1. Municipal Hospital of Caála, Huambo, Angola.
2. Medical School, University José Eduardo dos Santos, Huambo, Angola.
3. Municipal Hospital of Huambo, Huambo, Angola.
4. Department of Physiological Sciences, Medical School of the Agostinho Neto University, Luanda, Angola.
5. National School of Public Health (ENSP)-FIOCRUZ, Rio de Janeiro, Brazil.
6. Fernandes Figueira Institute (IFF)-FIOCRUZ, Rio de Janeiro, Brazil.