Browsing by Author "Akoko, James"

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    Ecological and Subject‐Level Drivers of Interepidemic Rift Valley Fever Virus Exposure in Humans and Livestock in Northern Kenya
    (UoEm, 2023) Mathew, Muturi; Athman, Mwatondo; Nijhof, Ard M; Akoko, James; Nyamota, Richard; Makori, Anita; Mutono, Nyamai; Nthiwa, Daniel; Wambua, Lilian; Roesel, Kristina; Thumbi, S. M.; Bett, Bernard
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    Incidence of Brucella infection in various livestock species raised under the pastoral production system in Isiolo County, Kenya
    (BMC, 2021-10) Njeru, Josiah; Nthiwa, Daniel, M.; Akoko, James; Oyas, Harry; Bett, Bernard
    Background: We implemented a longitudinal study to determine the incidence of Brucella infection in cattle, camels, sheep and goats that were being raised in a pastoral area in Isiolo County, Kenya. An initial cross-sectional survey was implemented to identify unexposed animals for follow up; that survey used 141 camels, 216 cattle, 208 sheep and 161 goats. Sera from these animals were screened for Brucella spp. using the Rose Bengal Plate test (RBPT), a modiied RBPT, and an indirect multispecies Enzyme Linked Immunosorbent Assay (iELISA). Results of RBPT and iELISA were interpreted in parallel to determine seroprevalence. A total of 30 camels, 31 cattle, 22 sheep and 32 goats that were seronegative by all the above tests were recruited in a subsequent longitudinal study for follow up. These animals were followed for 12 months and tested for anti-Brucella antibodies using iELISA. Seroconversion among these animals was deined by a positive iELISA test following a negative iELISA result in the previous sampling period. All seropositive samples were further tested using real-time PCR-based assays to identify Brucella species. These analyses targeted the alkB and BMEI1162 genes for B. abortus, and B. melitensis, respectively. Data from the longitudinal study were analysed using Cox proportional hazards model that accounted for within-herds clustering of Brucella infections. Results: The overall incidence rate of Brucella infection was 0.024 (95% conidence interval [CI]: 0.014–0.037) cases per animal-months at risk. Brucella infection incidence in camels, cattle, goats and sheep were 0.053 (0.022–0.104), 0.028 (0.010–0.061), 0.013 (0.003–0.036) and 0.006 (0.0002–0.034) cases per animal-month at risk, respectively. The incidence rate of Brucella infection among females and males were 0.020 (0.009–0.036) and 0.016 (0.004–0.091), respectively. Real-time PCR analyses showed that B. abortus was more prevalent than B. melitensis in the area. Results of multivariable Cox regression analysis identiied species (camels and cattle) as an important predictor of Brucella spp. exposure in animals. Conclusions: This study estimated an overall brucellosis incidence of 0.024 cases per animal-months at risk with camels and cattle having higher incidence than sheep and goats. These results will inform surveillance studies in the area.
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    Seroprevalence and related risk factors of Brucella spp. in livestock and humans in Garbatula subcounty, Isiolo county, Kenya
    (Uoem, 2023-10-16) Mwatondo, Athman; Nthiwa, Daniel; Muturi, Mathew; Akoko, James; Nyamota, Richard; Bett, Bernard; Omolo, Jack; Gichuhi, Stephen; Mureit, Marianne W.
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    Seroprevalence of Brucella spp. and Rift Valley fever virus among slaughterhouse workers in Isiolo County, northern Kenya
    (UoEm, 2023-10-05) Nyamota, Richard; Maina, Josphat; Mwatondo, Athman; Akoko, James; Nthiwa, Daniel; Bartlow, Andrew W.; Muturi, Mathew; Wambua, Lillian; Middlebrook, Earl A.; Bett, Bernard
    Brucella spp. and Rift Valley fever virus (RVFV) are classified as priority zoonotic agents in Kenya, based on their public health and socioeconomic impact on the country. Data on the pathogen-specific and co-exposure levels is scarce due to limited active surveillance. This study investigated seroprevalence and co-exposure of Brucella spp. and RVFV and associated risk factors among slaughterhouse workers in Isiolo County, northern Kenya. A crosssectional serosurvey was done in all 19 slaughterhouses in Isiolo County, enrolling 378 participants into the study. The overall seroprevalences for Brucella spp. and RVFV were 40.2% (95% CI: 35.2–45.4) and 18.3% (95% CI: 14.5–22.5), respectively while 10.3% (95% CI 7.4%-13.8%) of individuals were positive for antibodies against both Brucella spp. and RVFV. Virus neutralisation tests (VNT) confirmed anti-RVFV antibodies in 85% of ELISApositive samples. Our seroprevalence results were comparable to community-level seroprevalences previously reported in the area. Since most of the study participants were not from livestock-keeping households, our findings attribute most of the detected infections to occupational exposure. The high exposure levels indicate slaughterhouse workers are the most at-risk population and there is need for infection, prevention, and control programs among this high-risk group. This is the first VNT confirmation of virus-neutralising antibodies among slaughterhouse workers in Isiolo County and corroborates reports of the area being a high-risk RVFV area as occasioned by previously reported outbreaks. This necessitates sensitization campaigns to enhance awareness of the risks involved and appropriate mitigation measures.