Illustrated Articles

Cats + Infectious Diseases

  • Feline upper respiratory infection (URI) is one term for a respiratory infection caused by one or more viral or bacterial agents. Synonyms for this condition include feline infectious respiratory disease and feline upper respiratory disease complex (URD).

  • Usually caused by a bite from another cat, fight wound infections can lead to the development of an abscess (a pocket of pus) or cellulitis (pain and swelling in the area of the bite). A cat’s sharp canine teeth can easily puncture the skin of another cat, leaving small, deep, wounds that seal over quickly, so it is important that your cat is seen by a veterinarian for treatment as soon as possible after being bitten.

  • Flea and tick prevention consists of a variety of products used to control flea and/or tick infestations on your pet and to prevent infestations inside the home. Fleas and ticks can be found worldwide. Fleas can live in many climate zones, but they prefer humid and shady areas, such as under leaf litter. Ticks can also live in many climate zones, and prefer humid and shady environments, especially areas with woods, shrubs, weeds, and tall grasses. Prevention is key to avoid infestations in your home, severe allergic reactions (in both pets and people), and to prevent disease. Many flea and tick preventives are available. Your veterinarian will help you find an appropriate product that works best for your and your pet.

  • Giardiasis is an intestinal infection caused by a microscopic protozoan. The parasites attach themselves to the intestinal wall, and the damage causes an acute, sudden onset of foul-smelling diarrhea. Diagnosis may be by routine fecal flotation or presumptively based on clinical signs. Fenbendazole and metronidazole are the drugs most commonly used to kill Giardia. Giardiasis is the most common intestinal parasitic infection of man and can potentially be passed from cats to humans.

  • Heartworms (Dirofilaria immitis) are a blood-borne parasite that reside in the heart or adjacent large blood vessels of infected animals. Recent studies of cats with heart and respiratory diseases have found an incidence of heartworms that is far greater than previously thought. Veterinarians now strongly recommend that all cats receive year-round monthly heartworm preventives. There are excellent heartworm preventives now available for cats, making prevention of heartworm disease safe and easy.

  • Heartworms are blood-borne parasites that reside in the heart or adjacent large blood vessels of infected animals. There is no drug approved for treating heartworms in cats and surgical removal is generally the best option. Veterinarians now strongly recommend that all cats receive year-round monthly heartworm preventative in areas where mosquitoes are active all year round. Cats that live in colder areas, where mosquitoes are seasonal, should be given monthly preventives for at least six months of the year.

  • Feline viral rhinotracheitis (FVR) is an infectious disease caused by feline herpesvirus type-1. It is a major cause of upper respiratory disease in cats and is the most common cause of conjunctivitis. The typical symptoms of FVR involve the nose, throat, and eyes, and include sneezing, nasal congestion, conjunctivitis, excessive blinking, squinting, and discharges from the eyes and nose that range from clear and watery to thick and purulent (containing yellow/green pus). Treatment consists of supportive care, hydration of the environment, and control of secondary bacterial infections with antibiotics and antibiotic eye medications. An effective vaccine exists and is recommended for all cats.

  • Histoplasmosis is an infection caused by histoplasma, a fungus found in moist soils and especially prevalent around the Ohio, Mississippi, Missouri, and St. Lawrence Rivers, as well as the southern Great Lakes. Fungal spores are inhaled or ingested and cause infection in many sites including the lungs, gastrointestinal tract, eyes, joints, and spleen. Clinical signs can include fever, lethargy, anorexia, weight loss, coughing or trouble breathing, diarrhea, and straining to defecate. Diagnosis includes routine bloodwork, urinalysis, X-rays antigen testing, and cytology or histopathology. Treatment requires long term anti-fungal medication such as itraconazole. Prognosis is guarded depending on the severity of the symptoms. This disease is transmissible to humans, especially if they are immunocompromised.

  • Hookworm is a parasitic infection of the gastrointestinal tract of cats. Their name is derived from the hook-like mouthparts they use to anchor themselves to the lining of the intestinal wall. How the infection is spread along with clinical signs, diagnosis, treatment, and prevention are covered in this handout.

  • Idoxuridine is an antiviral topical medication used to treat viral infections of the eye, such as feline herpesvirus-1 in cats. Idoxuridine comes as eye drops or can be compounded by your veterinarian into an eye ointment. Give as directed. Side effects of idoxuridine include eye irritation. Pregnant women should NOT handle this medication.