A serologic study of human toxocariasis in the Canary Islands (Spain): environmental influences

The presence of anti-Toxocara antibodies in the human population of the Canarian Archipelago was studied by means of an indirect enzyme-linked immunosorbent assay with excretory/secretory antigen of infective-stage larva. A total of 14,074 were analyzed, resulting in the following distribution and prevalence by location: southern Tenerife 6,435 (2.5% positive), northern Tenerife 1,710 (6.7% positive), La Palma 1,214 (4.5% positive), La Gomera 264 (6.8% positive), El Hierro 204 (3.9% positive), Gran Canaria 2,875 (2.3% positive). Fuerteventura 277 (1.8% positive), and Lanzarote 1,095 (2.9% positive). The weighted average of the entire Archipelago was 3.4% positive. Neither age nor sex was found to be significantly associated with positive serology. The influence of the different Canarian mesoclimates on the spreading of this zoonosis is demonstrated, with significant differences being found between humid and arid islands. Likewise, a significant positive correlation was found between De Martonne's humidity-aridity index and percentage of people with evidence of parasite exposure on the different islands.