Can Your Pet Make You Sick?

Zoonotic diseases, also known as zoonoses, are any diseases that can be spread between animals and humans. Familiar examples include salmonellosis, ringworm, rabies and plague. In the last decade, public attention has focused on the potential transmission of diseases such as salmonellosis from reptiles to their owners.

Less attention and risk are associated with small animals compared to imported reptiles. However, sometimes pet owners wonder if they can catch a disease from a pet such as a hamster or rat. A host of potential pathogens including bacteria, internal parasites and fungi can be transmitted between animals and people, although no parasitic protozoan diseases are likely to be acquired by pet owners from small animals.

The following is a brief review of the ailments that have the greatest potential of being observed.

Ringworm
Ringworm - Microsporum spp and Trichophyton spp - is a highly contagious fungal disease that can be transmitted to people through direct contact with infected animals, and indirectly by spores in the hair or scales shed from infected animals. The ringworm fungi primarily affects the outer layers of skin, hair and nails. The name of the disease refers to the discrete, circular or ring-shaped pattern of hair loss and redness caused as the fungus grows in the skin. The lesions are usually hairless and scaly in the center. It can be a self-limiting disease with spontaneous remission occurring within one to three months of onset. Some animals can be asymptomatic carriers.

Ringworm is more common in dogs and cats than in small animals, but it has been recorded in ferrets and rabbits. The condition must be diagnosed and treated by a veterinarian. Diagnosis is based on skin scrapings, and one species will fluoresce under ultraviolet light. Some cases are resistant to treatment, lengthening the time until cured. A topical or oral antifungal medication is used, and the animal's environment must be disinfected with a 10 percent bleach solution. In humans, ringworm affect the scalp. or body. Children, immunocompromised individuals and the elderly are most susceptible.

Sarcoptic Mange
Sarcoptic mange is caused by a mite. It is transmitted to people by direct con-tact with the mite. In small animals, the general symptoms include hair loss and itchy skin at the site of infestation. In ferrets, one form affects only the feet and is known by the common name of foot rot. The paws become inflamed, swollen and crusted. In severe cases, the nails can become deformed. Not only must the affected animal be treated by a veterinarian, the animal's cage must be thoroughly cleaned and sterilized.

Salmonellosis
Salmonellosis, is a bacteria that can affect the gastrointestinal tract of humans. A variety of small animals are potential vectors, although cases of transmission from small animals to humans are infrequent when compared to reptiles such as iguanas.

Salmonella includes more 2,000 different species of bacteria and, of these, dozens have been isolated from reptiles. It is not surprising then, that contracting salmonella bacteria is always a danger for people who own reptiles.

Salmonella bacteria is shed in the feces and can be transferred by an iguana's feet, if it walks through matter. This is one reason why a clean cage is so important.

Salmonella also can be transmitted through scratches or bites. Iguana owners should not put their pets near their mouths or kiss them. In addition, they should not bathe their pets in the bathtub or sink-especially the kitchen sink-without disinfecting it for human use afterward. Iguanas should not be allowed to run loose in the house.

Owners should know that washing their hands with antibacterial soap after handling an iguana is one way to avoid catching salmonella. Children less than 5 years old should not be allowed to handle iguanas at all because they often stick their fingers or the animal's toes into their mouths.

Young children, pregnant women and immunocompromised people (those with HIV, for example) are at risk of infection and, therefore, should not keep iguanas as pets.

Please see this article for more detailed information about
Salmonella bacteria in reptiles.

Leptospirosis
This disease is caused by bacteria called leptospores, which are found in wild and domestic rodent reservoir hosts. The leptospores are carried and shed in the urine of healthy hosts. They can contaminate water supplies.

Species Specific Zoonotic Potential
Rats have historically been thought of as dirty animals. Many customers wonder whether rats can still transmit dreaded diseases such as bubonic plague. However, the disease problems associated with wild rat populations are rare to unknown in pet rats. Rats can potentially harbor salmonellosis. The most likely adverse zoonotic ailment among pet owners is that some individuals might be allergic to their rat's urine or dander. Pet mice can potentially carry salmonella. However, they rarely transmit any zoonotic diseases. Some pet owners develop allergies to their mouse's dander and urine. Gerbils represent few potential health hazards to people keeping the animal as a pet. Salmonella and tapeworms have rarely been reported in colonies of gerbils. Hamsters have a low zoonotic potential. Occasionally, salmonella and tapeworm have been documented in large colonies of hamsters, but such conditions are not typical of hamsters kept as pets

Rabbits can transmit ringworm sarcoptic mange and salmonella. Because rabbits often struggle if held improperly, pet owners can be scratched. The scratches can then become infected from bacteria.

Some pet owners develop allergic reactions to guinea pig hair and skin. Although rare, salmonella is a potential pathogen in guinea pigs. Two species of mange mites, the mange mite, Trixacarus caviae, and the sarcoptic mange mite can affect guinea pigs and be transmitted to people.

Influenza is the only documented zoonotic disease of ferrets. Ferrets are susceptible to the influenza virus, and the potential for transmission from humans to ferrets is much greater than the transmission from ferrets to humans.

Final Thoughts
Environmental stress such as overcrowding, poor sanitation, malnutrition, and concurrent infection are predisposing factors to most diseases, including those with zoonotic potential. Obtaining pets from clean sources is the first step in preventing diseases. The second step is maintaining the animals in a sanitary environment in the pet store. Educating owners on how to properly care for their pets in their own homes, including how to recognize any signs that could indicate their pets are sick can help reduce the likelihood of zoonotic diseases in small animals.

This information was largely taken from an article written by Susan Fox in the March 2000 issue of Pet Business.