Toxocariasis is an infection caused by small worms found in the poo of some dogs, cats and foxes. It's rare, but can sometimes cause serious problems.


Are there different types of toxocariasis?

There are two types of Toxocara. Toxocara T. canis is transmitted from dogs and foxes whilst Toxocara T.catis, is transmitted by cats.  Both come from the roundworm Toxocara. 

How many parks are infected with toxocara eggs?

Random soil sampling shows that the majority of the parks in the UK are contaminated with Toxocara eggs in various stages of development.

If parks are disinfected would that eradicate toxocara?

Toxocara eggs are resistant to freezing and disinfectants and can survive for two years or more. 

Are all dogs infected?

It is reasonable to assume that all puppies are infected with Toxocara T. canis and produce larger numbers of eggs than an adult dog. However, the prevalence of Toxocara diminishes as the dog grows older.

If I have a puppy how often should I worm it?

Virtually all puppies are born with the Toxocara infection; they may need to be wormed at two, four, six and eight weeks and thereafter every two months, depending on the worming product. Check details with your vet.

Do all dog owners worm their pets?

54% of dog owners stated that they had neither bought nor used worming tablets on their pets.

Is it dangerous for me to clear up after my dog? Won’t I get toxocariasis?

Toxocara eggs are not infectious until they embryonate. This is usually at least two to three weeks after they have been deposited by a dog. Therefore freshly deposited faeces are not infectious, and you can safely clear up after your dog.

Are there many eggs in dog mess?

A single dog mess can contain approximately 1 million microscopic eggs. 


How do you contract the disease?

Human infection of this disease is a direct consequence of soil or sand contamination with faeces carrying eggs of the parasite. As the parasite can last up to two years, contaminated soil and sand is often the carrier as the faeces degrade. The parasite can only infect humans if swallowed. Once swallowed the infection can last between six and 24 months. Frequently the infection is through hands, but also with the dogs themselves or through inanimate objects such as wheels of toys, soles of shoes, etc. Therefore the prevalence of the toxocariasis is dominant in children between 18 months and five years.

How many people in the uk have been infected with toxocariasis?

All reports reviewed indicate that human toxocariasis is potentially a serious infection. There is a debate, however, on the exact number of incidences in humans, which varies from 1 – 4% of adults. However, the study by Woodruff in 1970 is the most conclusive despite its age. He tested 700 people using a skin test and found 2% of them to be infected.

What are the solutions to the problem?

If every owner treated their dog with a worming preparation and cleared up after their dog, toxocariasis would be virtually eradicated. However, worming a dog will not eradicate Toxocara unless they are wormed regularly.

What are the symptoms of toxocariasis?

Eye disorders are the most commonly reported complaint associated with toxocariasis. This is by the transportation of larvae via the retinal artery to the eye, potentially causing blindness through the growth of non-malignant tumours or the development of detached retinas. The reporting of eye disorders in relation to toxocariasis may be due to the public and the medical profession being aware of the link. As the links to flu-like symptoms are not so obvious, it is very likely that a huge number of toxocariasis cases go unreported and unrecognised by either the public or by doctors. Other symptoms are vague aches, dizziness and nausea, asthma and epileptic seizures.

How many people suffer eye damage from toxocariasis?

In a report by Dr S. Gillespie, (November 1993), he noted approximately 100 cases diagnosed each year, with 50 having serious eye damage. Nearly all were children, who had contracted the disease as toddlers.

Are there any useful treatments or is there a cure?


Where are toxocara eggs most likely to be found?

Many infected soil samples are found in the vicinity of children’s play areas, even though dogs are often banned from these areas. Other samples are found on streets. In the UK, about half of the most serious cases of toxocariasis, such as blindness, occur in families who have never owned a dog or a cat.

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