Arboviruses in Serra Norte, Carajás region, Pará, Brazil

ABSTRACT

mhis report outlines studies carried out from 1982 to 1987 in Serra Norte, Carajás region, Pará State, to ascertain the existence of known or new arbovirus types in the area, especially those of medical interest, and to gather information about their natural patterns of activity. These studies have included both serological tests and attempts to isolate viruses from haematophagous insects, wild animals and man. A total of 184,884 haematophagous insects were collected and blood and tissue samples were obtained from 1,726 wild vertebrates caught in the area. Attempts to isolate viruses in suckling mice yielded 21 strains, including 15 different serological types, of which 7 have been shown to constitute new types, so far found only in the Brazilian Amazonian region, and two of them have already been confirmed to be new types to the world. Serological studies performed on 2,680 sera (1,380 humans and 1,300 wild animals) against selected arboviruses pointed out the circulation of several of these agents in the investigated area. The Carajás region therefore, maintains established ecosystems which are rich in arbovirus fauna, and exploration of these natural niches must be done carefully and rationally to avoid breaking out the current foci of infestation maintained in the forest. Further studies are necessary to obtain a better understanding of these agents in this region and of the threats that they may pose to the health of humans and livestock.