[1] Univ Pernambuco UPE, Postgrad Program Hlth Sci, Recife, Brazil
[2] Fdn Oswaldo Cruz FIOCRUZ, Inst Aggeu Magalhaes IAM, Dept Parasitol, Recife, Brazil
[3] Univ Fed Rural Pernambuco UFRPE, Postgrad Program Biometr & Appl Stat, Recife, Brazil
[4] Univ Pernambuco UPE, Postgrad Program Hlth Sci, Rua Arnobio Marques 310, BR-50100130 Recife, PE, Brazil