Bats can harbor zoonotic pathogens, but their status as reservoir hosts for Leptospira bacteria is unclear. During 2015–2017, kidneys from 47 of 173 bats captured in Grenada, West Indies, tested PCR-positive for Leptospira. Sequence analysis of the Leptospira rpoB gene from 31 of the positive samples showed 87–91% similarity to known Leptospira species. Pairwise and phylogenetic analysis of sequences indicate that bats from Grenada harbor as many as eight undescribed Leptospira genotypes that are most similar to known pathogenic Leptospira, including known zoonotic serovars. Warthin-Starry staining revealed leptospiral organisms colonizing the renal tubules in 70% of the PCR-positive bats examined. Mild inflammatory lesions in liver and kidney observed in some bats were not significantly correlated with renal Leptospira PCR-positivity. Our findings suggest that Grenada bats are asymptomatically infected with novel and diverse Leptospira genotypes phylogenetically related to known pathogenic strains, supporting the hypothesis that bats may be reservoirs for zoonotic Leptospira. Leptospirosis is a worldwide disease of humans and animals caused by pathogenic strains of Leptospira spp. These bacteria are transmitted in urine from infected and usually asymptomatic reservoir hosts. Leptospira have been detected in several species of animals in Grenada, and human cases of leptospirosis are reported annually. However, little is known about the source of infection, and while rats are the most commonly recognized reservoir host of Leptospira, there is growing evidence that bats may also be asymptomatic carriers in the wild. To examine this, we captured different species of bats in Grenada, West Indies, from 2015 to 2017, tested kidney tissue for Leptospira spp. bacteria by PCR, and performed histological examination to see whether there is any relationship between Leptospira infection and associated lesions. Our results suggest that two species of bats tested—Artibeus spp. and Glossophaga longirostris—are asymptomatically infected with several types of Leptospira bacteria that may be new to science and that are phylogenetically related to strains that are known to cause disease.

The mosquitoes Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae) and Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) are two major vectors of arthropod-borne pathogens in Grenada, West Indies. As conventional vector control methods present many challenges, alternatives are urgently needed. Manipulation of mosquito microbiota is emerging as a field for the development of vector control strategies. Critical to this vector control approach is knowledge of the microbiota of these mosquitoes and finding candidate microorganisms that are common to the vectors with properties that could be used in microbiota modification studies. Results showed that bacteria genera including Asaia, Escherichia, Pantoea, Pseudomonas, and Serratia are common to both major arboviral vectors in Grenada and have previously been shown to be good candidates for transgenetic studies. Also, for the first time, the presence of Grenada mosquito rhabdovirus 1 is reported in C. quinquefasciatus.

Arboviruses cause diseases of significant global health concerns. Interactions between mosquitoes and their microbiota as well as the important role of this interaction in the mosquito's capacity to harbor and transmit pathogens have emerged as important fields of research. Aedes aegypti is one of the most abundant mosquitoes in many geographic locations, a vector capable of transmitting a number of arboviruses such as dengue and Zika. Currently, there are few studies on the metavirome of this mosquito particularly in the Americas. This study analyzes the metavirome of A. aegypti from Grenada, a Caribbean nation with tropical weather, abundant A. aegypti, and both endemic and arboviral pathogens transmitted by this mosquito. Between January and December 2018, 1152 mosquitoes were collected from six semi-rural locations near houses in St. George Parish, Grenada, by weekly trapping using BG-Sentinel traps. From these, 300 A. aegypti were selected for analysis. The metavirome was analyzed using the Illumina HiSeq 1500 for deep sequencing. The generation sequencing library construction protocol used was NuGEN Universal RNA with an average read length of 125 bp. Reads were mapped to the A. aegypti assembly. Non-mosquito reads were analyzed using the tools FastViromeExplorer. The NCBI total virus, RNA virus, and eukaryotic virus databases were used as references. The metagenomic comparison analysis showed that the most abundant virus-related reads among all databases and assemblies was Phasi Charoen-like virus. The Phasi Charoen-like virus results are in agreement to other studies in America, Asia and Australia. Further studies using wild-caught mosquitoes is needed to assess the impact of this insect-specific virus on the A. aegypti lifecycle and vector capacity.

Blood-feeding patterns of mosquitoes affect the transmission and maintenance of arboviral diseases. In the Caribbean, Aedes aegypti (L.) and Culex quinquefasciatus Say mosquitoes are the dominant mosquito species in developed areas. However, no information is available on the bloodmeal hosts of these invasive vectors in Grenada, where arboviral pathogens such as dengue, chikungunya, and Zika viruses cause significant human suffering. To this end, Ae. aegypti and Cx. quinquefasciatus mosquitoes were investigated from five semirural locations near houses in St. George’s Parish, from 2017 to 2018. Polymerase chain reaction was conducted on DNA extracted from individual blood-fed mosquitoes using vertebrate-specific cytochrome b primers. The 32 Ae. aegypti bloodmeals included humans (70%), mongooses (18%), domestic dogs (6%), a domestic cat (3%), and an unidentified bird (3%). Thirty-seven Cx. quinquefasciatus mosquitoes took bloodmeals from seven species of birds (51%), humans (27%), domestic cats (8%), iguanas (5%), a domestic dog (3%), a rat (3%), and a common opossum (3%). The high percentage of human bloodmeal hosts in our study, especially by the normally anthropophilic Ae. aegypti, is expected. The bloodmeal sources and the percentage of nonhuman bloodmeals (30%) taken by Ae. aegypti are comparable to other studies. The large range of hosts may be explained in part by the semirural nature of most local housing. Accordingly, this may contribute to an exchange of pathogens between domestic, peridomestic, and sylvatic transmission cycles.

Group A rotavirus (RV) and coronavirus (CV) are common viral pathogens associated with neonatal diarrhoea in numerous animal species. The purpose of this work was to investigate the presence of these viral agents in two farm populations of captured guanacos (Lama guanicoe) in the Argentinean Patagonia region, that developed severe diarrhoea outbreaks. Stool and serum samples were analysed for RV and bovine CV antigen and antibody enzyme-linked immunosorbent assay. Rotavirus was detected in faeces from two new-born guanacos with acute diarrhoea, one in each farm. After electrophoretic analysis, each isolated strain, showed a distinctive long dsRNA electropherotype characteristic of group A rotaviruses (4:2:3:2). In addition, 95% (38 of 40) of the sampled animals were positive for RV antibodies, suggesting a high prevalence of RV infection in the populations tested. No evidence of CV circulation by antigen or antibody analysis was observed. To our knowledge, this is the first report of the detection and isolation of RV associated with neonatal diarrhoea in Lama guanicoe.

Chelonid alphaherpesvirus 5 (ChHV5) is strongly associated with fibropapillomatosis, a neoplastic disease of sea turtles that can result in debilitation and mortality. The objectives of this study were to examine green (Chelonia mydas), hawksbill (Eretmochelys imbricata), and leatherback (Dermochelys coriacea) sea turtles in Grenada, West Indies, for fibropapillomatosis and to utilize ChHV5-specific PCR, degenerate herpesvirus PCR, and serology to non-invasively evaluate the prevalence of ChHV5 infection and exposure. One-hundred and sixty-seven turtles examined from 2017 to 2019 demonstrated no external fibropapilloma-like lesions and no amplification of ChHV5 DNA from whole blood or skin biopsies. An ELISA performed on serum detected ChHV5-specific IgY in 18/52 (34.6%) of green turtles tested. In 2020, an adult, female green turtle presented for necropsy from the inshore waters of Grenada with severe emaciation and cutaneous fibropapillomas. Multiple tumors tested positive for ChHV5 by qPCR, providing the first confirmed case of ChHV5-associated fibropapillomatosis in Grenada. These results indicate that active ChHV5 infection is rare, although viral exposure in green sea turtles is relatively high. The impact of fibropapillomatosis in Grenada is suggested to be low at the present time and further studies comparing host genetics and immunologic factors, as well as examination into extrinsic factors that may influence disease, are warranted.