Bacterial Diseases In Cats : Part 3

PLAGUE

Plague (bubonic plague) is a devastating disease caused by the bacteria Yersinia pestis. About 13 cases occur in humans in the United States each year, with some evidence that the disease is on the increase. Ninety percent of human cases occur in New Mexico, Arizona, and California. New Mexico accounts for 50 percent of reported cases annually. This disease is of concern because of potential cat-to-human transmission.

In nature, plague is perpetuated as fleas move from one rodent to another. Squirrels and prairie dogs are frequently infected. Cats, dogs, wild carnivores, and humans are accidental hosts. Cats and other carnivores acquire the disease by mouth contact with infected rodents or by the bite of infected fleas. Cats are highly susceptible to the disease, although in 50 percent of cases, the infection is mild or unapparent. The death rate in cats with severe illness is 30 to 50 percent.

Signs of severe illness in cats appear shortly after exposure. They include high fever, loss of appetite, apathy and depression, dehydration, mouth ulcers, coughing, and difficulty breathing. Large swellings (bubos, hence the name bubonic plague) involve the lymph nodes, especially those beneath the jaw. These swellings form abscesses that drain infective material. This is the most common form. Plague can also show up as a septicemic disease in the bloodstream or pneumonic plague in the lungs. In that case, cats may spread the disease by coughing out infected air droplets.

Diagnosis is established by chest X-ray, blood and tissue cultures, gram stains, and serial antibody titers to Y. pestis.

Treatment:

Great care must be taken by all people involved in the care of a plague-infected cat. Strict hygienic and isolation precautions under professional guidance are required. Hospitalization and veterinary management are imperative. Because the disease can be rapidly fatal, treatment is started before the diagnosis is confirmed by a laboratory. Y. pestis is susceptible to a number of antibiotics, including streptomycin, gentamicin, doxycycline, tetracycline, and chloramphenicol (but not penicillins). Antibiotics may need to be given for weeks.  

TUBERCULOSIS 

This rare disease in cats is caused by the tubercle bacillus (Mycobacterium). There are three strains of bacilli that produce disease in humans, but only the bovine type (M. bovis) and the avian type (M. avian) infect cats. Cats are resistant to infection by the human type (M. tuberculosis). Avian tuberculosis is not common.

Tuberculosis in cats is usually acquired by ingesting infected cow’s milk or by eating contaminated uncooked beef. Even though there has been a steady decline in tuberculosis with pasteurization of milk and elimination of this disease from dairy herds, it has not been completely wiped out.

Feline tuberculosis (M. bovis) is primarily a gastrointestinal problem. Common signs include low-grade fever with chronic wasting and loss of condition despite good care and feeding. Abscesses form in the intestinal lymph nodes and liver. Lung infection may also occur. Occasionally, an open wound becomes infected, leading to skin involvement with draining sinuses and a discharge containing bacteria.

Respiratory tuberculosis causes rapid labored breathing, shortness of breath, and production of bloody sputum.

The finding of tubercle bacilli in the feces, in sputum, or in drainage from a wound makes the diagnosis. Special stains are needed when looking at samples on a slide under a microscope. A chest X-ray may be suggestive. The tuberculin skin test is not reliable in cats. A new blood test for nitric oxide may be useful for cats suspected of having tuberculosis.

Treatment:

Treatment, which involves antituberculous drugs, is difficult and prolonged. 

BORDETELLA 

Bordetella bronchiseptica is a cause of upper respiratory infection in cats. This bacteria is present in normal, healthy cats as well, so it seems to be a problem secondary to viral upper respiratory infections. Rarely, pneumonia will develop.

evelop. This illness is more severe in young cats and in shelters or situations with crowding, poor ventilation, and stress. Clinical signs include lethargy, fever, anorexia, coughing, sneezing, discharges from the eyes and nose, and swollen lymph nodes under the chin. Difficulty breathing suggests pneumonia.

Treatment: 

Supportive care is important, with antibiotics if needed. An intranasal vaccine is available.