Coxiella burnetii in Dromedary Camels (Camelus dromedarius): A Possible Threat for Humans and Livestock in North Africa and the Near and Middle East?

Abstract

The "One Health" concept recognizes that human health is connected to animal health and to the ecosystems. Coxiella burnetii-induced human Q fever is one of the most widespread neglected zoonosis. The main animal reservoirs responsible for C. burnetii transmission to humans are domesticated ruminants, primarily goats, sheep, and cattle. Although studies are still too sparse to draw definitive conclusions, the most recent C. burnetii serosurvey studies conducted in herds and farms in Africa, North Africa, Arabian Peninsula, and Asia highlighted that seroprevalence was strikingly higher in dromedary camels (Camelus dromedarius) than in other ruminants. The C. burnetii seroprevalence in camel herds can reach more than 60% in Egypt, Saudi Arabia, and Sudan, and 70 to 80% in Algeria and Chad, respectively. The highest seroprevalence was in female camels with a previous history of abortion. Moreover, C. burnetii infection was reported in ticks of the Hyalomma dromedarii and Hyalomma impeltatum species collected on camels. Even if dromedary camels represent <3% of the domesticated ruminants in the countries of the Mediterranean basin Southern coast, these animals play a major socioeconomic role for millions of people who live in the arid zones of Africa, Middle East, and Asia. In Chad and Somalia, camels account for about 7 and 21% of domesticated ruminants, respectively. To meet the growing consumers demand of camel meat and milk (>5 million tons/year of both raw and pasteurized milk according to the Food and Agriculture Organization) sustained by a rapid increase of population (growth rate: 2.26-3.76 per year in North Africa), dromedary camel breeding tends to increase from the Maghreb to the Arabic countries. Because of possible long-term persistence of C. burnetii in camel hump adipocytes, this pathogen could represent a threat for herds and breeding farms and ultimately for public health. Because this review highlights a hyperendemia of C. burnetii in dromedary camels, a proper screening of herds and breeding farms for C. burnetii is urgently needed in countries where camel breeding is on the rise. Moreover, the risk of C. burnetii transmission from camel to human should be further evaluated.

Emergence of Bat-Related Betacoronaviruses: Hazard and Risks

“…MERS-CoV was detected both in dromedaries and humans throughout the Arabian Peninsula, but not in any other livestock ( Reusken et al, 2013b ). The major dromedary camel producers are Chad, Somalia, Sudan and Kenya, with about 7.3, 7.2, 4.8, and 3.3 million heads, respectively ( Younan et al, 2016 ; Devaux et al, 2020a ). KSA and other Arabian Peninsula countries import numerous camels from these countries ( Younan et al, 2016 ; Devaux et al, 2020a ).…”

“…The major dromedary camel producers are Chad, Somalia, Sudan and Kenya, with about 7.3, 7.2, 4.8, and 3.3 million heads, respectively ( Younan et al, 2016 ; Devaux et al, 2020a ). KSA and other Arabian Peninsula countries import numerous camels from these countries ( Younan et al, 2016 ; Devaux et al, 2020a ). However, a serological survey conducted in Sudan and Qatar showed that no camel care-takers were found infected by MERS-CoV, whereas camels were indeed infected ( Farag et al, 2019 ).…”

“…In East Asia, after the successive outbreaks of SARS and COVID-19, risk factors have been identified and correspond to deforestation, land-use and anthropized environments, wet markets selling wild and live animals, population density, and mobility. The amplification loop of the emergence of MERS in the Arabian Peninsula seems to be different and linked to the camel trade ( Reusken et al, 2014 ; Younan et al, 2016 ; Devaux et al, 2020a ).…”

Serological evidence of single and mixed infections of Rift Valley fever virus, Brucella spp. and Coxiella burnetii in dromedary camels in Kenya

“…Previous studies have identified camels as reservoirs of three of the top priority zoonotic pathogens in Kenya; Brucella spp , Rift Valley fever virus ( RVFv ) and Coxiella burnetii , but data on infection patterns of these pathogens, and potential co-infections in camels is limited [ 2 , 8 , 10 ]. Serological studies, however, show that camels have high seroprevalences and may play an important role in the epidemiology of the three pathogens [ 2 , 11 ]. Camels have been reported to have the highest Brucella and Coxiella burnetii infection rates among Kenyan livestock, with one study reporting more than a two-fold increase in Brucella prevalence in livestock herds with camels versus those with none [ 8 , 12 , 13 ].…”

Ticks and tick-borne pathogens associated with dromedary camels (Camelus dromedarius) in northern Kenya

“…For Q fever, caused by C. burnetii, the association between camel exposure, seroprev-155 alence in camels and human Q fever infections is well documented from Chad (52). Q 156 fever is one of the most widespread neglected zoonosis worldwide with the highest sero-157 prevalence rates recorded in female camels with a history of abortion (75). Coxiella burnetii 158 infection has been found in Hy.…”