Apr 9, 2012 – Rodents and Disease
QUESTION:
I have a horse stable as a new account and have been asked some questions by the owner of the stable. Do all rats and mouse have the sickness Leptospirosis? If a horse gets the disease will it die quickly or would it take time before it is serious for the horse? Can it be treated in horses? She has 15 to 20 horses and rats in the area. If the rats are infected does it mean all horses will become infected with Leptospirosis? Could this lead to other health problems in the horse? Thanks for your answer and advice.
ANSWER:
Our peridomestic rodents (House Mouse, Norway and Roof Rats) are absolutely wonderful vectors of disease, and Leptospirosis is just one of nearly 60 different known pathogens or parasites passed to humans or domestic animals by these 3 species. This really needs to be kept in mind by those who advocate capture-and-release policies on them. These 3 species of rodents are exotic pests in North America and their presence can threaten the health and existence of many other native animals as well as humans. To capture a roof rat in a home and release it back outside now threatens the local birds, other native rodents, and anything else that rat intends to feed on and compete with.
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I have a horse stable as a new account and have been asked some questions by the owner of the stable. Do all rats and mouse have the sickness Leptospirosis? If a horse gets the disease will it die quickly or would it take time before it is serious for the horse? Can it be treated in horses? She has 15 to 20 horses and rats in the area. If the rats are infected does it mean all horses will become infected with Leptospirosis? Could this lead to other health problems in the horse? Thanks for your answer and advice.
ANSWER:
Our peridomestic rodents (House Mouse, Norway and Roof Rats) are absolutely wonderful vectors of disease, and Leptospirosis is just one of nearly 60 different known pathogens or parasites passed to humans or domestic animals by these 3 species. This really needs to be kept in mind by those who advocate capture-and-release policies on them. These 3 species of rodents are exotic pests in North America and their presence can threaten the health and existence of many other native animals as well as humans. To capture a roof rat in a home and release it back outside now threatens the local birds, other native rodents, and anything else that rat intends to feed on and compete with.
Leptospirosis is also called Weil's Disease and it is caused by a bacteria that may be present in both rats and mice. It is spread from these infected rodents to humans, dogs, livestock, and other animals in the urine of the rodents when that urine gets into drinking water or contacts the eyes or breaks in our skin. Dogs that lick rodent urine within a home or animals that drink water with rodent urine in it are susceptible to acquiring the disease. Many other wild animals also are capable of carrying the disease and being vectors of it. The bacteria can remain alive and viable as long as they remain in a moist situation. Even people swimming in contaminated lakes or streams may be infected. The symptoms of the disease in humans will be fever, rashes, headache, and sloughing of skin, according to Dr. Robert Corrigan's book on Rodent Control. But, complications from the disease are possible and potentially life threatening.
If rats are present on this property then we have to assume that they "could" be infected with this disease, and therefore "could" be presenting the opportunity for the horses to become infected as well. Exactly what percentage of rodents in any population are infected would be hard to say, but given the value of horses it's probably best to work on the assumption that the horses are at least at risk, and the rodents need to be eliminated to ensure the health of the horses. According to one veterinarian fact sheet on this disease and horses, some studies have shown up to 40% of horses may have been infected with the bacteria at some point in their lives. It appears that it is not particularly life threatening to horses, but it can lead to some chronic health problems, such as blood infections, kidney failure, heart complications, and a variety of other ailments. According to this veterinarian guide "the disease is typically seen as a self-limiting mild fever with anorexia".
This has to be the message to provide to your customer, and they should consult with their veterinarian on the prevalence of Leptospirosis in your area. A worst case scenario would be that all of the rats and mice could be infected and could be urinating in drinking troughs or on the food of the horses, and if this were the case all of the horses could be at risk and some of them could develop very serious complications. More realistically you might consider that some of the rodents likely are infected and in their daily activities are probably urinating where the horses will eat or drink that contaminated urine. Infected horses most likely would show only mild symptoms and recover, but you need to leave the decision on the horse care up to the customer and her veterinarian.
However, obviously it would be a really good idea to prevent any rats or mice from coexisting with these horses or any other domestic animals on this property. Even the humans would be at risk if they had a cut on their arm and stuck that arm into a watering trough that was contaminated by rodent urine.
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