Seasonal Dynamics of Tsetse and Trypanosomosis In Selected Sites of Southern Nation, Nationalities and Peoples Regional State (SNNPRS), Ethiopia

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Date

2004-06

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Publisher

AAU

Abstract

A seasonal dynamics of tsetse and tryp3nosomosis study was carried out in selected sitcs of Southern Nation, Nationalities and Peoples Regional State (SNNPRS). The purposes of the study were to determine the seasonal apparent density of tsetse and prc\'atcnce of trypanosomosis, to identify tselse and trypanosome species and to assess Ihe curative/prophylactic effect of isomctamidium chloride in selected ltilclt (BaJ ayc and Gadala PAs) of SNNPRS. Community members (n ;; 80) were inten'icwcd using prepared questionnaire format. Cross sectional studies were carried out from Oelober to April during late wei (October), early dry (December), latc dry (February) and carly wet (April) seasons in villages of 8adayc and GadaJa PAs. Samples for parasitological and entomological studies were collected from one village of Badaye and two villages of Gadala PAs per season. Bi conical traps used for entomological survey were deployed at grazing and watcring points of anima ls in the villages of Badaye and Gadala PAs. For parasitological study, a total of 1,509 blood samplcs were collected from randomly se lected canle within four seasons. For longitudinal fie ld study, parasitaemic Zebu callie (n = 64) were selected fo r isometamidium chloride block treatment Parasilaemic callie wi th 39 (60.9%) T. congo/elise, 24 (37.5%) T. vivax and I (1.6%) mixed (T. congo/elise and T. "imx) infections were treated wilh prophylactic dose of (I mg/kg bw) isometamidium chloride at day 0 and monitored at day [5, 30, 60 and 90. The result of questionnaire revealed that 97.5% of respondents depend on smugglers for trypanoc idal drugs and sick an imals were treated by smugglers and owners with hi gh treatment frequency (6 limes per cattle per year). The entomological fi nding revealed three tsetse species namely, G. m. sllbmorsilalls, G. / llscipes and G. paflidipes at Badaye and Gadala PAs, respectively. Higher catches of G. pa/lidipes were registered during late wei (October) and early dry (December) seasons in comparison with laIC dry (February) and early wet (April) seasons. There was a signi fi cant difference (p < 0.05) in mean calches of G. pallidipes belween seasons. The apparent density of G. palfidipes was positively correlated (r :::: 0.5176) with prevalence of trypanosome infection.The ovcr.J11 trypanosome infection prevalence in caule was \5.77%. During late wet and early dry seasons, the prevalence of trypanosomosis was high (2 1.5%) and during laIc dry and early wet seasons low (10.8%). During early wet season, significantly (p < 0.05) higher prevalence was registered at village of Badaye PA (1 5.38%) than the vi llages of Gada la PA (8.51 %). There was a significan t VIII difference (p < 0.00 1) in trypanosome infection preva lence between seasons. Giemsa stained blood smear examination revealed Ihe presence of T. congo/ense lind T. viva.r in the study area. T. congo/elise was dominant species and accounted for 63.4% in overall infections. TIle overall mean rev value was 24.02%. The mean rev values of different seasons were negatively correlated (r = ·0.3112) with the prevalence of trypanosomosis of corresponding seasons. There was a statistically signilicant difference (p < O. OOOl) between mean pev values of parasitacmic and aparasitaemic callIe tested duri ng differen t seasons. There was a significant difference (p < O.OOI) in trypanosome infections between different age groups of cattle. In longitudi nal field study, parasitaemia was demonstrated in 17 out of 64 cattle (26.56%) with in 15 days, 19 out of 64 cattie (29.7%) with in 30 days, 4\ out of 64 callie (64.06%) with in 60 days and 44 out of 64 (68.75%) with in 90 days post treatment of Imglkg bw isometamidium chloride. T. congo/elise was accounted for 85.5%. 89.5%. 78% and 79.5% of infections within 15. 30, 60 and 90 days post treatment of isometamidium chloride. respectively. Based on these results it is concluded that trypanosomosis is the major constraint of livestock production in the study siles.

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Keywords

Season. Tsetse fly, Trypanosomosis, Trypanosomes, Prevalence. Drug resistance. Isometamidium chloride, PA

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