Our pets bring us countless hours of pleasure, companionship and entertainment, but pet owners are quite often unaware of the need to protect both their pets and themselves from diseases that can be harmful to pet and master alike. Many of the parasitic infections which commonly afflict pets can have adverse effects on people as well. Most of these diseases are clinically silent or produce symptoms that are non-specific, such as diarrhea, weight loss, or poor coat quality. A brief review of the common parasites we find in pets should help educate most pet owners as to the need for monthly parasite preventative.

External parasites:

Fleas are the most common skin parasite that we see in southern California. These tiny insects feed off the blood of your pet and can cause intense itching and discomfort for him as well as for you. What many pet owners fail to realize is that fleas are the disease vectors for both Cat Scratch Fever (bartenellosis) and Bubonic Plague. It’s extremely unlikely that anyone is going to get the plague from their pet, but it is something that should raise an eyebrow. In addition, fleas are the intermediate host for the common tape worm, Dipylidium, which we frequently find in dogs and cats.

Ticks are gross. They are also virtually indestructible. Ticks are commonly found in the spring in areas with tall grass and tend to be most active in the morning and evening hours. Ticks are another blood-sucking parasite that can afflict your pet. They are as vector for a number of diseases including Lyme disease, Rocky Mountain Spotted Fever, and Canine Ehrlichiosis which causes severe decreases in blood platelet numbers. (Platelets are the cells that help clot blood, so these dogs are at risk for severe bleeding episodes.) While there are a number of products that help protect against tick infestation, none is highly effective. Your best best at preventing ticks from attaching to your dog is to avoid areas with tall grass, and to check your pet thoroughly after having him outside.

Internal parasites:

We have a growing mosquito population in southern California as well as an indigenous wild reservoir for heartworm infection, the coyote. This disease is spread when an infected mosquito bites another mammal such as a dog, cat or even a human. Tiny heartworm larvae are injected into the blood stream where they mature over the span of about 6 months until they reach adulthood in the veins of the pulmonary artery and lungs, where they reproduce and release microfilaria into the blood for the mosquito to ingest and pass on. In cats, heartworm infection is often fatal. In dogs, it produces symptoms of coughing and exercise intolerance and the severity usually depends on the number of worms present in the lungs. Heartworm infection in man, although rare is well documented and serious. The most effective way to prevent heartworm infection is through the monthly, year-round administration of a preventative

We find a number of intestinal parasites in pets that can cause harm to both pet and owner alike. Roundworms are very common in puppies, so common in fact that it is routine to deworm puppies without even testing them. Roundworms live in the small intestine, where the breed and release eggs into the environment. The eggs develop into larvae which when ingested and swallowed by a dog or cat migrate to the liver, then the lungs and are then coughed up, swallowed and mature to adult hood in the small intestine. This tissue migratory phase also produces a reservoir of viable larvae that can live for years encysted in the muscle tissue and are intermittently released during times of stress, such as during pregnancy or nursing. Puppies and kittens can be infected transplacentally or while nursing as the larvae pass into them with the mother’s milk.

When humans accidentally ingest round worm larvae, the same pattern of tissue migration occurs. Although the roundworm never reaches the mature stage in the intestine, it does form cysts in various organs. The percentage of people in the U.S. who have antibodies to roundworm is about 20%, so human infection is by no means rare. The importance of this is several fold. Larvae when they migrate to the eye can cause blindness. There are also documented cases of larvae migrating to the brain and across the placenta of pregnant women resulting in birth defects. These instances are rare, but not unheard of. The best way to virtually eliminate this risk is to have your pet on a monthly broad-spectrum parasite preventative.

Other parasites that we see in this area include hookworms and whipworms. Hookworms also have a larval phase when free-living and can penetrate the skin causing intensely itchy red linear tracts on the feet and legs.Don’t go bare foot atthe dog park or Dog Beach. They are blood suckers as well and can cause severe anemia in puppies if not detected. Whip worms have no effect on man, but they do produce a low grade chronic inflammation of the large intestine in dogs.

All Dogs, All Year. Because of the significant potential health risks to both pet and owner alike, we strongly recommend that all dogs be on year round parasite prevention. This is especially important if you have small children in the home or are, or are planning a pregnancy. Your choice of preventative is best discussed with you veterinarian who can recommend the best product for your pet.

For comprehensive information on parasites in pets, visit the Companion Animal Parasite Council website at www.CAPCVET.org