Animal trypanosomosis in clinically healthy cattle of north Cameroon: epidemiological implications.

Pierre Fongho Suh,Alexandre Njanloga,Mbunkah Daniel Achukwi,Aliyou Hayatou,Abdoulmoumini Mamoudou

doi:10.1186/s13071-016-1498-1

Abstract

BackgroundThe control of animal trypanosomosis consists, amongst other things, of the punctual treatment of new cases, primarily diagnosed by pastoralists on the basis of clinical signs. This practice suggests that many apparently healthy infected animals are left untreated. In this study animal trypanosomosis in clinically healthy zebu cattle was evaluated, the distribution of the vectors established and the epidemiological implications discussed.MethodsIn 2014 two cross-sectional surveys were carried out in the Cambeef ranch. A total of 866 blood samples were collected from cattle in different sites: 549 in the dry season and 317 in the rainy season. The blood samples were subjected to parasitological examination using the buffy coat method and to PCV determination. An entomological survey on animal trypanosomosis vectors was undertaken during tsetse flies caught were identified and the mid-gut of each living non-teneral tsetse fly was examined for infections using a microscope.ResultsAn overall trypanosomosis prevalence of 9 % was found in the cattle examined. There were significantly (P < 0.05) more trypanosome infected cattle in the dry season than the rainy season. Trypanosome-infected cattle had significantly (P < 0.05) lower Body Condition Scores (BCS) and Packed Cell Volumes (PCV) in the dry season than in the rainy season. Anemia was positively correlated with trypanosome infection. The likelihood for an animal to be parasitologically free of trypanosome infection was at least three times as high in the Gudali breed as compared with the white and red Fulani breeds. Species of trypanosomes identified were Trypanosoma vivax (73.23 %), Trypanosoma congolense (15.49 %) and Trypanosoma brucei (11.27 %). A total of 390 tsetse flies and 103 tabanids were trapped. Two species of tsetse flies were identified: Glossina tachinoides (33.59 %) and G. morsitans submorsitans (41 %). Nine of the 194 non-teneral flies were infected with trypanosomes.ConclusionCarriers of trypanosomes are present amongst apparently healthy cattle in the study site. Attempts to successfully reduce the population of reservoir trypanosomes within herds and control the disease will need to consider mass screening once every year and this should be associated with drug sensitivity tests.

Highlights

The control of animal trypanosomosis consists, amongst other things, of the punctual treatment of new cases, primarily diagnosed by pastoralists on the basis of clinical signs
The Mayo Rey division is the largest pastoral zone of the north region of Cameroon [1]. Livestock production in this zone is, like in many other areas in Africa, impeded by the presence of tsetse fly [2] which cyclically transmits animal trypanosomosis [3]. This disease contributes to the impoverishment of pastoralists by causing abortion, premature births, prenatal losses, infertility in males through testicular damage, the reduction of milk production in diary animals and increased spending on drugs
The risk of trypanosomosis transmission for most countries occurs between the end of the rainy season and the beginning of the cold dry season

Summary

Introduction

The control of animal trypanosomosis consists, amongst other things, of the punctual treatment of new cases, primarily diagnosed by pastoralists on the basis of clinical signs This practice suggests that many apparently healthy infected animals are left untreated. The Mayo Rey division is the largest pastoral zone of the north region of Cameroon [1] Livestock production in this zone is, like in many other areas in Africa, impeded by the presence of tsetse fly [2] which cyclically transmits animal trypanosomosis [3]. All animals should be protected during this period Beyond these periods, sporadic cases, generally diagnosed by herdsmen on the basis of clinical signs solely, are treated with diaminazene aceturate at 7 mg/kg [7].This practice suggests that many apparently healthy but infected animals are left untreated and may contribute to the persistence of the disease. In this study we evaluate the prevalence of animal trypanosomosis in zebu cattle apparently showing no sign of illness; compare health indicators, describe the trypanosomosis vector distribution in Cambeef ranch and discuss implications for the epidemiology of the disease

Methods

Results

Conclusion