Listeriosis in Chinchillas
Table of Contents
Listeriosis is one of the more common diseases of chinchillas, causing death at any age. It is a common infection in many other animal species, such as mice and rats, both domestic and wild, in many parts of the world.
The organism can also infect humans. Avoid ingesting the bacteria when handling infected animals or when in an infected environment.
Listeriosis is caused by a small, gram-positive rod-shaped bacteria called Listeria monocytogenes.
The bacteria may be introduced into a herd by infected chinchillas, by contact with another animal species or by contaminated feed. Feed may be contaminated while in the barn (e.g., in open feed bins), or the hay may be contaminated in the field (e.g., by mice) prior to processing. Chinchillas usually acquire the infection orally.
Once the bacteria infects a chinchilla, it is passed in the feces. Equipment, cages, feed and water contaminated with the infected feces are the most common vehicles for spreading the disease to other chinchillas within the herd.
Sickness due to listeriosis is slow in onset, with slow spread throughout the herd. There may be one death followed by the deaths of other chinchillas in 5-6 months; the affected animals will lose weight and condition. Diarrhea may occur, however, constipation is more common. Straining may result in prolapse of the rectum.
Less frequently, chinchillas may show blindness or nervous signs, such as convulsions or head tilt, if the bacteria invade the brain.
Eventually, the chinchillas appear to be in pain and will move only if urged. They may stop eating but continue to drink water. They may grit their teeth and vocalize. This occurs a day or so prior to death.
The most common finding is the presence of pin-point white spots throughout the liver. These areas of dead tissue are sometimes also seen in the spleen, bladder and intestinal wall. Examination of the intestinal content often reveals constipation with the presence of scant, hard, dry ingesta.
A presumptive diagnosis can be made based on the history and post-mortem findings. Listeria bacteria can be readily isolated from the liver of chinchillas with typical post-mortem findings. A diagnostic laboratory can identify the bacteria to help a veterinarian determine what antibiotics would be useful for treatment. This is important, since some bacteria may be resistant to certain commonly used antibiotics.
Some animals may not respond to treatment. Note that animals that appear to recover may remain carriers of the bacteria.
Good management practices, especially sanitation, are the best means of preventing listeriosis. This includes thorough cleaning and disinfecting of cages, water bottles and sand baths.
Only introduce new breeding stock from known healthy sources. Initially, raise these chinchillas in complete isolation from the rest of the herd.
Treat chinchillas that are infected with listeriosis with antibiotics, as recommended by a veterinarian, as soon as possible and isolate them to prevent spread within the herd. Cull and euthanize all badly affected chinchilla.
This Factsheet was originally written by Gwen Zellen, OMAFRA. It was updated by Brian Tapscott, Alternative Livestock Specialist, OMAFRA, Elora.
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