Preliminary molecular characterization of a fowl poxvirus isolate in Grenada.

Two 1-mo-old local breed chickens, with gross lesions in the skin of the head region suspected to be fowl poxvirus infection, were submitted to the Diagnostic Laboratory of the School of Veterinary Medicine, Grenada, West Indies. Cutaneous lesions were collected from these birds for virus isolation, histopathologic diagnosis, and molecular analysis. Fowl poxvirus infection was confirmed by virus isolation in chicken embryo and by histopathology. Molecular characterization of the fowl poxvirus was conducted by PCR amplification of selected genomic fragments and by nucleotide sequencing. Integration of reticuloendotheliosis virus fragments into the fowl poxvirus genome was confirmed by PCR and DNA sequencing. This is the first report from the Caribbean region on the preliminary molecular characterization of a fowl poxvirus isolate.

A serological study of Dirofilaria immitis in feral cats in Grenada, West Indies.

A study to determine the seroprevalence of Dirofilaria immitis was carried out in feral cats in Grenada. Of the 137 feral cats tested for circulating antibodies (IgG; lateral-flow immunoassay) and circulating antigens (Ag; enzyme-linked immunosorbent assay), 8% (95% confidence interval (CI) 3.5-12.5%) were antibody positive and 5.1% (95% CI 1.4-8.8%) were antigen positive. No significant difference between cats aged>1 to 4 years and cats less than 1 year of age was found (P>0.05, χ²). There was also no significant difference (P>0.05, χ²) between male and female cats. Dirofilaria immitis prevalence is relatively high in the feral cat population of Grenada. Evidence of D. immitis infection in feral cats coupled with the endemic nature of heartworm disease in dogs in Grenada leads us to suggest the introduction of heartworm prophylaxis in cats. To the authors' knowledge, this serological evidence of heartworm infection in feral cats in Grenada is the first report from the Caribbean region.

Existence of Angiostrongylus cantonensis in rats (Rattus norvegicus) in Grenada, West Indies.

The zoonotic rat lung worm, Angiostrongylus cantonensis is endemic to Asia, North America, Africa and Australia. The parasite is expanding geographically and has recently been recorded in some of the Greater Antilles in the northern part of the Caribbean. In this study A. cantonensis is reported for the first time in the Lesser Antilles in one of the southernmost islands, Grenada. Between September 2005 and September 2006, 192 rats (Rattus norvegicus) were trapped throughout the island. The rats were anesthetized, exsanguinated, necropsied and the lungs were fixed whole in 10% buffered formalin, trimmed, processed, cut at 3microm, stained with hematoxylin and eosin and examined microscopically. A total of 45 (23.4%) of the 192 rats examined were found to be infected with A. cantonensis and adult worms were found in the cardiopulmonary system of one of the rats. Microscopically, pulmonic lesions, consisting of pulmonary thrombosis, hypertrophy of pulmonary arteries and granulomatous pneumonia were associated with intralesional adults, larvae and embryonated eggs of A. cantonensis. An incidental finding of variably sized (2-7mm) solitary to multiple cysts containing larvae of Taenia taeniaformis were seen in the livers of 57 rats. This report of A. cantonensis in Grenada provides evidence of the further global expansion of this important zoonotic parasite and the public health implications of this discovery is discussed.

Prevalence of Cryptosporidium spp. in asymptomatic small ruminants in Grenada, West Indies.

Cryptosporidium spp. is a protozoan parasite that causes enteric infection in a wide range of hosts, including livestock and humans. The aim of this cross-sectional study was to estimate the prevalence of Cryptosporidium spp. in small ruminants in Grenada, West Indies. Fecal samples were collected from 100 sheep and 202 goats from 32 farms. The fecal samples were tested using an Enzyme-linked immunosorbent assay (ELISA) for qualitative detection of antigens in feces (Diagnostic Automation Inc., USA). The overall prevalence of Cryptosporidium spp. was 19.5% [95% confidence interval (CI): 15.4% to 24.4%] in both sheep and goats. The prevalence of Cryptosporidium spp. in sheep and goats was 14% (95% CI: 8.4% to 22.3%) and 22.3% (95% CI: 17.1% to 28.5%), respectively. There was no significant difference in the prevalence of Cryptosporidium spp. infection between sheep and goats (p = .42, Fisher's exact test) in Grenada. Of the 32 farms visited, 19 (59.4%) had at least one Cryptosporidium spp. positive animal.

Prevalence of Toxoplasma gondii in rats (Rattus norvegicus) in Grenada, West Indies.

Cats are important in the natural epidemiology of Toxoplasma gondii, because they are the only hosts that can excrete environmentally resistant oocysts. Cats are infected with T. gondii via predation on infected birds and rodents. During 2005, 238 rats (Rattus norvegicus) were trapped in Grenada, West Indies, and their sera along with tissue samples from their hearts and brains were examined for T. gondii infection. Antibodies to T. gondii were assayed by the modified agglutination test (MAT, titer 1:40 or higher); only 2 (0.8%) of 238 rats were found to be infected. Brains and hearts of all rats were bioassayed in mice. Toxoplasma gondii was isolated from the brain and the heart of only 1 rat, which had a MAT titer of 1:320. All of 5 mice inoculated with the heart tissue, and the 5 mice inoculated with the brain tissue of the infected rat remained asymptomatic, even though tissue cysts were found in their brains. Genetically, the isolates of T. gondii from the heart and the brain were identical and had genotype III by using the SAG1, SAG2, SAG3, BTUB, and GRA6 gene markers. These data indicate that rats are not important in the natural history of T. gondii in Grenada.

Serological evidence of antibodies to Neospora caninum in stray and owned Grenadian dogs.

Neospora caninum causes abortion in cattle and neuromuscular disease in dogs, world wide. Cattle become infected by ingesting oocysts voided by dogs. The aim of this study was to estimate the seroprevalence of Neospora caninum in two populations of dogs (stray and owned) in Grenada, West Indies. Sera were collected from 625 dogs from all parishes in Grenada. Three hundred and sixty eight dogs were stray, while 257 dogs were owned. Sera were tested for the presence of antibodies against N. caninum using an indirect enzyme linked immunosorbant assay (ELISA) IDvet, France. Antibodies to N. caninum were found in 6 (1.6%) (95% confidence interval (CI): 0.32% to 2.88%) of the stray dogs and in 3 (1.2%, 95% CI: 0.13% to 2.53%) of the owned dogs. Seroprevalence did not differ significantly between the two populations (p=0.74) and between the males and females (p=1). These results suggest that the prevalence of N. caninum infection in dogs in Grenada is low.

Retrospective study of canine heartworm disease with caval syndrome in Grenada, West Indies.

Canine heartworm disease caused by Dirofilaria immitis is an important disease of dogs. The aim of this retrospective study was to estimate the prevalence of canine heartworm disease and evaluate cases of caval syndrome in dogs submitted for necropsy in Grenada. Out of 1617 dogs necropsied over a period of 13 years (2001-2013), 249 were found to be infected with D. immitis; giving an overall prevalence of 15.4% (95% confidence interval, 13.6% to 17.1%). There was no significant difference between male and female dogs with respect to canine heartworm infection (p = 0.3). During this period, the annual prevalence of canine heartworm disease was 22% in 2001 before slightly declining to an average of 18% in 2002-2003 and peaking at 26.8% in 2004-2005. From 2006 onwards, annual prevalence rates have steadily been decreasing; reaching the lowest (9%) in 2013. Among the 249 positive cases, 33 (13.2%) of the dogs had caval syndrome. Caval syndrome cases presented with concurrent clinical signs and were associated with cardio-pulmonary and hepatic gross lesions at necropsy. Aberrant migration of D. immitis was also noted in 2 dogs with caval syndrome. This is the first report which presents the findings of canine heartworm disease with caval syndrome in Grenada.

Seroprevalence of Trypanosoma cruzi in stray and pet dogs in Grenada, West Indies.

American trypanosomiasis (Chagas disease) caused by the protozoan parasite Trypanosoma cruzi is endemic to parts of South America and the Caribbean. Infected dogs are important in the epidemiology of the parasite as they can play a role in the transmission of the parasite to humans. A total of 399 dog sera (242 stray and 157 pet dogs) were examined for T. cruzi infection; using a qualitative immunochromatographic dipstick test, based on recombinant antigens specific for American trypanosomiasis (Trypanosoma detect rapid test; InBios international, Inc., Seattle, Washington). Overall seroprevalence for T. cruzi was estimated at 10.5% (95% confidence interval: 7.5% to 13.5%); with stray dogs being significantly more affected (p<0.05, χ2). Results from this study indicate that dogs in Grenada are moderately exposed to T. cruzi compared to other areas in the region.

Serologic detection of antibodies to Brucella spp. using a commercial ELISA in cattle in Grenada, West Indies.

Bovine brucellosis, caused mainly by Brucella abortus, a zoonotic bacterium, has been reported from many areas of the world, including Central and South America, and the Caribbean island state of Trinidad and Tobago. Although brucellosis has been eradicated from domestic cattle in Canada it still exists in one or two herds in the United States. Serological tests are important in estimating prevalence of Brucella exposure in order to target eradication programmes. In this study, serum samples from 150 cattle were tested using a commercial competitive enzyme linked immunosorbent assay (SVANOVIR®Brucella-Ab C-ELISA) which detects antibodies to both B. abortus and Brucella melitensis. All cattle tested were greater than 6 months old and were unvaccinated. Sampled cattle were from 35 herds representing animals from all 6 parishes of Grenada. Nine of the 150 animals (6%) were positive for antibodies to B. abortus and/or melitensis by the C-ELISA. Of the 35 herds, 7 (20%) had C-ELISA- positive animals. Three of the 6 parishes contained positive herds. Based on the high sensitivity (98%) and specificity (99.7%) of the C-ELISA, these results strongly indicate the presence of cattle exposed to B. abortus and/or melitensis in Grenada.

Isolation and RFLP genotyping of Toxoplasma gondii from the domestic dogs (Canis familiaris) from Grenada, West Indies revealed high genetic variability.

Stray dogs are considered as sentinels in the epidemiology of Toxoplasma gondii because they are carnivores and eat a variety of foods, including garbage. In the present study, tissues and sera of 249 stray dogs (Canis familiaris) from Grenada, West Indies were examined for T. gondii infection. Sera were examined for antibodies to T. gondii by the modified agglutination test (MAT); 89 (35.7%) of 249 were seropositive with titers of 25 in seven dogs, 50 in 22 dogs, 100 in 22 dogs, 200 or higher in 38 dogs. Hearts of 76 seropositive dogs were bioassayed in mice. Viable T. gondii was isolated from 12 dogs; these isolates were designated TgDogGr1 to TgDogGr12. These isolates were further propagated in cell culture and DNA isolated from cell culture derived tachyzoites of 12 isolates was genotyped using 10 PCR-restriction fragment length polymorphism markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). The results revealed six genotypes, including ToxoDB PCR-RFLP #1, #2, #3, #7, #13 and #224, with 1, 6, 1, 2, 1 and 1 isolates, respectively. The result supports previous findings that T. gondii population genetics is highly diverse in Grenada.

Spirocercosis in owned and stray dogs in Grenada.

The aim of this retrospective study was to estimate the prevalence of Spirocerca lupi and its associated lesions in owned and stray dogs in Grenada. During 2001-2011 necropsies were carried out on 1022 owned and 450 stray dogs at the pathology diagnostic laboratory, School of Veterinary Medicine, St. George's University, Grenada. Lesions due to S. lupi characterized by focal to multifocal granulomatous esophagitis with aneurysms, mineralized plaques and nodules in the adjacent thoracic aorta were found in 90 (8.8%; 95% confidence interval, 7.1-10.5%) of owned dogs and 64 (14.2%; 95% CI, 11.2-17.6%) of stray dogs. Stray dogs were significantly more affected by spirocercosis than owned dogs (p=0.0022). Of the 90 owned dogs with spirocercosis, 3 dogs had aberrant migration to the thoracic vertebral column with resultant spondylitis; 1 dog each had aberrant migration involving the stomach and the lung. Two dogs had ruptured aorta with hemothorax. Among the 64 stray dogs with spirocercosis, one dog had an esophageal granuloma that transformed into a fibroblastic osteosarcoma; spondylitis due to aberrant migration of S. lupi and hypertrophic osteopathy. We report spirocercosis for the first time in the dogs from a tropical island of Grenada.

Neoplastic and nonneoplastic cutaneous tumors of dogs in grenada, west indies.

This retrospective survey was undertaken between 2002 and 2007 on samples from dogs residing in Grenada. The objectives of the study were to identify the most common histologic types of canine cutaneous tumors, determine the relative frequency of each tumor type, and compare results to reports from other regions. In a series of 225 skin masses examined, the proportion of neoplasms was 72% whereas nonneoplastic tumors accounted for 15.6%, and inflammatory conditions constituted 12.4%. There were 10 types of nonneoplastic tumors with hamartomas being the most common (28.5%), followed by sebaceous hyperplasia (25.7%) and fibroepithelial polyps (22.8%). The 10 most common cutaneous neoplasms were hemangiosarcomas (19.1%), histiocytomas (8.6%), melanocytomas (8%), mast cell tumors (6.8%), lipomas (6.8%), hemangiopericytomas (6.2%), papillomas (5.6%), fibrosarcomas (5.6%), hemangiomas (4.9%), and squamous cell carcinomas (4.3%). Tumors of vascular origin and transmissible venereal tumors were more common in dogs in our study than reported from other regions.

Seroprevalence of Toxoplasma gondii in pigs, sheep, goats, and cattle from Grenada and Carriacou, West Indies.

Prevalence of Toxoplasma gondii infection in pregnant women in Grenada is considered high. Little is known of the epidemiology of T. gondii infection in Caribbean Islands. Serum samples of 750 food animals in Grenada and Carriacou were tested for antibodies to T. gondii by the modified agglutination test (MAT). Antibodies to T. gondii (MAT, 1∶25 or higher) were found in 23.1% of 247 pigs, 44.1% of 204 sheep, 42.8% of 180 goats, and 8.4% of 119 cattle. Seroprevalence increased with age, indicating postnatal acquisition of T. gondii. Antibody titers of 1∶200 or higher were present in 65 of 90 seropositive sheep, 61 of 77 seropositive goats, and 23 of 57 seropositive pigs. However, none of the cattle had a MAT titer of 1∶200, suggesting that bovines are a poor host for T. gondii. Results indicate that pigs, sheep, and goats could be important sources of T. gondii infection if their meat is consumed undercooked.

Seroprevalence of Toxoplasma gondii and concurrent Bartonella spp., feline immunodeficiency virus, and feline leukemia virus infections in cats from Grenada, West Indies.

Toxoplasma gondii and Bartonella spp. are zoonotic pathogens of cats. Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLv) are related to human immunodeficiency virus, and human leukemia virus, respectively; all of these viruses are immunosuppressive. In the present study, the prevalence of antibodies to T. gondi, Bartonella spp., FIV, as well as FeLv antigen were determined in sera from 75 domestic and 101 feral cats (Felis catus) from the Caribbean island of Grenada, West Indies. Using a modified agglutination test, antibodies to T. gondii were found in 23 (30.6%) of the 75 pet cats with titers of 1:25 in 1, 1:50 in 3, 1:400 in 4, 1:500 in 12, 1:800 in 2, and 1:1,600 in 1, and 28 (27.7%) of 101 feral cats with titers of 1:25 in 4, 1:50 in 7, 1:200 in 4, 1:400 in 1, 1:500 in 3, 1:800 in 2, 1:1,600 in 3, and 1:3,200 in 4. Overall, in both pet and feral cats, the seroprevalence increased with age. Antibodies to Bartonella spp. were found in 38 (50.6%) of the 75 pet cats and 52.4% of 101 feral cats. Antibodies to FIV were found in 6 domestic and 22 feral cats. None of the 176 cats was positive for FeLv antigen. There was no correlation among T. gondii, Bartonella spp., and FIV seropositivity.

Antimicrobial drug resistance and genetic diversity of commensal Escherichia coli from caeca of chickens in Grenada.

The main goal of this study was to generate baseline data on resistance to 11 antimicrobial drugs of global importance among commensal Escherichia coli from healthy chicken in Grenada. For this purpose, a total of 183 commensal Escherichia coli isolates from 197 chickens (147 broilers and 50 layers) originating from 11 poultry farms in Grenada were studies using a standard disk diffusion method. The isolates were further studied for their haemolytic properties using sheep blood agar, and genotypes using the enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR). Sixty-six isolates were positive for alpha haemolysis, and the remaining were non-haemolytic. There was no difference in antimicrobial susceptibility between haemolytic and non-haemolytic isolates. Resistance was highest against tetracycline (58.5%) followed by streptomycin (44.3%) and lowest to chloramphenicol (0.55%). Only three isolates (1.6%) showed resistance to fluoroquinolones. Resistance rates to tetracycline, streptomycin, and gentamicin were significantly lower among isolates from layers, compared with those from broilers. Multiple resistance to three or more classes of drugs was found in 10.4% of total isolates; the most common R-profile was Amp, Str, Tet. Twenty genotypes were identified among 24 randomly selected isolates that originated from 11 unrelated farms and 5 geographical locations. Isolates sharing similar genomic fingerprints by ERIC-PCR had different resistance profiles, whereas isolates with different genotypes shared similar profiles. In conclusion, this study showed the genetic diversity of chicken isolates from Grenada, and their significance and the epidemiological significance of ERIC-PCR genotypes among poultry isolates need further study.

Seroprevalence of Hantavirus in Rattus norvegicus in Grenada, West Indies.

Hantavirus is an emerging zoonotic virus with potential for significant human disease and mortality. Rodents are the natural reservoir for the virus. This study reports the seroprevalence of hantavirus in brown rats (Rattus norvigicus) in Grenada. Serum samples from 198 brown rats were tested for the immunoglobulin G (IgG) antibody to hantavirus using an enzyme-linked immunosorbant assay (ELISA). A seroprevalence rate of 29.3% was found. This is the first report of hantavirus exposure in any species on the island of Grenada and documents the brown rat as a reservoir host on the island.

Antimicrobial drug resistance and genetic diversity of commensal Escherichia coli from caeca of chickens in Grenada.

The main goal of this study was to generate baseline data on resistance to 11 antimicrobial drugs of global importance among commensal Escherichia coli from healthy chicken in Grenada. For this purpose, a total of 183 commensal Escherichia coli isolates from 197 chickens (147 broilers and 50 layers) originating from 11 poultry farms in Grenada were studies using a standard disk diffusion method. The isolates were further studied for their haemolytic properties using sheep blood agar, and genotypes using the enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR). Sixty-six isolates were positive for alpha haemolysis, and the remaining were non-haemolytic. There was no difference in antimicrobial susceptibility between haemolytic and non-haemolytic isolates. Resistance was highest against tetracycline (58.5%) followed by streptomycin (44.3%) and lowest to chloramphenicol (0.55%). Only three isolates (1.6%) showed resistance to fluoroquinolones. Resistance rates to tetracycline, streptomycin, and gentamicin were significantly lower among isolates from layers, compared with those from broilers. Multiple resistance to three or more classes of drugs was found in 10.4% of total isolates; the most common R-profile was Amp, Str, Tet. Twenty genotypes were identified among 24 randomly selected isolates that originated from 11 unrelated farms and 5 geographical locations. Isolates sharing similar genomic fingerprints by ERIC-PCR had different resistance profiles, whereas isolates with different genotypes shared similar profiles. In conclusion, this study showed the genetic diversity of chicken isolates from Grenada, and their significance and the epidemiological significance of ERIC-PCR genotypes among poultry isolates need further study.

Seroprevalence of Hantavirus in Rattus norvegicus in Grenada, West Indies.

Hantavirus is an emerging zoonotic virus with potential for significant human disease and mortality. Rodents are the natural reservoir for the virus. This study reports the seroprevalence of hantavirus in brown rats (Rattus norvigicus) in Grenada. Serum samples from 198 brown rats were tested for the immunoglobulin G (IgG) antibody to hantavirus using an enzyme-linked immunosorbant assay (ELISA). A seroprevalence rate of 29.3% was found. This is the first report of hantavirus exposure in any species on the island of Grenada and documents the brown rat as a reservoir host on the island.

Prevalence of gastrointestinal parasites in free-range poultry in Grenada, West Indies.

Rural poultry production systems in Grenada are based on the scavenging indigenous domestic fowl (Gallus domesticus), the predominant species in the poultry sector. This study was done to establish the species and frequency of gastrointestinal parasites in 106 free-ranges chickens ages between 1-2 years, and collected from 13 households. Three nematodes and one tapeworm were identified: Gongylonema ingluvicola (29.2%); Ascaridia galli (10.3%); Heterakis gallinarum (4.7%); Capillaria contorta (2.83%); Railietina tertagona (38.6%). Helminth infections in free-range chickens, even when they occur in low numbers, may result in subclinical disease. High numbers can produce clinical disease. Further studies may be required to devise appropriate prevention and control methods, with improved management systems. This is the first report of gastrointestinal parasites of free-ranging poultry in Grenada.

Prevalence of gastrointestinal parasites in free-range poultry in Grenada, West Indies.

Rural poultry production systems in Grenada are based on the scavenging indigenous domestic fowl (Gallus domesticus), the predominant species in the poultry sector. This study was done to establish the species and frequency of gastrointestinal parasites in 106 free-ranges chickens ages between 1-2 years, and collected from 13 households. Three nematodes and one tapeworm were identified: Gongylonema ingluvicola (29.2%); Ascaridia galli (10.3%); Heterakis gallinarum (4.7%); Capillaria contorta (2.83%); Railietina tertagona (38.6%). Helminth infections in free-range chickens, even when they occur in low numbers, may result in subclinical disease. High numbers can produce clinical disease. Further studies may be required to devise appropriate prevention and control methods, with improved management systems. This is the first report of gastrointestinal parasites of free-ranging poultry in Grenada.