Completing the Puzzle: A Cluster of Hunting Dogs with Tick-Borne Illness from a Fishing Community in Tobago, West Indies.

Eight hunting dogs were visited by a state veterinarian on the island of Tobago, Trinidad and Tobago, West Indies, as owners reported anorexia and paralysis in five of their dogs. The veterinarian observed a combination of clinical signs consistent with tick-borne illness, including fever, anorexia, anaemia, lethargy and paralysis. Blood and ticks were collected from each dog and submitted to a diagnostic laboratory for analysis. Microscopic analysis revealed a mixed infection of intracytoplasmic organisms consistent with Babesia spp. (erythrocyte) and Ehrlichia spp. (monocyte), respectively, from one dog, while a complete blood count indicated a regenerative anaemia (n = 1; 12.5%), non-regenerative anaemia (n = 4; 50%), neutrophilia (n = 3; 37.5%), lymphocytosis (n = 2; 25%), thrombocytopaenia (n = 3; 37.5%) and pancytopaenia (n = 1; 12.5%). DNA isolated from the eight blood samples and 20 ticks (16 Rhipicephalus sanguineus and 4 Amblyomma ovale) were subjected to conventional PCR and next-generation sequencing of the 16S rRNA and 18S rRNA gene for Anaplasma/Ehrlichia and Babesia/Theileria/Hepatozoon, respectively. The DNA of Ehrlichia spp., closely related to Ehrlichia canis, was detected in the blood of three dogs (37.5%), Anaplasma spp., closely related to Anaplasma marginale, in two (25%), Babesia vogeli in one dog (12.5%) and seven ticks (35%) and Hepatozoon canis and Anaplasma spp., in one tick (5%), respectively. These findings highlight the need to test both the vector and host for the presence of tick-borne pathogens when undertaking diagnostic investigations. Further studies are also warranted to elucidate the susceptibility of canids to Anaplasma marginale.

The Prevalence of Gastrointestinal Parasites and Seroprevalence of Toxoplasma gondii in Captive Ocelots (Leopardus pardalis) in Trinidad, West Indies.

This study was conducted from November 2010 to June 2011 to determine the prevalence of gastrointestinal parasites and the seroprevalence of Toxoplasma gondii in captive ocelots (Leopardus pardalis) in Trinidad. Faecal samples were collected and analyzed using faecal flotation to identify helminth ova and protozoan cysts and oocysts. Serum samples from captive ocelots were screened for T. gondii using a latex agglutination test kit. Of the 19 ocelots examined, the most prevalent parasites noted were ova of ascarids, strongyles, and Capillaria spp. The serum of three of the 13 (23.1%) ocelots tested was positive for T. gondii antibodies. These ocelots are therefore a potential source of T. gondii infection to both humans and other animals. This is the first documented report of endoparasites in local captive ocelots within Trinidad and provides useful data to support further research of the captive and wild populations.

A field study on the occurrence of gastrointestinal nematodes in sheep over the wet and dry seasons in two West Indian Islands.

Gastrointestinal nematode (GIN) infestations are a major constraint to sheep production in the West Indies (WI). Intensive and semi-intensive management systems are most commonly employed. These islands display tropical weather patterns with wet and dry seasons. Semi-intensive farming combined with increased rainfall during the wet season has been reported to be most favourable for development and survival of GIN. This study was conducted to determine whether there was a relationship between GIN burdens in sheep with seasonality and management practices of farmers in Trinidad and Tobago (T&T). Farms were visited on a monthly basis from January to December 2017. A maximum of ten sheep, three to nine months of age, were selected from each farm. A total of 3,053 faecal samples were collected and analysed using the Modified McMaster technique. Environmental data on daily precipitation and temperature were collected from the Trinidad and Tobago Meteorological Office during the period of sampling. A mixed effects negative binomial regression model was constructed to analyse the relationship between gastrointestinal nematode faecal egg counts (GINFEC) with season, management system and use of dewormers as fixed effects and farm as a random effect. Average diurnal temperatures of T&T fluctuated between 23.2°C to 32.6°C and 23.9°C to 32.3°C in the dry and wet seasons, respectively. Average daily precipitation ranged between 1.6-1.8 mm and 6.1-8.5 mm during the dry and wet seasons, respectively. A decreased risk of 0.34 (95% CI 0.25-0.47, p < .0001) for GINFEC was observed in dewormed animals versus not dewormed. Semi-intensive management systems experienced an increased risk of GINFEC by 1.39 (95% CI 1.05-1.84, p = .021) compared with intensive and the risk of GINFEC was reduced by 0.40 (95% CI 0.33-0.49, p < .0001) in the wet season versus the dry. A higher prevalence of GIN was observed during the drier months of the year. Climatic conditions observed in T&T remained favourable for GIN survival, development and distribution year-round. Proper management is therefore required for reducing the occurrence of GIN in sheep of T&T throughout the year. This is the first reported study in the WI on the influence of seasonality and management on GIN infestations in sheep during the dry and wet seasons. Further investigation is needed to elucidate why GIN burdens appear to be higher in the dry season than the wet season. This study can be used as a baseline for public education in T&T as well as other developing countries.

Survey of ticks of domestic dogs and cattle in three Caribbean islands.

Ticks and the pathogens they transmit can cause high morbidity and mortality in domestic animals. As part of a larger study to determine the tick-borne pathogens infesting domestic animals and wildlife, the aim of this study was to survey the tick species infesting the canine and cattle populations in Trinidad, Tobago and St. Lucia. A total of 1,990 ticks were collected off 179 dogs in Trinidad (n = 163) and Tobago (n = 16) between June 2016 and 2018. Ticks were also collected from cattle throughout Trinidad (n = 1,098), Tobago (n = 306) and St. Lucia (n = 176). Collected ticks were morphologically identified using standard taxonomic keys. Tick-infested dogs were characterized as pets (n = 161) or hunting dogs (n = 18). Only two tick species, Rhipicephalus sanguineus (1,926; 96.8%) and Amblyomma ovale (64; 3.2%), were found on the dogs. A total of 169 (94.4%) dogs and 10 (5.6%) dogs were infested with R. sanguineus and A. ovale, respectively. Three dogs (1.7%) were infested with both tick species. Hunting dogs or those closely associated with them were infested with A. ovale. Rhipicephalus sanguineus was widely distributed throughout both islands, whereas A. ovale was restricted to small foci in three rural settlements in both Trinidad (n = 2) and Tobago (n = 1). Rhipicephalus (Boophilus) microplus (n = 1,404) was the only tick species found in cattle from Trinidad (n = 62) and Tobago (n = 20), whilst R. B. microplus (n = 171) and Amblyomma variegatum (n = 5) were found infesting 14 and two heads of cattle, respectively, in St. Lucia. These preliminary findings will aid in determining whether there are links between ticks and tick-borne pathogens associated with domestic, wildlife species and humans and give further insight into the potential movement of ticks and their pathogens between the human, animal and tropical forest interface.

Prospective study investigating transplacental transmission of equine piroplasmosis in thoroughbred foals in Trinidad.

Equine piroplasmosis caused by Theileria equi and Babesia caballi is endemic in Trinidad and Tobago. Transmission occurs by ticks of the family Ixodidae. T. equi can also be transmitted transplacentally; however transplacental transmission of B. caballi is unknown. This study aims to investigate transplacental transmission of equine piroplasmosis from thoroughbred mares naturally infected via the tick vector. Whole blood and serum samples were collected from 117 mares in the fifth month of pregnancy. Blood samples were also collected from each of their foals (89 in total) within the first 36h of birth. Additionally, all foals were observed for clinical signs within 30days post - partum. All samples were examined microscopically for intra-erythrocytic piroplasms. Serum ELISA tests and PCR analysis on whole blood were performed to determine the presence of T. equi and B. caballi. Thirty-four (30.6%) mares and 14 (15.7%) of their foals were seropositive for T. equi. Twenty-seven (24.3%) mares were positive for T. equi by conventional (c) PCR. Real time (q) PCR analysis based on the ema - 1 gene revealed that seven (8%) foals were positive for T. equi. Eighty-nine (76.1%) mares and 38 (42.7%) foals were seropositive for B. caballi. Four (3.4%) mares were positive for B. caballi by cPCR. Three out of the four cPCR positive mares either had resorptions, or stillbirths for that pregnancy. From this study, there is strong evidence that transplacental transmission of B. caballi can occur leading to foetal losses. Six foals (7%) were positive for B. caballi by qPCR. Of these six, four were born to B. caballi seropositive mares. In this study a foal born of a T. equi seropositive mare was 55.7 times more likely to be serologically positive for T. equi than a foal born to a T. equi seronegative mare. Similarly a foal born of a B. caballi seropositive mare was 39.4 times more likely to be serologically positive for B. caballi than a foal born to a mare that was serologically negative for B. caballi at the fifth month of pregnancy. This is as a result of the ingestion of colostrum containing antibodies to these pathogens. Mares should be screened during pregnancy and their foals closely monitored at parturition for evidence of equine piroplasmosis so that treatment can be implemented earlier for a better prognosis.

Characterization of Giardia duodenalis infections in dogs in Trinidad and Tobago.

To our knowledge, the zoonotic potential of Giardia duodenalis has not been assessed in companion animals in Trinidad and Tobago. This report details the first attempt to evaluate the potential zoonotic risk of G. duodenalis in dogs and identify assemblages of G. duodenalis found in dog populations on both islands. Fecal samples were collected from free-roaming dogs and dogs at the Trinidad and Tobago Society for the Prevention of Cruelty to Animals from October 2010 to June 2011. A total of 168 samples were collected of which 104 samples were analyzed for the presence of G. duodenalis by PCR amplification of the ssu-rRNA gene with subsequent assemblage-typing. A subset of samples was also analyzed by ELISA. Twenty-six samples were positive for G. duodenalis by PCR for an overall prevalence of 25%. Four samples were identified as assemblage C (15.4%), 21 as assemblage D (80.8%), and one as assemblage E (3.8%). Puppies were four-times more likely to be infected with G. duodenalis than adult dogs (OR 4.61, 95% CI 1.73-12.2). There was a significant agreement between ELISA and PCR in the detection of the protozoa (κ=0.67). We infer from our results that while the prevalence of G. duodenalis is relatively high in Trinidad and Tobago, the zoonotic risk of infection in humans is low since neither assemblage A nor B was identified in the study population.

Non-resolving pneumonia in a young boy--beware of foreign body aspiration.

A 4 1/2-year-old boy presented with recurrent cough and cold of 2 years duration. Chest x-ray revealed collapse consolidation of right lower lobe. Rigid bronchoscopy was done and the nozzle of a pen was extracted from right main bronchus. The radiological improvement took three months after extraction of the foreign body. Undetected foreign body aspiration is one of the causes of nonresolving pneumonia in children.