Toxocariasis

The toxocariasis is a zoonosis caused by Toxocara canis or the Hundespulwurm the Katzenspulwurm Toxocara mystax. Infection occurs by ingestion ( uptake via the mouth) of worm eggs collected from the feces of infected dogs and cats must be temperature - and humidity- dependent mature for 3-4 weeks in the environment before recording. We distinguish two main forms. While in the first form, the internal organs are affected (visceral larva migrans ), the second form deals with the eyes ( ocular larva migrans ).

Epidemiology

Toxocara canis and Toxocara mystax are common in dogs and cats worldwide. Almost all puppies are infected. As a source of infection for children especially noteworthy are sandboxes. Wheelchair users, as they absorb the egg on the hands, often affected.

Course of the disease

After recording, the eggs, the larvae hatch in the small intestine of man and penetrate the mucosa. Then they pass through hematogenous ( through the blood vessels ) or lymphatic (via the lymphatic vessels ) scattering in various organs. In the organs they destroy cells and tissues and trigger an inflammatory response from the host. Symptoms develop only when a mass infestation. The Toxocara larvae show a tropism for the eye and brain, however, can in principle involve any organ. The incubation period is usually weeks to months. Asymptomatic or dormant infections are common and can turn into a visceral or ocular larva migrans even after ten years. Common differential diagnoses of ocular larva migrans are a toxoplasmosis, Coats' disease, macular degeneration, hemorrhagic chorioretinitis and retinoblastoma.

Diagnosis

As the life cycle in man is not complete, go no adult worms in the gut. Thus, no worm eggs, larvae or adult worms can be detected in the stool. The detection of the infection can be done by ELISA. In patients with symptomatic toxocariasis IgE levels are significantly increased. Further, there is a eosinophilia and leukocytosis.

Prevention

In order to avoid human infection dogs and cats should be wormed regularly, especially in young animals, make sure because of the strong prevalence. Similarly, the hands should be washed after contact with animals, as the eggs are liable within the fur. The contamination of sandpits with dog or cat feces should be avoided or at least changed the sand regularly.

Therapy

Treatment is with thiabendazole or diethylcarbamazine. Because of treatment-related massive release of decomposition products of the larvae, the use of anthelmintics is controversial. In ocular larva migrans, a Photoagglutination the larvae can be carried out using a laser.