How a dog gets infected by worms depends on the kind of worms the dog has. The most common ones in dogs in general are:-


In this article, we will explain the differences between each type.

It isn’t always easy to tell if your dog has worms, unless he or she has a heavy infestation thus making the symptoms more obvious.


Roundworms look like spaghetti. On average, they are about 3-5 inches (7-12 cm) long. They live in the labradors intestines and consume partially digested food.
Roundworms can be picked up from the ground, where you take your dog for walks, and by your 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. Your Labrador dog picks them up on its coat, paws and muzzle and then ingests them while grooming – thus infecting the dog, and so the cycle goes on. They can also be picked up by nursing from an infected mother dog. (This is true even if the mother tests negative for roundworms as roundworm larvae (immature worms) encyst in the mother’s muscle tissue and are not detected by tests for adult worms)

Types of roundworm:
There are two different types of roundworms affecting dogs and puppies: Toxocara canis and Toxascaris leonina .

The symptoms will range from none to vomiting, diarrhea, pot-bellied appearance, dehydration, weight loss and loss of condition. With large infestations, sometimes lung damage can occur resulting in breathing problems.

Prevention & Treatment:
Both of these roundworms are treated with the same medication protocol so it is not necessary to determine which of the two species is present. Treatment is quite simple. Several very safe and effective drugs are available to kill roundworms in the intestine. Some of these drugs temporarily anesthetize the worms so that they pass out of the dog with a normal bowel movement. The live or dead worms are found in the stool. Speak to your vet regarding treatment and prevention medicine, who will prescribe accordingly. Accurate diagnosis of roundworms is important since they can cause serious problems, if you have any doubts you should take a stool sample from your dog to the vet to be examined.


Hookworms are smaller than roundworms. They are called hookworms because they feed by hooking onto the wall of the intestine.
Hookworms have pretty sharp teeth and can cause the dog’s intestine to bleed. Since hookworms eat blood, they like this situation, but too many of them can be very bad for the dog. Dogs can get hookworms from the ground where other dogs have passed eggs before, or from the milk of their mother if she was infected. In adult dogs, a fairly large worm load may be tolerated, but in puppies, hookworms can be life-threatening.
Puppies exposed to hookworms generally grow up with some degree of immunity against future infections.

Hookworms Symptoms:
Dermatitis, pneumonia, enteritis, bloody diarrhea, blood loss and anemia. Some dogs may also lose weight due to the bloodsucking of hookworms.

Prevention & Treatment:
It is once again important for you to speak to your vet if you suspect your dog has hookworms, who will then take a stool sample and issue the relevant treatment for your dog.


Whipworms are intestinal parasites which are about 1/4 inch ( 6 mm ) long.
Adult whipworms look like pieces of thread with one end enlarged. Whipworms pass microscopic eggs in the dogs stool. The eggs are very resistant to drying and heat, so they can remain viable in the dog’s environment for years. They mature and are able to reinfect the dog in 10-60 days. The eggs are swallowed and return to the lower intestinal tract to complete the life cycle.
Whipworms live in the cecum and colon of dogs where they cause severe irritation to the lining of those organs. The most common method of whipworm transmission is through the feces of dogs, but it is also suspected that they may be transmitted through soil. The eggs that pass through the feces can be swallowed unhatched by a healthy dog, where they will hatch inside .

If your dog has whipworms symptoms can include watery, bloody diarrhea, weight loss, and general debilitation.

Prevention & Treatment:
Avoid taking young puppies to areas where other dogs may be or may have been. If you suspect your dog has whipworms, speak to your vet who will examine your dog & its stool, and prescribe the correct treatment.


Tapeworms are called tapeworms because of their long, flat, ribbon tape appearance.
Adult tapeworms live in the guts of dogs, where they lay their eggs. The eggs are released with the dog’s feces, where they then dwell. Adult tapeworms may reach 8 inches (20 cm) in length. The adult worm is actually made up of many small segments about 1/8 inch (3 mm) long.
In order for a dog to become infected with the common tapeworm, Dipylidium, the dog must swallow a flea that contains tapeworm eggs. This process begins when tapeworm eggs are swallowed by flea larvae (an immature stage of the flea). Contact between flea larvae and tapeworm eggs is thought to occur most frequently in contaminated bedding or carpet. Next, the dog chews or licks its skin as a flea bites; the flea is then swallowed. As the flea is digested within the dog’s intestine, the tapeworm hatches and anchors itself to the intestinal lining.

Your labrador may have an itchy anus, leading to bad hygiene. Occasionally, the mobile segments can be seen crawling near the anus or on the surface of a fresh bowel movement. These segments look like grains of rice and contain tapeworm eggs; the eggs are released into the environment when the segment dries. The dried segments are small (about 1/16”, or 2 mm), hard and golden in color. These dried segments can sometimes be seen stuck to the hair around the dog’s anus. They may cause debilitation and weight loss when they occur in large numbers.

Prevention & Treatment:
Tapeworms are not usually detected by the routine fecal examination performed by the vet. Because of this, vets depend on the owner to notify them of possible tapeworm infection in the dog. Once advised, treatment can be given to treat the tapeworms. NB: Control of fleas is very important in the management and prevention of tapeworm infection. Flea control involves treatment of your dog, the indoor environment and the outdoor environment where the dog resides. A lot of vets recommend an effective flea protector called ‘frontline’.


Heartworms are found in the heart and large adjacent vessels of infected dogs. The female worm is 6 to 14 inches (2.3 to 5.5 cm) long and 1/8 inch (5 mm) wide; the male is about half the size of the female. One dog may have as many as 300 worms.
Heartworm is a potentially dangerous parasitic worm spread by mosquitoes.
Heartworms Adult heartworms live in the heart and pulmonary arteries of infected dogs. They have been found in other areas of the body, but this is unusual. They survive up to 5 years and, during this time, the female produces millions of young (microfilaria). These microfilaria live in the bloodstream, mainly in the small blood vessels. The immature heartworms cannot complete the entire life cycle in the dog; the mosquito is required for some stages of the heartworm life cycle. The microfilaria are therefore not infective (cannot grow to adulthood) in the dog, although they do cause problems. As many as 30 species of mosquitoes can transmit heartworms. The female mosquito bites the infected dog and ingests the microfilariae during a blood meal. The microfilariae develop further for 10 to 30 days in the mosquito and then enter the mouth parts of the mosquito. The microfilariae are now called infective larvae because at this stage of development, they will grow to adulthood when they enter a dog. The mosquito bites the dog where the haircoat is thinnest. However, having long hair does not prevent a dog from getting heartworms. When fully developed, the infective larvae enter the bloodstream and move to the heart and adjacent vessels, where they grow to maturity in 2 to 3 months and start reproducing, thereby completing the full life cycle. Canine heartworm disease occurs all over the world. In the United States , it was once limited to the south and southeast regions. However, the disease is spreading and is now found in most regions of the United States and Canada , particularly where mosquitoes are prevalent

The most obvious signs are a soft, dry, chronic cough, shortness of breath, weakness, nervousness, listlessness, and loss of stamina. All of these signs are most noticeable following exercise, when some dogs may even faint. There may also be evidence of weight loss, poor condition, and anemia.

Prevention & Treatment:
Listening to the chest with a stethoscope will often reveal abnormal lung and heart sounds. There is some risk involved in treating dogs with heartworms, although fatalities are rare. The drug that is used contains arsenic. The amount of arsenic is sufficient to kill heartworms without undue risk to the dog. However, dogs with poor liver or kidney function may have difficulty breaking down and eliminating the arsenic. In spite of this we able to treat more than 95% of dogs with heartworms successfully. If you live in an area with mosquitos, speak to your vet who will prescribe you treatment for your dog to help prevent them getting heartworm.

Q & A

What is the best thing to do when a new puppy is born?
Get puppies tested as early as three weeks after birth. They will often already be infested with worms and will need to be treated.

How often should I give worming treatment to my dog?
It is best to speak to your vet regarding treatment, however, most UK vets recommend puppies under three months of age should be wormed every two weeks from two weeks of age onwards. Once the pup reaches three months of age is it advisable to worm it every month until it is six months old and thereafter it should be wormed every three months.

Can humans catch worms?
Yes, some worms can be passed on to humans. Whipworms are not infectious to people; they are parasites of the dog.

Is it ok to use over-the-counter pet store drugs to prevent and treat worms?
It is always best to obtain worming treatment from your vet. The products from your vet are strong and effective.

My dog is older now, can he still get worms?
Yes, dogs of all ages are at risk, but puppies are particularly vulnerable to worms.

What happens to the worms after my vet has given them treatment?
After your vet has de-wormed your puppy or dog, do not be alarmed at the stool immediately following the medication. The worms are expelled over a 24 to 48 hour basis and the stool may be full of worms. Do not be alarmed — this is normal.

Please note, all of the above information has been written as a guide only, please consult your vet with any further questions you may have about worms, and always follow the advice of your own vet, as they will know your animal best.

4th March 2008