Detection of Toxocara canis larvae by PCR in the liver of experimentally infected Mongolian gerbils (Meriones unguiculatus)

Toxocariasis is a common human zoonosis, which induces a clinically unapparent course of infection. Diagnosis is difficult and relies upon serological testing (searching of specific IgG antibodies by ELISA), laboratory abnormalities and clinical manifestations. The polymerase chain reaction (PCR) technique was adapted for the detection of Toxocara canis larvae in a host tissue. Mongolian gerbils (Meriones unguiculatus) were used as an animal model for human toxocariasis. 8 animals were inoculated with 1000 T. canis eggs, four uninfected were used as control. At 3, 5, 7, and 14 days post-infection, 2 infected and 1 control gerbil were killed and their livers were used for molecular analysis. Specific primer in the PCR reaction allowed identification of T. canis larvae, with the parasite gDNA found in the liver of all infected gerbils. The results indicate that the PCR method has a potential as a supporting technique for the diagnosis of human toxocariasis.