Risk factors for MERS coronavirus infection in dromedary camels in Burkina Faso, Ethiopia, and Morocco, 2015

Abstract

Understanding Middle East respiratory syndrome coronavirus (MERS-CoV) transmission in dromedary camels is important, as they consitute a source of zoonotic infection to humans. To identify risk factors for MERS-CoV infection in camels bred in diverse conditions in Burkina Faso, Ethiopia and Morocco, blood samples and nasal swabs were sampled in February–March 2015. A relatively high MERS-CoV RNA rate was detected in Ethiopia (up to 15.7%; 95% confidence interval (CI): 8.2–28.0), followed by Burkina Faso (up to 12.2%; 95% CI: 7–20.4) and Morocco (up to 7.6%; 95% CI: 1.9–26.1). The RNA detection rate was higher in camels bred for milk or meat than in camels for transport (p = 0.01) as well as in younger camels (p = 0.06). High seropositivity rates (up to 100%; 95% CI: 100–100 and 99.4%; 95% CI: 95.4–99.9) were found in Morocco and Ethiopia, followed by Burkina Faso (up to 84.6%; 95% CI: 77.2–89.9). Seropositivity rates were higher in large/medium herds (≥51 camels) than small herds (p = 0.061), in camels raised for meat or milk than for transport (p = 0.01), and in nomadic or sedentary herds than in herds with a mix of these lifestyles (p < 0.005).

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

“…Large and medium herd-size was a significant risk factor for seropositivity across Burkina Faso, Morocco and Ethiopia, as well as nomadic and sedentary husbandry systems as opposed to a mixed lifestyle (Miguel et al, 2017). Conversely, in Kenya there was a non-statistically significant trend for smaller herds to have higher seroprevalence (Deem et al, 2015).…”

“…A. Dighe, et al Epidemics 29 (2019) 100350 Increase with age p = 0.032 (Miguel et al, 2017) Egypt < 2yrs 52% (n = 81) ≥2yrs 87% (n = 950)…”

“…In a study conducted across Burkina Faso, Morocco and Ethiopia, dromedaries used for milk and meat had higher seroprevalence than those used for transport (Miguel et al, 2017). In most of the studies that stratified by sex, little difference was seen, but in Kenya females had statistically significantly higher seroprevalence than males (93% vs. 81% in one study (Munyua et al, 2017), and 74% vs. 54% in another (Ommeh et al 2018)) whereas males had significantly higher seroprevalence in Egypt and in KSA (72% and 84% in males vs. 66% in females) (Ali et al, 2017b;Kasem et al, 2018b).…”

“…Our search found that dromedary populations in 16 countries have been tested for MERS-CoV RNA, 13 of which report positive results indicating active infection. These include KSA (0.12-56%) (Alagaili et al, 2014;Khalafalla et al, 2015;Sabir et al, 2016;Alfuwaires et al, 2017;Kasem et al, 2018a, b), UAE (0-29% (Wernery et al, 2015a, b;Yusof et al, 2015;Li et al, 2017;Yusof et al, 2017) or 0-100% if dromedaries epidemiologically linked to human MERS-CoV cases are included(Al Hammadi et al, 2015;Muhairi et al, 2016;Paden et al, 2018)), Qatar (22-79%) Reusken et al, 2014a;Farag et al, 2015;Mohran et al, 2016), Oman (7%) (Nowotny and Kolodziejek, 2014), Iraq (15%) (Al Salihi and Alrodhan, 2017), and Jordan (62%) (van Doremalen et al, 2017), as well as Egypt (4-15%) , Ali et al, 2017a, Ethiopia (10%) (Miguel et al, 2017), Kenya (0.35-0.95%) (Kiambi et al, 2018;Ommeh et al, 2018), Nigeria (3-11%) So et al, 2018), Burkina Faso (5%) (Miguel et al, 2017), Morocco (2%) (Miguel et al, 2017), and Pakistan (3%) . See Fig.…”

Focus on Middle East respiratory syndrome coronavirus (MERS-CoV)

“…The investigation of dromedary camel serum collections, some of which collected as early as 1983, demonstrated that the virus was already widespread (seropositivity rate > 80%) in the East African countries (Somalia, Sudan and Egypt). These countries export dromedary camels to Arabian countries, but also in Kenya, Nigeria, Tunisia, Ethiopia, Burkina Faso and Morocco [12][13][14]. Phylogenetic analysis revealed 5 distinct coronavirus lineages in dromedary camels, including one recombinant lineage that led to the MERS-CoV epidemic in humans [15].…”