Toxocara canis IgG antibodies

Serological diagnosis of toxocariasis, a disease caused by the nematode Toxocara canis. Determination of serum levels of IgG antibodies specific for T. canis antigens

Toxocariasis is a parasitic disease caused by the nematode Toxocara canis (dog roundworm) or Toxocara cati (cat roundworm). Infection occurs via the oral route – the eggs of the parasite can be transmitted into the mouth on hands soiled with soil or on toys (shovels, buckets), through unwashed vegetables, etc.  Infection in humans can affect the liver, heart, lungs, muscles, eye and mzguard. The disease can take one of three forms, as:

• latent toxocariasis – in children, with a clandestine course and mild subclinical symptoms;
• visceral toxocariasis – wandering larvae in internal organs – with symptoms associated with inflammatory reaction of organs 
• ocular toxocariasis – larva migrating to the back of the eye – with possible loss of vision, in older children and young adults.

The adult form of T. canis lives in the small intestine of dogsw and puppiesw, almost always infected shortly after birth. Excreted in the feces of dogsw, the eggs end up in the soil. The eggs residing in the soil developy an embryo thaty develops into an invasive larval form after 2 to 5 weeks. Toxocara eggs survive in the environment for years.

The severity of the disease depends on the number of eggs ingested and the severity of the body's allergic reaction. The disease is almost always mild, sparse or asymptomatic, and is a self-limiting process, although the course can be severe if the mzguard is involved. Symptoms of the acute phase of the disease consist of abdominal painl, decreased appetite, fever, cough, nervousness, wheezing, urticaria, decreased visual acuity (when the eye is involved).

ElISA tests play a significant role in the diagnosis of the disease. The test allows the determination of serum levels of IgG antibodies specific for T. canis antigens.  The presence of antibodies  confirms a past or current infection with minor inflammation. If the eye is involved, antibody levels may be low. Other tests supporting the diagnosis of toxocariasis include determination of total IgE antibody levels and eosinophilia.