Evidence of zoonotic MERS-COV infection among a high-risk population in Morocco

ABSTRACT

Objectives: There have been recurrent spillovers from dromedaries into the human population since the emergence of Middle East respiratory syndrome coronavirus (MERS-CoV). All known zoonotic MERS disease had hitherto occurred in the Arabian Peninsula, with none reported in Africa. This study assesses zoonotic MERS-CoV infection in high-risk groups in Morocco. Method(s) The study adapted a World Health Organization (WHO) MERS-CoV protocol to assess the seroprevalence of MERS-CoV and the risk factors of infection among high-risk populations in three study sites in the south of Morocco with high-densities of dromedaries. Demographic and camel exposure data was obtained using a questionnaire for three set study groups - members of the general population, slaughterhouse workers, and camel herders. Human sera samples were tested for MERS-CoV IgG antibodies through ELISA, pseudoparticule neutralisation, and plaque reduction neutralisation assay. Result(s) Blood samples from 479 participants enrolled in the study were collected between November 2017 and January 2018. The results produced the first evidence in Africa of human primary cases of MERS-CoV infection with documented direct exposure to dromedaries. Three out of 137 slaughterhouse workers and one of 186 from the general population group showed the neutralizing MERS-CoV antibody. Conclusion(s) This is the first time MERS-CoV transmission risk factors have been examined in Morocco through a seroprevalence study among high-risk populations. It provided evidence of zoonotic transmission, underlining the need for exhaustive investigations of human ARI in likely areas for evidence of MERS circulation.