Inclusion Body Disease (IBD) in Snakes

IBD is a disease that causes neurological signs in snakes belonging to the families Boidae (Boas) and Pythonidae (Pythons). The disease was first discovered in a Burmese python in America in the 1970's, and is now occurring worldwide in captive populations.

The causative agent of this disease is currently still unknown, a retrovirus is suspected to be the cause. The transmission of IBD between snakes is also not completely determined. Snakes most likely transmit the disease via direct contact, furthermore snake mites (Ophionyssus natricis) are also suspected to transmit the infectious agent. IBD is possible also transmitted from mother to young.

Snakes can have a subclinical infection of IBD, so this means that they are carrying the disease but do not show clinical signs yet. The most typical clinical signs involve central nervous system abnormalities, such as;

  • torticollis (wry neck, contraction of neck muscles that produces a torsion of the neck)
  •  disequilibrium (loss of stability)
  • opisthotonos (the spinal column is arched resulting in the head being drawn backwards)
  • inability to right itself when placed in dorsal recumbency (on their back)
  • flaccid paralysis especially in the last half of the body (the muscles in the body are totally relaxed).

Pythons will show central nervous system signs earlier and more severe than boas. Snakes affected with IBD can regurgitate their food some days after feeding and show anorexia. Anorexia and regurgitation are often the first clinical signs observed. Furthermore, snakes can show stomatitis (inflammation of the mouth, 'mouth rot'), pneumonia, lymphoproliferative disorders (excessive production of lymphocytes) and tumours. Some snakes will deteriorate quickly and die within several weeks, others die after several months of first showing clinical signs.

The disease can be diagnosed through taking a tissue sample of a dead snake or a biopsy from the liver of a live snake. This sample is examined by histopathology or electron microscopy, where the intracytoplasmic inclusion is visualised. These inclusions are built up by inclusion body disease proteins. These inclusions are in some cases only found in the central nervous system, which can result in false negative test results. Currently, research is conducted to develop easier and more reliable diagnostic methods.

Currently no treatment is available to treat snakes with IBD, therefore prevention is very important. Force-feeding and rehydrating the affected snakes can improve the general condition of the snake. However, due to the contagious nature of this disease, euthanasia is often required. Preventing your snake to contract IBD is not an easy task. No vaccination is available. The risk of contracting IBD can be reduced by quarantining new snakes, preventing mites and by taking your pet to the vet if he is showing clinical signs of illness.

A large concern is that IBD will start affecting the wild population of pythons and boas. In South Africa, the African Rock Python will be of high risk to get exposed to this disease.

It is essential to quarantine a new snake for at least six months before it is introduced into the area where the other snakes are kept. It is important to treat the snakes several times for mites during the quarantine period. Snakes showing anorexia and weight loss or clinical signs of illness should never be bought or added to the existing snakes in the household.

There are many diseases that show similar clinical symptoms as IBD. Differential diagnoses are for example; bacterial septicaemia with meningitis, stomatitis, neoplasia, foreign body, intoxication or coccidiosis. The most important differential diagnosis is paramyxovirosis, which is another viral infection, causing central nervous signs and respiratory signs.


Please contact us for more information about IBD and caring for your snake.

Sources

  • Chang, L.-W., & Jacobson, E. R. (2010). Inclusion Body Disease, A Worldwide Infectious Disease of Boid Snakes: A Review. Journal of Exotic Pet Medicine, 19(3), 216–225. doi:10.1053/j.jepm.2010.07.014
  • Ilyasu Y, Abba Y, Zunita Z, Mohd-Azmi, M M Noordin (2015) Diagnosis of Boid Inclusion Body Disease: Challenges and Future Prospects, Journal of Agriculture and Veterinary Science, 8(3) II, 77-82.
  • Jacobson ER: Viruses and viral diseases of reptiles (2007), in Jacobson ER (ed): Infectious Diseases and Pathology of Reptiles: A Color Atlas and Text. Boca Raton, FL, CRC Press, pp 395-460, 2007
  • Vanncraeynest D, Pasmans F, Martel A, Chiers K, Meulemans G, Mast J, Zwart P and R Ducatelle. (2006) Inclusion body disease in snakes: a review and description of three cases in boa constrictors in Belgium. Vet Rec 158, 757-761.
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