Toxocara canis

Abstract

Toxocara canis is considered by the Centers for Disease Control (CDC) as one of five neglected parasitic infections in the USA and is targeted as a priority for public health action. Toxocariasis not only affects those in the USA but is widely distributed throughout the world, with an estimated seroprevalence of 19% in a recent meta-analysis study. The life cycle involves a canid definitive host which passes eggs into the environment that embryonate over a period of 2–6 weeks. Humans can be infected with T. canis either through ingestion of embryonated eggs in the environment or through ingestion of L3 larvae in undercooked meat of paratenic hosts. Most infected people do not develop disease; however, in rare cases, particularly with repeated exposure, or infection with high egg or larval numbers, the larvae can migrate throughout the body, causing visceral, ocular, and neural larval migrans, resulting in debilitating conditions and rare fatal outcomes.