Individuals with reduced immunity are more susceptible to Zoonoses, i.e., people undergoing cancer therapy and/or those positive for HIV, and should take extra precautions around pets.
According to a recent survey, the two disease agents of greatest concern for immune compromised individuals are Salmonella species and Toxoplasma gondii. Veterinarians listed Salmonella first. Because of the high incidence of Salmonella in reptiles, most vets recommend that immune compromised persons not own reptiles. Physicians listed Toxoplasma gondii as their greatest concern. This is why many medical doctors advise against pet cat ownership in immune compromised persons.
The potential health risks with these two disease agents also pose several questions. For both, contact with pets is not the only or even the most important source of infection for people. Contaminated foods are the most common source of disease transmission for Salmonella. Ingestion of undercooked meat and handling raw meat are much more important in transmission of Toxoplasma gondii than contact with infected pet cat feces. In addition, up to ¼ of the lamb and pork we eat already contains infective Toxoplasma tissue cysts. Cat ownership has not been associated with an increase in Toxoplasma positive blood tests (seroconversion) among HIV infected people.
Communication between physicians and veterinarians about Zoonotic diseases is minimal at best. The two groups also have significantly different views regarding the risks posed by certain infectious agents. Consideration to broader scale links between health care professionals would foster a wider consensus concerning infectious disease risks and would facilitate prevention of Zoonotic diseases for all of us, man and animal, in the future.