A serological study for research into arbovirus antibodies in the human population in the Ribeira Valley: IV - survey among school-children in Iguape County (S. Paulo State, Brazil)

Abstract

A serological survey for research on antibodies of 17 arbovirus was carried out among 337 school-children from 6 to 14 years old, living in four ecologically different areas of Iguape County, Ribeira Valley, S. Paulo State, Brazil: 1 - urban zone of Iguape; 2 - Rocio, a peripheric city district of rural characteristics; 3 - zone of extensive banana plantation on the coastal plain; 4 - forested area close to the northern mountain range. It was observed that 8.31% of the children presented HI antibodies to arbovirus of groups A, B, C, Bunyamwera, Simbu or Anopheles A. There was a significant difference between the proportion of positive sera in banana plantation and forest dwellers (19.05% and 16.67%) and those from the central urban zone and Rocio district (1.89% and 3.81%). Children who have always lived in the urban zone and do not usually go into the neighboring forest show neutralizing antibodies to Caraparu or Rocio virus, which suggests urban transmission. The absence of specific IGM in positive sera to Rocio probably means that there has been no recent infection by this agent in the school-children under investigation.