Shaping the future of animal health

Intestinal worms in dogs and cats


hookworm Hookworm infection can be fatal. Hookworm can infect dogs and cats of all ages but are most commonly found in puppies.

Hookworm larvae are found in the soil and are ingested or can penetrate the dog’s skin through the feet and legs. Puppies can become infected by suckling their mother’s milk or through the placenta before they are born. The hookworm attaches itself to the intestine and sucks blood.

The main danger with hookworm is the potential for anaemia and diarrhoea. Signs of hookworm infection in dogs and cats include weight loss, poor appetite, a ‘big belly’, black, tarry faeces, diarrhoea, depression and lethargy.


Roundworm is also potentially fatal. Roundworms affect dogs and cats of all ages, however puppies and kittens are the most susceptible to infection and disease.The eggs of these worms can be ingested from the environment or larval stages can be passed through the placenta or mother’s milk to the puppy or kitten.

Although roundworm does not suck blood, they do attach to the lining of the animal’s intestine and feed on the digested food in the intestine. If left untreated, roundworm can obstruct the flow of food through the intestine. This can lead to a blockage of the intestine and this may be fatal.

Signs of roundworm infection in dogs and cats may include a dull coat, coughing, lack of growth, diarrhoea, vomiting, poor appetite, lethargy, weight loss and a ‘big belly’. In extreme cases, the worms can block the intestine and this may lead to rupture of the intestine and leakage of the intestinal contents into the abdomen (peritonitis). This is a very serious complication and can be fatal.


Whipworm parasitic life stages can only be ingested and cannot be passed on to puppies or kittens through their mother’s milk. Whipworm live in the large intestine, mainly in the caecum.

These worms attach to the wall of the intestine and cause irritation and inflammation. Signs of whipworm infection in dogs and cats may include intermittent diarrhoea, often with mucus and fresh blood, dehydration and debilitation. In severe infections anaemia may also develop. In extreme cases, death may occur.


tapewormTapeworm are usually the least dangerous of the intestinal worms for dogs and cats. The ‘flea tapeworm’ is the most common tapeworm infecting dogs and cats in Australia. It is usually contracted when dogs or cats eat a flea (whilst grooming) infected with the tapeworm larvae.

A different type of tapeworm, the ‘hydatid tapeworm’ infects dogs when they eat hydatid cysts present in the offal of infected species such as sheep. Hydatid tapeworms pose a serious threat to human health in certain areas. Read more information on how tapeworm is transmitted and the signs to look for to determine whether your dog has tapeworm.