Parasite Control in Small Animals

Intestinal Worms

Both dogs and cats require regular worming to remove parasitic worms which live in the intestine.

Puppies and kittens should be treated for worms every 2 weeks until 3 months of age and then monthly until they are 6 months old. After this, all dogs and cats should be treated for roundworm, hookworm and tapeworm once every 3 months.

There are multiple products available for small animal intestinal worming including both tablets and spot-on preparations. For dogs, these include Drontal (puppy syrup, tablets and chewable tablets), Milbemax and Popantel. For cats, there are spot-on preparations, such as Profender and tablets, for example, Drontal and Milbemax.


Flea treatment and control is an important part of parasite prevention in dogs and cats. Adult fleas get their nutrition from biting pets and getting a meal of blood. If left untreated fleas can, over a period of time, cause the dog or cat to have an insufficient number of red blood cells, a problem which is known as anaemia. In young or debilitated animals, the anaemia may be severe enough to cause problems such as weakness and lethargy.

Flea allergy dermatitis (FAD) is the most common hypersensitivity (allergy) seen in veterinary clinical practice. This disease develops when a dog or cat becomes allergic to the saliva in the flea’s mouth and when bitten by a flea, intense itching occurs, causing the pet to chew and scratch continuously. Common areas affected the lower back, tail and groin region.

Fleas are also a necessary intermediate host for tapeworms. Controlling fleas assists greatly in reducing the chance of tapeworm infestation.

Flea control involves both treating the pet and also treating the environment. There are many products available to assist with this control.


Heartworm disease (dirofilariasis) is caused by a parasitic infection with Dirofilaria immitus. The worms, as the name suggests, live mainly in the heart and pulmonary arteries of infected dogs (and cats). They survive for many years and during this time the female produces millions of young (microfilaria). The adult worms and the immature microfilaria can cause disease to the heart and blood vessels of many organs, particularly the lungs, liver and kidneys. The disease is not spread directly from animal to animal and an intermediate host, the mosquito, is required for transmission.

It is possible to diagnose and treat heartworm disease but due to the potential severity of this disease and the side effects of treatment, prevention is highly recommended. The options for preventative treatment include daily and monthly medications or an annual injection.