Serosurvey for dengue virus infection among pregnant women in the West Nile virus enzootic community of El Paso Texas.

All 4 dengue viruses (DENV) cause sporadic outbreaks of human disease in the Rio Grande Valley along the US-Mexico border. In addition, West Nile virus (WNV) is enzootic in most border communities, and is the only arbovirus known to cause human disease in the El Paso, Texas community. In an effort to determine if DENV were also endemic in the El Paso community, a serosurvey was conducted among mothers at the time of delivery of their babies in selected hospitals. Cord-blood plasma samples obtained from mothers were tested for DENV antibody by an enzyme-linked immuno-sorbent assay (ELISA), plaque reduction neutralization test (PRNT) and a multiplex microsphere immunoassay. All DENV antibody positive plasma samples were also tested for WNV antibody by the same assays to consider the possibility that DENV antibody positive samples reflected WNV cross reactive antibody. The results indicated that 0.74% (11/1,472) of the mothers had a previous DENV infection and that 3.3% (48/1,472) had a previous WNV infection. Of these mothers, 0.20% (3/1,472) had antibody to both DENV and WNV as evidence of infection by both viruses. The results indicated that 0.2% (3/1472) of the mothers were positive for antibody to only WNV envelope, thus suggesting an undetermined flavivirus infection. Although 6 of the 11 DENV antibody positive mothers did not have a history of travel to a DENV endemic country, the findings of this survey provided further evidence of local transmission of WNV and suggested the possibility of focal autochthonous transmission of DENV in the El Paso community.

Integrated Arbovirus Surveillance Improves the Detection Onset of Zika Virus in Panama.

We tested 700 serum samples collected throughout Panama from 2015 to 2016 for detecting antibodies and RNA of arboviruses. In convalescent specimens, microsphere immunoassay detected an antibody prevalence of 59.3% for dengue virus (DENV) and 30.3% for Zika virus (ZIKV), which included samples that were collected before the Panamanian surveillance system reported the first case of Zika in the country. For acute sera, the most common arbovirus was DENV with 18 positive samples (6%), followed by four (1.3%) of ZIKV and one (0.6%) of chikungunya virus (CHIKV). Our results indicate a change in the chronology of when ZIKV was first detected in Panama and stress the importance of integrating various approaches to enable improved surveillance of both endemic and emerging arboviruses.

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 Nearctic-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.

Serologic evidence of West Nile virus transmission, Jamaica, West Indies.

In spring 2002, an intensive avian serosurvey was initiated in Jamaica, Puerto Rico, and Mexico. We collected >1,600 specimens from resident and nonresident neotropical migratory birds before their northerly migrations. Plaque reduction neutralization test results indicated specific neutralizing antibodies to West Nile virus in 11 resident species from Jamaica.