TRYPNET: New Hemoparasite Information Networka

zy zyxw zyxw TRYPNET New Hemoparasite Information Network” s. VOKATY,~M. DESQUESNES,”L. APPLEWHAITE,~ J. FAVRE: R. LIEUW-A-JOE! M. PARRIS-AARON: AND L. BANSSE-IISAf zyxwvutsr zyxwv zyxwv blnter-American Institute f o r Cooperation on Agriculture (IICAJ Georgetown, Guyana ‘Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement- Elevage et Medecine Veterinaire des Pays Tropicaux (CIRAD-EMVT) Institut Pasteur Cayenne, French Guiana dMinistry of Agriculture Georgetown, Guyana eServices Veterinaires Departementaux Cayenne, French Guiana fMinisterie Van Landbouw Veeteelt & Visserij Paramaribo, Suriname INTRODUCTION The “Guianas” are three little-known countries located in the humid tropical region on the north coast of South America. These three countries share borders and historic and geographic similarities, but have maintained little contact, due to language, political, administrative, and economic differences. Guyana, the former British Guiana, is an independent democratic country, whose national language is English. It has a human population of 750,000 and a bovine population of almost 300,000. Suriname, the former Dutch Guiana, is also an independent democratic country, whose national language is Dutch. It has a human population of approximately 400,000 and a bovine population of just under 100,000.French Guiana (or Guyane Francaise) is an overseas department of France, therefore not a sovereign nation. It has a human population of 115,000 and a bovine population of 7000. Guyana and Suriname are considered to be developing countries. As a French overseas department, French Guiana enjoys social and economic benefits similar to those in metropolitan France. In all three countries, the great majority (80-90%) of human and livestock populations are concentrated along the Atlantic coastline. zyxw This project received funding from the European Community and French Interministerial Fund for the Caribbean (FIC). 166 zyxwvutsr zyxwvu zy VOKATY et al.: TRYPNET 167 Due to their geographic proximity, similar climates, and ecosystems, these countries share various livestock pests and diseases. The difference lies in their ability to respond to such problems. Due to its significant technical, financial, and human resources, as well as its relatively small livestock population, French Guiana has been able to conduct animal disease research, monitoring, and control programs. As a consequence of economic crisis and structural adjustment programs, the veterinary services of Guyana and Suriname have been confronted with scarce technical, material, financial, and human resources. Guyana’s veterinary diagnostic laboratory ceased operations in 1990. Suriname’s laboratory continues to operate on a limited basis, but has great difficulty with material supply and equipment maintenance, due to a shortage of foreign exchange. These limitations make it difficult or impossible for the veterinary services of Guyana and Suriname to implement livestock disease monitoring and control programs. The livestock hemoparasitic diseases anaplasmosis and trypanosomiasis and babesiosis and their arthropod vectors constitute important constraints to animal health and livestock production in tropical South American countries. In South America, Anaplasma marginale is transmitted by biting insects and ticks. This disease causes fever, anemia, weight loss, jaundice, abortion, and mortality in cattle.’ The epidemiology, clinical significance, and economic impact of non-tsetse transmitted trypanosomes are less clearly understood in the Americas. In South America, the trypanosomes Trypanosoma v i v a and Trypanosoma evansi are mechanically transmitted by biting insects including Taban~s,~.’ Cryptotyl~s,~ and Stomoxys species. Vampire bats (Desmodus rotundus): ticks,”.’ and triatomine bugs8 have also been suggested as vectors in the transmission of T. vivax. In French Guiana, a temporal association has been found between dry season (November to January), high Tabanid density, and Trypanosoma vivax clinical outbreak^.^ Serological evidence for Trypanosoma vivax has been found in the Americas from El Salvador to Paraguay.” The organism is believed to have been imported with a shipment of cattle from Senegal to French Guiana, Martinique, and Guadeloupe in 1830.’’ Previous studies in Guyana have found high seroprevalence rates to T. v i v a in sheep in coastal Guyana. Applewhaite found a seroprevalence rate of 63.4% in sheep on ELISA (enzyme linked immunosorbent assay).12 Vokaty et al. found 64% seroprevalence to Trypanosoma sp. in sheep in coastal Guyana on indirect fluorescent antibody test.13 In French Guiana, a survey of 3000 cattle yielded a seroprevalence rate of 22% on ELISA testing for T. vivax antibody? T. vivax has been found to be prevalent in cattle, water buffalo, and sheep in Colombia, but outbreaks of severe disease are sporadic. In Colombia and French Guiana, these outbreaks in adult cattle are characterized by fever, anemia, decreased milk yields, However, calves may show rapid weight loss, abortion, and occasional m~rtalities.’~,’~ high parasitemias without clinical signs. The sporadic clinical outbreaks have been attributed to decreased herd immunity caused by stress such as poor nutrition, intercurrent infection, or vaccination.” Trypanosoma evansi has been found in South America from Panama to Argentina.’* It causes clinical disease in horses, donkeys, buffalo, mules, and dogs. The disease is known as S u m in Africa and Asia, and as “Ma1 de Caderas” in Brazil and Argentina. This disease is characterized by intermittent fever, anemia, dependent edema, lethargy, weigh loss, nervous signs, and eventually death.“ Epidemics of zy z 168 zy zyxwvuts ANNALS NEW YORK ACADEMY OF SCIENCES “Ma1 de Caderas” have caused significant mortality in horses in the Pantanal region in southern Brazil, thereby limiting development of the cattle ranching i n d ~ s t r y . ‘ ~ Significant T. evansi epidemics have also been described in Colombia and Venezuela.lo Natural infections have been detected in several South American wildlife species including the capybara (Hydrochoerus hydrochaeris),”’ coatis (Nasua nasua), and vampire bats (Desmodus rotundus).’ Serological evidence exists for T. evansi in sheep in coastal Guyana, but clinical disease has not been reported.I3 HEMOPARASITE NETWORK The project “Hemoparasite Network for the Guianas” is a collaborative effort between the Inter-American Institute for Cooperation on Agriculture (IICA) in Guyana and Suriname, the Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement -Elevage et Medecine Veterinaire Tropicale (CIRADEMVT), which has a specialized laboratory for research into arthropod-borne diseases in Cayenne, and the government veterinary services of Guyana, Suriname, and French Guiana. The general objective of the project is “to increase knowledge of the epidemiology, clinical and economic importance of hemoparasites, particularly trypanosomes, in Guyana, Suriname and French Guiana in order to develop effective control methods and thus improve the health and productivity of livestock.” The specific objectives are: i. To exchange information on hemoparasites, especially Trypanosomes, with researchers in Latin America and the Caribbean by formation of a Hemoparasite Information Network (TRYPNET) ii. To strengthen the diagnostic capabilities of the veterinary services of Guyana and Suriname by: a. Creation of a Hemoparasite Reference Laboratory for the Guianas at CIRAD-EMVT in Cayenne. b. Training Guyanese and Surinamese technicians in hemoparasite diagnostic techniques. c. Purchase of materials and regents for the veterinary diagnostic laboratories in Suriname and Guyana. d. Laboratory support for other livestock disease investigations whenever possible. iii. To increase information on hemoparasites, particularly Trypanosomes, in South America, by conducting an epidemiological study in cattle in Guyana, Suriname, and French Guiana. TRYPNET: HEMOPARASITE INFORMATION NETWORK zyxwv zyxwvuts The Hemoparasite Information Network was initiated in 1994 and is ongoing. Two CIRAD-EMVT publications were translated from French to English and distributed to livestock production and animal health professionals in Guyana and Suriname. The English versions were titled ‘‘Horseflies of the Guyanas: Biology, Veterinary Significance & Control Methods” and “The Cattle Tick, Boophilus microplus.” A quarterly zyxwvutsr zyxwvutsrqp zyxwvu zyxwv zyxwv zyxwvuts VOKATY et al.: TRYPNET 169 Preliminary Results of Hernoparasite Survey in Guyana, Suriname, and French Guiana TABLE I. French Guiana Suriname Guyana n +CCT" 507 503 408 13 5 10 Adj. + CCTb 0 0 3 Anaplasma % +ELISA TRP AB' % 2.6 1 0.7 33 163 168 6.5 32.4 41.2 n + 469 259 308 d 106 131 78 % 22.6 50.6 25.3 Positive for Trypanosome sp. on capillary centrifuge technique (WOO)." Adjusted for T. v i v a positive. Positive o n ELISA for Trypanosone sp. antibody-Ferenc method.2" Positive for Anaplasma on stained blood smear. newsletter called Trypnews has published two issues in English and Spanish. These are sent to animal health professionals and researchers in North, Central, South America, the Caribbean, Africa, and Europe. Initial response has been enthusiastic, and an expansion of the network to include Venezuela and Brazil is planned. A small technical meeting on hemoparasites, especially New World Trypanosomes, is planned in Georgetown, Guyana in 1996. EPIDEMIOLOGIC STUDY IN FRENCH GUIANA, GUYANA, AND SURINAME Materials and Methods Bovine blood samples and demographic data are collected by the veterinary services in Guyana and Suriname, in both field and abattoir. Two thin blood smears are made for each sample and stained with RAL stain.8 One is read locally and the other at the Hemoparasite Reference Laboratory. Packed cell volume (PCV) and capillary centrifuge technique (WOO test) are conducted within 3 hours of sampling. Blood is centrifuged, and serum samples are split into two; one is stored in a local frozen serum bank and the other half is sent to the Hemoparasite Reference Laboratory, where ELISA tests for trypanosome antigen and antibody are performed. Preliminary Results Survey results to date appear in TABLE1. Discussion The relatively high seroprevalence rates on ELISA test suggest that trypanosomes, most likely T. v i v a , are endemic in cattle in Guyana and Suriname. This finding agrees g Hematovet Kit RAL, Rhone Merieux, contains methanol, eosin, and methylene blue stains. z 170 zyxwvutsr zy zy ANNALS NEW YORK ACADEMY OF SCIENCES with previous small ruminant studies in Guyana done by Vokaty and Applewhaite. T. evansi has yet to be conclusively identified in the Guianas. However, there is anecdotal evidence for equine trypanosomiasis in the Rupununi, the ranching area in southern Guyana that borders on BraziL2’ Further studies are necessary to determine the epidemiology, clinical significance, and economic impact of T. v i v a and T. evansi infection in livestock in South America. However, improved laboratory tests would be necessary to conduct such research. Serologic tests developed for African trypanosomes do not always work well for South American strains of T. v i v m and T. evansi.22By putting New World trypanosome researchers in contact to share technical information, it is hoped that TRYPNET will help to solve such challenging questions. SUMMARY 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 Intemationale en Recherche Agronomique pour le Developpement-Elevage et Medecine Veterinaire des Pays Tropicaux), jointly developed a collaborative project between the veterinary services of the three countries entitled “Hemoparasite Network for 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 Hernoparasite Reference Laboratory for the Guianas has been created at the CIRAD-EMVT laboratory in Cayenne, French Guiana. Besides processing ruminant serum samples from 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 hemoparasites 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 v i v a and 7’. evansi. 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. zyxwvuts REFERENCES zyxw zyx BLOOD,D. C. & 0. M. RADOSTITS, Eds. 1989. Veterinary Medicine. 7th Edit. Bailliere Tindall. London, England. 2. RAYMOND, H. L. 1990. Tabanus importunus, vecteur mecanique experimental de Trypanosoma v i v a en Guyane Francaise. Ann. Parasitol. Hum. Comp. 65( I): 4 4 4 6 . 3. OTTE,M. J. & J. Y. ABUABARA, 1991. Transmission of South American Trypanosoma viva by the neotropical horsefly Tabanus nebulosus. Acta Tropica 49: 73 -76. 4. FERENC, S . , H. L. RAYMOND & R. LANCELOT. 1988. Mechanical transmission of South American Trypanosoma v i v a by the Tabanid Crypiotylus unicolor. Proceedings of the 18th Congress of Entomology: 295. 1. zyxwvutsr zy zyxwv zy zyx VOKATY et al.: TRYPNET 171 5. HOARE, C. A. 1965. Vampire bats as vectors and hosts of equine and bovine trypanosomes. Acta Trop. 22: 204. 6. MORZARIA, S. P., A. A. LATIF,F. JONCEJAN & A. R. WALKER, 1986. Transmission of a Trypanosoma sp. to cattle by the tick Hyalomma anatolicum anatolicum. Vet. Parasitol. 19: 13-21. 7. LOPEZ,G. V., K. C. THOMPSON & H. BAZALAR, 1979. Transmission experimental de Trypanosomav i v a por la garrapata Boophillus microplus. 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