Searching for animal models and potential target species for emerging pathogens: Experience gained from Middle East respiratory syndrome (MERS) coronavirus

Vergara-Alert, Júlia; Vidal, Enric; Bensaid, Albert; Segalés, Joaquim

Researchers worldwide have identified several animal species which could have a role in the transmission of MERS-CoV to humans (summarized in Fig. 1 ). Bats have been suggested to be the reservoir for MERS-CoV, but RNA of MERS-like CoVs (and no MERS-CoV) has been found in several bat families (Vespertillionidae, Molosidae, Nycteridae and Emballonuridae) in Africa, America, Asia and Europe [37, 38] . Recently, an experimental infection with Jamaican fruit bats (Artibeus jamaicensis) confirmed that MERS-CoV can replicate in bats [39] . However, MERS-CoV strains causing disease in humans have not been so far identified in bats. The presence of MERS-CoV neutralizing antibodies has been reported in dromedary camels (Camelus dromedaries) [40, 41] and, more recently, a link between MERS-CoV infection in camels and a human infection in Qatar has been suggested [42] [43] [44] [45] . Most importantly, the MERS-CoV strain that caused the 2015 human outbreak was found in dromedary camels; in fact, phylogenetic analyses indicate that MERS-CoV was generated in this species by recombination [46] . In addition, Adney and collaborators have provided experimental evidence to support the role of dromedary camels as a MERS-CoV reservoir [47] . Recently, evidence was provided that other members of the Camelidae family such as alpaca (Vicugna pacos) and llama (Lama glama), are also susceptible to MERS-CoV infection [48] [49] [50] . Field studies with alpacas performed in Qatar confirmed this finding [51] . A recently published experimental study has demonstrated that domestic pigs are also susceptible to MERS-CoV infection, suggesting the possibility of MERS-CoV circulation in other unsuspected animal species such suidae [50] . While DPP4 in silico predictions and in vitro studies suggested that other livestock species such as goats, sheep, or horses could be susceptible to MERS-CoV infection, experimental data suggested the opposite [50] . Each natural and potential host for MERS-CoV infection is discussed below in detail and summarized in Tables 1 and 2.