What is it?
Toxocariasis is a cosmopolitan parasitic infection. It concerns more particularly children and is caused by the parasite: Toxocara. Different species of this parasite exist according to the host hope:
– T. canes, in the dog;
– T. cacti, in the cat.
This is a zoonosis. Either a disease transmitted from the animal to the man. The parasite thus contaminates the intestinal system of the animal (dog or cat) at first. The transmission of the pathogenic agent to humans is therefore carried out by the fecal-oral route, when carrying contaminated elements to the mouth.
Anyone can be infected, both children and adults. People with these pets are at greater risk of being infected with Toxocara.
The transmission of the disease is thus made by the fecal-oral route since the excretion of faeces of cats and dogs. Children are at greater risk of infection from the point of view of being more likely to put their hands in their mouths after playing in an outdoor environment.
This parasite is widely found throughout the world and preferentially affects cats, dogs and foxes.
Symptoms of Toxocariasis
Most people with toxocariosis have no symptoms. In addition, some patients may develop certain clinical manifestations including:
– Ocular toxocariasis, in the context of a migration of the parasite in the eyes. Associated symptoms include loss of vision, eye inflammation or retinal damage. Generally, only one of the two eyes is impacted;
– visceral toxocariasis, when the parasite migrates to different organs and / or tissues, such as the liver or the central nervous system. The characteristic symptoms are: fever, fatigue, and coughing, wheezing or abdominal pain.
In the majority of cases, subjects infected with Toxocara do not have a severe form of the disease. In addition, many adults infected with the parasite in its larval form may not notice any symptoms. The severe form of the disease is therefore rare and generally concerns more young children who play regularly in outdoor areas whose surfaces may be contaminated by dog and / or cat faeces.
The most widespread parasitic species across the planet is T. canis. Contamination usually occurs when the puppy is born or while breastfeeding. Mature larvae spread rapidly within the puppy’s gut for the first 3-4 weeks. Then, develops a large number of eggs that can contaminate the environment via the excrement of the animal.
The origins of the disease
Toxocariasis is the general term for infections with the parasitic species Toxocara (T oxocara canisor Toxocara cacti). These two species belong to the roundworm nematodes of the order Ascaridida, the superfamily Ascaridiodea and the toxocaridae family.
The definitive host of this parasite is the cat or the dog. The adult form of the parasite lives in the lumen of the small intestine of these animals. Contamination of animals can be by ingestion of the viable form of the parasite, its embryonic form or an infection in utero (trans-placental, since the infected mother). Infective larvae can wander in the body for several months to years, causing progressive damage to organs and tissues. The ability of a eukaryotic parasite to survive in any mammal for such a period of time is unusual.
The infected animal will then contaminate the environment during the excretion of its faeces. Man can, in turn, be contaminated by the fecal-oral route. Children are more subject to the development of the disease because of more contact with the external environment and more frequent hand-to-mouth carriage.
Inter-human transmission has been sidelined in the context of this disease.
Risk factors for Toxocariasis
The risk factors that an individual is contaminated by this parasite are the ingestion of it via the fecal-oral mode.
Prevention and treatment of Toxocariasis
The treatment of toxocarosis depends directly on the form of the disease.
Ocular toxocariasis is difficult to manage and the treatment is almost exclusively preventive measures to prevent the development of eye damage.
Isceral toxocariasis is treated with anti-parasitic drugs.
The prevention of the disease comes under several aspects:
– the treatment of pets with adequate vaccination monitoring and a vaccine against Toxocara;
– washing hands after playing with pets or other animals, after outdoor activities or before eating;
– children’s learning about good hand hygiene practices;
– do not let children play in places soiled with animal excrement;
– clean litters, niches, etc. at least once a week ;
– the learning of children about the dangerousness of mouthing dirty objects.