Serpentovirinae

Serpentovirinae, commonly known as serptentoviruses, is a virus subfamily within the family Tobaniviridae which is within the order Nidovirales. The virions of Serpentovirinae have a viral envelope and a positive-sense single-strand RNA genome. They infect vertebrates, mostly Ophidians, but sequencing has identified serpentovirinae infections in other reptiles including turtles, chameleons, and lizards. Although clinical significance varies across the clade, several pathogenic infections by this subfamily have been observed and studied, primarily in snakes with some observations in other groups. This subfamily comprises seven genera and 12 subgenera.

Transmission
Serpentoviruses have exhibited fomite transmission and transmission via the air. One study showed that there is no vertical transmission; the eggs of a mating pair of infected pythons were positive for serpentovirinae RNA, but the hatchlings were RNA negative when tested.

Host susceptibility by phylogenetics
Phylogenetic analysis has shown that the different genera and species of serpentovirinae infect specific groups of snakes, and that some species exclusively infect non-serpent reptiles. However, it is currently understood that pythonidae are the most susceptible to serpentovirus infection generally, with colubridae and boidae exhibiting the highest non-python-hosted species diversity. Additionally, sequencing of viral RNA from infected animals has shown the ability of serpentoviruses to become recombinant during replication.

Symptoms and diagnosis of infection
The symptoms of serpentovirus infections in reptiles are similar to some coronavirus symptoms in mammals (the coronaviridae family also belongs to the order Nidovirales). Symptoms include shortness of breath, difficulty breathing, increased oral mucous secretion, oral mucosal reddening, anorexia, and eventually weight loss. Serpentoviral infections have also been found to cause lesions in the upper respiratory tract, upper gastrointestinal tract, and even the lungs. These lesions are usually inflammed and pneumonic, and can cause greater complications and morbidity when the animal is also infected with bacterial bronchopneumonia.

Reverse transcriptase polymerase chain reaction can be used to detect viral RNA and is the most common form of diagnosis. Oral/nasal swabs are used to obtain samples both pre- and post-mortem. It is also possible to detect virions and viral RNA within the stool of infected pythons due to nematode species being able to bioaccumulate the viruses. However, the nematodes themselves are not infected. Specific treatments and therapeutics have not yet been discovered or perscribed, but research is ongoing to determine best practices and potential therapeutics.

Taxonomy
The subfamily Serpentovirinae contains the following seven identified genera and 12 identified subgenera:


 * Infratovirus
 * Hepoptovirus, Selatovirus, and Xintolivirus
 * Lyctovirus
 * Chalatovirus and Rebatovirus
 * Pregotovirus
 * Roypretovirus, Snaturtovirus, and Tilitovirus
 * Sectovirus
 * Sanematovirus
 * Septovirus
 * Sekatovirus
 * Sertovirus
 * Serecovirus
 * Vebetovirus
 * Chabetovirus