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, but a retrovirus is suspected to be the culprit. The mode of transmission of IBD between snakes has also not been definitely established. Snakes most likely transmit the disease via direct contact, furthermore snake mites (Ophionyssus natricis) are also suspected to transmit the infectious agent. It is also speculated that IBD can be transmitted from mother to young.

Snakes can have a subclinical infection of IBD, which 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 more severe central nervous system signs earlier in the course of infection than boas. Snakes affected with IBD may regurgitate their food after feeding and develop anorexia. These symptoms are often the first clinical signs observed following infection. Furthermore, snakes can develop stomatitis (inflammation of the mouth, ‘mouthrot’), pneumonia, lymphoproliferative disorders (excessive production of lymphocytes) and tumours. Some snakes can deteriorate rapidly and die within a matter of weeks’, while others may live for several months after starting to show clinical signs.

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

Currently no treatment is available to treat snakes with IBD, therefore prevention is of the utmost importance. Treatment is supportive and involves force feeding and rehydrating the affected snakes to improve their general condition. However, due to the contagious nature of this disease euthanasia is often recommended. Preventing your snake from contracting 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 it is showing clinical signs of illness.

A current significant concern is that IBD will start affecting the wild population of pythons and boas. In South Africa the African Rock Python will be of particular relevance and concern of being exposed to this disease.

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

There are many diseases that show clinical symptoms similar to IBD. Differential diagnoses include 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, that causes central nervous symptoms 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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