Angiostrongylus cantonensis is the causative agent of human eosinophil
ic meningoencephalitis in the Pacific Islands and Southeast Asia. Prom
inent eosinophilia in the cerebrospinal fluid (CSF) of the patients ha
s been used as one of the diagnostic criteria for the disease but the
role(s) of the CSF eosinophils has remained to be elucidated. In this
article, Kentaro Yoshimura, Hiroko Sugaya and Kazuto Ishida discuss th
e involvement of CSF eosinophils in the killing of intracranial worms
and the damage of the central nervous system of the hosts, and conside
r why eosinophils in A. cantonensis infection play a more important ro
le in nonpermissive hosts (including humans) than in the permissive ra
t host.