Serological evidence of Flavivirus circulation in human populations in Northern Kenya: an assessment of disease risk 2016–2017

Virology Journal

F. Eyase¹  J. Lutomiah²  S. L. Konongoi²  M. Venter³  C. Tigoi⁴  R. Sang⁴  D. P. Tchouassi⁴  E. Chepkorir⁵  Z. Irura⁶ 

[1] 0000 0000 9146 7108, grid.411943.a, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 606, Village Market, Nairobi, Kenya;0000 0001 0155 5938, grid.33058.3d, Center for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya;0000 0001 2107 2298, grid.49697.35, Center for Viral Zoonoses, Department of Medical Virology, University of Pretoria, P. O. Box 323, 0007, Arcadia, South Africa;0000 0004 1794 5158, grid.419326.b, International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya;0000 0004 1794 5158, grid.419326.b, International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya;0000 0001 2107 2298, grid.49697.35, Center for Viral Zoonoses, Department of Medical Virology, University of Pretoria, P. O. Box 323, 0007, Arcadia, South Africa;grid.415727.2, Division of Disease Surveillance and Response, Ministry of Health, P. O. Box 20781-00202, Nairobi, Kenya;

关键词: Dengue virus;    Yellow fever virus;    West Nile virus;    Zika virus;    Seroprevalence;    Plaque reduction neutralization test;    Flaviviruses;    Northern Kenya;   

DOI  :  10.1186/s12985-019-1176-y

来源: publisher

【 摘 要 】

BackgroundYellow fever, Dengue, West Nile and Zika viruses are re-emerging mosquito-borne Flaviviruses of public health concern. However, the extent of human exposure to these viruses and associated disease burden in Kenya and Africa at large remains unknown. We assessed the seroprevalence of Yellow fever and other Flaviviruses in human populations in West Pokot and Turkana Counties of Kenya. These areas border Uganda, South Sudan and Ethiopia where recent outbreaks of Yellow fever and Dengue have been reported, with possibility of spillover to Kenya.MethodologyHuman serum samples collected through a cross-sectional survey in West Pokot and Turkana Counties were screened for neutralizing antibodies to Yellow fever, Dengue-2, West Nile and Zika virus using the Plaque Reduction Neutralization Test (PRNT). Seroprevalence was compared by county, site and important human demographic characteristics. Adjusted odds ratios (aOR) were estimated using Firth logistic regression model.ResultsOf 877 samples tested, 127 neutralized with at least one of the four flaviviruses (14.5, 95% CI 12.3–17.0%), with a higher proportion in Turkana (21.1%, n = 87/413) than in West Pokot (8.6%, n = 40/464). Zika virus seroprevalence was significantly higher in West Pokot (7.11%) than in Turkana County (0.24%; χ2P < 0.0001). A significantly higher Yellow fever virus seroprevalence was also observed in Turkana (10.7%) compared to West Pokot (1.29%; χ2 P < 0.0001). A high prevalence of West Nile virus was detected in Turkana County only (10.2%) while Dengue was only detected in one sample, from West Pokot. The odds of infection with West Nile virus was significantly higher in males than in females (aOR = 2.55, 95% CI 1.22–5.34). Similarly, the risk of Zika virus infection in West Pokot was twice higher in males than females (aOR = 2.01, 95% CI 0.91–4.41).ConclusionEvidence of neutralizing antibodies to West Nile and Zika viruses indicates that they have been circulating undetected in human populations in these areas. While the observed Yellow Fever prevalence in Turkana and West Pokot Counties may imply virus activity, we speculate that this could also be as a result of vaccination following the Yellow Fever outbreak in the Omo river valley, South Sudan and Uganda across the border.

【 授权许可】

CC BY