A large number of parasites are known to infect the zander's skin, eyes and internal organs. Its gastrointestinal tract can host the nematode Anisakis, which can be transmitted to humans if the fish is smoked, fried or otherwise cooked at temperatures lower than 50 °C (122 °F). The zander is also a vector of the trematode Bucephalus polymorphus and may have been responsible for spreading the parasite to some French river systems during the 1960s and 1970s, leading to decreases in populations of native cyprinids.[1]