Low Prevalence of Middle East Respiratory Syndrome Coronavirus Infection in Camel-Exposed Patients Presenting with Respiratory Symptoms in Northern Kenya.

Abstract

Middle East respiratory syndrome coronavirus (MERS-CoV) is a zoonotic virus that causes acute respiratory disease after transmission via close contact with camels. In contrast to the incidence of MERS-CoV human infections in the Middle East, MERS-CoV infections in the Horn of Africa have been rarely reported despite the high number of camels and common camel-human interactions in the area. Whether passive cross-sectional sampling misses active human cases is a significant gap in our understanding of MERS-CoV epidemiology and its impact in the Horn of Africa. To address this gap, we conducted a prospective cross-sectional study at Laisamis Catholic Hospital in northern Kenya's camel pastoralist community. A total of 942 patients with acute respiratory symptoms were enrolled over 18 months (August 2022-February 2024); 54% of these individuals reported frequent contact with camels and consumption of camel products. Testing via reverse transcriptase - polymerase chain reaction (RT-PCR) revealed that all patients (N = 942) had negative results for MERS-CoV RNA on either nasopharyngeal or oropharyngeal swabs at the time of presentation. Because polymerase chain reaction testing may only detect active cases with higher levels of viral shedding, serology was also performed on a randomly selected subset of 297 individuals from the total sample pool to detect IgG antibodies. Only eight individuals (2.7%) exhibited positive results by serology; accounting for the test specificity of 99.8%, the 95% CI for true MERS-CoV seropositivity was 0.72-4.27%. Despite frequent camel interactions, MERS-CoV seroprevalence was low, suggesting limited zoonotic transmission in this setting and highlighting the need for more comprehensive diagnostics to identify prevalent causes of acute respiratory illness in pastoralist communities.