Lack of serological evidence of Middle East respiratory syndrome coronavirus infection in virus exposed camel abattoir workers in Nigeria, 2016

Middle East respiratory syndrome coronavirus (MERS-CoV) is an ongoing threat to global public health [1]. Serological and virological studies have shown evidence of MERS-CoV infection in camels in the Middle East, as well as in East, North and West Africa [2-5] and in Central Asia [6]. In spite of MERS-CoV being enzootic in camels in Africa, zoonotic MERS has not been reported from the African continent. Our recent genetic and phenotypic analysis of MERS-CoV from camels in West (Burkina Faso, Nigeria) Africa has shown that West African viruses were phylogenetically and phenotypically distinct from those associated with human disease in the Arabian Peninsula [7], raising the possibility that virus strain differences may be associated with differences in zoonotic potential. Abattoir workers with exposure to infected camels are a high-risk group for MERS-CoV infection in the Arabian Peninsula [8]. However, there is a paucity of serological data on MERS-CoV infection in people occupationally exposed to camels in Africa, a knowledge gap identified as a priority research question at a Food and Agriculture Organization of the United Nations-World Organisation for Animal Health-World Health Organization (FAO-OIE-WHO) Global Technical Meeting on MERS in September 2017 [1]. A previous study in Egypt in 2013 showed no serologic evidence of MERS-CoV among 179 serum samples from humans working in two camel abattoirs [3]. None of 760 people with household exposure to seropositive camels in Kenya in 2013 had evidence of MERS-CoV antibody [9]. Another study in Kenya in 2013–14 of 1,122 people (not with necessarily high exposure to camels) found two sera with low and inconclusive levels of neutralising antibody to MERS-CoV [10]. It remains important to carry out more sero-epidemiological studies on humans with occupational exposure to infected camels to understand whether or not zoonotic transmission is taking place in Africa. We therefore investigated for serological evidence of MERS-CoV infection of humans occupationally exposed to infected dromedary camels in an abattoir in Kano, Nigeria.