CHI3L1 and infection: As the populations are similar in ethnicity and in exposure to other common infections such as Plasmodium, the only differing characteristic being exposure to schistosome infection [37], this result suggests that the difference in schistosome infection may contribute to differences in CHI3L1 levels and is supported by the observation that schistosome infected people had higher levels of CHI3L1 than uninfected people, independent of residential area.