The no-good, the bad and the ugly

Few people can hear the word “worms” without cringing – especially if it is related to a beloved pet. Unfortunately, parasites living in the stomach and intestines occur all too common in our dogs and cats. These parasites live in the digestive tract, causing damage and robbing your pet of much needed nutrients. The amount of damage they cause depends on the type and number of worms your pet has.

The signs associated with worm infestations are fairly non-specific. They include a dull hair coat, vomiting, diarrhoea, slimy or bloody stools, loss of appetite, not gaining weight (puppies and kittens), an itchy bum and dried up worm segments around the anal area.

There are four common intestinal worms found in dogs and cats: Roundworms, hookworms, whipworms and tapeworms. Each worm type is “contracted” differently and has different effects on your pet and on humans.


Roundworms are long white worms that look like strands of spaghetti. They are very common in puppies and kittens because they are often directly infected by their mother – through the womb or through the mother's milk. This is why most puppies and kittens can be born with worms! Adult pets can become infected when they ingest eggs that were deposited in infected stools. The adult worms live in the pet’s intestines, where they use the animal's nutrients and cause irritation. The worms can become so many that your pet may vomit them up, or worse, in puppies and kittens they can cause a blockage in the intestines, threatening the puppy/kitten’s life. More often these little ones have trouble gaining weight and may have a pot belly and dull hair coat. Proper weight gain is one good way to see whether a puppy or kitten is healthy when you buy them from a breeder – a good breeder will always deworm from an early age.

Importance in humans:

Visceral larval migrans (worm life stages which burrow their way through human tissue) and ocular larval migrans (worm stages which burrow in the eyes) are diseases caused by the migration of roundworm larvae through the tissue of people, more so in children. These conditions in humans occur after ingestion of the roundworm eggs. The eggs hatch in the intestines and the larvae from these eggs are then released into the bloodstream and find their way to all parts of the body, including the liver, lungs, heart, brain and eyes. Most human patients are children between the ages of 2 and 4 years who become infected after playing in sandboxes or soil contaminated by pet stools.


Hookworms are small worms that attach to the inside of the intestinal wall where they attach and feed on blood. Infection is often passed directly from mother to the puppies or the kittens, but pets also become infected by eating infested soil, or even coming into skin contact with infested soil. These worms can consume large amounts of blood. If the infestation in the pet is severe enough, anaemia (lack of blood) can occur. The pet's stools will appear black (digested blood) and like tar. If too much blood is lost (especially in very young animals) it can be fatal.

Importance in humans:

These worms are again transmissible via soil contaminated with dog or cat stools. The hookworms eggs hatch in the soil, the larvae then hatch from these and infect a human either by ingestion or by penetration of the skin. In skin penetration, humans can develop an itchy rash called cutaneous larval migrans or otherwise also known as “Sandworm”.


Whipworms are long, whip-shaped worms that live within the wall and lining of the large intestine. Pets must ingest whipworm eggs to become infected. Luckily whipworm infestations cause relatively mild symptoms, but exceptions do occur. Heavy infestations can result in bouts of diarrhoea and stools may be streaked with fresh blood and appear to have a slimy layer. Kittens, puppies or animals with a chronic infection can lose weight and become anaemic (lack of blood).


Tapeworms are long, segmented white worms that live in the small intestine. Two types of tapeworm exist, with the most common one being acquired by swallowing fleas. The second one is more common in cats where they become infected by eating infected rodents or other prey. These worms consume nutrients from your pet’s food in the digestive tract. Many pets infected with tapeworms do not show symptoms, but signs may include abdominal discomfort, nervousness, itching around the anus, vomiting and weight loss.

Humans can become infected, but seldom do, as they also have to swallow a flea!

Ringworm – the exception

People often ask their vet about deworming their animals against ringworm. Ringworm, however, this is NOT a type of worm. It is actually a fungus which grows on the skin of animals and people. The treatment for it is completely different to that of worms. It is very common in puppies and kittens and initially presents as a small circular area of hair loss on the skin. It is quite contagious to other, mostly young, animals and humans and needs treatment by a veterinarian.

How do you prevent a worm infestation in your pet, yourself and your children?

Preventing children’s contact with contaminated soil and/or sandboxes will reduce the risk of infection. This means prohibiting children to have access to the cat’s sandbox and preventing pets from defecating in the children’s sandpit. Also teach your children to wash their hands after playing with your pet, as well as before eating.

Prevent your pet from hunting (if possible) – remember that small prey carry worms. Also be sure to treat your pet for fleas on a regular monthly basis with a quality product which you can get from your veterinary practice.

Do not let your pet eat stools, not his own or that of other animals. This is especially important in puppies as they tend to eat anything! Clean up straight after they have passed a stool and keep a good eye on them when you take them for a walk. Also, remember that dogs love to eat cat stools – it is suspected that it tastes good due to their high protein content – which means the daily removal of stools from a sandbox is necessary. If possible restrict access for your dog to the area in the garden your cat uses as a toilet.

Scooting (dragging the bum along the floor) might also be an indication of worms. This is normally seen in dogs as a result of an itchy bum. This symptom can also be related to blocked anal glands and it is therefore important to ask your veterinarian if you are unsure. Treatment for blocked anal glands requires a visit to the vet (fortunately it is a quick and easy problem to fix).

The best way to prevent worm infestations in your pet is by regular deworming. In an adult animal this means deworming 3-4 times per year. Treatment for puppies and kittens are slightly different (more frequently during the first few months of their lives) and your vet will explain their deworming schedule when you take them for their first vaccination. It is also important to note that not all deworming medicines treat all types of worms and therefore it is strongly recommended that you buy the deworming medication from your vet rather than using products on a trial and error basis if you diagnose the problem yourself. Most of the dewormers sold by vets treat all the worms and there are even newer products available from your vet which treat worms AND fleas at the same time!

To prevent mother to baby transmission of worms, it is recommended to deworm your bitch or queen when they are pregnant. Your vet will be able to best advise you on the correct time during the pregnancy to do the deworming.

If you are at all unsure whether your pet has worms (especially if you see some of the above symptoms), ask your vet! There is a very easy non-invasive way to check where the vet will take a stool sample and do a faecal float. This is a special test where a specific fluid is added to the sample which causes the worm eggs to float to the top of the solution. The vet will then look at this under a microscope and can determine exactly if your pet has worms and if so, which type of worms. Deworming medicine is sold over the counter in veterinary clinics and is therefore easily available. It is a good idea though to weigh your pet before you purchase a dewormer, as it is sold according to the weight of your pet.

Worms are unfortunately a part of being a pet owner. We cannot control everything our pets eat even if we try, and they will therefore most likely ingest a worm egg or two at some stage in their lives. Fortunately it is very easy to treat. Most of the time it simply involves giving a tablet every 3 months. Cats are not that easy to give tablets to and fortunately a new product has come on the market that will prevent you from losing an arm or a leg while trying to get a pill into your cat. It works as a spot-on, meaning that the product is applied on the skin between the shoulder blades. It works just as well as regular dewormers, without the potential blood, sweat and tears.

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