Common Intestinal Worms and Parasites

Intestinal parasitism is a common and potentially severe problem in veterinary medicine. The number of organisms that can infect our domestic animals is staggering. Only the most common parasites of dogs and cats found in this part of the country are discussed in this article.

Current recommendations by the American Veterinary Medical Association are that all young companion animals should be dewormed at least two times and have routine fecal exams to identify any intestinal parasites not eliminated by the deworming.

Roundworms

¨ Location - Live in the small intestine, look like thin spaghetti.

¨ Diet - Feed on the nutrients in the hosts' diet.

¨ Transmission - Eggs are passed in the feces and ingested by the next host. Additional means of infection are the transmission of larvae from mother to fetus in the uterus or in the milk after birth. Infection can also be acquired by hunting and eating smaller animals infected with the parasite.

¨ Diagnosis - Finding eggs in a fecal sample or an actual worm in feces or vomitus.

¨ Treatment - Oral deworming medication.

¨ Importance - Can cause unthriftyness in young animals, poor coat, vomiting and pot-bellied appearance. Can cause malnutrition in any age animal. Can be transmitted to humans although the occurrence is low.

¨ Frequency of infection - very common, especially young animals.

Hookworms

¨ Location - Live in the small intestine, very small worms.

¨ Diet - Feed on blood. Can kill a puppy or small animal due to blood loss.

¨ Transmission - Eggs are passed in the feces. The eggs develop into larvae in the environment. These larvae can then be ingested or actually penetrate the skin and migrate to the intestines. Puppies can also be infected through their mother’s milk.

¨ Diagnosis - Finding eggs in a fecal sample or suspicious symptoms.

¨ Treatment - Oral de-worming medication.

¨ Importance - Can cause death in young animals due to anemia. Can cause severe bloody diarrhea, dehydration and anemia in any age animal. Can be transmitted to people although the occurrence is low.

¨ Frequency of infection - very common, both young and mature animals.

Whipworms

¨ Location - Found in the cecum (portion of large intestine).

¨ Diet - Feed on blood.

(Whipworms continued)

¨ Transmission - Eggs are passed in the feces. The next host ingests the eggs and gets infected. Eggs can withstand severe weather conditions (heat and cold).

¨ Diagnosis - Finding eggs in a fecal sample.

¨ Treatment - Oral deworming medication

¨ Importance - Can cause bloody diarrhea and dehydration.

¨ Frequency of infection - very common, both young and mature animals.

Tapeworms

¨ Location - Adult worms live in the small intestines of dogs and cats.

¨ Diet - Absorbs nutrients from the hosts' digestive tract.

¨ Transmission - Most commonly contracted by eating fleas that carry the parasite. Can also be acquired from hunting and eating rodents or rabbits.

¨ Diagnosis - Noting segments (possibly moving) on a fecal sample or adhered to the pets fur. Look like grains of rice. Eggs are not usually found in fecal samples.

¨ Treatment - Oral or injectable dewormer. Requires different drug than the other intestinal worms.

¨ Importance - Of little importance in healthy adult animals, however, they are quite aesthetically disturbing. A new variety of tapeworm (Echinococcus) is becoming more widespread and may become very important as it is transmissible to people with serious consequences. It is currently not found in southern Indiana.

¨ Frequency of infection - very common, especially if fleas are a problem.

Coccidia

¨ Location - Protozoal parasite of the small intestine

¨ Transmission - Eggs are passed in the feces. The eggs are either ingested directly by the next animal or a rodent may consume the eggs and subsequently be eaten by the next host.

¨ Diagnosis - Appearance of feces and/or eggs found in a stool sample.

¨ Treatment - Oral antibiotic

¨ Importance - Can cause dehydration and mucousy diarrhea, especially in young animals. Adult animals may have no symptoms.

¨ Frequency of infection - Very common in unsanitary conditions. Frequently diagnosed in animals purchased from pet stores.

Giardia

¨ Location - Protozoal parasite found in the small intestine

¨ Transmission - Ingested from contaminated water sources (ponds, streams).

¨ Diagnosis - Giardia is difficult to find in fecal samples. Diagnosis is based on the clinical signs (chronic diarrhea with or without blood.)

¨ Treatment - Oral antibiotic

¨ Importance - Can cause diarrhea and dehydration. Potential for human transmission is primarily from the contaminated water source.

¨ Frequency of infection - Actual frequency is not known as infections are difficult to verify.