We often hear about tapeworms and roundworms in our dogs, but did you know that there are many different types of worms under the umbrella of the “roundworm”? A common roundworm which is seen in dogs is the hookworm. These blood sucking worms are a smaller type of roundworm and grow up to 16mm in length. Even though the hookworm is smaller in size than some of the others, they can still cause problems in our dogs. 

There are two types of hookworm seen in the UK; the more common of the two is Uncinaria stenocephala. The less common is the Ancylostoma species which are capable of causing more severe disease. This is more commonly seen in dogs that travel abroad.

What do hookworms look like?

Hookworms have very sharp jaws which they use to hold on to the side of the small intestinal wall. They can then feed off blood from the small wound they have made near the vessels there. 

Uncinaria stenocephala (the more common hookworm) has a mouth opening with two cutting plates. This species of hookworm is very resourceful and has adapted itself to temperate climates, meaning that the eggs can develop at low temperatures and the larvae from the hookworm are easily able to survive in the environment of northern and western Europe.

Ancylostoma caninum (the rarer species) can be identified as they have two large dental plates which contain three teeth on each plate. This type of hookworm is more prominent in warmer climates.

What is the lifecycle of the hookworm?

It can actually take two to three weeks from your dog ingesting the worm before it can start to affect your dog’s health. The basic lifecycle is:

  1. The hookworm hooks (attaches) themselves to your dog’s intestine to feed on their blood to survive.
  2. After mating, the adult hookworm then lays eggs in the dogs small intestine 
  3. These eggs are then released in the dogs faeces about 10-21 days after infection depending on the conditions
  4. The faeces that contain the eggs then contaminate the area where your dog has been to the toilet, this could be in your garden or in public places such as the park. Larvae hatch from the egg and develop.
  5. The larvae are picked up by another dog and the process starts again.

How are hookworm transmitted?

There are four main ways in which hookworm can affect your dog.

1. Ingestion of Larvae

The hookworm larvae may be ingested through contaminated food, water or soil. If a dog sniffs or tries to eat something they shouldn’t then it is possible for the dog to ingest larvae of hookworm (or any type of larvae from any parasitic worm)

Once ingested, most larvae migrate to the intestine where they mature into adults and remain. Like roundworms, some larvae may decide to stop their migration for a while and encyst in muscles, fat, or other tissues, especially in potential prey species. However, “larval leak” from muscles back to the gut has been described.

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2. Skin Penetration

Larvae can also gain entry to a dog’s body through the skin (usually the footpads). Once the larvae have penetrated the skin, the larvae travel to the lungs and the trachea by the bloodstream.

While in the respiratory system, they cause irritation and coughing in the dog. The larvae are coughed up and re-swallowed. Then they migrate all the way down to the intestine where they attach themselves to the intestinal wall and grow into adults.

3. In-utero Transmission

Hookworm larvae may in some cases be able to become encysted and infect unborn puppies through their placenta.

4. Transmission while feeding puppies

Not only can the hookworm larvae live in a dog’s uterus, hookworms can also migrate to the mammary gland of a mother dog, thus infecting puppies while they are being nursed. The swallowed larvae then migrate to the puppy’s digestive system where they mature in the intestine. 

What are the signs of hookworm in my dog?

Symptoms of intestinal infection may include:

  • Diarrhoea, possibly with dark faeces.
  • Pale gums.
  • Going off food.
  • Tiredness.
  • In young puppies, a large infestation can lead to death.

As mentioned, hookworms can cause intestinal signs via infection through the skin:

  • Swollen pads.
  • Itchiness.
  • Red spots on the skin.
  • Hair-loss in the area.
  • Skin thickening.

If you think your dog is experiencing any of the above signs then you should seek veterinary advice who will advise you on the best cause of action.

Is hookworm zoonotic?

Hookworms can cause dermatitis in humans, known as “creeping eruption”, also known as cutaneous larva migrans. This is when the hookworm larvae burrow into your skin. It occurs through skin contact and the most common areas to come into contact with this is sandy areas or soil that has been contaminated via the faeces of a contaminated dog. In humans, you would notice reddening of the site of infection and you will be extremely itchy. If you notice these signs, you should seek medical; advice. 

How can I prevent and treat hookworms in my dog?

Making sure you regularly worm your dog with an appropriate wormer. In addition to prescription products, one example of an NFA-VPS (Non-Food Animal- Veterinary surgeon, Pharmacist and SQP) product which is used in the treatment for hookworms is Drontal for dogs. Drontal is a broad spectrum de-wormer which is effective against all major roundworms (including hookworms) and tapeworms. 

That said, there are other wormers on the market and it is important to discuss with your SQP or veterinary surgeon which is appropriate for your dog. Dogs should be wormed regularly; the normal suggestion is worm every month until 6 months of age and then every 3 months for life. But the best protocol for you and your dog should be discussed with your veterinary surgeon or SQP. 

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We need to de-worm our dog because:

  • It will interrupt the lifecycle of the hookworm (and other worms) before the eggs and larvae are passed into the environment.
  • Help dogs eliminate the parasite before they reproduce
  • Minimise the risk of disease the parasites could cause to animal and human

Other preventions are:

Clean up after your dog quickly. This will help prevent further spread of all worms.

Make sure to worm pregnant or lactating females as this will help prevent the puppies from becoming infected.

If dogs are housed outside, check their paws for any signs of irritation. 

All dog owners should be aware of the signs and symptoms of hookworm infestation within their dogs, plus how to take steps to prevent its occurrence and treat any problems that arise. If you have any concerns about hookworm, other parasitic worms or worming products please seek advice from your qualified RAMA or veterinary surgeon.

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