[1] ASTAR, Singapore Immunol Network, Singapore 138648, Singapore
[2] Natl Environm Agcy, Environm Hlth Inst, Singapore, Singapore
[3] Univ Kelaniya, Fac Med, Dept Parasitol, Ragama, Sri Lanka
[4] Univ Liverpool, Inst Infect & Global Hlth, Liverpool L69 3BX, Merseyside, England