It isn't always easy to tell if your dog has worms, unless the dog has a heavy infestation thus making the symptoms more obvious. A good way to remember which type of worm is which is that roundworms look like spaghetti and tapeworms resemble grains of rice. Both of these can be picked up from the ground, where you take your dog for walks, and by the dog sniffing the ground, and in particular, sniffing the faeces of other dogs. Roundworms are passed from dog to dog via eggs and larvae in their faeces. These eggs and larvae can live in the soil for months or even years. The dog picks them up on it's coat, paws and muzzle and then ingests them while grooming - thus infecting the dog, and so the cycle goes on. Worming treatments for your dog must be carried out on a regular basis to prevent reinfestation.
The symptoms will range from none to vomiting, diarrhoea, pot-bellied appearance, dehydration, weight loss and loss of condition. Sometimes lung damage can occur resulting in breathing problems.
Toxocara canis is a white roundworm which most frequently infects young puppies, being passed via the uterus and the mother's milk. When the bitch becomes pregnant the hormones that she releases stimulates the roundworm larvae, which can be lying dormant in the tissues. Some will go to the uterus and into the developing puppies, some will go to the mammary glands and be passed to the puppies through the milk and others will stay in the intestine. Pregnant dogs should be treated for worms while pregnant and while feeding the puppies, also the puppies should be treated every few weeks in their own right. This roundworm, in a heavy infestation, can be life threatening in puppies. The adult roundworms lay their eggs in the small intestine which are then shed into the environment via the dogs faeces. There is a slight risk to humans from toxocara canis, acquired by accidental ingestion of these roundworms, mainly from dogs and possibly from cats. This disease is called visceral larval migrans, the roundworm larvae travel around the body and may settle in the eye and, in some cases, cause impairment of vision. If you follow the basic rules of hygiene the risk of infection is further reduced.
Toxascaris leonina is also a white roundworm, very similar to Toxocara cati. Infection of this roundworm occurs when dogs ingest the eggs, which then hatch in the intestine, and develop into the adult worms. This type of roundworm is not passed from the mother to her puppies from her womb or milk.
Diplidium caninum is a segmented tapeworm which lives in the dogs small intestine. Each segment of the worm contains maturing eggs. These segments, when passed from the dog, resemble grains of rice, you may even notice them around the dogs anus, on the dogs coat or bedding. These segments can cause anal irritation and excessive licking of this area.
Tapeworms are spread by the ingestion of fleas. The flea larvae swallows the eggs from the tapeworm segment, these eggs mature as the flea matures, making the adult flea infectious to the dog. When the dog ingests the flea, the tapeworm larvae are released into the small intestine and so the cycle goes on again. To treat this tapeworm you will also need to carry out flea treatment to help prevent reinfestation. The symptoms of this type of tapeworm infection can be, in severe cases, abdominal pain, diarrhoea and poor growth of the puppy. Tapeworms can infect humans, but this is rare, so dogs should be wormed regularly and a flea control programme carried out.
Toxoplasma gondii is a small parasite that lives in the cells lining the intestines of cats and uses dogs as an intermediate host. The eggs from this parasite are passed out in the cats faeces. These eggs become infectious and other animals can become infected if they eat them. The egg matures inside the dog and the parasite invades the tissues and forms cysts. These cysts are mainly formed in the muscles and occasionally in the brain. They can become active if the dog is stressed, for example when pregnant or ill. The dog will show no signs that it has this parasite unless it has a severe infection, the signs of which are diarrhoea, muscle weakness and respiratory infections. This infection can be transmitted to humans, it can be very serious in pregnant women, the baby can be affected or even aborted. To minimise the risk of this infection to humans, normal hygiene guidelines should be followed and common sense used at all times.