested for lead using graphite furnace atomic absorption spectroscopy. Results: We enrolled 130 children, 65 from each settlement. Fifty-nine (45%) were males and the median age was 39 months (interquartile range (IQR): 30-52 months). BLLs ranged from 1 μg/dL to 31 μg/dL, with 45 (69%) children from Owino Uhuru and 18 (28%) children from Bangladesh settlement with BLLs > 5 μg/dL. For Owino Uhuru, the geometric mean BLL in children was 7.4 μg/dL (geometric standard deviation (GSD); 1.9) compared to 3.7 μg/ dL (GSD: 1.9) in Bangladesh settlement (p < 0.05). The geometric mean lead concentration of soil samples from Owino Uhuru was 146.5 mg/Kg (GSD: 5.2) and 11.5 mg/Kg (GSD: 3.9) (p < 0.001) in Bangladesh settlement. Children who resided < 200 m from the lead smelter were more likely to have a BLL ≧5 μg/dL than children residing ≥200 m from the lead smelter (adjusted odds ratio (aOR): 33.6 (95% confidence interval (CI): 7.4-153.3). Males were also more likely than females to have a BLL ≧5 μg/dL (39, 62%) compared to a BLL < 5 μg/dL [aOR: 2.4 (95% CI: 1.0-5.5)]. Conclusions. Children in Owino Uhuru had significantly higher BLLs compared with children in Bangladesh settlement. Interventions to diminish continued exposure to lead in the settlement should be undertaken. Continued monitoring of levels in children with detectable levels can evaluate whether interventions to reduce exposure are effective. Participant Consent. Obtained Ethics Approval. Scientific approval for the study was obtained from the Ministry of Health, lead poisoning technical working group. Since this investigation was considered a public health response of immediate concern, expedited ethical approval was obtained from the Kenya Medical Research Institute and further approval from the Mombasa County Department of Health Services. The investigation was considered a non-research public health response activity by the CDC. Competing Interests. The authors declare no competing financial interests. |
Quantifying the intensity of permethrin insecticide resistance in Anopheles mosquitoes in western Kenya
Omondi S , Mukabana WR , Ochomo E , Muchoki M , Kemei B , Mbogo C , Bayoh N . Parasit Vectors 2017 10 (1) 548 BACKGROUND: The development and spread of resistance among local vectors to the major classes of insecticides used in Long-Lasting Insecticidal Nets (LLINs) and Indoor Residual Spraying (IRS) poses a major challenge to malaria vector control programs worldwide. The main methods of evaluating insecticide resistance in malaria vectors are the WHO tube bioassay and CDC bottle assays, with their weakness being determination of resistance at a fixed dose for variable populations. The CDC bottle assay using different insecticide dosages has proved applicable in ascertaining the intensity of resistance. METHODS: We determined the status and intensity of permethrin resistance and investigated the efficacy of commonly used LLINs (PermaNet(R) 2.0, PermaNet(R) 3.0 and Olyset(R)) against 3-5 day-old adult female Anopheles mosquitoes from four sub-counties; Teso, Bondo, Rachuonyo and Nyando in western Kenya. Knockdown was assessed to 4 doses of permethrin; 1x (21.5 mug/ml), 2x (43 mug/ml), 5x (107.5 mug/ml) and 10x (215 mug/ml) using CDC bottle assays. RESULTS: Mortality for 0.75% permethrin ranged from 23.5% to 96.1% in the WHO tube assay. Intensity of permethrin resistance was highest in Barkanyango Bondo, with 84% knockdown at the 30 min diagnostic time when exposed to the 10x dose. When exposed to the LLINs, mortality ranged between- 0-39% for Olyset(R), 12-88% for PermaNet(R) 2.0 and 26-89% for PermaNet(R) 3.0. The efficacy of nets was reduced in Bondo and Teso. Results from this study show that there was confirmed resistance in all the sites; however, intensity assays were able to differentiate Bondo and Teso as the sites with the highest levels of resistance, which coincidentally were the two sub-counties with reduced net efficacy. CONCLUSIONS: There was a reduced efficacy of nets in areas with high resistance portraying that at certain intensities of resistance, vector control using LLINs may be compromised. It is necessary to incorporate intensity assays in order to determine the extent of threat that resistance poses to malaria control. |
Randomized controlled field trial to assess the immunogenicity and safety of Rift Valley fever clone 13 vaccine in livestock
Njenga MK , Njagi L , Thumbi SM , Kahariri S , Githinji J , Omondi E , Baden A , Murithi M , Paweska J , Ithondeka PM , Ngeiywa KJ , Dungu B , Donadeu M , Munyua PM . PLoS Negl Trop Dis 2015 9 (3) e0003550 BACKGROUND: Although livestock vaccination is effective in preventing Rift Valley fever (RVF) epidemics, there are concerns about safety and effectiveness of the only commercially available RVF Smithburn vaccine. We conducted a randomized controlled field trial to evaluate the immunogenicity and safety of the new RVF Clone 13 vaccine, recently registered in South Africa. METHODS: In a blinded randomized controlled field trial, 404 animals (85 cattle, 168 sheep, and 151 goats) in three farms in Kenya were divided into three groups. Group A included males and non-pregnant females that were randomized and assigned to two groups; one vaccinated with RVF Clone 13 and the other given placebo. Groups B included animals in 1st half of pregnancy, and group C animals in 2nd half of pregnancy, which were also randomized and either vaccinated and given placebo. Animals were monitored for one year and virus antibodies titers assessed on days 14, 28, 56, 183 and 365. RESULTS: In vaccinated goats (N = 72), 72% developed anti-RVF virus IgM antibodies and 97% neutralizing IgG antibodies. In vaccinated sheep (N = 77), 84% developed IgM and 91% neutralizing IgG antibodies. Vaccinated cattle (N = 42) did not develop IgM antibodies but 67% developed neutralizing IgG antibodies. At day 14 post-vaccination, the odds of being seropositive for IgG in the vaccine group was 3.6 (95% CI, 1.5 - 9.2) in cattle, 90.0 (95% CI, 25.1 - 579.2) in goats, and 40.0 (95% CI, 16.5 - 110.5) in sheep. Abortion was observed in one vaccinated goat but histopathologic analysis did not indicate RVF virus infection. There was no evidence of teratogenicity in vaccinated or placebo animals. CONCLUSIONS: The results suggest RVF Clone 13 vaccine is safe to use and has high (>90%) immunogenicity in sheep and goats but moderate (> 65%) immunogenicity in cattle. |
Using information and communications technology in a national population-based survey: the Kenya AIDS Indicator Survey 2012
Ojwang JK , Lee VC , Waruru A , Ssempijja V , Ng'ang'a JG , Wakhutu BE , Kandege NO , Koske DK , Kamiru SM , Omondi KO , Kakinyi M , Kim AA , Oluoch T . J Acquir Immune Defic Syndr 2014 66 Suppl 1 S123-9 BACKGROUND: With improvements in technology, electronic data capture (EDC) for large surveys is feasible. EDC offers benefits over traditional paper-based data collection, including more accurate data, greater completeness of data, and decreased data cleaning burden. METHODS: The second Kenya AIDS Indicator Survey (KAIS 2012) was a population-based survey of persons aged 18 months to 64 years. A software application was designed to capture the interview, specimen collection, and home-based testing and counseling data. The application included: interview translations for local languages; options for single, multiple, and fill-in responses; and automated participant eligibility determination. Data quality checks were programmed to automate skip patterns and prohibit outlier responses. A data sharing architecture was developed to transmit the data in real-time from the field to a central server over a virtual private network. RESULTS: KAIS 2012 was conducted between October 2012 and February 2013. Overall, 68,202 records for the interviews, specimen collection, and home-based testing and counseling were entered into the application. Challenges arose during implementation, including poor connectivity and a systems malfunction that created duplicate records, which prevented timely data transmission to the central server. Data cleaning was minimal given the data quality control measures. CONCLUSIONS: KAIS 2012 demonstrated the feasibility of using EDC in a population-based survey. The benefits of EDC were apparent in data quality and minimal time needed for data cleaning. Several important lessons were learned, such as the time and monetary investment required before survey implementation, the importance of continuous application testing, and contingency plans for data transmission due to connectivity challenges. |
Dried tube specimens: a simple and cost-effective method for preparation of HIV proficiency testing panels and quality control materials for use in resource-limited settings
Parekh BS , Anyanwu J , Patel H , Downer M , Kalou M , Gichimu C , Keipkerich BS , Clement N , Omondi M , Mayer O , Ou CY , Nkengasong JN . J Virol Methods 2009 163 (2) 295-300 HIV testing has rapidly expanded worldwide, but proficiency testing (PT) programs to monitor and improve the quality of testing are often lacking in resource-limited settings (RLS). Traditional PT programs and quality control reagents use serum/plasma specimens requiring stringent conditions for storage and transportation. A novel, simple and easy to use approach, based on dried tube specimens (DTS), was developed that can help monitor the quality of HIV antibody testing in RLS. DTS were prepared by drying 20mul of specimen overnight at room temperature. The addition of a green dye (0.1%) made the DTS pellets visible without affecting the test results. Before testing, the DTS were rehydrated with 200mul of PBS/Tween buffer. A panel of 303 DTS samples (135 HIV positive and 168 negative) was evaluated with two rapid tests. Sensitivity and specificity with the Determine HIV-1/2 test were 99.3% and 99.4%, respectively, and with OraQuick were 98.5% and 100%, respectively. Stability studies showed that HIV-specific antibodies in the DTS specimens were stable at 4 degrees and 25 degrees for 4 weeks, with only marginal decline at 37 degrees and 45 degrees C over 4 weeks. The DTS-based PT program was piloted successfully in 24 testing sites in Kenya. Results demonstrate that the DTS is a simple to use, practical method to prepare and distribute PT panels and quality control specimens to monitor HIV testing practices in RLS. |
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