On May 6, 2005, the Centers for Disease Control reported the first cases of Salmonella infections in people that were linked to pet rodents in the United States. Two reported cases of Salmonella typhimurium in young children were initially linked to recent exposure to pet rodents (a sick hamster in one case and a sick mouse in the other). Then, a similar strain of Salmonella was found in several sick hamsters, which prompted a search of a national database for other cases of human infections with the same strain of Salmonella. 28 cases of human infection with the bacteria were found from December of 2003 to October of 2004. These cases were questioned about recent exposure to pet rodents, and 15 patients infected with this bacteria reported recent exposure (primary or secondary) to pet hamsters, mice or rats. Perhaps most alarming, the strain of Salmonella typhimurium found in the human and animal cases was resistant to multiple antibiotics.
While the cases were geographically spread out, the affected rodents were tracked back to three main distributors. However, no common link was found between the distributors, although it was not possible to fully track the movement of pet rodents from breeders to distibutors.
The Risks: Don't Panic, Don't Ignore
Reports like this sound scary, but it is important to remember that these cases were isolated incidents, and the risk of getting Salmonella from rodents are proabably minimal and very manageable. Still, it is important to not ignore the risks. While there were only a few cases, there are probably more that were not diagnosed or reported. A report like this helps raise awareness in health care providers to look for possible exposures they might not otherwise consider. It also provides a reminder that pet owners need to take proper precautions because all animals can carry bacteria, some more dangerous than others. Indeed, many reptiles carry Salmonella and there have been a number of cases of Salmonellaifections in people linked to pet reptiles. Human cases have also been reported due to contact with pet chicks, ducklings, kittens, and hedgehogs.
Some Perspective According to the CDC, there are approximately 1.4 million cases of Salmonella infections in people every year (only 30 to 40 thousand are confirmed by culture, however). The vast majority of these cases originate from contaminated food. The CDC estimates that only 6% come from exposure to reptiles. Therefore, even if under-diagnosed and under-reported, the number of cases of Salmonella associated with pet rodents is very small, relative to other causes/sources.
Some Implications for the Pet Industry
According to the CDC, Salmonella was cultured from shipping cages, food, and bedding at one of the affected distributor's facilities. This is a problem because the contaminated equipment coule easily spread the infection. The importance of proper hygiene and infection control by breeders, distributors and pet stores needs attention to help prevent outbreaks.
Additionally, the problem of antibiotic resistance is an ever-increasing concern, and is thought to be caused by the indiscriminate or improper use of antibiotics in both animals and people. The CDC report also indicated that the use of broad spectrum antibiotics is common when it comes to the care of pet rodents, especially for the treatment and prevention of non specific (i.e. cause not diagnosed) diarrhea, and this may ultimately have contributed to this outbreak. The routine use of preventative antibiotics should carefully be re-evaluated, and antibiotics only used to treat known susceptible diseases.
- Owners of rodents should be aware of the possibility of Salmonella transmission from their pets, however remote.
- Hands should be thoroughly washed with soap and water each time a rodent or its cage, equipment, or bedding is handled. If you have small children, it is important to supervise their interactions with your pets and ensure that they thoroughly wash their hands afterwards.
- Keep pet rodents out of the kitchen and away from your food and your mouth.
- Ideally, cages and equipment should not be cleaned in the kitchen or near food preparation areas or dishes. Additionally, sinks or tubs used for cleaning pet rodent cages and equipment should be disinfected with a bleach solution (1/4 cup liquid chlorine bleach to 1 gallon of water) afterwards.
- If you or your family members have symptoms similar to Salmonella (may include cramps, vomiting, diarrhea, fever), remember to mention exposure to pets or other animals to your health care provider.