Risk factors for serological evidence of MERS-CoV in camels, Kenya, 2016–2017

Abstract

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is an emerging viral disease and dromedary camels are known to be the source of human spill over events. A cross-sectional epidemiological surveillance study was carried out in Kenya in 2017 to, 1) estimate MERS-CoV antibody seropositivity in the camel-dense counties of Turkana, Marsabit, Isiolo, Laikipia and Nakuru to identify, and 2) determine the risk factors associated with seropositivity in camels. Blood samples were collected from a total of 1421 camels selected using a multi-stage sampling method. Data were also collected from camel owners or herders using a pre-tested structured questionnaire. The sera from camel samples were tested for the presence circulating antibodies to MERS-CoV using the anti-MERS-CoV IgG ELISA test. Univariate and multivariable statistical analysis were used to investigate factors potentially associated with MERS-CoV seropositivity in camels. The overall seropositivity in camel sera was 62.9 %, with the highest seropositivity recorded in Isiolo County (77.7 %), and the lowest seropositivity was recorded in Nakuru County (14.0 %). When risk factors for seropositivity were assessed, the “ Type of camel production system ” {(aOR = 5.40(95 %CI: 1.67–17.49)}, “ Age between 1–2 years, 2–3 years and above 3 years ” {(aOR = 1.64 (95 %CI: 1.04–2.59}”, {(aOR = 3.27 (95 %CI: 3.66–5.61)}” and {(aOR = 6.12 (95 %CI: 4.04–9.30)} respectively and “ Sex of camels ” {(aOR = 1.75 (95 %CI: 1.27–2.41)} were identified as significant predictors of MERS-CoV seropositivity. Our studies indicate a high level of seropositivity to MERS-CoV in camels in the counties surveyed, and highlights the important risk factors associated with MERS-CoV seropositivity in camels. Given that MERS-CoV is a zoonosis, and Kenya possesses the fourth largest camel population in Africa, these findings are important to inform the development of efficient and risk-based prevention and mitigation strategies against MERS-CoV transmission to humans.

Spatial examination of social and environmental drivers of Middle East respiratory syndrome coronavirus (MERS-CoV) across Kenya

“…= 414) had a 51% positivity, and the upper Eastern region (n = 1964, pos. = 1510) had a 77% positivity (Gardner et al, 2019;Ommeh et al, 2018;Sitawa et al, 2020). Spatial correlation of MERS-CoV extended a distance of roughly 400 km across the upper Rift Valley and Eastern regions between 2016 and 2018.…”

“…Given that much of the socio-demographic data were from after 2010 and that the MERS-CoV data in the upper Northeastern region were only from 2008, we focused the spatial correlation analysis of MERS-CoV on 2016 through 2018 in the upper Rift Valley and upper Eastern Regions. The 2016-2018 MERS-CoV data were reported without (Corman et al, 2014;Gardner et al, 2019;Ommeh et al, 2018;Sitawa et al, 2020) specifying the date or year that each observation was collected and we therefore spatially analyzed the data as representing a single unit of time (i.e., 3-year time period). Further, we distributed the data evenly between the northern and southern parts of each county to satisfy the practical rule that a variogram should only be applied over a specified distance for which the number of pairs is greater than 30, and because the data were not further spatially identified (Journel and Huijbregts, 1978).…”

The intersection of land use and human behavior as risk factors for zoonotic pathogen exposure in Laikipia County, Kenya

“…Though MERS is only endemic in the Middle East and an outbreak has never been detected in Kenya, MERS has been declared a priority pathogen by the World Health Organization with acknowledgement of seropositivity in camels throughout Kenya [ 43 , 44 ]. A recent study by Sitwa et al found a 69% seropositivity rate among camels in Kenyan pastoral systems, indicating potential transmission risk for people in contact with camels [ 45 ]. Shifting trends in herd composition, stemming from climate and herder preference, suggests new possible risk factors [ 19 ].…”