Intestinal Worms
In cats, the most common intestinal parasites are roundworms, hookworms and tapeworms. Roundworms and hookworms are usually passed through contact with contaminated feces. Tapeworms require a secondary host, such as fleas or infected prey, to spread.
Intestinal worms can damage the digestive tract and cause anemia. Early symptoms include vomiting and diarrhea. If the infection is severe, cats will begin to lose weight and condition.
Symptoms of anemia include pale gums, weakness and poor appetite.
Regular treatments with over-the-counter feline wormer are effective against most gastrointestinal worms, but a separate product may be required for tapeworms. Prescription cat wormer paste products are more targeted and may be more effective against your cat's particular infection.
Protozoan Parasites
Toxoplasmosis is a microscopic parasite that lives in the cells of your cat's digestive tract. Toxoplasmosis may cause mild digestive upset in cats, but it is a dangerous illness in pregnant women, young children or those with compromised immune systems. These individuals should not handle cat litter, a common source of toxoplasmosis spread.
Coccidia and giardiasis are also protozoan parasites. Coccidia cause diarrhea in younger cats and those with weak immune systems. As kittens grow older, they become immune to coccidia, shedding cysts in their feces but showing no adverse symptoms.
In older cats, giardiasis is usually asymptomatic, but in kittens it may cause acute, intermittent or chronic diarrhea and weight loss. Feces may be pale colored.
Flukes and Lungworms
Outdoor cats are more likely to become infected with flukes or lungworms. Aquatic animals such as frogs and snails are the primary hosts for the larvae of these parasites. Testing is done by fecal sample.
Flukes and lungworms can cause damage to the lungs, liver and intestines of infected cats. Signs of a severe fluke infection include jaundice, anorexia, vomiting, weight loss and abdominal distension. Lungworms may cause coughing and respiratory distress.
External Parasites: Fleas, Ticks and Mites
Fleas, ticks and mites affect indoor and outdoor cats. Signs of a flea infection include itching and the presence of "flea dirt," small specks of dried blood in the fur of your cat. Fleas are the main source of tapeworms in cats as well. Monthly "spot on" flea treatments will eliminate fleas quickly.
Ticks can be as small as the head of a pin, making them very difficult to locate until they have become engorged with blood. Ticks cause a variety of illnesses including Lyme disease (painful or stiff muscles and joints, fatigue, fever and anorexia), Babesiosis (anorexia, lethargy, weakness, and a rough haircoat) and Ehrlichiosis (swollen glands, breathing difficulties, fever and discharge from the eyes).
Mange mites and ear mites cause intense itching and red, scaly skin. Ear mites will cause head shaking, itching and secondary bacterial infections of the ear. Many "spot on" flea preparations manage mite populations as well.
Most common parasitic infections in cats are easily treated if caught early. Regular veterinary checkups combined with a sharp eye for your cat's overall health and well-being will keep a mild infection from becoming something more serious.