Eucestoda the "broad tapeworm" or "fish tapeworm") and related species. Humans become infected by eating raw, undercooked, or marinated fish acting as a second intermediate or paratenic host harboring metacestodes or plerocercoid larvae. Clinical symptoms are due to the large size of the tapeworm, which often reaches a length exceeding 15 m. The most common symptom is pernicious anemia, caused by the absorption of vitamin B12 by the worm. Other symptoms include various intestinal issues, slight leukocytosis, and eosinophilia. This condition is caused by the plerocercoid larvae of the tapeworm "Spirometra". Humans become infected by drinking contaminated water, eating raw or
Toxocariasis canis" and "Toxocara cati" eggs require a several week incubation period in moist, humid, weather, outside a host before becoming infective, so fresh eggs cannot cause toxocariasis. Many objects and surfaces can become contaminated with infectious "Toxocara" eggs. Flies that feed on feces can spread "Toxocara" eggs to surfaces or foods. Young children who put contaminated objects in their mouths or eat dirt (pica) are at risk of developing symptoms. Humans can also contaminate foods by not washing their hands before eating. Humans are not the only accidental hosts of "Toxocara". Eating undercooked rabbit, chicken, or sheep can lead to