[1] Mahidol Univ, Fac Trop Med, Dept Helminthol, Bangkok 10400, Thailand
[2] Ban Rai Hosp, Ban Rai Dist, Uthai Thani Pro, Thailand
[3] Uthai Thani Prov Hosp, Uthai Thani Province, Thailand
[4] Off Dis Prevent & Control 8, Nakhon Sawan Province, Thailand
[5] Ist Super Sanita, Dept Infect Parasit & Immunomediated Dis, I-00161 Rome, Italy