Intestinal Worms




There are two broad categories of worms that may affect our pet dogs and cats, intestinal worms and heartworms.  Please see our heartworm page for more information on heartworm.


Intestinal Worms


Worming is one of the first health care issues pet owners need to address as pups and kittens are the most susceptible to the ill effects of heavy intestinal parasite burdens. Many of the worms carried by puppies and kittens (and older dogs and cats) are zoonoses (parasites capable of transferring from animal to man and vice versa) so they can also cause clinical diseases in humans.


As their name suggests, intestinal worms are parasites that live inside your pet’s intestines. These worms range in size from small to surprisingly large (up to 18cm in length). Regardless of their size however, they all have negative, and potentially deadly effects.


Most species of animal, as well as humans, can be infected with intestinal worms including dogs, cats, rabbits, horses, fish, birds and reptiles.


Common intestinal worms in Australian pets are:

  • Roundworm

  • Tapeworm

  • Whipworm

  • Hookworm


If your pet has a large number of worms it may find it difficult to maintain body condition and it can lose weight. In some cases it can cause vomiting, diarrhoea and even anaemia (a low red blood cell level). Occasionally, heavy intestinal worm burdens can cause death.

Worms sometimes have complex lifecycles which involve a period of existence and development outside your pet. Understanding the life cycle of a specific worm is important so that strategies for treatment and prevention can be designed and implemented.  For instance, some tapeworms need to pass through fleas to complete their lifecycle, so flea prevention is an important method of controlling tapeworms.




What are roundworms?


The roundworms Toxocara canis and Toxocara leonina are intestinal parasites found in dogs and cats respectively. Toxocara canis is probably the most important of the two.  The adult dog roundworm is a whitish worm up to 10cm in length. The adult worms live in the small intestine of the dog.


Life cycle.


Adult worms live in the small intestine and one female can lay up to 200,000 eggs a day. The eggs pass out in the dog's droppings and on to the ground where the larva develops inside the egg shell into a second stage larva as it waits to be picked up and ingested by another dog. The eggs are sticky and will stick to the fur or feet of dogs, entering the mouth when the dog licks itself. The thick egg shell protects the larva against adverse environmental conditions including many disinfectants.


Eggs on the ground take about 2 weeks for larvae to develop into the second stage larvae. Once they reach the second stage of their development they are infectious. Eggs swallowed by a dog or pup enter the stomach, the shell is dissolved and the larvae released to move into the small intestine from where they burrow through the gut wall into blood vessels that lead them to the liver. After migrating through the liver they develop into a third stage larva, migrate via blood vessels to the heart and then into the lungs, grow some more then break out of the lung tissue to be coughed up and swallowed by the host dog to end up initially back in the stomach, and then the small intestine where they grow into adults. The new adult females begin to lay eggs within 2-3 weeks of once again entering the small intestine.


The whole life cycle takes around 6 weeks from egg to adult. The time from infection to detection and disease (the length of the life cycle) is known at the Prepatent period.



Life cycle in the pregnant bitch.


Young bitches will carry dormant migratory roundworm larvae in their tissues, larvae that do not complete the entire life cycle while the bitch is a pup. During pregnancy, these larvae are "reactivated" and many of them find their way into the uterus where they burrow through to infect the pups. Within 2 weeks after birth, pups can actually have adult roundworms in their intestines. For this reason it is necessary to treat pups for roundworm at a very early stage in their lives. The rest of the "reactivated" larvae complete their life cycle as per usual. The whole life cycle may take as little as 6 weeks.


What problems do roundworms cause?


Roundworm infection can be fatal in young puppies and kittens. Migrating roundworms can cause pneumonia and inflammation of the lungs, as well as intestinal blockage. Roundworms also rob young animals of much needed nourishment. In healthy adult animals roundworms are seldom cause serious health issues.


Symptoms of infection.


In young animals:


  • potbelly
  • diarrhoea
  • gas or flatulence
  • vomiting
  • lethargy
  • pale gums (white instead of pink)
  • stunted or slow growth
  • dull, starry coat
  • coughing
  • colic.




Diagnosis can be made by observing spaghetti-like roundworms in vomit or faeces or by microscopic examination of a faecal sample to check for roundworm eggs.


What is the treatment for roundworm?


If roundworm infections are severe, puppies or kittens may require hospitalization and treatment.


A basic programme for treating puppies for roundworm revolves around specific treatments being given at 2, 4, 8 and 12 weeks of age then once every 3 months throughout the life of the pet. For the 3 monthly treatments we recommend two wormings a fortnight apart.  The parasite control programmes we recommend will depend on how many pets you own, the environment they live in and whether or not children make up part of the household.


Roundworm as a zoonosis.


A zoonosis is a disease that can be transmitted from animals to man and man to animals. Roundworms are capable of infecting humans. When they do they cause a disease known as visceral larvae migrans. Young children are infected by eating dirt contaminated with roundworm eggs that have come from animal faeces. Because humans are not their normal hosts, roundworms don't complete their normal migration and tend to remain in various parts of the body. They particularly like nervous tissue and are associated with blindness when they reach the optic nerve.


Because roundworm infection is a zoonosis we recommend that where children under 12 years of age are part of a household with pets, particularly dogs, monthly worming for intestinal worms becomes the normal protocol. Ask us which worming programme best suits your needs and we will advise you on the right programme for your household that considers your pets as well as you.


To prevent this disease, encourage your children to wash their hands after play and before eating. Remove and dispose of animal faeces in yards. Keep sand pits covered when not in use.




The are three types of hookworm in Australia and although different types of hookworm occur in different parts of the country, hookworm disease occurs anywhere in Australia. The three types are:


  • Ancylostoma caninum - prefers warm climates, probably the most dangerous of the three types of hookworm
  • Ancylostoma braziliense - prefers tropical climates
  • Uncinaria stenocephala - prefers cooler climates.


All three types of hookworm can infect dogs of all ages. They cause problems by latching onto the gut wall and sucking blood directly from the host. A single hookworm can suck as much as 1ml of blood from a host each day.


Life cycle of hookworms.


A single female hookworm can lay up to 30,000 eggs a day!



An infected animal passes hookworm eggs in its faeces. The eggs hatch into free-living larvae under the right conditions. These larvae are quite resistant to adverse conditions but they do like shade and they need moisture to move about in. They are most active in warm humid conditions burrowing into the soil and remaining alive there for some weeks.


Infection takes place either directly through the skin of the foot or accidentally by swallowing larvae in water and food or when the animal sniffs a contaminated area. If the larvae enter the host dog by penetrating the skin they move through the blood vessels up into the lungs, then burst out of the lungs and are swallowed, eventually establishing themselves as adults in the small intestine. If they enter by ingestion through the mouth they immediately go straight to the small intestine.


The life cycle for hookworms is very short, as little as two weeks from the time of infection to the establishment of adults in the small intestine. This is important to know because you may, as an owner, think you have wormed your pet only to find that within two weeks your dog has hookworm again. Oral worming preparations only kill the hookworms actually in the intestines at the time.


Hookworms are capable of infecting young puppies after larvae establish themselves in the tissues of the bitch in a similar fashion to roundworms, re-activating themselves when the hormones of the bitch change in response to coming into heat and falling pregnant. Although pups may occasionally be infected in the uterus, most pups are infected by hookworm through the mammary glands as they suckle. This means pups as young as two and three weeks of age can carry adult hookworms.


What problems do hookworms cause and what are the signs of infection?


  • Severe and even fatal blood loss, especially in puppies.
  • The teeth of hookworms can physically damage the wall of the small intestine leaving bleeding wounds causing further blood loss.
  • Dark, bloody faeces.
  • Bloody diarrhoea.
  • Weight loss.
  • Pale gums indicating anaemia.
  • Dry coat.


How is infection diagnoses?


Infection is diagnosed by clinical examination of the symptoms of illness and by microscopic examination of a sample of faeces, looking for hookworm eggs.


What is the treatment?


We can offer you pet a range of oral and spot-on products that will control all intestinal worms including hookworms. In most cases it's as simple as giving worm tablets in the correct manner and at the correct dose. Our staff can guide you in this matter. In more severe cases, pups especially may need to be hospitalized, given supportive therapy and treated for blood loss.


Prevention and control of hookworm.


There are ten important points in a hookworm control programme:


  1. keep dog runs dry;
  2. avoid having shade over the dirt part of the run; shaded parts should be concreted or provided with raised boards.;
  3. minimise dirt in runs and drain well;
  4. pick up droppings daily from the backyard or dog runs where practical;
  5. prevent grass outside dog runs growing through the dog run or backyard fence and providing shade (dogs like to lie in the shade along a fence, and hookworm larvae prefer the shade as well, so when a dog lies where there are larvae they can burrow in through the dog's skin and foot pads very easily, infecting the dog);
  6. make any dirt runs as large as possible (if dirt is unavoidable) - this will have a diluting effect - infective larvae will be more spread out; try to minimise the number of dirt patches in the backyard;
  7. if breeding dogs - try not to run pups and young dogs successively in the same areas; if the grounds cannot be spelled between pups and young dogs then follow pups on after older dogs;
  8. in a breeding situation - change around the whelping units and try to give them a period of weeks or preferably months between batches of litters;
  9. adopt a strict worming programme - contact the clinic for more information on worming dogs for hookworm as we have a variety of products designed to suit all sorts of household and pet needs which will cover all the intestinal worms, not just hookworm;
  10. breeding bitches should be treated for hookworm at 3 weekly intervals if using oral worming preparations, commencing shortly before mating and continuing until puppies are weaned; with some of the new spot-on products this will not be necessary - we can advise you on the best way to approach your situation - just visit the clinic or give us a call.

Young pups can be wormed from one week of age with oral worming syrups and suspensions, then again at 2 weeks, 3 weeks, 4 weeks, 6 weeks, 8 weeks, 10 weeks and 12 weeks. During this time the products that you use can be changed according to the situation, and advice can be obtained from the clinic in this respect. Be guided by the correct dosing regimes prescribed on product flyers, and any advice we give you.


Older dogs can be placed onto an oral 3 monthly worming protocol or a monthly topical treatment regime.




What are whipworms?


Whipworms are also intestinal parasites of dogs. Their scientific name is Trichuris vulpis. This worm lives in the caecum of the dog (a part of the large intestine). They mainly infect dogs over 12 weeks of age so can be a problem in adult dogs. Adult worms look like a stock whip and can measure up to 4-7cm long.


Life Cycle.




Infected dogs pass whipworm eggs in their faeces and other dogs become infected when they ingest these eggs. The egg of the whipworm has a very thick shell which has a plug at either end. It is from these plugs that the developing larvae emerge into the intestine of the dog. Because of their thick shells, the eggs can last for years in the environment so once a whipworm infestation exists on a property, it is probable it will remain for a long time.


After the eggs are swallowed, they pass to the intestine where they hatch into larvae  that develop into adults. The adults then lay eggs which are passed out in the faeces to lie around in the environment ready to be picked up and ingested by another dog. Bitches can infect puppies from their own droppings. The life cycle of the whipworm is about12-17 weeks in total.


What problems do whipworms cause?


Whipworms attach to the wall of the gut and suck blood for nourishment. This causes inflammation and irritation to the gut wall and can result in diarrhoea and anaemia, and in extreme cases, death.


What are the signs of whipworm infection?


If the infection is mild there will be no obvious symptoms. More serious cases might show signs of:


  • weight loss;
  • diarrhoea;
  • blood or mucous in the faeces;
  • anaemia (white or pale gums are an obvious sign);
  • weakness; and
  • death.

How is this disease diagnosed?


A microscopic examination of a fresh faecal sample is performed to detect whipworm eggs. This can be done right here at the clinic.


What is the treatment and what sort of a control programme can be implemented?


Treatment consists of the administration of an appropriate de-worming medication that kills the worms. If your dog is showing any of the more severe signs of a whipworm infection it may be necessary to hospitalise your pet and treat the symptoms using a variety of supporting therapies.


To control this parasite:


  • careful attention to hygiene - regularly remove all droppings from the kennel, yard and any dog runs;
  • don't use dirt runs and minimise areas of dirt in yards;
  • implement a regular treatment programme - call us for advice.




The most common tapeworms that affect dogs in Australia are:


  1. the flea tapeworm - Dipylidium caninum which also affects cats; and
  2. the hydatid tapeworm - Echinococcus granulosus - which from the human health point of view is an important tapeworm that uses the dog as an intermediate host in its life cycle.


Unlike roundworms, tapeworms consist of a head part, which attaches to the lining of the dog's intestine, and a body part consisting of numerous segments, which hang into the inside of the dog's gut.


The flea tapeworm is quite large (up to 50cm long) and its segments are often seen in the droppings of dogs and cats and sticking to the fur around the backside or even to the anus. The segments look like small white melon seeds and often move.



The hydatid tapeworm is a lot smaller (4-6mm) and the segments in dog's droppings cannot be seen with the naked eye.


How do pets become infected with tapeworms?


Tapeworms have a complicated life cycle. Adult tapeworms shed segments inside the intestines which are passed out in the faeces of dogs and cats from time to time. The segments of the flea tapeworm can often be seen stuck to the fur around the anus or attached to the anus itself. They look like small white melon seeds and often move. Unlike the roundworms mentioned above, tapeworms must go through a development stage in another animal known as an intermediate host before they can reinfect a dog or cat.



The intermediate host for the flea tapeworm is the flea. Flea tapeworm segments full of eggs fall out into the environment in the faeces. There they rupture and the eggs are released. Some eggs will be consumed by flea larvae which look like very tiny maggots. Once consumed, the eggs develop into cysts inside the flea. When a dog or a cat chews at itself in response to the itchiness caused by fleas biting and moving around on their skin they may accidentally swallow a flea which is then digested. The flea tapeworm cysts are released into the gut and develop into adult tapeworms in the animal's intestines. The life cycle then begins all over again. The whole cycle takes about 6-8 weeks to complete.


The intermediate host of the hydatid tapeworm is one of a number of farm animals including sheep, cattle and pigs. Man can also act as an intermediate host. When animals graze areas of grass contaminated with droppings of hydatid tapeworm infected dogs, they will pick up eggs of the tapeworm from the contaminated droppings. Once consumed, the eggs develop inside the grazing into large cysts called hydatids. These cysts are usually found in the offal (liver, lungs etc) of the intermediate host. If a dog should eat offal contaminated with hydatid cysts it will become infected with adult hydatid tapeworms. The whole life cycle of hydatid tapeworms takes about 6-7 months.




What problems do tapeworms cause?


Flea tapeworms seldom cause serious problems in dogs and cats. The parasites do absorb nutrients from the intestinal tract thus depriving them of some nutrition but they don't feed directly from their hosts by attaching to the gut lining. The most serious problem caused by flea tapeworms is an intestinal blockage.


Hydatid tapeworms are mainly a risk to humans and are considered to be a serious zoonotic disease that can cause considerable public health problems, particularly in sheep producing regions. The problems today are nowhere near as bad as they have been in the past.


Man can act as an intermediate host, becoming infected by picking up eggs from the droppings of dogs - a problem where dogs have been allowed to defaecate in vegetable patches, for example. The eggs develop into cysts or hydatids in the organs of humans in the same way they will in sheep or other intermediate hosts. The most common organs affected in man are the lungs, the liver and the brain and the disease can be so severe as to cause death. A cure can only be achieved by surgery to remove the hydatids.


Note: man cannot become infected by eating hydatids in offal meats, only by ingesting eggs from out of the environment where an infected dog has defaecated. It is important to realize that it is the hydatid which affects man, not the adult worm.


What are the signs of tapeworm infection?


Often a pet infected with flea tapeworm will scoot along the ground on its rear to relieve itching caused by crawling egg-containing segments. Other symptoms can include:


  • mild diarrhoea
  • flatulence or wind
  • vomiting
  • lack of energy
  • weight loss
  • dull coat.


Dogs infected with hydatid tapeworms will show absolutely no symptoms whatsoever that they are infected, or that they and pose a danger to humans and other animals.


How is tapeworm diagnosed?


Diagnosis of flea tapeworm is by the presence of the tiny white melon or cucumber shaped seeds in fresh faeces and around the pet's anus or in their bedding. A microscopic examination of a faecal sample will detect the presence of eggs, and of hydatid tapeworm.


What treatment is recommended and how can you prevent your pets from becoming infected with tapeworms?


  1. Flea tapeworm: we can provide you with the latest products for controlling this parasite. Careful management of fleas on your pets reduces the chances that they become infected with the tapeworm. There are worm tablets and topical spot-on products available to use so all you need to do is discuss the problem with our nurses and a parasite control programme can be tailored to suit your household and pet's needs.
  2. Hydatid tapeworm: even if you live in a metropolitan environment, or a rural town it is still important to be aware of this parasite and the problems it can cause. To avoid infecting dogs it's best not to feed raw offal meats (especially in the country) and in high risk areas, worming working dogs and pets once every 6 weeks with the right drugs will prevent the build-up of hydatid tapeworms. If offal meat is to be feed, the hydatids can be killed by boiling or cooking the offal first. Talk to our staff for more information on how to control this potential human health problem.
  3. Good hygiene will prevent pet owners from becoming infected with tapeworms.




Prevention of re-infection with intestinal worms.

It is important to maintain a routine worming treatment for your pets, to reduce the incidence of infection and to reduce environmental contamination. There are many worming treatments available for the various worm infections that occur in our pets. These are available as tablets, spot-ons, or pastes. Re-infection is a common problem, particularly in pets that are in contact with a heavily contaminated environment. Another very important reason to worm your pets is to protect your family as children in particular can become infected with certain dog and cat worms.


In the case of tapeworms, eliminating the dangers posed by intermediate hosts is very important. A good flea control programme is essential and quarantining pets and working dogs from raw offal meats is important.


Below are some tips to consider regarding worm prevention:

  • Promptly clean up pet faeces

  • Practice good hygiene, always encourage children to wash their hands regularly (especially after playing in dirt or sandpits, playing with pets or prior to eating)

  • Prevent children from playing where the soil may be contaminated

  • Keep your pet's environment clean

  • Always dispose of dog faeces in public parks and playgrounds

Please call us to discuss an intestinal worming program for your pet.