Large, unmanaged feral cat colonies are particularly susceptible to the spread of disease. The combination of poor nutrition coupled with the physical stress of pregnancy and nursing, and blood contact between breeding or fighting males make these cats vulnerable to parasites, bacteria, and viral infections. RMACA recommends feral cat colonies be sterilized, vaccinated, and managed by a caretaker to reduce the risk of disease. Feral cats should be vaccinated for panleukopenia, upper respiratory viruses, and rabies. It’s important to keep your own pets isolated from unfamiliar cats until the possibility of contagious diseases has been ruled out.
FeLV can cause a variety of disorders including cancer, anemia, and immunosuppression. This virus is found in approximately 2% of feral cats, usually in family groups. It is spread by repeated, close contact with other cats through infected saliva, in utero from a mother to her kittens, or blood contact (fighting). Some cats develop immunity, while others may become carriers without ever becoming ill. Symptoms of FeLV may include chronic infections, upper respiratory infections, tumors, sores that fail to heal, weight loss, diarrhea, or they may just look ill. The vaccination (two shots several weeks apart, followed by annual boosters) is generally impractical for ferals.
FIV is NOT transmissible to humans but is common among older, unneutered males - though females can contract the disease as well. FIV is spread through blood contact (such as fighting), thus the higher incidence among unneutered males. Kittens testing positive for FIV may only be showing antibodies to the virus. Most test negative four to 12 weeks later. Although FIV is eventually fatal, a cat may live many years before showing any signs of illness, and can live for several more after that if secondary illnesses can be treated. A new vaccine against FIV is available, but should not be given to ferals because it can produce false positive results in future tests, and also because once a cat has tested negative and is neutered, there is little risk of contracting the disease.
Feline distemper is a deadly and extremely contagious virus. It can be characterized by depression, diarrhea, vomiting, high fever, and excessive thirst. In unmanaged feral colonies, many cats may "drop dead" over a short period of time. If caught early in kittens or tame strays, panleukopenia can be successfully treated with an intensive course of antibiotics. If a cat is exposed to distemper and survives, it is immune for life. Vaccines are available, extremely effective, and inexpensive. All ferals should be vaccinated against panleukopenia.
Runny eyes or sneezing are symptoms of an upper respiratory virus which is highly contagious and potentially blinding or lethal to young kittens. These viruses must "run their course," but secondary bacterial infections (goopy eyes and congested lungs) can be treated with antibiotics. Sometimes upper respiratory infection is secondary to other viruses such as FeLV and FIV. Vaccines will not always prevent upper respiratory infections, but can lessen their severity. All ferals should be vaccinated for upper respiratory infections.
Rabies, tularemia, and plague are among the “scary” diseases that are transmissible to humans. Although rabies transmitted from cats to humans is extremely rare, feral cats should be vaccinated for rabies.
The risk to humans for contracting plague (usually transmitted by fleas) or tularemia (transmitted through bites) is greater with housecats, since close contact with ferals in the short window of time before they die from these diseases is unlikely. The two forms of plague (bubonic and pneumonic) arise most often in rural or semi-rural areas. ANY cat displaying sudden illness should be handled with extreme caution and taken to a veterinarian for diagnosis immediately.
The greatest risk to humans from any cat is not from viral infections such as rabies, but from bites that can cause an extremely rapid and dangerous infection from a common bacterial organism called pasteurella multocida. Always use caution when handling unfamiliar cats and ALWAYS contact your doctor immediately if you are bitten.
Parasites can affect both feral and free roaming, owned cats. Roundworms and tapeworms are common; occurring after a cat ingests rodents carrying the parasites. Roundworms can be passed from a mother to her kittens in-utero, and from one cat to another from contact with feces containing eggs. Roundworms may cause diarrhea, malnutrition, bloating of the abdomen, and vomiting. Tapeworms must be ingested directly, and cannot be passed from one cat to another. If you see something that looks like a rice grain near a cat’s anus, this is most likely a tapeworm segment. As the tapeworm becomes very large, it can cause the same symptoms as roundworm. Both are easily treated with medication.
Giardia and Coccidia are intestinal micro-organisms that can cause severe diarrhea and sometimes vomiting. Both require a two to three week course of treatment not possible for adult ferals. Ear mites, mange mites, and fleas can be treated in ferals at the time of neutering if indicated. Ringworm (a fungus, not a worm) is difficult to treat in all cats, but is not life threatening.