What is Toxocara Canis ?

Toxocara canis is the common roundworm which lives in the intestines of almost all new-born puppies and in some adult dogs. It is also found in a larval form in the tissues of all dogs and in many birds and mammals, including humans.

How do dogs and people become infected?

Dogs which harbor adult worms pass the Toxocara canis eggs into the environment in their faeces. During a period of maturation a larva develops within the egg and it is then ineffective if ingested. Young people are most commonly infected when they eat soil contaminated with eggs or put objects contaminated with eggs in their mouths.

Life cycle of Toxocara canis

The life cycle is complex and there are five routes of infection:
1. Prenatal (transplacental)
2. Colostral (via milk)
3. Direct ingestion of mature eggs (the only way for humans)
4. Ingestion by bitches of expelled larvae and eggs in puppies' faeces.
5. Ingestion of infected transport hosts e.g. mice, chickens.

Why is Toxocara a problem?

Toxocara canis has a world-wide distribution and effects all dogs and puppies. It may cause ill-thrift, poor growth and other signs of disease in the adult dog. Human toxocariasis is a common infection in the U.K. as well as in many other parts of the world. In a survey of healthy adults in London, 2.6% had evidence of infection. Infection rates are higher than in the normal population in adults who are occupationally exposed to dogs, such as dog breeders and animal hospital employees. However these data underestimate the number of human cases because most infections are acquired in childhood. For example, a survey of children in Bedford found that 14.6% had a serological evidence of toxocariasis.
Toxocara infection in humans, usually young children, causes variable clinical symptoms in response to the larvae migrating through the tissues. Probably the most serious outcome is blindness or serious visual impairment which can result when larvae are trapped in the eye. Over 100 people are affected in this way in the U.K. each year.

Unembryonated (uninfective)  Toxocara Canis egg

Environmental contamination; the problem:

With an estimated population of about six million dogs in the U.K. producing 1000 tons of faeces daily, dog fouling is clearly a problem. Under the climatic conditions which prevail in Britain some toxocara eggs can survive in soil for up to three years. By laws are available to local authorities to help limit the fouling of parks and open spaces with dog faeces but also with a view to reducing the risk of children becoming infected by the dog roundworm.

Control of Toxocariasis

The main reasons for Toxocara canis control are to reduce the effects of worms in puppies and to prevent human infection. Control measures seek to avoid or reduce environmental contamination with Toxocara canis eggs.

Embryonated (infective) Toxocara canis egg
There are three main goals:
1. To eliminate Toxocara canis infection from dogs.
2. To prevent dog fouling in areas frequented by humans.
3. To educate the public about the infection potential and control of toxocariasis.

Elimination of Toxocara canis infection from dogs:

There are several efficacious worming products available to control Toxocara canis in puppies and adult dogs. Worming drugs may be supplied and advice sought from a veterinary surgeon.
Puppies should be wormed from the age of two weeks and fortnightly until they are twelve weeks old, or according to the drugs manufacturers instructions. They should be wormed again at six months and every three to six months throughout their lives.
You may be the owner of a new puppy. If there is any doubt about the worming schedule which has been followed until then, the puppy should be wormed at least twice, once at each vaccination appointment.
Prevention of dog fouling of areas frequented by humans:
Concerned dog owners should collect all faeces passed by their dogs and dispose of them in a bin or they may be burnt. The Toxocara eggs take a minimum of two weeks to develop to the ineffective stage and therefore, prompt removal and disposal is quite safe for the owner to carry out. Local authorities frequently use byelaws to try and keep areas free from dog faeces, but unfortunately many dog owners ignore the byelaws and they are extremely difficult to enforce.

Clean up after your hound

Where Armillatox makes a difference:

A disinfectant for hard surfaces to reduce contamination from the eggs of Toxocara canis.
Toxocara canis eggs have been found to resist all common disinfectants at conventional strengths until the discovery that ARMILLATOX can greatly reduce their infectivity.
Armillatox may be used on any hard surface which has been fouled by dog excrement or where contamination with Toxocara canis is suspected, provided the safety precautions indicated on the label are followed. (The Control of Pesticides Regulations 1986 - Do apply to this area of work). Multi or single dog households may also benefit from Armillatox disinfection, particularly if young children have access to areas where puppies or breeding bitches are kept.
There are two main situations where Armillatox may be used:-
Where there has been dog fouling in the past or there is a relatively low risk of contamination with Toxocara canis eggs e.g. sites which have been fouled and are going to be made into dog free areas.
As the Toxocara canis eggs require a maturation period of at least 2-3 weeks in the environment in order to become infective, surfaces which are continually being soiled should be disinfected at fortnightly intervals in order to kill eggs before they reach the infective stage.
Surfaces which have been fouled in the past, and therefore the age of the Toxocara canis eggs is unknown, may be disinfected at any time. A site may benefit from two or more treatments and Armillatox is most effective in warm conditions.
Surfaces which are fouled by dogs which are known to b wormed regularly may be disinfected two weeks after the dogs are wormed, minimising the risk of contamination with Toxocara canis eggs.

Toxocariasis is largely preventable.

•  Remember to worm your dogs.
• Dispose of their faeces promptly and carefully.
• Wash your hands before handling food.
• Wash children's hands after they been handling dogs or soil.
• Watch out for toddlers eating soil and try to prevent it.

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