Nidovirus/ Serpentovirus FAQ
does my snake have nidovirus/serpentovirus?
While signs of respiratory disease can be fairly obvious (mucus production, noises while breathing, etc.), a majority of serpentovirus- positive cases are subclinical and don’t present with symptoms of respiratory infection. The only way to tell if nidovirus is present in a colony is through molecular PCR diagnostic testing, which range in price proportionate to the quality of the result. Cheaper tests are very likely to miss even moderately divergent viral strains.
Additional evidence for periodic viral shedding complicate determining true serpentovirus-negative snakes. For this reason, across studies in both the US and Europe, between 25% to 30% of adult pythons are positive. While prevalence appears much much lower for boas, colubirds, and other species (<5%), any sizable population of captive pythons almost certainly has one of these viruses. THIS MEANS YOU, EVEN IF YOU HAVE A COLONY THAT “NEVER GETS SICK”!
A qualified veterinary should be the appropriate resource in discussing treatment options for clinical snakes, as sometimes treatment of secondary bacterial infection via antibiotics and improved husbandry can improve animal health.
Additional evidence for periodic viral shedding complicate determining true serpentovirus-negative snakes. For this reason, across studies in both the US and Europe, between 25% to 30% of adult pythons are positive. While prevalence appears much much lower for boas, colubirds, and other species (<5%), any sizable population of captive pythons almost certainly has one of these viruses. THIS MEANS YOU, EVEN IF YOU HAVE A COLONY THAT “NEVER GETS SICK”!
A qualified veterinary should be the appropriate resource in discussing treatment options for clinical snakes, as sometimes treatment of secondary bacterial infection via antibiotics and improved husbandry can improve animal health.
How long does nidovirus/serpentovirus last in the environment?
Lab studies of 3 different python serpentoviruses show these viruses last 10-12 days at room temperature, 8-10 days at warmer temperatures, but potentially months to years at cold or sub-zero temperatures. While virus can still persist up to 10 days at warmer temperatures, large decreases in the number of infectious virions can be observed within 2 days.
What sanitizers kill nidovirus/serpentovirus?
Serpentoviruses are enveloped viruses, meaning that disruption of the lipid membrane is all that is needed to inactivate virus. A variety of sanitizers including bleach, ethanol, peroxide, F10 (QAC), and Chlorhexidine have been shown to effectively do this in 1 to 3 minutes for serpentoviruses. Essentially any sanitizer used for at least 3 minutes seems sufficient to render virus inert.
How many nidovirus/serpentovirus species are there?
Viral taxonomy is a complicated field, with entities such as “viral quasispecies” making an actual species count essentially impossible in many cases. According to ICTV there are 7 described genera and 14 subgenera within the subfamily of Serpentovirus. Within these genera are dozens of viral species and even more strains. Additional genera, subgenera, and potentially subfamilies are likely. However, currently viruses infecting pythons are limited to just 2 genera: Pregotovirus and Septovirus. Furthermore, viruses associated with clinical respiratory disease in captive pythons are so far limited to just the genus Pregotovirus. When reptile keepers talk about “nidovirus,” Pregotovirus is the actual genus of viruses they intend to refer to. Within this genus is large genetic diversity and host species. This genus of serpentovirus is the most well characterized, but it is still apparent multiple species and strains remain to be described. Viruses from the genus Pregotovirus are also the only serpentoviruses that have been successfully isolated (grown in lab cell cultures).
what is the host range of nidoviruses/serpentoviruses?
Within the 7 genera of serpentovirus multiple host taxa is observed in snakes, lizards, and turtles.
Captivity:
-Pythons: Most species including ball pythons, blood pythons, womas, retics, burmese and many Morelia (Highest prevalence and diversity is in green tree pythons).
-Boas: Dumerils boa and Emerald tree boa
-Colubirds: Honduran milksnake
-Misc. Viperidae
-Veiled Chameleons
-Blue tongue skink
Wild:
-Florida Burmese pythons
-Florida corn snake and watersnakes
-Australian Bellinger river turtle
-Australian shingleback skinks
-(?)Misc. chinese colubirds (No specific background given)
It is unclear how wide the host range for any particular strain might be, but currently transmission of serpentovirus between reptile families has not been observed. Although multiple host taxa within the same viral genus suggests such spillover between families may happen on rare occasions, often representing large resultant splits in the viral phylogeny.
Captivity:
-Pythons: Most species including ball pythons, blood pythons, womas, retics, burmese and many Morelia (Highest prevalence and diversity is in green tree pythons).
-Boas: Dumerils boa and Emerald tree boa
-Colubirds: Honduran milksnake
-Misc. Viperidae
-Veiled Chameleons
-Blue tongue skink
Wild:
-Florida Burmese pythons
-Florida corn snake and watersnakes
-Australian Bellinger river turtle
-Australian shingleback skinks
-(?)Misc. chinese colubirds (No specific background given)
It is unclear how wide the host range for any particular strain might be, but currently transmission of serpentovirus between reptile families has not been observed. Although multiple host taxa within the same viral genus suggests such spillover between families may happen on rare occasions, often representing large resultant splits in the viral phylogeny.
What is the role these viruses play in wild reptiles?
The role serpentoviruses play in wild populations is an under-explored area, however 3 studies exist describing serpentoviruses in wild reptile populations. One study in Florida snakes found virus without disease in 24.4% of wild Burmese pythons and 2.3% of native snakes (cornsnake and watersnakes).
Australian studies of Shingleback skinks and Bellinger river turtles have been associated with respiratory disease outbreaks in wild populations. However, in both studies a high viral prevalence was also observed in healthy animals of the population which was maintained after the outbreak.
As a whole it appears these viruses live in some type of equilibrium in wild populations without disease. In wild Florida Burmese pythons, Septovirus-genus serpentoviruses are carried at a high level without disease with evidence of seasonal intermittent viral shedding. However, circumstances likely exist that can cause flairs of respiratory disease in at least some wild reptiles, as seen in Australia.
Australian studies of Shingleback skinks and Bellinger river turtles have been associated with respiratory disease outbreaks in wild populations. However, in both studies a high viral prevalence was also observed in healthy animals of the population which was maintained after the outbreak.
As a whole it appears these viruses live in some type of equilibrium in wild populations without disease. In wild Florida Burmese pythons, Septovirus-genus serpentoviruses are carried at a high level without disease with evidence of seasonal intermittent viral shedding. However, circumstances likely exist that can cause flairs of respiratory disease in at least some wild reptiles, as seen in Australia.
If the dam is virus positive, is it passed to her offspring?
There is no evidence for vertical transmission of serpentovirus between parent and offspring. There are functional exceptions to this however (maternal incubation, boa giving birth in cage, etc.)
In my personal opinion though, I prefer not to rule this out as a possibility because viral RNA has been found in low levels in oviduct and other tissues outside the mouth and lungs. Although I repeat; there is no direct evidence of vertical transmission.
In my personal opinion though, I prefer not to rule this out as a possibility because viral RNA has been found in low levels in oviduct and other tissues outside the mouth and lungs. Although I repeat; there is no direct evidence of vertical transmission.
Are nidoviruses differnt from serpentoviruses?
No, but the term "serpentovirus" is considered more scientifically accurate. The term "nidovirus" refers to the viral order- Nidovirales. This is a HUGE order of viruses containing many types of viruses. For example, coronaviruses are a human nidovirus. It's like referring to a ball python as an "reptile." There are more specific terms you can use like "snake" or "python" that are more helpful. When serpentoviruses were first discovered, the were described in the most broad sense possible- as a novel nidovirus. That group of novel nidoviruses has now been given a name as a new viral subfamily- Serpentovirinae. As such, "serpentovirus" is the more appropriate name for these viruses.