Publikationsdatenbank

Management of trypanocidal drug resistance in cattle in identified chemoresistance hot spots in the administrative District of Sikasso, south- east Mali (2010)

Art

Hochschulschrift

Autor

Ouma, Erick Mungube (WE 13)

Quelle

Berlin: Mensch und Buch Verlag, 2010 — XI, 197 Seiten

ISBN: 978-3-86664-845-6

Sprache

Englisch

Verweise

URL (Volltext): https://refubium.fu-berlin.de/handle/fub188/9280

Kontakt

Institut für Parasitologie und Tropenveterinärmedizin

Robert-von-Ostertag-Str. 7-13
14163 Berlin
+49 30 838 62310
parasitologie@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Animal trypanosomosis still remains a major disease constraining livestock production across sub-Saharan Africa. Additionally; the development and spread of chemoresistance further severely threatens the cattle-based livelihoods of the rural poor in the cotton belt of West Africa. If not addressed; it will exacerbate rural poverty. Best-bet strategies; including tsetse control and strategic helminth control were tested for their efficacy to contain and or reverse trypanocide resistance in Sikasso; south-east Mali; where drug resistance had earlier been detected. The study was implemented in three phases: pre-intervention; intervention and post-intervention phase. Two areas of Sikasso; the eastern sector and the western sector; with comparable ecology and production systems were covered. The study was conducted in four villages from each sector. The pre-intervention phase; conducted between November and December 2007; involved a cross-sectional (tsetse catches; trypanosome prevalence and drug use practices) and a longitudinal (drug sensitivity testing) survey. Two tsetse species; Glossina palpalis gambiensis and G. tachinoides occurred in the study area. The eastern sector had a mean trypanosome prevalence of 13.9% which was not significantly different (p > 0.05) from 17.5% in the western sector. Two trypanocidal drugs; isometamidium chloride (ISMM) for prophylaxis and diminazene aceturate (DIM) for therapy; were found to be commonly used. Multiple drug-resistant Trypanosoma congolense were prevalent in both areas while T. vivax were sensitive to 3.5 mg/Kg bw DIM. Effects of tsetse control and de-worming to contain and reverse trypanocide resistance were assessed during in the intervention phase. In the intervention area (eastern sector); targets (N=957) impregnated in 0.4% deltamethrin (DECIS®; Roussel-Uclaf; France) (dry season) and targeted treatment of cattle (spraying on the limbs; lower abdominal area; brisket and perineal area) with 0.05% deltamethrin (Butox®; Intervet; the Netherlands) (rainy season) were used to control tsetse between March 2008 and November 2009. Additionally; strategic helminth treatment of risk group cattle (3-12 months) with 10mg/kg bw albendazole (10% Albenzole®; Kela; Belgium) was conducted in the intervention and control areas between June 2009 and November 2009. Albendazole was first used in June 2008 and repeated during the November 2008; June 2009 and November 2009 monitoring visits after randomly allocating the animals at risk into an albendazole treatment group and a control group. Five epidemiological visits (June 2008; November 2008; February 2009; June 2009 and November 2009) were conducted to estimate the resultant dynamics in tsetse catches; trypanosome infections and helminth infections in the two areas. All trypanosome positive risk cattle and those with PCV ≤ 20% were treated with 3.5mg/kg bw DIM. Tsetse control resulted; respectively; in 91.3% and 97.3% reductions of G. p. gambiensis and G. tachinoides catches in the intervention area. A reduction of 18.3% for the former and of 37.1% for the latter fly species also occurred in the control area. Significantly (p < 0.001) lower trypanosome infections in the intervention area than in the control area were observed at herd; village and area levels. Strongyle eggs; Strongyloides species eggs; Toxocara species eggs and Moniezia species eggs; among others; were detected. No Fasciola species eggs were detected in cattle of both areas. In the intervention area; the probability of albendazole treated cattle to acquire new trypanosome infections was calculated as 0.003 which was not significantly (p > 0.05) different from 0.007 for the control group. The post-intervention phase involved a cross-sectional and a longitudinal survey and was conducted from November to December 2009. As for the pre-intervention phase; trypanosome prevalence and drug sensitivity investigations were undertaken. There was a significant (p < 0.05) reduction in trypanosome prevalence in the intervention area from 13.9% during the pre- intervention phase to < 1% after intervention. In contrast; trypanosome prevalence remained unchanged in the control area. Only 3 T. vivax cases remained in the intervention area of which one was resistant to 0.5mg/kg bw ISMM but was cleared by 3.5 mg/kg bw DIM. Trypanocidal resistance patterns in the control area did not change. A faecal egg count reduction test (FECRT) to estimate the efficacy of albendazole revealed a 55.6% reduction of strongyle faecal egg counts. The low FECRT warrants further evaluation before concluding that resistance in strongyle helminths does exist. This investigation has shown that in a region of high trypanosomosis risk and trypanocidal drug resistance; tsetse control undertaken simultaneously with strategic helminth control and targeted treatment with trypanocidal drugs is likely to reduce trypanosomosis risk to negligible levels.