Our newest addition to the team is Charlotte Hitch, who has come on board the good ship Vet School Success to bring you some fascinating articles with a more exotic flavour. It’s great to have Charlotte on the team and she takes up the role of Vet News Exotics Editor. Welcome Charlotte 🙂
Lymphocytic Choriomeningitis Virus (LCMV) in Marmosets
Charlotte Hitch (Vet News Exotics Editor)
Lymphocytic choriomeningitis is an infectious zoonotic viral disease which affects a family of New World monkeys called Callitrichids, including the species Callithrix jacchus, or the common marmoset, an increasingly popular exotic pet especially in the United Kingdom and USA. In 1991, in a zoo in Texas, 5 of 7 pygmy marmosets died after exposure to infected neonatal mice. Hence, the LCM virus, once present in a population of Callitrichids, poses a significant risk to simian health.
The secondary effects of contracting LCM, an arenavirus-induced condition, include aseptic meningitis and Callitrichid hepatitis (CH), a commonly fatal disease which presents itself in the form of clinical signs such as dyspnoea (shortness of breath), anorexia (loss of appetite), lethargy (extreme tiredness), and jaundice (yellowish pigmentation of the skin and the ocular sclera). In basic terms, the pathology of CH consists of an inflamed liver which may be likely to develop cirrhosis or fibrosis, and metabolic disorders often follow.
The LCM virus can be carried by the common house mouse, Mus musculus, and can be caught through exposure to the faeces, saliva, milk, nasal secretions, semen or urine of an infected specimen. M. musculus are a reservoir species; they are able to carry and spread the virus to other species without being harmed or killed by it. Captive marmosets are particularly at risk due to unnatural contact with infected house mice, and also because of the difficulty in controlling such carriers.
Transmission can also be vertical, i.e. to unborn foetuses in utero through the placenta – possibly producing infected offspring.
While its effectiveness has not yet be confirmed, the drug ribavirin may be used on a trial basis to treat the initial LCMV infection; however once CH develops, the chances of survival are greatly reduced. Additionally, ribavirin is teratogenic (may lead to the formation of teratomas). The virus may be inactivated by hypochlorite solution, heat, UV light or gamma irradiation if disinfecting a contaminated area. Corticosterone, an anti-inflammatory drug, may be used to treat the encephalitic effects of the infection – reducing the cerebral and spinal cord inflammation. It is also highly recommended to avoid feeding captive marmosets mouse pups, as other proteinous food items such as mealworms should suffice; however this preventative method will be ineffective once infection has already occurred.
Currently, Callitrichid Hepatitis is incurable but treatable with increased rest and diet regulation, through reduction of dietary fats. Future developments in regenerative medicine may allow treatment of CH through intravenous transplantation of cord blood stem cells into the liver, replacing damaged hepatocytes and restoring normal hepatic and immune function. While these ideas are still in the development and pre-testing stages, precautions must be taken to control reservoir species such as mice to prevent rodent-borne transmission to captive marmosets.
Pathology and Immunohistochemistry of Callitrichid Hepatitis, an Emerging Disease of Captive New World Primates Caused by Lymphocytic Choriomeningitis Virus, American Journal of Pathology, Vol. 148, No. 5, November 1995