Chitotriosidase levels can be elevated in serum, e.g. in acute falciparum malaria (Barone et al., 2003), and as adult hookworms are thought to ingest 0.03–0.2 ml of blood daily, they may be exposed to high levels of chitotriosidase. Here, CHIT1 is linked to Plasmodium falciparum malaria.