TRYPNET: new hemoparasite information network

Although Guyana, Suriname and French Guiana share borders and climatic and geographic similarities, the countries have maintained little contact, due to language, political, and administrative differences. In 1993, two international organizations involved in the improvement of animal health, the Inter-American Institute for Cooperation on Agriculture (IICA) and CIRAD-EMVT (Centre de Cooperation en Recherche Agronomique pour le Developement-Elevage et Medicine Veterinaire des Pays Tropicaux), jointly developed a collaborative project between the veterinary services of the three countries entitled Hemoparsite Network of the Guianas. This project seeks to pool livestock, laboratory, and technical resources between the three countries in order to generate and exchange information on hemoparasites of livestock. A Hemoparasite Reference Laboratory for the Guianas has been created at the CIRAD-EMVT laboratory in Cayenne, French Guiana. Besides processing ruminant serum samples for the three countries, specialists from this organization conduct training in hemoparasite diagnostic techniques for laboratory personnel from Guyana and Suriname. A large-scale epidemiologic study of cattle in the three countries is under way, to determine the prevalence, distribution, and clinical and economic significance of hemoparasites in the three countries, particularly Trypanosoma vivax and T. envansi. Preliminary results are presented and discussed. A hemoparasite information Network (TRYPNET) has been initiated, including a quarterly hemoparasite newsletter (TRYPNEWS), published in English and Spanish and disseminated to researchers in the Americas, Europe, and Africa. In 1995/96, it is proposed to expand the network's scope to include Venezuela and Brazil. (AU)

Ovine trypanosomosis: a seroepidemiological survey in coastal Guyana

The objective of this study was to determine the seroprevalence rates of Trypanosoma vivax and Trypanosoma evansi in sheep in coastal Guyana. Blood samples were taken from a systematic random sample of one hundred and ninety-three (193) sheep on twenty-two (22) farms in Region 5, Mahaica/Berbice, a coastal area of Guyana. Age, breed, sex, and farm of origin were recorded for all sampled sheep. One hundred and seventy-six (176) serum samples were submitted for Indirect Fluorescent Antibody (IFA) testing for T. vivax and T. evansi. Fluorescence was graded as 0 (negative), 1+(very weak), 2+(weak), 3+(strong) or 4+(very strong), as measured at 1:160 dilution of serum. Samples were considered to be sero-positive if any fluorescence was observed. Indirect Fluorescent Antibody results were received for one hundred and sixty-one (161) samples. One hundred and three (64 percent) sera were sero-positive for Trypanosoma sp. Of these, 38 (23.6 percent) sera were positive to T. evansi only, 11(6.8 percent) were positive to T. vivax only and 54 (33.5 percent) were positive for both. As cross reactions occur between T. vivax and T. evansi, it was difficult to determine the true species of exposure for the sera which tested positive to both species. The overall sero-prevalence rate of 64 percent suggests that trypanosomosis is endemic in sheep in coastal Guyana. This was the first serological evidence of T. evansi in Guyana. Although T. vivax is believed to be pathogenic in sheep, the clinical siginficance of T. evansi remains unknown. The vector of both species of trypansomes in sheep on the north of South America also is not known (AU)

Small ruminant trypanosomiasis in Guyana--a preliminary report.

Trypanosomes identified as Trypanosoma vivax were found infecting nine sheep (4.6%) and one goat (1.3%) on four of 11 farms surveyed on coastal Guyana. Animals sampled on another farm situated in the Rupununi savannahs gave negative results. Haematological techniques preferred for studies of this nature were the haematocrit centrifuge technique (HCT) and the thick blood smear technique.

Small ruminant trypanosomiasis in Guyana - a preliminary report [published erratum appears in Br Vet J 1990 Nov-Dec: 146(6): 581]

Trypanosomes identified as Trypanosoma vivax were found infecting nine sheep (4.6 percent) and one goat (1.3 percent) on four of 11 farms surveyed on coastal Guyana. Animals sampled on another farm situated in the Rupununi savannahs gave negative results. Haematological techniques preferred for studies of this nature were the hematocrit centrifuge technique (HCT) and the thick blood smear technique. (AU)

Screwworm (Diptera: calliphoridae) myiasis in the Southern Caribbean, and proposals for its management

In a random sample of animal producers and animal health personnel, 33 percent of the respondents in Trinidad, 15 percent in Guyana, and 11 percent in Suriname recalled at least one case of human myiasis due to Cochliomyia hominivorax (Coquerel). During 1981, respondents in Suriname (88 percent), Guyana (85 percent), and Trinidad and Tobago (82 percent) found at least one case of myiasis in their livestock, mainly cattle, pigs, and dogs. Feral animals- e.g., jaguars- were also found to be infested. The initial wounds were mainly the umbilicus neonates, whereas arbitrary cuts, castration wounds, and vampire bite were also affected. Fifty-three to 78 percent of all respondents examined their livestock daily for wounds and infestation by the screwworm. Daily examinations of livestock are now done as a result of the screwworm threat. Annual estimates of losses (in U.S. dollars) due to surveillance and medication ranged from $4.82 to $10.71 per animal. These national losses amounted to $0.30 million (Suriname) $1.02 million (Trinidad and Tobago), and $4.33 million (Guyana). Other losses, such as failure to thrive, reduction in milk production, and hide injury due to screwworm activity, were not available. Most producers found that the greatest infestation occurred in the wet season. Also, most (68 to 83 percent) found the screwworm to be second in importance to the Boophilus spp. ticks as a pest of livestock, but of greater significance than biting flies such as tabanids and stable flies. Eradication of the screwworm can be recommended for the islands of Trinidad and Tobago. Eradication for Suriname and Guyana seems feasible only on the 100-km wide coastal strips, where most human and livestock populations exist. (AU)

Serological prevalence of bovine babesiosis in Guyana.

The serological prevalence of bovine babesiosis in Guyana was determined utilising the indirect fluorescent antibody (IFA) and the complement fixation (CF) tests. Babesia bigemina IFA and CF antibody activity was detected in 80% and 40% respectively of the sera from native cattle while IFA and CF antibody activity to Babesia bovis was observed in 61% and 16% of the sera. The prevalence of antibody was compared between calves less than 6 months of age and mature cattle. There was little difference between the CF and IFA tests for B. bigemina in the calves but the prevalence of IFA antibody activity to B. bovis in calves and to B. bovis and B. bigemina was greater in adult cattle. Examination of sequential serum samples from imported calves revealed that CF antibody activity appeared earlier but by day 51 following exposure to natural infection the prevalence of antibody as determined by both tests was the same.