Abstract

We implemented a cross-sectional study in Tana River County, Kenya, a Rift Valley fever (RVF)-endemic area, to quantify the strength of association between RVF virus (RVFv) seroprevalences in livestock and humans, and their respective intra-cluster correlation coefficients (ICCs). The study involved 1932 livestock from 152 households and 552 humans from 170 households. Serum samples were collected and screened for anti-RVFv immunoglobulin G (IgG) antibodies using inhibition IgG enzyme-linked immunosorbent assay (ELISA). Data collected were analysed using generalised linear mixed effects models, with herd/household and village being fitted as random variables. The overall RVFv seroprevalences in livestock and humans were 25.41% (95% confidence interval (CI) 23.49-27.42%) and 21.20% (17.86-24.85%), respectively. The presence of at least one seropositive animal in a household was associated with an increased odds of exposure in people of 2.23 (95% CI 1.03-4.84). The ICCs associated with RVF virus seroprevalence in livestock were 0.30 (95% CI 0.19-0.44) and 0.22 (95% CI 0.12-0.38) within and between herds, respectively. These findings suggest that there is a greater variability of RVF virus exposure between than within herds. We discuss ways of using these ICC estimates in observational surveys for RVF in endemic areas and postulate that the design of the sentinel herd surveillance should consider patterns of RVF clustering to enhance its effectiveness as an early warning system for RVF epidemics.

Keywords

Hierarchical modelling; intra-cluster correlation coefficients; Rift Valley fever; risk factors; seroprevalence

Published in

Epidemiology and Infection
2019, Volume: 147, article number: UNSP e67
Publisher: CAMBRIDGE UNIV PRESS

SLU Authors

• Lindahl, Johanna

  • Department of Clinical Sciences, Swedish University of Agricultural Sciences
    
  • International Livestock Research Institute (ILRI)
  • Uppsala University

Sustainable Development Goals

SDG3 Ensure healthy lives and promote well-being for all at all ages


UKÄ Subject classification

Clinical Science


Publication identifier

DOI: https://doi.org/10.1017/S0950268818003242

Permanent link to this page (URI)

https://res.slu.se/id/publ/98203