Heartworm control in Grenada, West Indies: Results of a field study using imidacloprid 10% + moxidectin 2.5% and doxycycline for naturally-acquired Dirofilaria immitis infections.

Canine heartworm disease (CHD) results from infection with Dirofilaria immitis and while it is of global concern, it is most prevalent in tropical climates where conditions support the parasite and vector life cycles. Melarsomine dihydrochloride is the sole treatment for CHD recommended by the American Heartworm Society. However, in cases where cost or access to melarsomine precludes treatment of an infected dog, therapeutic alternatives are warranted. This randomized, controlled field study evaluated the adulticidal efficacy of a combination therapeutic protocol using 10 % imidacloprid + 2.5 % moxidectin spot-on and a single 28-day course of doxycycline and compared with that of a 2-dose melarsomine dihydrochloride protocol. Of 37 naturally-infected domestic dogs with class 1, 2 or early class 3 CHD enrolled in the study, 30 were evaluated for a minimum of 12 months. Seven dogs were withdrawn due to canine ehrlichiosis, non-compliance, or wrongful inclusion. Dogs were randomly assigned to a control (CP, n = 15) or investigational (IVP, n = 15) treatment group. CP dogs received two injections of melarsomine dihydrochloride (2.5 mg/kg) 24 -hs apart and maintained on monthly ivermectin/pyrantel. IVP dogs were treated with oral doxycycline (10 mg/kg twice daily for 28 days) and topical 10 % imidacloprid + 2.5 % moxidectin once monthly for 9 months. Dogs were evaluated up to 18 months - monthly for the first 9 months, then every 3 months. Parasiticidal efficacy was based on antigen status using the IDEXX PetChek® 34 Heartworm-PF Antigen test. By month 18, antigen was not detected in any study dog except one from the IVP group. One other IVP dog was persistently antigenemic and treated with melarsomine at month 12 according to the initial study protocol. Mean antigen concentration (based on optical density) decreased more rapidly in the CP group and by month 15 was 0.11 for the IVP and 0.07 for CP groups, with equivalent median concentrations (0.04) in both groups. Conversion following heat-treatment of antigen-negative samples occurred frequently and at similar rates in both treatment groups. Based on the bias of diagnostic tests towards detection of female worms, we conclude that monthly application of 10 % imidacloprid + 2.5 % moxidectin for 9 months combined with a course of doxycycline twice daily for 28 days resulted in effective therapy against female adults in CHD. This therapeutic option may be particularly useful in cases where financial constraint or access to melarsomine precludes treatment of an infected individual. This study was supported by Bayer Animal Health.

The current prevalence and potential elimination of the soil transmitted helminth’s from Grenada

OBJECTIVE: This study formed part of a soil transmitted helminth elimination program in Grenada. The study assessed the prevalence of soil transmitted helminths (STH’s) in Grenadian primary school children. DESIGN AND METHODS: A longitudinal study was carried out on students attending 39 out of all 54 (72.2%) primary schools in Grenada, Carriacou and Petite Martinique between March 2013 and December 2014. The schools were randomly selected for inclusion in the study. Zinc Sulphate Floatation with centrifugation and Microscopy was used to assess the prevalence of STH’s in stool samples from Grenadian primary school children. RESULTS: The overall prevalence of STH was 1.3% (95% CI= 0.54-2.72). In 4 of the 8 parishes the prevalence was 0%. The highest prevalence was 3.9% (0.48-13.46) in St. Patrick. The STH identified were Ancylostoma duodenale, Ascaris lumbricoides and Trichuris trichuria. CONCLUSION: The prevalence of STH’s in the initial survey was 1.3%. This low prevalence indicates that the elimination program which utilizes a multi pronged approach including targeted chemotherapy and education may be feasible.

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.