SHORT REPORT: SEROLOGIC EVIDENCE FOR WEST NILE VIRUS TRANSMISSION IN PUERTO RICO AND CUBA

During the spring of 2004, approximately 1,950 blood specimens were collected from resident and Nearc- tic-Neotropical migratory birds on the Caribbean islands of Puerto Rico and Cuba prior to northerly spring migrations. Eleven birds and seven birds, collected in Puerto Rico and Cuba, respectively, showed evidence of antibody in a flavivirus enzyme-linked immunosorbent assay. Confirmatory plaque-reduction neutralization test results indicated neutralizing antibodies to West Nile virus in non-migratory resident birds from Puerto Rico and Cuba, which indicated local transmission. West Nile virus (WNV) is a flavivirus (Flaviviridae) distrib- uted throughout Africa, the Middle East, Australasia, Eu- rope, and North America, and is maintained in nature be- tween birds and ornithophilic Culex species mosquitoes. 1,2 Since the discovery of the virus in New York City in 1999, WNV has spread throughout the United States, Canada, and Mexico. 3-5 Equines and numerous species of Neotropical resident birds also have been found with WNV neutralizing antibodies, indicating local transmission, in Central America,