Physiological reactions to Toxocara infection depend on the host's immune response and the parasitic load. Most cases of Toxocara infection are asymptomatic, especially in adults. When symptoms do occur, they are the result of migration of second stage Toxocara larvae through the body. Covert<unk>  is the least serious of the three syndromes and is believed to be due to chronic exposure. Signs and symptoms of covert<unk>  are coughing, fever, abdominal pain, headaches, and changes in behavior and ability to sleep. Upon medical examination, wheezing, hepatomegaly, and lymphadenitis are often noted. High parasitic loads or repeated infection can lead to visceral larva migrans (VLM). VLM is primarily diagnosed in young children, because they are more prone to exposure and ingestion of infective eggs. Toxocara infection commonly resolves itself within weeks, but chronic eosinophilia may result. In VLM, larvae migration incites inflammation of internal organs and sometimes the central nervous system. Symptoms depend on the organs affected. Patients can present with pallor, fatigue, weight loss, anorexia, fever, headache, skin rash, cough, asthma, chest tightness, increased irritability, abdominal pain, nausea, and vomiting. Sometimes the subcutaneous migration tracks of the larvae can be seen. Patients are commonly diagnosed with pneumonia, bronchospasms, chronic pulmonary inflammation, hypereosinophilia, hepatomegaly, hypergammaglobulinaemia (IgM, IgG, and IgE classes), leukocytosis, and elevated anti-A and anti-B isohaemagglutinins. Severe cases have occurred in people who are hypersensitive to allergens; in rare cases, epilepsy, inflammation of the heart, pleural effusion, respiratory failure, and death have resulted from VLM. Ocular larva migrans (OLM) is rare compared with VLM. A light Toxocara burden is thought to induce a low immune response, allowing a larva to enter the host's eye. Although there have been cases of concurrent OLM and VLM, these are extremely exceptional. OLM often occurs in just one eye and from a single larva migrating into and encysting within the orbit. Loss of vision occurs over days or weeks. Other signs and symptoms are red eye, white pupil, fixed pupil, retinal fibrosis, retinal detachment, inflammation of the eye tissues, retinal granulomas, and strabismus. Ocular granulomas resulting from OLM are frequently misdiagnosed as retinoblastomas. Toxocara damage in the eye is permanent and can result in blindness. A case study published in 2008 supported the hypothesis that eosinophilic cellulitis may also be caused by infection with Toxocara. In this study, the adult patient presented with eosinophilic cellulitis, hepatosplenomegaly, anemia, and a positive ELISA for T. canis.
Toxocariasis
Filariasis
Acariasis
Helminthiasis
Paragonimiasis
Metagonimiasis
Leishmaniasis
Isosporiasis