Risk Modeling of Bat Rabies in the Caribbean Islands.

Rabies surveillance and control measures vary significantly between Caribbean islands. The Centers for Disease Control and Prevention currently recommends certain groups of U.S. travelers to any Caribbean island receive pre-exposure rabies immunization. However, most islands self-declare as "rabies free", and have never publicly released data to support rabies-free claims. We used the Analytic Hierarchy Process to create pairwise comparison values among five risk factors determined by subject matter experts. Risk factor weights were calculated and used in a geospatial analysis to calculate a risk value for each island nation (higher values indicate higher risk). Risk values ranged from 8.73 (Trinidad) to 1.57 (The Bahamas, Turks and Caicos Islands). All four countries that have documented occurrences of laboratory confirmed rabid bats were ranked highest (Trinidad and Tobago, Grenada, Cuba, Dominican Republic), as well as Haiti. The top five highest risk countries that currently have no reports of bat rabies include St. Vincent and the Grenadines, Jamaica, Puerto Rico, the Cayman Islands, and Dominica. This study reviews the inter-island movement potential of bats, designates areas of high risk for bat-associated rabies within the Caribbean islands, and demonstrates a need for further surveillance efforts in bat populations within islands that self-declare as rabies free.

Serological Evidence for Henipa-like and Filo-like Viruses in Trinidad Bats.

Bat-borne zoonotic pathogens belonging to the family Paramxyoviridae, including Nipah and Hendra viruses, and the family Filoviridae, including Ebola and Marburg viruses, can cause severe disease and high mortality rates on spillover into human populations. Surveillance efforts for henipaviruses and filoviruses have been largely restricted to the Old World; however, recent studies suggest a potentially broader distribution for henipaviruses and filoviruses than previously recognized. In the current study, we screened for henipaviruses and filoviruses in New World bats collected across 4 locations in Trinidad near the coast of Venezuela. Bat tissue samples were screened using previously established reverse-transcription polymerase chain reaction assays. Serum were screened using a multiplex immunoassay to detect antibodies reactive with the envelope glycoprotein of viruses in the genus Henipavirus and the family Filoviridae. Serum samples were also screened by means of enzyme-linked immunosorbent assay for antibodies reactive with Nipah G and F glycoproteins. Of 84 serum samples, 28 were reactive with ≥1 henipavirus glycoprotein by ≥1 serological method, and 6 serum samples were reactive against ≥1 filovirus glycoproteins. These data provide evidence of potential circulation of viruses related to the henipaviruses and filoviruses in New World bats.

The Serological Prevalence of Rabies Virus-Neutralizing Antibodies in the Bat Population on the Caribbean Island of Trinidad.

: Rabies virus (RABV) is the only lyssavirus known to be present within the Caribbean. The island of Trinidad, is richly diverse in chiropteran fauna and endemic for bat-transmitted rabies with low RABV isolation rates observed in this population. We aimed to determine the seroprevalence of rabies virus neutralizing antibodies (RVNA) in light of spatio-temporal and bat demographic factors to infer the extent of natural exposure to RABV in the Trinidadian bat population. RVNA titers were determined by the RABV micro-neutralization test on 383 bat samples representing 21 species, comprising 30.9% of local bat diversity, from 31 locations across the island over 5 years. RVNA was positively detected in 33 samples (8.6%) representing 6 bat species (mainly frugivorous) with titers ranging from 0.1 to 19 IU/mL (mean 1.66 IU/mL). The analyses based on a multivariable binomial generalised linear mixed-effects model showed that bat age and year of capture were significant predictors of seropositivity. Thus, juvenile bats were more likely to be seropositive when compared to adults (estimate 1.13; p = 0.04) which may suggest early exposure to the RABV with possible implications for viral amplification in this population. Temporal variation in rabies seropositivity, 2012-2014 versus 2015-2017 (estimate 1.07; p = 0.03) may have been related to the prevailing rabies epizootic situation. Regarding other factors investigated, RVNA was found in bats from both rural and non-rural areas, as well as in both hematophagous and non-hematophagous bat species. The most common seropositive species, Artibeusjamaicensisplanirostris is ubiquitous throughout the island which may potentially facilitate human exposure. The findings of this study should be factored into public health assessments on the potential for rabies transmission by non-hematophagous bats in Trinidad.

NOVEL POXVIRAL INFECTION IN THREE FINCH SPECIES ILLEGALLY IMPORTED INTO TRINIDAD, WEST INDIES, WITH IMPLICATIONS FOR NATIVE BIRDS.

Oryzoborus angolensis (Lesser Seed-Finch), Oryzoborus crassirostris (Large-billed Seed-Finch), and Sporophila intermedia (Grey Seedeater) are finch species native to the Caribbean island of Trinidad. These species are locally trapped and kept for their song, but with declining native populations, enthusiasts have turned to illegally importing birds from the South American mainland. The smuggling of wild birds from South America poses significant disease risks to the native bird species of Trinidad. Herein we describe the first case of poxviral infection in these illegally imported birds in Trinidad and partial genome sequence of the causative agent. Phylogenetic analysis of the 4b core protein sequence indicated that the avian poxvirus identified was most closely related to a 2012 avian pox sequence from Brazil, with 96.2% and 98.1% identity at the nucleotide and amino acid level.

Of bats and livestock: The epidemiology of rabies in Trinidad, West Indies.

Vampire bat-transmitted human rabies was first recognized in Trinidad during a major outbreak during the first half of the 20th century. To date, Trinidad is the only Caribbean island with vampire bat-transmitted rabies. Herein, we summarized the epidemiological situation of rabies in Trinidad during the period 1971-2015 through the analysis of field and laboratory records. During the study period, 259 domestic and wild animal rabies cases were laboratory confirmed with an annual median of 2 animal rabies cases. Over the 45 years, five significant epizootic events occurred (in 1974, 1997-1998, 2000, 2010 and 2012-2013) over which there was a significant increasing trend for the occurrence of rabies cases. The highest number of cases (87 cases) occurred during the 1997-1998 event, and the rabies positive proportion, was highest (0.7, 95% CI 0.52-0.84) for the year 2000. Rabies risk was highest for cattle (negative binomial parameter estimate 4.84, 95% CI 3.45-6.76), although numerous rabies cases were seen in the caprine population during the study period. In light of this finding, consideration should be given to including the small ruminant population in the national rabies vaccination program. Outbreaks affected mainly the counties of St. Patrick and St. George East, with epidemic progression outwards, and these areas should be prioritized for prevention and control efforts.

Rabies in the Caribbean: A Situational Analysis and Historic Review.

Rabies virus is the only Lyssavirus species found in the Americas. In discussions about rabies, Latin America and the Caribbean are often grouped together. Our study aimed to independently analyse the rabies situation in the Caribbean and examine changes in rabies spatiotemporal epidemiology. A questionnaire was administered to the 33 member countries and territories of the Caribbean Animal Health Network (CaribVET) to collect current data, which was collated with a literature review. Rabies was endemic in ten Caribbean localities, with the dog, mongoose, and vampire bat identified as enzootic reservoirs. The majority of animal cases occurred in Puerto Rico, the Dominican Republic, and Haiti, while human cases only consistently occurred in the latter two areas. Rabies vaccination was conducted for high-risk animal populations with variable coverage, and rabies diagnostic capacities varied widely throughout the region. Illegal importation and natural migration of animals may facilitate the introduction of rabies virus variants into virus-naïve areas. Passive surveillance, together with enhanced methods and serological screening techniques, can therefore be of value. The insularity of the Caribbean makes it ideal for conducting pilot studies on reservoir host population management. Best practice guidelines developed for these reservoir hosts can be individually modified to the epidemiological status and available resources within each locality.

The History of Rabies in Trinidad: Epidemiology and Control Measures.

Vampire bat-transmitted rabies was first recognized in Trinidad during a major outbreak reported in 1925. Trinidad is the only Caribbean island with vampire bat-transmitted rabies. We conducted a literature review to describe the changing epidemiology of rabies in Trinidad and give a historical perspective to rabies prevention and control measures on the island. The last human case of rabies occurred in 1937 and although no case of canine-transmitted rabies was reported since 1914, sporadic outbreaks of bat-transmitted rabies still occur in livestock to date. Over the last century, seven notable epidemics were recorded in Trinidad with the loss of over 3000 animals. During the 1950s, several measures were effectively adopted for the prevention and control of the disease which led to a significant reduction in the number of cases. These measures include: vampire bat population control, livestock vaccination, and animal surveillance. However, due to lapses in these measures over the years (e.g., periods of limited vampire control and incomplete herd vaccination), epidemics have occurred. In light of the significant negative impact of rabies on animal production and human health, rabies surveillance in Trinidad should be enhanced and cases evaluated towards the design and implementation of more evidence-based prevention and control programs.

Evolutionary history and phylogeography of rabies viruses associated with outbreaks in Trinidad.

Bat rabies is an emerging disease of public health significance in the Americas. The Caribbean island of Trinidad experiences periodic outbreaks within the livestock population. We performed molecular characterisation of Trinidad rabies virus (RABV) and used a Bayesian phylogeographic approach to investigate the extent to which outbreaks are a result of in situ evolution versus importation of virus from the nearby South American mainland. Trinidadian RABV sequences were confirmed as bat variant and clustered with Desmodus rotundus (vampire bat) related sequences. They fell into two largely temporally defined lineages designated Trinidad I and II. The Trinidad I lineage which included sequences from 1997-2000 (all but two of which were from the northeast of the island) was most closely related to RABV from Ecuador (2005, 2007), French Guiana (1990) and Venezuela (1993, 1994). Trinidad II comprised sequences from the southwest of the island, which clustered into two groups: Trinidad IIa, which included one sequence each from 2000 and 2007, and Trinidad IIb including all 2010 sequences. The Trinidad II sequences were most closely related to sequences from Brazil (1999, 2004) and Uruguay (2007, 2008). Phylogeographic analyses support three separate RABV introductions from the mainland from which each of the three Trinidadian lineages arose. The estimated dates for the introductions and subsequent lineage expansions suggest periods of in situ evolution within Trinidad following each introduction. These data also indicate co-circulation of Trinidad lineage I and IIa during 2000. In light of these findings and the likely vampire bat origin of Trinidadian RABV, further studies should be conducted to investigate the relationship between RABV spatiotemporal dynamics and vampire bat population ecology, in particular any movement between the mainland and Trinidad.