High MERS-CoV seropositivity associated with camel herd profile, husbandry practices and household socio-demographic characteristics in Northern Kenya

Abstract

Despite high exposure to Middle East respiratory syndrome coronavirus (MERS-CoV), the predictors for seropositivity in the context of husbandry practices for camels in Eastern Africa are not well understood. We conducted a cross-sectional survey to describe the camel herd profile and determine the factors associated with MERS-CoV seropositivity in Northern Kenya. We enrolled 29 camel-owning households and administered questionnaires to collect herd and household data. Serum samples collected from 493 randomly selected camels were tested for anti-MERS-CoV antibodies using a microneutralisation assay, and regression analysis used to correlate herd and household characteristics with camel seropositivity. Households reared camels (median = 23 camels and IQR 16-56), and at least one other livestock species in two distinct herds; a home herd kept near homesteads, and a range/fora herd that resided far from the homestead. The overall MERS-CoV IgG seropositivity was 76.3%, with no statistically significant difference between home and fora herds. Significant predictors for seropositivity (P ⩽ 0.05) included camels 6-10 years old (aOR 2.3, 95% CI 1.0-5.2), herds with ⩾25 camels (aOR 2.0, 95% CI 1.2-3.4) and camels from Gabra community (aOR 2.3, 95% CI 1.2-4.2). These results suggest high levels of virus transmission among camels, with potential for human infection.

Keywords: Kenya; Middle East respiratory syndrome coronavirus; nomadic communities; seroprevalence; zoonoses.

Fig. 1.

Location of the study area in Marsabit County with the spatial distribution of sampled herds (red dots) within Saku sub-county. This map was drawn on QGIS Version 2.18.15 using mapping resources from the International Livestock Research Institute (ILRI) [29].

Fig. 2.

Distribution of MERS-CoV seropositivity in camels by age categories, 2018. Dataset includes serum samples from 493 randomly selected camels from among 29 herds in Marsabit Central, Kenya. Samples were tested for anti-MERS-CoV antibodies using a microneutralisation assay and the % seropositivity (blue line) and the number of camels tested (orange bars) were plotted against camel age categories as shown in the chart.