Sero-epidemiology of Peste des petits ruminants virus infection in Turkana County, Kenya

Abstract

BackgroundPeste des petits ruminants (PPR) is a contagious viral disease of small ruminants. Serum samples from sheep (n = 431) and goats (n = 538) of all ages were collected in a cross-sectional study in Turkana County, Kenya. The objective was to estimate the sero-prevalence of PPR virus (PPRV) infection and associated risk factors in both species.PPRV competitive enzyme-linked immuno-sorbent assay (c-ELISA) analysed the presence of antibodies in the samples. All analyses were conducted for each species separately. Multivariable logistic regression models were fitted to the data to assess the relationship between the risk factors and PPRV sero-positivity. Mixed-effect models using an administrative sub-location as a random effect were also fitted to adjust for possible clustering of PPRV sero-positivity. Intra-cluster correlation coefficients (ρ) that described the degree of similarity among sero-positive responses for each species in each of the six administrative divisions were estimated.ResultsGoats had a significantly higher sero-prevalence of 40% [95% confidence interval (CI): 36%, 44%] compared to sheep with 32% [95% CI: 27%, 36%] (P = 0.008). Combined sero-prevalence estimates were heterogeneous across administrative divisions (n = 6) (range 22% to 65%) and even more across sub-locations (n = 46) (range 0% to 78%). Assuming that PPRV antibodies are protective of infection, a large pool of PPRV susceptible middle age group (>6 months and < 24 months) in both species was estimated. This was based on the low sero-prevalence in this group in goats (14% [95% CI: 10%, 20%]) and in sheep (18% [95% CI: 13%, 25%]). Regression analysis returned significant risk factors across species: in sheep - vaccination status, age and administrative division; in goats - sex, age, administrative division and sex*age interaction. The intra-sub-location correlation coefficients varied widely across divisions (range <0.001 to 0.42) and across species within divisions.ConclusionsBiological, spatial and socio-ecological factors are hypothesized as possible explanations for variation in PPRV sero-positivity in the Turkana pastoral ecosystem.

Spatial Multicriteria Evaluation for Mapping the Risk of Occurrence of Peste des Petits Ruminants in Eastern Africa and the Union of the Comoros

“…In Kenya, the Turkana region located in the north-western part of the country is identified as high risk: in 2011 in this area, PPRV Lineage III was detected from tissue samples collected from goats suspected of having died of PPR (45). The results of a seroprevalence study showed that 40% of the sheep (n = 431) and 32% of the goats (n = 538) sampled were seropositive (46). In 2016, PPR occurrence was confirmed in both camels and goats in the second main area identified at risk by our model, i.e., the north-eastern part of the country including Mandera, Wajir, Isiolo, and Marsabit districts (22).…”

A One Health framework for integrated service delivery in Turkana County, Kenya

“…Infectious diseases pose a serious threat to these livestock. For example, the 2007 PPR outbreak caused an estimated 19.1 million USD in losses in Turkana and spread out to other ASALs in Kenya (FAO 2009;Kihu et al 2015a). In 2015, the PPR seroprevalence in Turkana was estimated at 40% and 32% in goats and sheep, respectively (Kihu et al 2015b).…”

Molecular Detection of Peste des Petits Ruminants virus from Different Sample Materials of Sheep, Northeastern Turkey

“…Diagnosis of PPR infection is based on four fundamental principles, namely virus isolation, antigen detection, nucleic acid detection and antibody identification from serum with sequencing. The ELISA test is widely used in field studies (Balamurugan et al, 2012;Kihu et al, 2015). Virus isolation and neutralization tests in cell cultures are time-consuming, costly and not very productive.…”