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4. Trypanotolerance in Djallonke sheep and West African Dwarf goats : Importance of trypanosomosis, nutrition, helminth infections and management factors

Author

Osaer, S., Goossens, B., and University Utrecht

Subjects
Diergeneeskunde, helminthosis, trypanosomosis, Djallonke sheep, husbandry, Trypanotolerance, West Africa, intensive feeding gardens, tick borne diseases, West African Dwarf goats, rural development
Abstract

The main breeds of sheep and goats in The Gambia, the Djallonke sheep and West African Dwarf goats are trypanotolerant. The Djallonke sheep, however, have a higher degree of trypanotolerance than the WAD goats. This trait is genetically linked although the mechanism of trypanotolerance is different from the one in cattle. It is defined as a resilience to infection rather than resistance. Both breeds are well adapted to the locally prevailing diseases and environmental conditions under which they live. Moreover, they feature the capacity of making good use of low quality feed resources. For the rural farmer, small ruminant production is an attractive enterprise and seems to be profitable even under a low input management system. Small ruminant production also has a large potential under more intensified peri-urban conditions. Trypanosomosis remains an important constraint to optimal productivity. In particular when combined with other diseases, poor nutritional status and poor husbandry practises there is a clear effect on productivity and thus profitability. All these factors should be regarded as equally important. Based on the results of research and surveys presented in this thesis, some recommendations are formulated for interventions in order to reduce the disease constraint, improve the nutritional status and adapt the management of small ruminant production systems. Further research will be carried out to study the impact of the proposed interventions and their adaptation to the local conditions.

Published
1999

5. Prevalence and incidence of trypanosomosis in horses and donkeys in the Gambia

Author

UCL - SSS/IRSS - Institut de recherche santé et société, Faye, D, de Almeida, PJLP, Goossens, B, Osaer, S, Ndao, M, Berkvens, D, Speybroeck, Niko, Nieberding, F, Geerts, S, UCL - SSS/IRSS - Institut de recherche santé et société, Faye, D, de Almeida, PJLP, Goossens, B, Osaer, S, Ndao, M, Berkvens, D, Speybroeck, Niko, Nieberding, F, and Geerts, S

Abstract

In a study of the prevalence and incidence of trypanosomosis in horses and donkeys in two regions of the Gambia, surveys were carried out at Niamina east and Bansang south with a high and low to moderate tsetse challenge, respectively. Eleven horses and 67 donkeys were sampled monthly from August 1997 to September 1998. Blood samples were examined for trypanosomes using the buffy-coat (BC) method and polymerase chain reaction (PCR). Three primer sets were used, specific for either Trypanosoma vivax (TVW), Trypanosoma congolense (GOL) or Trypanosoma brucei (ORPHON5J). The BC results showed that the prevalence (August 1997) and the average monthly incidence (September 1997-1998) of trypanosome infections in horses (45.5 and 16%, respectively) were significantly higher than in donkeys (6.2 and 9%, respectively). Using PCR, the number of detected cases was seven times higher than using the BC. T congolense was the most frequently observed species, followed by T vivax and T brucei. This study confirms earlier observations by other authors that donkeys, which are exposed to a similar tsetse challenge as horses, are significantly less infected with trypanosomes than the latter. (C) 2001 Elsevier Science B.V. All rights reserved.

Published
2001

19. Trypanotolerance in small ruminants of sub-Saharan Africa.

Author

Geerts S, Osaer S, Goossens B, and Faye D

Subjects
Africa South of the Sahara, Animals, Goats genetics, Host-Parasite Interactions, Immunity, Innate genetics, Sheep genetics, Species Specificity, Trypanosoma congolense pathogenicity, Trypanosoma vivax pathogenicity, Trypanosomiasis, African genetics, Trypanosomiasis, African immunology, Animals, Domestic parasitology, Goats parasitology, Sheep parasitology, Trypanosoma congolense physiology, Trypanosoma vivax physiology, Trypanosomiasis, African veterinary
Abstract

Although a lot of information is currently available on trypanotolerance in cattle, until recently the trypanotolerant nature of small ruminants was not well known. Trypanotolerance in small ruminants is less pronounced than in cattle and should be considered as resilience rather than resistance. West African Dwarf (WAD) goats seem to be less trypanotolerant than Djallonke sheep. However, recent studies have shown that there is an important introgression of genes of trypanosusceptible breeds into WAD goat populations, which possibly explains the loss of trypanotolerance in these animals. Measures need to be taken to safeguard and upgrade the genetic purity of trypanotolerant goat and sheep breeds in Africa.

Published
2009
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20. PCR primer evaluation for the detection of trypanosome DNA in naturally infected goats.

Author

Pereira de Almeida PJ, Ndao M, Goossens B, and Osaer S

Subjects
Animals, DNA Primers chemistry, Electrophoresis, Agar Gel veterinary, Gambia epidemiology, Goat Diseases epidemiology, Goats, Polymerase Chain Reaction methods, Sensitivity and Specificity, Trypanosoma isolation & purification, Trypanosomiasis, African diagnosis, Trypanosomiasis, African epidemiology, DNA, Protozoan blood, Goat Diseases diagnosis, Polymerase Chain Reaction veterinary, Trypanosoma genetics, Trypanosomiasis, African veterinary
Abstract

The buffy coat of 76 roaming goats from the Bansang and Missira regions in Gambia, was examined for the presence of trypanosomes. From these animals, extractions from dry blood samples on filter paper were subjected to PCR using three different primer sets, ORPHON5J, GOL and TVW, specific for Trypanosoma brucei/Trypanosoma evansi, Trypanosoma congolense and Trypanosoma vivax, respectively. PCR results for T. congolense were 100% concordant with buffy coat examination. Besides the three T. vivax buffy coat-positive samples, another 15 yielded positive with the TVW primers. The ORPHON5J primers yielded no positive results. Analyses with the GOL primers of putatively negative samples, yielded aberrant band patterns whose diagnostic significance still remains to be determined.

Published
1998
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