Bat coronaviruses (Bt-CoVs) are thought to be the precursors of severe acute respiratory syndrome coronavirus. We detected Bt-CoVs in 2 bat species from Trinidad. Phylogenetic analysis of the RNA-dependent RNA polymerase gene and helicase confirmed them as group 1 coronaviruses.

Bats are one of the most widely distributed mammals in the world, and they are reservoirs or carriers of several zoonoses. Bats were trapped in 27 geographic locations across Trinidad and Tobago, and following euthanasia, gastrointestinal tracts were aseptically removed. Contents were subjected to bacteriologic analysis to detect Salmonella spp., Escherichia coli, and Campylobacter spp. Isolates of Salmonella were serotyped, and E. coli isolates were screened for O157 strains and antimicrobial sensitivity to eight antimicrobial agents; phenotypic characteristics also were determined. Of 377 tested bats, representing 12 species, four bats (1.1%) were positive for Samonella spp, 49 (13.0%) were positive for E. coli, and no bats were positive for E. coli O157 strain or Campylobacter spp. Isolated serotypes of Salmonella included Rubislaw and Molade, both from Noctilio leporinus, a fish-eating bat, Caracas recovered from Molossus major, and Salmonella Group I from Molossus ater, both insect-eating bats. Of the 49 isolates of E. coli tested, 40 (82%) exhibited resistance to one or more antimicrobial agents, and the prevalence of resistant strains was comparatively high to erythromycin (61%) and streptomycin (27%) but lower to gentamycin (0%) and sulphamethozaxole/trimethoprim (2%).

A serosurvey of antibodies against selected flaviviruses and alphaviruses in 384 bats (representing 10 genera and 14 species) was conducted in the Caribbean island of Trinidad. Sera were analysed using epitope-blocking enzyme-linked immunosorbent assays (ELISAs) specific for antibodies against West Nile virus (WNV), Venezuelan equine encephalitis virus (VEEV) and eastern equine encephalitis virus (EEEV), all of which are zoonotic viruses of public health significance in the region. Overall, the ELISAs resulted in the detection of VEEV-specific antibodies in 11 (2.9%) of 384 bats. Antibodies to WNV and EEEV were not detected in any sera. Of the 384 sera, 308 were also screened using hemagglutination inhibition assay (HIA) for antibodies to the aforementioned viruses as well as St. Louis encephalitis virus (SLEV; which also causes epidemic disease in humans), Rio Bravo virus (RBV), Tamana bat virus (TABV) and western equine encephalitis virus (WEEV). Using this approach, antibodies to TABV and RBV were detected in 47 (15.3%) and 3 (1.0%) bats, respectively. HIA results also suggest the presence of antibodies to an undetermined flavivirus(es) in 8 (2.6%) bats. Seropositivity for TABV was significantly (P<0.05; χ2) associated with bat species, location and feeding preference, and for VEEV with roost type and location. Differences in prevalence rates between urban and rural locations were statistically significant (P<0.05; χ2) for TABV only. None of the aforementioned factors was significantly associated with RBV seropositivity rates.

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.

In the 1950s and 1960s, alphaviruses in the Venezuelan equine encephalitis (VEE) antigenic complex were the most frequently isolated arboviruses in Trinidad. Since then, there has been very little research performed with these viruses. Herein, we report on the isolation, sequencing, and phylogenetic analyses of Mucambo virus (MUCV; VEE complex subtype IIIA), including 6 recently isolated from Culex (Melanoconion) portesi mosquitoes and 11 previously isolated in Trinidad and Brazil. Results show that nucleotide and amino acid identities across the complete structural polyprotein for the MUCV isolates were 96.6 – 100% and 98.7 – 100%, respectively, and the phylogenetic tree inferred for MUCV was highly geographically- and temporally- structured. Bayesian analyses suggest the sampled MUCV lineages have a recent common ancestry of approximately 198 years (with a 95% highest posterior density (HPD) interval of 63 – 448 years) prior to 2007, and an overall rate of evolution of 1.28 × 10−4 substitutions/site/yr.

Hantaviruses are established causative agents of hemorrhagic fevers and renal diseases amongst other clinical manifestations in humans, with most diagnosis based on serological assays. The disease, which is rodent-borne, has been reported in numerous countries worldwide but information about the disease is scanty in the Caribbean. The objective of this investigation is to determine the frequency of exposure to hantaviruses in a selected apparently healthy human population associated with abattoirs and livestock farms in Trinidad using a hantavirus immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA). Of a total of 236 individuals tested, 27 (11.4%) were seropositive for hantavirus infection. Amongst abattoir workers the frequency of infection was 9.4% (6 of 64) compared with seropositivity rate of 12.4% (18 of 145) and 11.1% (3 of 27) amongst livestock farm workers and office workers and other individuals with minimal animal contact respectively. The differences were, however, not statistically significant (p > .05; χ(2) test). Age, gender, and race did not significantly affect the infection rate by hantavirus in the workers studied. This is considered the first documented evidence of hantavirus infection in Trinidad and Tobago. It is imperative for local physicians to consider hantavirus as a differential diagnosis in patients with hemorrhagic fever and renal diseases, since there may be a number of undiagnosed cases of hantavirus disease in the human population in the country.

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