Cross-sectional prevalence study of MERS-CoV in local and imported dromedary camels in Saudi Arabia, 2016-2018

Tolah, A.; Masaudi, S. A.; El-Kafrawy, S.; Mirza, A.; Harakeh, S.; Hassan, A.; Alzahrani, A.; Alsaaidi, G.; Alagaili, A.; Hashem, A.; Azhar, E.

The Middle East Respiratory Syndrome-Coronavirus (MERS-CoV) is an endemic virus in Middle Eastern and African dromedaries Annually, Saudi Arabia imports thousands of camels from the Horn of Africa, yet the epidemiology of the virus in these animals is largely unknown Here, MERS-CoV prevalence was compared in imported African camels and their local counterparts A total of 1399 paired sera and nasal swabs were collected between 2016 and 2018 from camels from Sudan (n = 829), Djibouti (n = 328) and Jeddah (n = 242) Imported animals were sampled on incoming ships at Jeddah Islamic seaport before unloading Samples were screened for neutralizing antibodies (nAbs) and MERS-CoV viral RNA by RT-PCR The overall seroprevalence was 92 7% and RNA detection rate was 17 2 % Imported camels had higher seroprevalence compared to resident herds (93 8% vs 87 6%, p 87 % of the RNA positive animals, increased with age and was sex-dependent Importantly, reduced viral RNA load was positively correlated with nAb titers Our data confirm MERS-CoV widespread in imported and domestic camels in Saudi Arabia and highlight the need for continuous active surveillance and better prevention measures Further studies are also warranted to understand the correlates of protection in camels for proper vaccine development