Nidovirales

Coronaviridae is a family of enveloped, positive-strand RNA viruses which infect fish, amphibians, birds, and mammals. The group includes the subfamilies Letovirinae, Orthocoronavirinae, and Pitovirinae. The members of the subfamily Orthocoronavirinae are known as coronaviruses.

Nidovirales is an order of enveloped, positive-strand RNA viruses which infect vertebrates and invertebrates. Host organisms include mammals, birds, reptiles, amphibians, fish, arthropods, molluscs, and helminths. The order includes the families Coronaviridae, Arteriviridae, Roniviridae, Tobaniviridae, and Mesoniviridae.

Arteriviridae is a family of enveloped, positive-strand RNA viruses in the order Nidovirales which infect vertebrates. Host organisms include equids, pigs, Possums, nonhuman primates, and rodents. The family includes, for example, equine arteritis virus in horses which causes mild-to-severe respiratory disease and reproductive failure, porcine reproductive and respiratory syndrome virus type 1 and type 2 in pigs which causes a similar disease, simian hemorrhagic fever virus which causes a highly lethal fever, lactate dehydrogenase–elevating virus which affects mice, and wobbly possum disease v