A comparative longitudinal study of bovine trypanosomiasis in tsetse-free and tsetse-infested zones of the Amhara Region, northwest Ethiopia

A study was conducted to determine the incidence of trypanosome infections in cattle in tsetse-free and tsetse-infested zones of the Amhara Region of northwest Ethiopia. A total of six sentinel herds were established and the cattle observed during a period of 8 consecutive months. The prevalence of seropositive cattle was high in both the tsetse-free and tsetse-infested zones. The average monthly incidence of trypanosome infection, determined using molecular diagnostic tools, was 20.9% and 25.7% in the tsetse-free and the tsetse-infested zones, respectively. In the tsetse-free, Trypanosoma vivax was responsible for 90.9% of the cattle trypanosome infections. In the tsetse-infested zone, Trypanosoma congolense and T. vivax contributed almost equally to the trypanosome infections in cattle. Trypanosome infection, regardless of species, resulted in anaemia as evidenced by a significant decrease in the packed cell volume of the infected animal. The outcome of this longitudinal study suggests that control of trypanosomiasis in the Amhara Region cannot be achieved by tsetse control alone. Supplemental measures to include drug therapy and biting fly control are discussed.     

Parasitological prevalence of bovine trypanosomosis in Kindo Koisha district,Wollaita zone,south Ethiopia

A cross sectional survey to determine the distribution and prevalence of trypanosomosis was conducted in Kindo Koisha district, in the Wollaita zone in southern Ethiopia. A total of 1 008 adult cattle was examined at eight different localities. Dark field examination of the buffy coat, as well as stained thin blood film examination and packed cell volume (PCV) evaluation were the diagnostic techniques used. The overall prevalence of bovine trypanosomosis was 15 %. Among the positive animals, 108 (71.1%), 43 (28.4%) and 1 (0.6%) were due to Trypanosoma vivax, Trypanosoma congolense and mixed infection (T. vivax and T. congolense), respectively. The infection rate of T. vivax and T. congolense varied significantly (P < 0.01). The mean PCV of the positive and negative animals ranged between 18.3-32.1% and 26.8-33.4%, respectively. The mean PCV of negative animals (28 %) was significantly higher than the mean PCV of positive animals (22.3%) (P < 0.001). There was an inverse association of PCV with the prevalence of trypanosomosis (P > 0.05). The herd average PCV values of each site decreased with increasing proportion of the positive herds of that particular site. Of the diagnostic tests employed, the microhaematocrit buffy coat technique is relatively sensitive and it has an added advantage of indicating the general condition of the animal by haematocrit measurement. In view of the risk of trypanosomosis, a control intervention through the strategic application of appropriate trypanocidal drugs is recommended. A tsetse fly control scheme to reduce host-tsetse fly contact is equally as important as chemotherapy and chemoprophylaxis against trypanosomosis.     

Economic burden of bovine trypanosomosis in three villages of Metekel zone,Northwest Ethiopia

The study was carried out to assess the economic burden of trypanosomosis in three villages of the Metekel zone in 2009. The disease was found to cause substantial economic losses through cattle mortality, drug purchase, and draft power loss of infected oxen. The farmers in the area were spending a significantly (p < 0.05) higher amount of money for the treatment of trypanosomosis than all other diseases combined. The overall mortality rate of cattle due to trypanosomosis was 4.4%. The mortality was significantly higher (p < 0.05) in an area where trypanosomosis prevalence was also higher. Many of the farmers prioritized losses of draft power as the most important impact of the disease. The overall prevalence of the disease was 12.1%. The disease burden was significantly (p < 0.05) higher in the rainy season than at other times of the year. In general, farmers had good knowledge on the signs and seasonality of trypanosomosis. Thus, tsetse suppression activities that involve the local community can be an important tool towards minimizing the economic burden of the disease in the area.     

Ingestion of indigestible foreign materials by free grazing ruminants in Amhara Region, Ethiopia

Ruminants slaughtered in Bahir-Dar, northern Ethiopia, were studied to estimate the prevalence and types of foreign bodies in the rumen and reticulum. Of the 400 cattle, 320 sheep, and 320 goats examined between November 2011 and May 2012, 41.8, 20.6 and 11.9 %, respectively, contained one or more types of foreign bodies. The prevalence of foreign bodies was significantly (P?<?0.05) higher (i) in cattle than in sheep and goats, (ii) in cattle in poor body condition than those in good condition, and (iii) in the rumen than in the reticulum. The most commonly encountered materials were plastics, which resulted from the widespread use of plastic bags and improper waste disposal. Other materials found were cloth, rope, metal, and leather. The study demonstrated that ruminants in the area are ingesting various types of indigestible foreign bodies, which can hamper their health and productivity. To avert the problem, collaborative intervention schemes need to be applied involving professionals, policy makers, livestock keepers, and environmental activists.     

Community-based tsetse fly control minimizes the effect of trypanosomosis on livestock in Metekel zone,Ethiopia

Tropical Animal Health and Production - Tsetse-related trypanosomosis threatens integrated crop-livestock production system in Ethiopia. Metekel zone is among the tsetse-infested areas in Ethiopia....     

Bovine trypanosomosis and its vectors in two districts of Bench Maji zone,South Western Ethiopia

A cross-sectional study was carried out from November 2008 to February 2009 in Guraferda and Sheko districts of Bench Maji Zone, South Western Ethiopia. The objective of the study was to determine the prevalence of bovine trypanosomosis and the density of its vectors. An overall prevalence of trypanosome infection in the study area was 4.4%. Trypanosoma congolense (36.36%) was the dominant trypanosome species followed by Trypanosoma vivax (18.18%) and Trypanosoma brucei (9.09%). Mean packed cell volume value of parasitemic animals (21.8%) was significantly (P < 0.05) lower than that of aparasitemic animals (27.7%). Biconical and NGU traps were deployed for 72 h, and the result indicated Glossina pallidipes followed by Glossina fuscipes as the only tsetse fly species caught in the study area along with other biting flies like Stomoxys and Tabanus. The apparent density of tsetse flies was 2.83 flies trap⁻¹ day⁻¹. NGU trap caught more of G. pallidipes while biconical trap caught more G. fuscipes, and the difference was significant (P < 0.05). Although the current study indicated low prevalence of trypanosomosis in the study area, the impacts of trypanosomosis on cattle production and productivity should not be neglected. Therefore, attention should be given to control the disease and also the vector.     

Sero-prevalence of bovine brucellosis and its risk factors in Jimma zone of Oromia Region,South-western Ethiopia

A cross sectional sero-prevalence study was conducted on 1,595 cattle in Jimma zone, Ethiopia to investigate the status of bovine brucellosis and identify potential risk factors. Sera samples were analyzed using Rose Bengal Plate Test (RBPT) and Complement Fixation Test (CFT). The overall individual and herd level sero-prevalences were 3.1% (n = 1,595) and 15.0% (n = 227), respectively. The sero-prevalence of bovine brucellosis at individual animal level was significantly higher in non-pregnant (11.18%) than pregnant (2.77%) and lactating (22.35%) than non-lactating animals (2.46%). Moreover, significantly higher sero-prevalence was observed in herds of larger sizes. Individual animal sero-prevalence was also positively associated with the occurrence of abortion (26.98 and 1.54% in those with and without previous history of abortion, respectively). Generally, the sero-prevalence of bovine brucellosis found in Jimma area was not high and the sero-prevalence was closely associated with some of the risk factors considered at individual animal and herd level.     

Knowledge and attitudes of cattle owners regarding trypanosomosis control in tsetse-infested areas of Uganda

A pilot survey using a structured questionnaire was conducted in Tororo and Busia districts of Uganda on the knowledge and attitudes of cattle owners regarding tsetse fly and trypanosomosis control, in order to understand factors that hindered their full participation. A total of 81 cattle owners was randomly selected and interviewed, of which 92.5% were aware of tsetse flies and trypanosomosis and 87.6% recognised animal trypanosomosis as a problem in the area. Most cattle owners were aware of tsetse fly trapping (76.5%), isometamidium chloride use (55.5%), diminazene aceturate use (48%) and pour-on applications (18.5%). However, knowledge did not coincide with the application of control measures. Despite the widespread awareness, tsetse fly trapping and pour-on applications were used by only a small percentage of cattle owners (7.5% applied tsetse fly trapping while 76.5% were aware of it; 1.2% applied pour-on insecticides while 18.5% were aware of them). Differences between awareness and application were highly significant for tsetse fly trapping (chi2 = 67.8, d.f. = 1, P < 0.001) and pour-on applications (chi2 = 10.8, d.f. = 1, P < 0.05), but not for isometamidium chloride use (chi2 = 0.08, d.f. = 1, P = 0.77) and diminazene aceturate use (chi2 = 0.00, d.f. = 1, P = 1.00). Most cattle owners (97.5%) were willing to participate in future control programmes, but preferred participating on a group basis (85.2%) rather than individually (14.8%). The 4 most favoured control options in order of importance were: fly traps supplied by the government and maintained by cattle owners; contribution of labour by cattle owners for trap deployment; self-financing of trypanocidal drugs and self-financing of pour-on insecticide. The control options that should be selected in order to elicit full participation by cattle owners are discussed.     

Milk yield and reproductive performance of dairy cattle under smallholder management system in North-eastern Amhara Region,Ethiopia

This study was conducted in South Wollo Zone of Amhara Regional State, Ethiopia, to assess the milk yield and reproductive performance of indigenous and crossbred cattle under smallholder management conditions. Questionnaire survey was used to collect retrospective data on the performance of dairy cattle in 186 households. Thirty two postpartum cows (16 indigenous and 16 crossbred) were selected purposively and monitored for five months and milk samples were collected twice per week from each cow to determine postpartum ovarian activity using ELISA techniques. Daily milk yields at all stages of lactation were significantly (P < 0.01) higher in crossbred than indigenous cows. Crossbred cows had significantly (P < 0.01) longer lactation length and shorter age at first calving, while calving interval was significantly shorter in cows that gave previous calves during the wet season than the dry season. Only six cows (18.8%) showed heat signs on an average of 136 days postpartum of which one was a crossbred and five were indigenous. While, 11 cows (34.3%) resumed ovarian activity until 150^th day postpartum among which three were crossbred and eight were indigenous.     

Low prevalence of bovine tuberculosis in Somali pastoral livestock, southeast Ethiopia

A cross-sectional study of bovine tuberculosis (BTB) detected by the comparative intradermal tuberculin test (CIDT) was conducted in livestock of the Somali region in southeast Ethiopia??in four pastoral associations from January to August 2009. In 94 herds, each of 15 cattle, camels, and goats was tested per herd leading to a total of 1,418 CIDT tested animals, with 421 cattle, 479 camels, and 518 goats. A herd was considered positive if it had at least one reactor. Prevalence per animal species was calculated using a xtgee model for each species. The individual animal prevalence was 2.0% [95% confidence interval (CI), 0.5?C8.4], 0.4% (95% CI, 0.1?C3%), and 0.2% (95% CI, 0.03?C1.3) in cattle, camels, and goats, respectively. Prevalence of avian mycobacterium purified protein derivative (PPD) reactors in cattle, camels, and goats was 0.7% (95% CI, 0.2?C2.0%), 10.0% (95% CI, 7.0?C14.0%), and 1.9 (95% CI, 0.9?C4.0%), respectively, whereby camels had an odds ratio of 16.5 (95% CI, 5.0?C55.0) when compared to cattle. There was no significant difference between livestock species in BTB positivity. In the present study, the prevalence of bovine tuberculosis was low in Somali pastoral livestock in general and in camels and goats in particular. The high proportion of camel reactors to avian PPD needs further investigation of its impact on camel production.     

The parasitological and serological prevalence of tsetse-transmitted bovine trypanosomosis in the Eastern Caprivi (Caprivi District, Namibia).

Between August 1995 and June 1997 a survey to determine the distribution of tsetse-transmitted trypanosomosis was conducted in the Eastern Caprivi (Caprivi District, Namibia). A total of 1,481 adult cattle was examined at 33 sampling sites. Direct parasitological diagnostic tests were used and eluted blood spots were screened for the presence of anti-trypanosomal antibodies. Tsetse-transmitted trypanosomal infections were detected in 66 animals (4.5%) from 14 different locations. The parasitological and serological prevalence of trypanosomosis was highest in the Mamili area. Trypanosomosis was virtually absent in the Linyanti/Chobe area and the target barrier along the Kwando River had significantly reduced the prevalence of trypanosomosis in cattle grazing to the east of it. This suggests that anti-trypanosomal antibody prevalence data can be used to evaluate and monitor the effectiveness of tsetse control measures. Survey results suggest that in the Katima Mulilo area, trypanosomal infections were being acquired when cattle grazed along the Zambezi River. Moreover, survey results indicate that tsetse have not been able to establish themselves in the Katima Mulilo area. The parasitological prevalence in a herd and the respective prevalence of anti-trypanosomal antibodies was significantly correlated to the percentage of anaemic animals in that herd. Furthermore, the parasitological prevalence in a herd was positively correlated with the prevalence of anti-trypanosomal antibodies of that herd. It is concluded that the prevalence of anti-trypanosomal antibodies in a herd can be used as an additional indicator of the extent of infection in that particular herd.     

Modelling bovine trypanosomosis spatial distribution by GIS in an agro-pastoral zone of Burkina Faso

Modelling of the spatial distribution of bovine trypanosomosis prevalence in Sideradougou district Burkina Faso was performed by using a combination of spatial and statistical analysis. Based on a comprehensive and geographically representative census of herds and farms in the area, more than 2000 cattle were randomly chosen and their blood sampled during field survey. Data on livestock farming practices were recorded for each farm. All data were mapped within a GIS to generate new information on spatial constraints in the area.Surveys results were analysed and serological prevalence data were modelled using logistic regression. The model allowed identification and quantification of risk factors. In a second step the statistical model was used predictively on the entire farm population in the area. This method was successful in predicting the serological prevalence for each individual herd in the sample, from their livestock management patterns and spatial location. Predicted prevalences were represented within the GIS, taking daily movements of animals into account. Spatial distribution of prevalence would illustrate specific locations at risk from an epidemiological viewpoint. It gives evidence that the hydrological network and land occupation patterns in the savanna-type countryside are playing an important part when structuring a so-called "trypanosomosis space".     

Status of bovine tuberculosis and its zoonotic implications in Borana zone,Southern Ethiopia

A cross-sectional study was carried out from April 2015 to June 2016 to estimate the status of bovine tuberculosis (BTB), assessment of community’s current knowledge, and zoonotic importance on this disease in Borana zone, southern Ethiopia. In this study, comparative intradermal tuberculin (CIDT) test, structured questionnaires, and retrospective data were used, while the result indicated 3.8% prevalence at individual animal level with 5.6% (31/554) of doubtful reactors. Among related risk factors included, old animals were significantly infected by BTB than young one (χ ²?=?32.005, P?=?0.001). Parity number again showed significant difference (χ ²?=?29.163, P?=?0.001) where animals with many parity were more reactive to conducted test than few parity numbers. Animals born in the breeding center managed under semi-intensive production system were more infected (χ ²?=?10.795, P?=?0.029) than those brought from outside of the center. Questionnaire survey in this study indicated that out of 130 interviewed respondents, only 30% pastoralists knew what BTB mean; whereas the level of individual knowledge from interviewed showed about 72.3% of respondents had poor understanding of BTB and only about 11.5% of them knew its zoonotic importance. Meat eating habit of communities in the area were culturally inhabited to eat cooked meat and only 12.3% (16/130) of respondents gave response on habit of eating both raw and cooked meat. Milk drinking habit of pastoralist in the area showed about 79.2% drunk raw milk and the rest 20.8% used both raw and boiled milk. A retrospective data from Yabello Hospital indicated that current prevalence of human TB as 38.79% and showing the disease was highly increasing from year to year in the study area. This implies a great importance of human tuberculosis and its future concern in Borana zone. From this, there should be detail awareness of communities on BTB, its zoonotic importance, and the need of further investigation to develop control and prevention strategies according to the pastoral settings.     

Prevalence of bovine trypanosomosis and trypanocidal drug sensitivity studies on Trypanosoma congolense in Wolyta and Dawero zones of southern Ethiopia

Cross-sectional studies were conducted in tsetse and non-tsetse-controlled areas of the Southern Nation Nationalities and Peoples Regional State (SNNPRS) of Ethiopia to determine the prevalence of bovine trypanosomosis as well as drug sensitivity tests on Trypanosoma congolense in both naturally and experimentally infected cattle and mice, respectively. A total trypanosome prevalence of 4.8% (95% CI: 1.8-7.5) and 20.4% (95% CI: 14-26.8) were recorded in the tsetse-controlled study area of Humbo district and the non-tsetse-controlled area of Mareka district, respectively, indicated statistically significant difference between the two areas (P<0.001). The mean PCV value for Humbo and Mareka was 26.2 (95%: 25.7-26.7) and 22.7 (95% CI: 22.1-23.3), respectively, which were also statistically significant (P<0.001). The prophylactic activity of isometamidium chloride (ISMM) was observed in Humbo on nine naturally positive zebu cattle. Breakthrough infections were recorded in (6/9) 66.7% of the cases in less than 5 weeks. A qualitative assay on mice was conducted on two T. congolense isolates obtained from the breakthrough cases with ranges of doses of ISMM and diminazene diaceturate (DA). Thereafter the mice were followed for relapse infection. ISMM at doses 0.5-4 mg/kg body weight (bw) and DA at doses of 3.5-28 mg/kg bw failed completely to cure T. congolense infections in any of the mice. A quantitative assay on mice was conducted on four T. congolense isolates obtained from Mareka. The four isolates were pooled into two pools (Pool-1 and Pool-2) for the quantitative assay on mice. The pooled isolates were tested with the same trypanocidal drugs and ranges of doses as it was used for the qualitative assay on mice. The minimum curative dose (MCD) of ISMM that cleared T. congolense infected mice was 4 and 2mg/kg bw for Pool-1 and Pool-2, respectively, whereas MCD of DA was 28 and 14 mg/kg bw, in Pool-1 and Pool-2, respectively. Although cloned populations were not used to prove whether the observed resistance was at the individual level or not, the results show that there is resistance to both ISMM and DA; failure of the "sanative pair".