An overview of Arbovirology in Brazil and neighbouring countries

32 SUMMARY A few arboviruses and related viroses have genotypic and phenotypic corollaries in both subtropical south Florida and tropical Brazil. Their occurrences in these areas may be due to intercontinental movement by viremic birds, to commerce, to convergent evolutionary pressures brought to bear by similar ecologic circumstances ar, most likely, to divergent virus evolution indivergently evolving hosts. It is counterintuitive that ecologic similarities and the presence of rodents and certain genera of mosquitoes alone would be sufficient to bring about convergent evolution and account for nucleotide similarities of such close arder. Although relatively few, pairings such as these may indicate common ancestry and subsequent evolution.