Longitudinal study of Middle East Respiratory Syndrome coronavirus infection in dromedary camel herds in Saudi Arabia, 2014–2015

Abstract

Two herds of dromedary camels were longitudinally sampled with nasal and rectal swabs and serum, between September 2014 and May 2015, and the samples were tested for Middle East Respiratory Syndrome (MERS) coronavirus RNA and antibodies. Evidence of MERS-CoV infection was confirmed in one herd on the basis of detection of virus RNA in nasal swabs from three camels and significant increases in the antibody titers from three others. The three viruses were genetically identical, thus indicating introduction of a single virus into this herd. There was evidence of reinfection of camels that were previously seropositive, thus suggesting that prior infection does not provide complete immunity from reinfection, a finding that is relevant to camel vaccination strategies as a means to prevent zoonotic transmission.

A systematic review of MERS-CoV seroprevalence and RNA prevalence in dromedary camels: Implications for animal vaccination

“…We found 10 longitudinal studies describing 9 incidences of natural infection on farms and in quarantine facilities -1 in Egypt (Ali et al, 2017b), 4 in KSA (Azhar et al, 2014;Hemida et al, 2014a;Memish et al, 2014;Hemida et al, 2017a), 5 in UAE (Al Hammadi et al, 2015;Wernery et al, 2015a;Meyer et al, 2016;Muhairi et al, 2016;Yusof et al, 2017) and 1 study taking monthly samples of 430 dromedaries in Kenya (Kiambi et al, 2018).…”

“…Three studies have found dromedaries to be shedding MERS-CoV RNA despite having high antibody titres months or weeks prior to detectable infection. Both older animals whose antibodies reflect past exposure (Meyer et al, 2016;Ali et al, 2017b;Hemida et al, 2017a), and young calves whose high antibody titres were maternally-acquired immediately post-partum, became infected (Meyer et al, 2016).…”

MERS coronavirus outbreak: Implications for emerging viral infections

“…Recent studies, including those based on serological evidence, support the role of dromedary camels as important zoonotic sources of human MERS-CoV infection. MERS-CoV antibodies are present in more than 90% of dromedary camels tested in the Middle East and in many African countries (Ali et al, 2017a;Chu et al, 2015;Farag et al, 2015;Hemida et al, 2013Hemida et al, , 2014Hemida et al, , 2017aMüller et al, 2015;Reusken et al, 2014). Dromedary camel exposure within 2 weeks of illness onset has been identified as a significant risk factor in a study examining MERS-CoV infection cases documented between May and November 2014 in KSA (Alraddadi et al, 2016a).…”

“…Thus, in KSA the emergence of MERS-CoV has had an impact on the agricultural, animal husbandry, food production and veterinary fields, as well as infection and prevention control procedures in healthcare settings (Hemida et al, 2017b). For example, the association between the calving season and MERS-CoV infection in dromedary camels and the highest risk of MERS-CoV infection in calves compared to adult cows, has led to suggestions that weaning of calves could be delayed to reduce the opportunity for human exposure to calves (Hemida et al, 2014(Hemida et al, , 2017a. Furthermore, there is a need to increase understanding of the implications in terms of MERS-CoV transmission and spread, as well as viral exchange, amplification and dissemination, of the economically important bidirectional movement of camels between African countries and the Middle East, including KSA (Hemida et al, 2017b).…”

An opportunistic Pathogen Afforded Ample Opportunities: Middle East Respiratory Syndrome Coronavirus

“…In each animal, antibodies to MERS-CoV are short-lived and do not prevent reinfection. [50,72,73] Human contact with camels is often associated with the collection, preparation and ingestion of camel milk or meat. Female camels, especially those bred for milking, have the highest rates of MERS-CoV seropositivity.…”