Toxocariasis: A Neglected Parasitic Disease with Public Health Importance

Toxocariasis together with Chagas disease, neurocysticercosis, toxoplasmosis and trichmoniasis are considered as the five most important neglected parasitic diseases [1]. Toxocariasis is a helminthic zoonosis mostly caused by two species of the ascarid nematodes Toxocara canis and to a lesser extent T. cati [2-4]. However, Toxocaris leonina belonging to the family Ascarididae can produce mixed infections with both Tocoxara species in dogs and cats [4]. In addition, it is able to infect humans; therefore it has zoonotic and public health importance [4,5]. Toxocaris leonina has been regarded as a causative agent of visceral larval migrans in human beings [5]. Toxocara canis and T. cati are common roundworms of the small intestine of canids and felids, respectively [4,6]. Toxocariasis carries a major health risk particularly in developing countries [7]. Human toxocariasis tends to be more prevalent in tropical and subtropical countries and rural populations than in temperate, urban and industrialized ones [4,7,8]. In tropical and subtropical regions, the humid climate provides surviving of parasite eggs in soil and this limits the control, preventive and eradicative programs [4]. Despite the poor hygiene and inappropriate anthelmintic treatments in dogs in rural settings, environmental contamination with Toxocara eggs is common in outdoor parks of urban and suburban settings [4,8,9]. Human beings as paratenic hosts become infected by ingestion of embryonated eggs in soil, from contaminated vegetables and fruits or consuming raw or undercooked meat and viscera of infected paratenic hosts including chicken, calves and lambs [7,10-12].