Hookworms in Dogs

Claire Dunling

Hookworms are far lower on the worm-threat spectrum here in the UK but it doesn’t mean you can ignore them. You need to be aware of their potential threat – especially to puppies, who are less able to withstand the symptoms – so you can act accordingly.

So what is a ‘hookworm’?

As with most parasites the clue’s in the name. These get their names from the hook-like mouths which they use to grab the intestinal wall. They are physically tiny about 3mm in length but they suck disproportionately large amounts of blood. So much blood in fact, that very bad infestations can cause anaemia. This is why they present a problem specifically to puppies, as the ratio of blood lost to total blood supply tips towards anaemia more quickly than in adults.

The hookworm

How do dogs get hookworms?

There are three main routes for infection. The first two come from a mother who has hookworm. She can pass it on before birth or through milk while suckling. Both of these pass the hookworm larvae into the puppy’s blood stream. The third way, and most common to adult dogs, is infection through the environment. Here the hookworms work their way through the skin and into the blood. In all cases once in the blood they eventually migrate to the bowel where the complete their life-cycle and start to cause problems.

What are the symptoms of hookworm infection?

At the point of infection or shortly afterwards there may be skin irritation and itching as the hookworm larvae burrow into the skin. Once they’re in and infection is established, the symptoms are caused by blood loss.

So the key signs are initial scurfy patches followed intestinal problems and anaemia – look for pale gums, diarrhoea, or weakness. Some dogs exhibit weight loss, blood in their faeces and (in the case of puppies) poor growth.

How do I know if my dog has hookworm?

If you see any of these signs, get your dog to the vets so they can conduct some conclusive tests. You may suspect it, but only they can confirm it. First they will run blood tests to see if your dog is anaemic and they also require stool samples so they can get it microscopically examined.

Adult female hookworms can produce upward of 15,000 eggs per day and it is these the lucky lab tech will be looking for; but large numbers of worms need to be present before these appear in the faeces. Again for puppies this is bad news, as this means stool sample examination is less reliable.

Treating hookworm

Luckily there very effective drugs with few side effects which will kill hookworms. These are given either by injection or orally as tablets. However, these drugs are only effective against adult hookworms. So it is often necessary to give an initial treatment, then second course 2-4 weeks later to catch larvae that are present but not yet mature at the time of the first treatment.

Hookworms and humans

Adult canine hookworms can infect humans, but it is very rare. The dog hookworm larvae can burrow into human skin (having mistaken the host) and cause itching “ground itch” but this requires direct skin exposure to soil ‘seeded’ with hookworm larvae, which is fortunately rare.

It is then feasible that canine hookworm can penetrate into deeper tissues and partially mature in the human intestine. So you should always practice good hygiene practices (inside out bagging, using a scoop and washing your hands after a walk).

Nursing females should be treated along with the pups; as nursing often is a trigger that reactivates a dormant infection in mum
John Campbell, Head Vet of Pet Drugs Online

How to prevent hookworms:

Strict hygiene is important in the prevention of hooworm, especially for children. Do not allow children to play in potentially contaminated environments.

Always pick up after your dog and then dispose of used poop bags promptly – you always knew you should, this is just one of the many reasons you must.

Most broad spectrum wormers are effective against hookworms, so worm adult dogs regularly keeps the hookworm population in abeyance. And of course full course (as directed by your vet) worming must be undertaken when an infestation is detected.

This post is an opinion and should only be used as a guide. You should discuss any change to your pet’s care or lifestyle thoroughly with your vet before starting any program or treatment.

If in doubt contact your veterinary practice

And always keep your vet's phone number handy - just in case!