Each year in the United States, a vast number of Salmonella infections are caused by contact with reptiles. Salmonella is the general name for a large "family" of bacteria usually associated with food poisoning from contaminated or undercooked foods that usually lives in the gastrointestinal tract.
Up to 90 percent of reptiles carry Salmonella in their intestinal tracts, which is then shed in the feces. The Salmonella is then transferred to their cages and their skin. As humans come into contact with the reptiles environment, they can walk away with the bacteria on their hands, and consequently the human environment, too.
Not all Salmonella are bad. Many reptiles are accustomed to their own serotypes of Salmonella so they rarely get sick. In fact some serotypes provide a healthy population of bacteria in the gut. These serotypes of Salmonella may or may not cause disease in humans or other species of reptiles.
Reptiles who harbor potentially disease causing Salmonella in their gut but do not show signs of disease themselves are called sub-clinical carriers. Some serotypes of Salmonella are highly pathogenic (disease causing) and nearly always cause disease even in healthy reptiles or people.
People who own or handle reptiles should know that Salmonella is most commonly transmitted to people when reptile fecal material is allowed to come into contact with food preparation surfaces, bathing areas, or, especially in small children, the mouth.
Reptiles that are malnourished, housed under less than ideal conditions, carrying intestinal parasites or suffering from other diseases are more likely to succumb to a Salmonella infection. These highly stressed animals are also more likely to shed large quantities of Salmonella in their feces and therefore pose more of a health risk to owners and other animals.
Although the presence of Salmonella in imported green iguanas has been well publicized, it is important to remember that ALL reptiles are prone to carry some serotype of Salmonella.
What To Watch For
Salmonella infections can result in a variety of illnesses, such as pneumonia, meningitis and septicemia. The most common clinical signs for both reptiles and people include:
- Extreme diarrhea
- High fever
Your veterinarian will begin by a physical examination, including a complete history. In addition, some diagnostic tests are needed to specifically diagnose Salmonella and exclude other diseases. These may include:
- Fecal culture. This will determine the presence of Salmonella. In addition, because Salmonella as a family has a tendency to be resistant to many antibiotics, it is very important to determine the antibiotic sensitivity pattern.
- Additional tests that are often required to assess the severity of the infection are red and white blood cell counts, and blood tests to evaluate liver and kidney function.
- Reptiles with Salmonella infections often have other infections at the same time, so your veterinarian may recommend fecal tests to look for intestinal parasites or routine bacterial cultures to rule out other types of bacteria.
Most healthy reptiles only shed Salmonella in their feces intermittently, so one or even ten negative Salmonella cultures does not guarantee that a reptile does not carry Salmonella. Negative cultures may give an owner a false sense of security.
In general, using fecal cultures to screen for Salmonella is most useful for a population of reptiles. In this case, when multiple reptiles are surveyed over a prolonged period of time, the exact identity and average occurrence of different serotypes of Salmonella can be determined for THAT population.
The two most important treatments for a Salmonella infection are antibiotics BASED ON CULTURE AND SENSITIVITY and treatment of dehydration.
Your veterinarian most likely will start your reptile on an antibiotic while you are awaiting the culture and sensitivity results. If a fecal examination shows that your reptile is also infected with parasites, your veterinarian may also administer a dewormer. After the antibiotic sensitivity results are back, your veterinarian may need to change the antibiotic.
Your veterinarian will probably suggest that you give antibiotics by injection or orally at home. In addition, it is very common for veterinarians to have reptile owners administer subcutaneous fluids (fluids given under the skin) at home in order to maintain normal hydration. If an owner is able to do this, it allows the reptile to be housed in his regular cage and decreases the cost of treatment.
Depending on your reptile's history and his exact clinical signs your veterinarian may need to administer other treatments or even hospitalize your reptile.
Home Care and Prevention
- Administer antibiotics according to your veterinarian's instructions. Be sure to finish the entire course, do not stop early. Administer oral or subcutaneous (under the skin) fluids as directed by your veterinarian.
- Observe the general activity level, appetite, and stool consistency and production of your pet. If these do not improve within 24 to 48 hours of starting antibiotics, contact your veterinarian.
- If needed, improve husbandry. Make sure you provide the temperature range that is recommended by your veterinarian. Reptiles that are too cool or too hot are immunocompromised and cannot fight off infections as well as reptiles kept in their optimum temperature range.
- In order to decrease the spread of Salmonella, isolate your reptile from other reptiles and minimize contact with people.
Although antibiotics can be used to decrease the numbers of Salmonella bacteria enough to treat most active infections, antibiotics almost never kill all of the Salmonella bacteria. In fact, the bacteria that survive are usually resistant to the antibiotic that was just used to treat the patient and so will be harder to kill in the future.
This is a big problem. It means that it is impossible to create a Salmonella free pet reptile and trying to do so will only result in more pathogenic (disease causing) bacteria. This means that owners of reptiles need to take the precautions listed below to limit the spread of Salmonella and its ability to cause disease.
- Minimize stress. Keep reptiles in the best husbandry situation possible. Avoid mixing species.
- Proper hygiene is essential. Disinfect and clean cages regularly, but do not clean cages in food preparation or bathing areas. Wash hands/equipment between animals, after handling, and before eating or smoking.
- There is less risk of Salmonella contamination if reptiles are not allowed to roam freely in the house. It is also recommended that people not kiss or share food with reptiles.
- Have your veterinarian perform necropsies (autopsies) on pet reptiles that have died in order to determine if they were carrying a serotype of Salmonella that is frequently associated with disease.
- Reptiles are not recommended pets for people with compromised immune systems. Some people belonging to this group are infants, toddlers, the aged, pregnant women, chemotherapy recipients, transplant recipients, and AIDS patients. The Center for Disease Control recommends that children under the age of 5 not handle reptiles and that homes with children less than 1 year of age not keep reptiles.
- Reptiles should not be kept as pets for day care centers.