Human toxocariasis

SUMMARYHuman toxocariasis is a globally prevalent zoonotic parasitic infection caused by larvae of Toxocara species, primarily Toxocara canis and Toxocara cati. Toxocariasis is commonly transmitted to humans through the ingestion of embryonated Toxocara eggs found in contaminated soil, water, or on surfaces contaminated with animal feces. Unlike in dogs and cats, humans are not definitive hosts for Toxocara spp., and, as a result, Toxocara larvae do not complete their life cycle in humans. Instead, following accidental oral ingestion of embryonated eggs, Toxocara larvae undergo an aberrant larval migratory cycle to various organs including the lungs, liver, muscles, and central nervous system, and do not return to the intestines to develop into mature adult worms. As the Toxocara larvae do not complete their life cycle in the human host, they will ultimately die in human tissue. This comprehensive systematic review of human toxocariasis analyzes and synthesizes existing research to provide a detailed and updated understanding of this zoonotic parasitic infection of global importance. This review provides an in-depth analysis of various aspects of toxocariasis, including its epidemiology, microbiology, pathogenesis, clinical manifestations, diagnostic methods, and treatment strategies.