Tularemia in cats and dogs in Sioux Falls
Tularemia has been diagnosed in five dogs and cats in Sioux Falls, South Dakota. At least one of the pets has died. Tularemia, sometimes referred to as "rabbit fever" is caused by the bacterium Francisella tularensis. Infections occur throughout much of the Northern Hemisphere but are much more common in certain regions, such as the central US. This bacterium has received a lot more attention over the past decade because of its potential use as a bioterrorism agent, but infections have been occurring in people and pets for a long time. In North America, the cottontail rabbit, wild hares and some rodents are the main reservoirs. People and other animals get infected through close contact with infected animals (e.g. rabbit hunting) or through bites from blood-feeding insects.
There was no mention of human cases in the recent report from South Dakota. One of the implications of identifying this disease in pets is that whatever infected the pet could also be a risk for people. If the pets were infected by contact with wild animals, people with similar contact with wild animals could also be exposed. If there is no chance the animals had contact with infected wildlife, then insect-transmission is most likely, and the same could happen to human members of the household (or elsewhere in the area). Therefore, diagnosis of tularemia in a person or pet should put both veterinarians and physicians on the lookout for further cases in all species.
Transmission of tularemia from infected pets to humans is also a concern. This has been reported in numerous instances, most often with cats. There are published reports of transmission from dogs to humans, but these are less convincing than the numerous cat-to-human reports. There's also a report of tularemia transmission from a hamster to a child. The overall risk of transmission is probably low, but tularemia can be spread from pets to people by scratches, bites, and perhaps regular close contact.
You can reduce the risk of your pet being exposed to tularemia by:
- Keeping pets indoors as much as possible. Cats should stay indoors. Dogs should not have uncontrolled outdoor access.
- Dogs should not be allowed to hunt rabbits in areas where tularemia is endemic.
- Animals that venture outside should be checked regularly for ticks and a preventive medicine program for ticks should be in place.
- Routine measures to reduce bites and scratches from dogs and cats should be taken.
Tularemia Trouble
A case of pneumonic tularemia was recently reported in New York City.
Tularemia is a disease caused by the bacterium Francisella tularensis. It causes different signs of illness depending on how the bacteria enter the body. If the bacteria are inhaled, it tends to cause pneumonia (pneumonic tularemia). If the bacteria get in through a break in the skin, infection may cause the local lymph nodes (glands) to become very swollen, and in some cases the skin itself may become infected resulting in the formation of large sores (ulcers). Infection can also cause sores in the mouth and diarrhea. The earliest, most common signs are things like fever, headache, chills, sore muscles, and sore throat which often come on very abruptly. The infection can be treated with antibiotics, but it is important to see a doctor and start treatment as soon as possible.
Tularemia is also sometimes called "rabbit fever," because the bacteria are often carried by animals such as rabbits and hares. Rodents (including beavers, rats, mice, squirrels etc.) can also carry F. tularensis, and occasionally so can cats and dogs. Some biting insects like deerflies and certain species of ticks can carry the bacteria and transmit it when they bite. Francisella tularensis can also survive in water and soil for a long time. People can become infected by being bitten by an infected insect, handling an infected animal (dead or alive), or coming into contact with feces from an infected animal. Occasionally a person may inhale the bacteria if it is in the air, as may happen with disturbed, dusty, contaminated soil.
More information on tularemia can be found on the CDC's tularemia website.
Things you can do to avoid tularemia:
Avoid touching or handling wildlife (dead or alive), especially rabbits and rodents.
Don't let your pet touch or eat dead animals.
Always wash your hands if you have been working outside in the dirt/soil.
Wear insect repellent containing DEET (visit the Health Canada website for more safety tips)
Make sure you only wash food with and drink water that has been properly treated.
One of the reasons tularemia is such a big deal is it is very infectious - as few a ten bacteria can be enough to make even a healthy person sick! But it is still quite uncommon in North America - about 100-200 cases are reported in people in the USA every year. Between 2002-2004 there were 34 cases reported in Canada, most of which occurred in Quebec and in adults. However, infection can be fatal in a very small number of cases, especially if proper treatment is not given as soon as possible.
