Clinical Features of Covert Toxocariasis

Abstract

The clinical features found in 14 children with toxocara ELISA titres of greater than or equal to 0.7 were compared with those found in 34 toxocara negative children. Blood eosinophils were elevated in 7 of the 14 patients and the highest eosinophilia was 14%. There was a highly significant association between hepatomegaly, cough, sleep disturbance and a raised titre (p less than 0.01). Behaviour disturbance, abdominal pain and headache were also significantly associated with a raised titre (p less than 0.05). The combination of abdominal pain, headache and cough was even more significantly associated with a high titre (p less than 0.0005) than were individual clinical features. It is suggested that in addition to the two well recognised clinical conditions of visceral larva migrans and ocular toxocariasis the clinical entity of covert toxocariasis should receive recognition. Eosinophilia may or may not be present in this condition.

Human toxocariasis: a seroepidemiological survey in the Amazonian city of Yurimaguas, Peru

“…On this point, many authors are in agreement that toxocariasis cases are more frequently associated and diagnosed in pediatric patients. However, VLM cases are less frequent in comparison with other forms of toxocariasis, such as incomplete VLM or covert toxocariasis 22,24,34 .…”

“…Ownership of pets such as dogs or cats and their presence at home is frequently associated with toxocariasis, as mentioned by many authors 5,22,24,28,[34][35][36][37] . However, this fact was not associated with the seropositivity in the studied population (p = 0.107).…”

“…VLM or visceral toxocariasis is characterized mainly by fever, hepatomegaly, splenomegaly, respiratory disorders, hypergammaglobulinemia and eosinophilia; OLM is the result after a larval invasion to the eye and their pathological effects including leucocoria, chorioretinitis, optic papillitis, endophthalmitis, can lead to a partial or complete loss of vision. Nevertheless, other syndromes such as covert toxocariasis (CT), neurotoxocariasis (NLM) and other forms have also been described 12,22,24,33,34 .…”

Human toxocariasis: contribution by Brazilian researchers

“…Despite the high antiToxocara antibody titers determined in these patients the level of blood eosinophils is sometimes not very high 12,98 .…”

“…In 1956, NICHOLS 76 identified Toxocara canis larvae in enucleated eye sections from certain patients supposedly presenting retinoblastoma, describing the clinical and anatomopathological features of ocular larva migrans (OLM). Approximately three decades later, other aspects of the syndrome known as covert toxocariasis (CT), characterized by abdominal pain, coughing, headache and normal or mildly elevated eosinophilia, with the presence of serum anti-Toxocara antibodies, were described 12,98 .…”