#Serological #evidence of #Flavivirus #circulation in #human populations in Northern #Kenya: an assessment of disease risk 2016-2017 (Virol J., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Virol J. 2019 May 17;16(1):65. doi: 10.1186/s12985-019-1176-y.

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

Chepkorir E1,2, Tchouassi DP3, Konongoi SL4, Lutomiah J4, Tigoi C3, Irura Z5, Eyase F6, Venter M7, Sang R3.

Author information: 1 International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya. echepkorir@icipe.org. 2 Center for Viral Zoonoses, Department of Medical Virology, University of Pretoria, P. O. Box 323, Arcadia, 0007, South Africa. echepkorir@icipe.org. 3 International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya. 4 Center for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya. 5 Division of Disease Surveillance and Response, Ministry of Health, P. O. Box 20781-00202, Nairobi, Kenya. 6 Jomo Kenyatta University of Agriculture and Technology, P.O. Box 606, Village Market, Nairobi, Kenya. 7 Center for Viral Zoonoses, Department of Medical Virology, University of Pretoria, P. O. Box 323, Arcadia, 0007, South Africa.

 

Abstract

BACKGROUND:

Yellow 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.

METHODOLOGY:

Human 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.

RESULTS:

Of 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%; χ2 P < 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).

CONCLUSION:

Evidence 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.

KEYWORDS: Dengue virus; Flaviviruses risk assessment; Northern Kenya; Plaque reduction neutralization test; Seroprevalence; West Nile virus; Yellow fever virus; Zika virus

PMID: 31101058 DOI: 10.1186/s12985-019-1176-y

Keywords: Flavivirus; WNV; Zika Virus; Dengue Fever; Yellow Fever; Serology; Seroprevalence; Kenya.

——

Published by

Giuseppe Michieli

I am an Italian blogger, active since 2005 with main focus on emerging infectious diseases such as avian influenza, SARS, antibiotics resistance, and many other global Health issues. Other fields of interest are: climate change, global warming, geological and biological sciences. My activity consists mainly in collection and analysis of news, public services updates, confronting sources and making decision about what are the 'signals' of an impending crisis (an outbreak, for example). When a signal is detected, I follow traces during the entire course of an event. I started in 2005 my blog ''A TIME'S MEMORY'', now with more than 40,000 posts and 3 millions of web interactions. Subsequently I added an Italian Language blog, then discontinued because of very low traffic and interest. I contributed for seven years to a public forum (FluTrackers.com) in the midst of the Ebola epidemic in West Africa in 2014, I left the site to continue alone my data tracking job.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s