Serological Evidence of Flaviviruses and Alphaviruses in Livestock and Wildlife in Trinidad

Abstract

Seroprevalence rates of selected arboviruses in animal populations in Trinidad were determined using serum samples collected between 2006 and 2009 from horses (n = 506), cattle (n = 163), sheep (n = 198), goats (n = 82), pigs (n = 184), birds (n = 140), rodents (n = 116), and other vertebrates (n = 23). The sera were screened for antibodies to West Nile virus (WNV), St. Louis encephalitis virus (SLEV), Ilheus virus (ILHV), Bussuquara virus (BSQV), Venezuelan equine encephalitis virus (VEEV), eastern equine encephalitis virus (EEEV), and western equine encephalitis virus (WEEV), using hemagglutination inhibition assay (HIA) and epitope-blocking enzyme-linked immunosorbent assays (ELISA). Antibodies to SLEV were detected in a total of 49 (9.7%) horses, 8 (4.9%) cattle, 1 (1.2%) goat, 2 (1.4%) wild birds, and 3 (2.2%) wild rodents by both methods. In contrast, antibodies to EEEV, VEEV, and WNV were detected only in horses, at rates of 4.3%, 0.8%, and 17.2%, respectively, by ELISA, and IgM capture ELISA was WNV-positive in 3 (0.6%) of these sera. Among locally bred unvaccinated horses that had never left Trinidad, seroprevalence rates against WNV were 12.1% and 17.2% by ELISA and HIA, respectively. The presence of WNV-and SLEV-specific antibodies in a representative sample of horse sera that were both ELISA-and HIA-seropositive was confirmed by plaque reduction neutralization testing (PRNT). Antibodies to ILHV and BSQV were not detected in any of the serum samples tested (i.e., sera from horses, other livestock, and wild birds in the case of ILHV, and wild mammals in the case of BSQV). The data indicate the presence of WNV in Trinidad, and continuing low-level circulation of SLEV, EEEV, and VEEV.

Seroepidemiology of Selected Alphaviruses and Flaviviruses in Bats in Trinidad

“…However, in contrast to our study, the latter detected antibodies to EEEV, albeit at a low rate (0.6%) (Price, ). In the case of WNV, a recent study demonstrated the presence of WNV reactive antibodies among horses in Trinidad, but all livestock and wildlife (including birds) tested were seronegative (Thompson et al., ).…”

Serological evidence for Saint Louis encephalitis virus in free-ranging New World monkeys and horses within the upper Paraná River basin region, Southern Brazil

“…The classical HI and MNT methodologies used during this investigation are based on the conventional serologic diagnosis of fl avivirus due to the presence of virus-specifi c antibodies in the serum. Similar serological strategies have been used to detect SLEV in primates 23 , white-tailed deer 19,29 , livestock 11 , mules 19 , and horses 8,10,11,17,18 . The importance of these results lies primarily in the observation of SLEV circulation in a completely new habitat within Brazil, considering that most cases of SLEV have been described within the Amazon region 4,[20][21][22] .…”

“…Alternatively, in a seroepidemiological survey conducted in French Guiana, primates had low antibody titers to SLEV (HI <40) but elevated titers to yellow fever (HI >320), and the authors suggested that that SLEV antibodies identifi ed could have been due to crossreactions with yellow fever virus 23 . Low titers of SLEV were also identifi ed in horses, livestock, and wildlife from the island of Trinidad 11 . However, during this investigation, seropositivity was only identifi ed for SLEV, and negative results were obtained with all other viruses by HI, indicating that there was no crossreaction with any similarly related virus.…”

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): Venezuelan equine encephalitis

“…In Costa Rica, the seroprevalence in two‐toed sloths ( Choloepus spp.) was 11%; in Mexico, the seroprevalence in cattle was 45%, in Trinidad, the seroprevalence in horses was 0.8% for samples taken between 2006 and 2009 (Thompson et al., ) and in bats it was 2.9% (2006–2008) (Thompson et al., ).…”