Spatial distribution of Glossina sp. and Trypanosoma sp. in south-western Ethiopia

Epidemiological study on cattle trypanosomiasis and its vectors distributions in the Gambella regional state, southwestern Ethiopia

African animal trypanosomosis is a parasitic disease that causes significant economic losses in livestock due to anaemia, loss of condition, emaciation, and mortality. It is a key impediment to increased cattle output and productivity in Ethiopia. Cross-sectional entomological and parasitological studies were performed in the Gambella Region state of southwestern Ethiopia to estimate the prevalence of bovine trypanosomosis, apparent fly density, and potential risk factors. Blood samples were taken from 546 cattle for the parasitological study and analyzed using the buffy coat technique and stained with Giemsa. A total of 189 biconical (89) and NGU (100) traps were deployed in the specified districts for the entomological survey. The overall prevalence of trypanosomosis at the animal level was 5.5% (95% CI: 3.86-7.75). Trypanosoma vivax (50.0%), T. congolense (30.0%), T. brucei (20.0%), and no mixed trypanosome species were found. The prevalence of trypanosomosis was significantly (p < 0.05) affected by altitude, body score conditions, age, mean packed cell volume (PCV), and peasant associations, while sex and coat color had no significant effect. According to the entomological survey results, a total of 2303 flies were captured and identified as tsetse (Glossina pallidipes (5.3%)) and G. fuscipes fuscipes (3.3%) and other biting flies (Tabanus (60.1%) and Stomoxys (31.3%)). In the current study, the overall apparent density was 4.1 flies/trap/day. This study shows that trypanosomosis remains a significant cattle disease in the Gambella regional state even during the dry season. Thus, the findings support the necessity to improve vector and parasite control measures in the area.

Entomological study on vectorial density, temporal variation of tsetse fly and other biting flies in intervention and non-intervention areas of South Omo Zone, Ethiopia

A repeated cross-sectional entomological survey was conducted to estimate Glossina (tsetse) and other biting flies density, their seasonal variation and associated risk factors in intervention and non- intervention areas of South Omo Zone, Southwest Ethiopia from January 2019-November 2019. In both dry and wet seasons, a total of 96 NGU traps (64 traps in tsetse intervention districts and 32 traps in tsetse non- intervention districts) were deployed at an interval of about 100-200 m in purposively selected and suspected tsetse habitats. Thus, Glossina pallidipes was found to be the only cyclical vector along with mechanical vectors of Tabanus, Stomoxys and Haematopota. In tsetse intervention areas, G. pallidipes apparent density of 2.64 F/T/D and 0.42 F/T/D was recorded in dry and wet season respectively. Mechanical vectors (dry; wet) of Tabanus (205; 155), Stomoxys (34; 54) and Haematopota (50; 33) were also recorded in tsetse intervened areas. Whereas, in non- intervention areas, apparent density of G. pallidipes was 2.03 F/T/D and 0.56 F/T/D, respectively in dry and wet season. Similarly, Tabanus (22; 56), Stomoxys (10; 8) and Haematopota (5; 7) respectively in dry and wet (dry; wet) season were recorded in tsetse non- intervention areas. According to Negative Binomial Regression (NBR), season was the only variable significantly affecting (P < 0.05) the Glossina count in the current study area. Accordingly, the incidence G. pallidipes during wet season was decreased by the factor of 0.21 (CI; 0.097-0.47) when compared to its incidence in dry season by holding other variables constant. In conclusion, cyclical vectors were playing vital role in transmission of trypanosomosis in South Omo Zone along with numerous mechanical vectors even though there have been vector intervention activities in the areas. Therefore, strong, sustainable, environmentally friend and community participating vector control strategies should be followed to tackle the vector distribution in the area.

Parasitological investigation of bovine Trypanosomosis, vector distribution and tsetse flies infection rate study, Dabo Hana District, Buno Bedelle Zone, Southwest Ethiopia

A cross-sectional study was conducted to explore the prevalence of Trypanosome infections in cattle and within the tsetse flies from December 2020 to May 2021 in Dabo Hana district, Buno Bedelle Zone, Southwest Ethiopia. A total of 415 blood samples were examined utilizing Buffy coat and Giemsa-stained thin blood smear techniques. Vector distribution and tsetse fly infection rate were studied by deploying 60 traps in four purposively chosen villages of the district. The prevalence of Trypanosomes was 10.6% and 6.5% in cattle and in tsetse flies, respectively. Trypanosoma congolense (59.1%) in cattle and T. vivax (62.5%) in tsetse flies, were the foremost common species distinguished in the area. A significant difference (P ≤ 0.05) was observed in the prevalence of bovine Trypanosomosis between body condition scores of cattle. However, differences were not significant between coat color, sex, and age categories (P > 0.05). The mean PCV values of Trypanosome-infected cattle (22.6 ± 0.6) were significantly (P < 0.05) lower than those of non-infected cattle (25.6 ± 0.3). Out of 1441 flies caught, 1242 (86.2%) were Glossina, 113 (7.84%) were Stomoxys, and 86 (5.97%) were Tabanus. Of 1242 Glossina, 85% were G. tachinoides and the remaining 15% were G. m. sub-morsitans. This finding revealed that, three Trypanosoma species are circulating in cattle as well as in tsetse flies. It is recommended that, sustainable and integrated tsetse and Trypanosomosis control practices should be implemented to foster live stock health and agricultural development in the district. Other sensitive methods should be employed to determine the true picture of infection in the area.

Seasonal prevalence of bovine trypanosomosis and trypanosome species distribution in Jimma Horo district, Oromia regional state, Western Ethiopia

A study was conducted to determine the prevalence of bovine trypanosomosis in rainy (June 2019) and dry (February 2020) seasons in Jimma Horoo district, Kellem Wollega Zone, Oromia Regional State, Ethiopia. A total of 720 blood samples were examined using buffy coat and thin blood smear techniques. The packed cell volume (PCV) of each animal was determined. The overall bovine trypanosomosis prevalence was 4.3% (χ² = 1.25, P = 0.26). The prevalence was 5% (95% CI = 4.1-8.3) and 3.3% (95% CI = 2.7-6.3) in the dry and rainy reasons, respectively (P > 0.05). Trypanosoma congolense, T. vivax and T. b. brucei were detected in (60%), (33.3%) and (6.7%) of infected cattle, respectively. The highest trypanosome prevalence was observed in Burka Gudina (7.6%), and the lowest in Melka Nega village (2.1%). There were significant variations between trypanosome prevalence in relation to body condition scores (χ² = 23.16; P = 0.0.00) of examined cattle. No significant difference (P > 0.05) was observed between seasons, age, and sex categories of cattle. The PCV values of trypanosome infected (22.94%) was significantly lower than non-infected cattle (26.47%) (χ² = 19.60; (P < 0.05). The prevalence of bovine trypanosomosis in Jimma Horo district was low and it can be controlled by treatment of infected cattle using sanative pairs of trypanocidal drugs with additional application of deltamethrin pour-on in the dry season. Further, in view of poor sensitivity of buffy coat technique used the use of molecular techniques should be encouraged.

Glossina pallidipes Density and Trypanosome Infection Rate in Arba Minch Zuria District of Gamo Zone, Southern Ethiopia

Background

African trypanosomosis is a disease of both animals and humans resulting from infection with parasitaemic protozoa of the genus Trypanosoma transmitted mainly by the tsetse flies (Glossina species). The disease has been reported in different parts of the country. However, information on the apparent density and trypanosome infection rates of the vectors is very limited in the Southern part of Ethiopia. Therefore, this study was conducted to estimate the apparent density, infection rate of trypanosomes in Glossina pallidipes, and the trypanosome species involved in Arba Minch Zuria district of Southern Ethiopia.

Methods

A cross-sectional study was conducted from January to June 2018 in two purposely selected kebeles of Arbaminch Zuria district and in the escarpments of Nech Sar National Park of Southern Ethiopia. For entomological survey, a total of 40 standard NGU traps were deployed around the watering and grazing areas. A total of 300 fresh Glossina pallidipes were examined for trypanosome infection using a dissection procedure as described by the FAO Training manual for tsetse control personnel.

Results

The study revealed the presence of only one Glossina species, known as Glossina pallidipes, and biting flies including Stomoxys and Tabanus. A total of 2176 flies were caught of which 1803 (82.86%) belong to Glossina pallidipes and the remaining 373 (17.14%) were biting flies. The overall apparent density of Glossina pallidipes and biting flies in the study area were 15.03 fly/trap/day (F/T/D) and 3.11 F/T/D, respectively. Relatively higher Glossina pallidipes and biting flies, respectively, were caught in a wood-grass land (15.87 F/T/D and 3.69 F/T/D) and riverine forest (15.13 F/T/D and 3.42 F/T/D) than bush land vegetation types (13.87 F/T/D and 1.76 F/T/D). The overall trypanosome infection rate of Glossina pallidipes was 17.67% (53/300). Two trypanosome species, namely, Trypanosoma congolense (66.04%) and Trypanosoma vivax (33.96%), were responsible for Glossina pallidipes infection in the study area. Trypanosome infection rate was significantly higher in female G. pallidipes than in male (OR = 3.39, 95%CI = 1.53‐7.52). Significantly, higher trypanosome infection rate was observed in flies older than 20 days (OR = 2.5, 95%CI = 1.12‐5.56) and in hunger stage 1 flies (OR = 14.24, 95%CI = 4.01‐50.59). Glossina pallidipes infection was significantly higher in and around park grazing areas (OR = 3.41, 95%CI = 1.76‐6.6) and wood-grass land vegetation type (OR = 2.7, 95%CI = 1.2‐6.5).

Conclusion

The current study revealed high apparent density and trypanosome infection in Glossina pallidipes in Arba Minch Zuria district of Southern Ethiopia. So, this study warrants the need for strengthening both vector and parasite control strategies in the study area.

African Animal Trypanosomiasis: A Systematic Review on Prevalence, Risk Factors and Drug Resistance in Sub-Saharan Africa

African animal trypanosomiasis (AAT) a parasitic disease of livestock in sub-Saharan Africa causing tremendous loses. Sub-Saharan continental estimation of mean prevalence in both large and small domestic animals, risk factors, tsetse and non-tsetse prevalence and drug resistance is lacking. A review and meta-analysis was done to better comprehend changes in AAT prevalence and drug resistance. Publish/Perish software was used to search and extract peer-reviewed articles in Google scholar, PubMed and CrossRef. In addition, ResearchGate and African Journals Online (AJOL) were used. Screening and selection of articles from 2000-2021 was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Articles 304 were retrieved; on domestic animals 192, tsetse and non-tsetse vectors 44, risk factors 49 and trypanocidal drug resistance 30. Prevalence varied by, host animals in different countries, diagnostic methods and species of Trypanosoma. Cattle had the highest prevalence with Ethiopia and Nigeria leading, T. congolense (11.80-13.40%) and T. vivax (10.50-18.80%) being detected most. This was followed by camels and pigs. Common diagnostic method used was buffy coat microscopy. However; polymerase chain reaction (PCR), CATT and ELISA had higher detection rates. G. pallidipes caused most infections in Eastern regions while G. palpalis followed by G. mortisans in Western Africa. Eastern Africa reported more non-tsetse biting flies with Stomoxys leading. Common risk factors were, body conditions, breed type, age, sex and seasons. Ethiopia and Nigeria had the highest trypanocidal resistance 30.00-35.00% and highest AAT prevalence. Isometamidium and diminazene showed more resistance with T. congolense being most resistant species 11.00-83.00%.

Study on Bovine Trypanosomiasis and Associated Risk Factors in Benatsemay District, Southern Ethiopia

Trypanosomosis is an endemic livestock disease in Ethiopia that hinders livestock production and productivity, especially in fertile agricultural western and southwestern areas. A cross-sectional questionnaire-based and parasitological studies were conducted from October 2020 to July 2021 in the Benatsemay district, southern Ethiopia to assess the knowledge of livestock owners about trypanosomosis, its prevalence, and host-related risk factors associated with bovine trypanosomosis in the area. According to the questionnaire survey, trypanosomosis was the main bottleneck to cattle in two of the selected study Sites in the Benatsemay district. The parasitological survey revealed that 11.46% (44/384) of the cattle were infected with trypanosomosis. Moreover, Trypanosoma congolense (9.11%) is the leading trypanosome species in the area, followed by T. vivax (31.8%). The adult age group (16.15%), poor-conditioned cattle (22.22%), and black-skinned cattle (34.24%) were significantly associated (P < .05) with trypanosomosis infection in the study area. Furthermore, the mean packed cell volume (PCV) of parasitaemic cattle (22.75%) was significantly (P < .05) lower than that of aparasitaemic cattle (29.23%). Therefore, the present study revealed that the prevalence of bovine trypanosomosis in the study area and participatory vector control and the rational use of trypanocidal drugs should be implemented to control trypanosomosis in the area.

Seasonal Patterns: Bovine Trypanosomosis, Glossina pallidipes Density, and Infection in Rift Valleys of Gamo Zone, Southern Ethiopia

Bovine trypanosomosis is a parasitic disease causing serious economic losses in livestock productivity and agricultural development. The disease has been reported in different parts of Ethiopia. However, seasonal pattern of trypanosomosis, tsetse fly apparent density, and infection are very limited in the southern rift valley of the country, particularly in Gamo Zone. Therefore, the objective of this cross-sectional study design was to estimate seasonal prevalence of bovine trypanosomosis, assessing tsetse fly apparent density and its infection by trypanosomes. For the parasitological study, a total of 600 cattle (300 in each season) were sampled and assayed using the buffy coat technique. A total of 80 standard NGU traps were deployed around the watering and grazing areas for the entomological survey. An overall prevalence of trypanosomosis was 10.17% (61/600), of which 7.33% (22/300) and 13% (39/300) accounted for the dry and wet seasons, respectively. The prevalence of trypanosomosis was significantly higher during the wet season (OR = 2.47; p < 0.05), in black coat color (OR = 7.2, p < 0.05), and poor body-conditioned (OR = 3.15; p < 0.05) animals. Two species of trypanosomes, Trypanosoma congolense, 68.85% (42/61), and Trypanosoma vivax, 31.15% (19/61), were circulating in the area. The mean PCV value in infected animals (22.56 ± 4.61) was significantly lower than in non-infected animals (25.3 ± 4.75). Entomological result indicated that Glossina pallidipes (G. pallidipes) was the only species of tsetse found in the study area. Totally, 3,789 flies were caught of which 81.42% (3,085/3,789) belong to G. pallidipes and 18.58% (704/3,789) were other biting flies. The overall apparent density of G. pallidipes was 12.85 flies/trap/day (FTD). Relatively higher G. pallidipes/trap/day were caught in the wet season (13.64 F/T/D) than in the dry season (12.07F/T/D). Of the flies caught, 342 G. pallidipes were randomly selected and dissected. The overall proportion of G. pallidipes infection was 18.42% (63/342) of which 12.28% (21/171) and 24.56% (42/171) were accounted in the dry and wet seasons, respectively. Infection in G. pallidipes was significantly higher during the wet season (OR = 2.32; p < 0.05) and in park grazing areas (OR = 2.45; p < 0.05). In conclusion, trypanosomosis is the major challenge for cattle productivity in the district. So this study warrants the need for strengthening the vector and parasite control interventions in the area.

Prevalence of Bovine Trypanosomosis and Its Associated Risk Factor in Hawa Galan District, Kelem Wollega Zone of Ethiopia

An analytical cross-sectional study was performed between November 2015 and April 2016 at Hawa Galan woreda, Kelem Wollega Zone, Oromia Region, Ethiopia, to estimate the proportion of cattle with trypanosomosis and to evaluate the elements associated with the prevalence of bovine trypanosomosis. A haemoparasitological examination of the Buffy coat method was implemented to determine the proportion of trypanosomosis-positive cattle. A study population of 428 bovines was randomly selected from three peasant associations (PAs) and tested for the presence of the disease. Findings of the laboratory results indicate that among all animals tested at the study time, 26 (6%) animals were positive for the disease. Among the positive results, the proportion of trypanosome species was Trypanosoma congolense 18 (69.3%) and Trypanosoma vivax 8 (30.7%). The prevalence at the selected PAs was 12.5%, 3.8%, and 3% for Lemlem, Madawalkituma, and Ifajiru, respectively. From this finding, the relationship has a statistically significant variation (P < 0.05) among peasant associations and body condition state, and the proportion was significantly greater (P < 0.05) in animals categorized under poor body condition score. The relationships between age and sex of cattle show no statistically significant variation among them (P > 0.05). This study indicates that the proportion of trypanosomosis was greater in anemic (PCV<24%) cattle than nonanemic (PCV≥24%). Therefore, based on this finding, the proportion of bovine trypanosomosis is evident that can cause a major effect on the health of cattle in the study population in the study area. So, effective control methods could be applied to decrease the disease and its related economic loss.

Epidemiological investigation of bovine trypanosomosis and distribution of vectors in Jimma zone, Ethiopia

Trypanosomosis is highly reliant on the distribution of vectors responsible for transmission. A cross-sectional study was conducted to determine the prevalence and associated risk factors of bovine trypanosomosis as well as the distribution of vectors in the Jimma zone, Ethiopia. Blood samples from a total of 2088 cattle were collected and tested using a buffy coat and Giemsa techniques. An overall 13.36% prevalence of trypanosomosis was recorded in study areas. The highest proportion of the infections was caused by T. vivax (44.80%) followed by T. congolense (36.92%) and mixed infection (18.28%) of both species. The study also revealed that trypanosomosis was associated with anemia as the mean PCV was significantly lower among trypanosome-infected animals (20.34 ± 4.39) than non-infected ones (27.98 ± 3.68). Moreover, anemia was more pronounced with T. congolense infection (19.54 ± 3.22) than T. vivax (21.07 ± 3.96) and mixed infection of both species (20.16 ± 2.71). This study identified age, body condition, and agro-ecology as risk factors for the occurrence of trypanosomosis in cattle. Vector survey was conducted by deploying 377 mono-pyramidal traps in selected districts. Accordingly, Glossina species and other biting flies (Stomoxys and Tabanus) were identified with an apparent density of 5.27 and 1.74 fly/trap/day, respectively. Moreover, a higher 4.49 fly/trap/day of G. tachinoides than G. morsitans submorsitans (0.79 fly/trap/day) was noted in study areas. The present study indicated that trypanosomosis is the major cattle production constraint in the areas. Hence, applicable management techniques of the disease and its vector should be implemented and further investigation involving molecular technique should be conducted in different seasons.

Epidemiological investigation of bovine trypanosomosis in Bedele district, Buno Bedele zone, Oromia regional state, Ethiopia

A cross-sectional study was conducted in December 2018 in four purposively selected villages of Bedele district, Oromia Regional State, Southwest Ethiopia. The study aimed to determine the prevalence of bovine trypanosomosis and associated risk factors of trypanosome infections in cattle. A total of 384 blood samples were collected from systematically selected cattle and examined using buffy coat and thin blood smear examination methods. The overall prevalence of bovine trypanosomosis was 8.3%. Trypanosoma congolense (68.8%) and T. vivax (31.2%) were the prevailing trypanosome species identified in the area. A statistically significant difference (P < 0.05) was observed in the prevalence of bovine trypanosomosis between body condition scores of cattle. The prevalence of bovine trypanosomosis was slightly higher in female (9%) as opposed to male (7.3%) cattle, but the difference was not statistically significant (P > 0.05). Similarly, no statistically significant difference (P > 0.05) was observed between age categories of cattle. The mean PCV value of trypanosome infected cattle (21.4 ± 3.6) was significantly (P < 0.05) lower than that of non-infected (25.6 ± 4.6). The current study indicated that, despite vector control measures implemented for several years, bovine trypanosomosis persists and continues to be a core problem to cattle health and production in the Bedele district. Therefore, more attention should be given to control the disease and its vectors based on temporal and spatial distribution. Also, the use of molecular techniques should be encouraged in view of their greater sensitivity when compared to the buffy coat method.

Anaemia Associated with Trypanosomes Infections in Cattle of West Gojjam Zone, Northwest Ethiopia

Background

African animal trypanosomosis is a major veterinary problem over a large area of the tsetse belt region of Africa. Anaemia is a cardinal sign of trypanosome infections. The mechanism of anaemia due to trypanosomosis is complex and multifactorial in origin. Packed cell volume (PCV) usually gives an indication of the anaemia and disease status of a trypanosome-infected animal.

Methods

A cross-sectional study was conducted from December 2017 to January 2018 in West Gojjam zone, Northwest Ethiopia, to determine the trypanosome infections rate and the possible correlation between parasitic infection and anaemia using the dark ground buffy coat technique, Giemsa-stained thin blood smear, and PCV reading on a haematocrit reader.

Results

The overall trypanosomosis prevalence was 7.81%, 95% CI = 7.45–8.17. Trypanosoma congolense (4.25%) and T. vivax (3.56%) were the trypanosomes species identified in the studied area. PCV for all sampled cattle was analysed to estimate the degree of anaemia. From the total examined animals (N = 730), 356 (48.77%) were anaemic and 374 (51.23%) were nonanaemic. The mean PCV of parasitemic cattle was significantly lower (21.09%, 95% CI = 20.13–22.05) than that of aparasitemic ones (25.96%, 95% CI = 25.68–26.24). There was a positive association between trypanosome infection and anaemia. Although both trypanosome species are significantly associated with a decreased herd mean PCV (<24), the mean PCV of cattle infected with T. congolense (19.45%) was lower than that of infected with T. vivax (23.04%). The herd mean PCV was not significantly associated to locations, age, and sex of the studied animals.

Conclusions

The study confirms that the prevalence of trypanosomes infections and herd mean PCV has a significant association. The mean herd PCV can be a useful cheap tool to screen for possible trypanosome infection. However, there were cattle positive for trypanosomes having mean PCV within the reference interval and negative animals with anaemia. Furthermore, PCV reading should be confirmed by other diagnostic techniques to accurately conclude that trypanosomosis is the only cause of anaemia.

Genital lesions in cows naturally infected with trypanosomes in Abuja, Nigeria

Background and Aim:

Different species of trypanosomes have been reported to cause varying degrees of reproductive disorders in pregnant and non-pregnant animals under experimental infections. Information on reproductive disorders and losses in animals naturally infected with trypanosome species are few. This study was carried out to assess the abnormalities in the genital organs (ovaries, oviduct, uterus, cervix, and vagina) of female cattle naturally infected with trypanosomes in and around Abuja, Nigeria.

Materials and Methods:

Cows showing signs such as emaciation, weakness, or anemia were selected and examined at Gwagwalada and Karu abattoirs, respectively. Venous blood samples were taken from 108 of such animals and screened using standard trypanosome detection methods. The genital organs were also collected and inspected for gross and histopathological lesions in the laboratory.

Results:

Six (5.55%) out of the 108 animals were positive for trypanosomes; 4 (66.7%) were infected with Trypanosomavivax and 2 (33.3%) were infected with Trypanosoma congolense. The mean packed cell volume of the infected animals was 22.83%. Grossly, congestion and ecchymotic hemorrhages were observed in the endometrium, myometrium, and cervical submucosa. Mucometra, hydrometra, and pyometra were also seen in the uterus. Histologically, necrosis of the epithelium and endometrial glands accompanied by mononuclear cellular infiltration was observed in the uterus. There was also sloughing of the endometrial epithelium, vascular congestion, and hypertrophy of serosa of the uterus. There was atropy of the granulosa cells, increased numbers of degenerating tertiary follicles, and absence of corpora lutea in the ovary. No gross or histopathological lesions were observed in the fallopian tube and vagina.

Conclusion:

The lesions observed were restricted to the uterus and ovary of the animals and were less severe when compared to lesions observed under experimental conditions as reported by previous authors.

Seasonal prevalence of trypanosomosis, Glossina density and infection along the escarpment of Omo River, Loma district, southern Ethiopia

Background

The temporal information of trypanosomosis and tsetse apparent density is very limited in the southern part of the country. So, the study was conducted to estimate the temporal, dry and wet seasons, prevalence of cattle trypanosomosis, and tsetse fly apparent density and its infection by trypanosome along the escarpment of Omo River, Loma district, Southern Ethiopia.

Methods

A total of 964 cattle (482 in each seasons) were examined for trypanosomosis using buffy coat technique. For Glossina and biting flies study a total of 80 odor-baited, acetone and aged cow urine, NGU traps were deployed around the watering and grazing areas.

Results

The overall prevalence of cattle trypanosomosis was 4.98% of which 3.1% and 6.8% accounted to dry and wet seasons, respectively. The prevalence of trypanosomosis was significantly higher during wet season (OR = 1.93, P < 0.05), in poor body condition (OR = 3.71, P < 0.05) and in black coat colour (OR = 13.18, P < 0.05) animals. Two species of Trypanosome, T. congolense and T. vivax, were circulating in the area both in dry and wet seasons. A total of 327 Glossina (126 G. pallidipes and 201 G. fuscipes) were traped by using odour baited 80 NGU traps. The overall apparent density of Glossina was 4.1 Flies/Trap/Day. Relatively higher Glossina/Trap/Day caught in wet season (4.9 Flies/Trap/Day) than dry season (3.3 Flies/Trap/Day). Two species of Glossina namely G. pallidipes and G. fuscipes were distributed in the study areas. From the flies caught 127 Glossina were randomly selected and dissected. The overall proportion of Glossina infection was 15% with higher proportion of infection in wet season (19.6%) than the dry season (11.3%). Higher infection proportion was observed in G. pallidipes.

Conclusion

Trypansomosis is the major challenge for cattle productivity in the district. So to reduce the impact trypanosomosis and Glossina active community participation can play a key role.

Global distribution, host range and prevalence of Trypanosoma vivax: a systematic review and meta-analysis

BACKGROUND

Trypanosomosis caused by Trypanosoma vivax is one of the diseases threatening the health and productivity of livestock in Africa and Latin America. Trypanosoma vivax is mainly transmitted by tsetse flies; however, the parasite has also acquired the ability to be transmitted mechanically by hematophagous dipterans. Understanding its distribution, host range and prevalence is a key step in local and global efforts to control the disease.

METHODS

The study was conducted according to the methodological recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. A systematic literature search was conducted on three search engines, namely PubMed, Scopus and CAB Direct, to identify all publications reporting natural infection of T. vivax across the world. All the three search engines were screened using the search term Trypanosoma vivax without time and language restrictions. Publications on T. vivax that met our inclusion criteria were considered for systematic review and meta-analysis.

RESULT

The study provides a global database of T. vivax, consisting of 899 records from 245 peer-reviewed articles in 41 countries. A total of 232, 6277 tests were performed on 97 different mammalian hosts, including a wide range of wild animals. Natural infections of T. vivax were recorded in 39 different African and Latin American countries and 47 mammalian host species. All the 245 articles were included into the qualitative analysis, while information from 186 cross-sectional studies was used in the quantitative analysis mainly to estimate the pooled prevalence. Pooled prevalence estimates of T. vivax in domestic buffalo, cattle, dog, dromedary camel, equine, pig, small ruminant and wild animals were 30.6%, 6.4%, 2.6%, 8.4%, 3.7%, 5.5%, 3.8% and 12.9%, respectively. Stratified according to the diagnostic method, the highest pooled prevalences were found with serological techniques in domesticated buffalo (57.6%) followed by equine (50.0%) and wild animals (49.3%).

CONCLUSION

The study provides a comprehensive dataset on the geographical distribution and host range of T. vivax and demonstrates the potential of this parasite to invade other countries out of Africa and Latin America.

Bovine trypanosomosis: Prevalence and vector distribution in Sadi Chanka district, Kellem Wollega zone, Oromia regional state, Ethiopia

Bovine trypanosomosis remains an important livestock disease constraint, which is threatening livestock health and production, despite ongoing tsetse and trypanosomosis control efforts in Sadi Chanka district, Kellem Wollega zone, Oromia regional state, Ethiopia. A cross-sectional study was conducted in May 2018, to determine the prevalence of bovine trypanosomosis and distribution of the vectors of disease in Sadi Chanka district, Western Ethiopia. A total of 370 blood samples were collected from randomly selected local Horro and Abigar cattle breeds covering five villages of the district. The collected samples were examined using buffy coat microscopy and Giemsa-stained thin blood smear techniques. In this study, 12.4% (95% CI: 12.3-12.4) of the animals were found to be infected with trypanosomes. The study showed that 69.6% of trypanosome infections were caused by T. congolense followed by 26.1% T. vivax and 4.3% mixed T. congolense and T. vivax. In the present study, the association of bovine trypanosomosis was assessed in releation to body condition scores, sex, and age of cattle, and a significant association (P < 0.05) was observed between body condition scores. However, significant differences were not observed between sex and age categories (P > 0.05). The Mean Packed Cell Volume (PCV) of infected (21.6%) and non-infected (24.5%) groups of cattle had significant variation (P < 0.05). In an entomological survey, a total of 616 flies were trapped, of which 280 (45.5%) were Glossina and the remaining 336 (54.5%) were Stomoxys, Tabanus, and Haematopota. The apparent density of Glossina, Stomoxys, Tabanus, and Haematopota was 3.5, 3.1, 0.7 and 0.4 fly per trap per day, respectively. This study generated basic scientific data on the epidemiology of bovine trypanosomosis and its vectors in Sadi Chanka district, which can be used in planning the control of bovine trypanosomosis in the area.

Bovine trypanosomosis in upstream and downstream of Ghibe-III hydroelectric dam: parasitological and entomological study, southern Ethiopia

Two-point cross-sectional study design in dry and rainy seasons was employed near Ghibe-III Dam from December 2018 to July 2019. Trypanosomosis prevalence comparison between downstream (Kindodidaye) and upstream (Loma districts), associated risk factors, vector dispersion, identification and vector infection rate considered. Blood sample collected from 1280 cattle from two districts during dry and rainy seasons; the assumed risk factors recorded. Samples were examined using heamatological and parasitological techniques. In this study 9.1% (116/1280) trypanosomosis prevalence recorded. Prevalence was significantly (p < 0.05) different between Kindodidaye (11.7%) and Loma (6.4%). Most of the infections were due to T. congolense (79.3%) followed by T. vivax (17.2%) and T. brucei (2.6%) and one mixed infection recorded. Significant (p < 0.05) difference observed in season, within district and between districts. Among the assumed risk factors: district, season, Kebele and body condition score showed significant (p < 0.05) difference; whereas sex, age, color weren't significantly (p > 0.05) different. Significantly (p < 0.05) low mean PCV observed in infected group, dry season and Kindodidaye district. Entomological survey revealed 1030 tsetse spp. (G. pallidipes and G. fuscipes) and 2045 biting flies mainly Stomoxysis and Tabanus, and other unidentified spp. recorded. Tsetse apparent density were significantly (p < 0.05) high in Kindodidaye and rainy season with value of 5.3 and 7.1 F/T/D, respectively. Out of 182 tsetse fly dissected twenty seven (14.6%) of them were infected. A proportion of 23.0%, 30.8% and 46.2% infection rate recorded in proboscis, salivary gland and mid gut, respectively. The study shows Kindodidaye and rainy season had high trypanosomosis and tsetse apparent density than Loma. The difference might be associated with water reserve created due to Ghibe III hydroelectric dam and this could be a golden opportunity in the area to contribute tsetse control program. Stakeholders' need to aware to use this opportunity before tsetse adapts itself into new environment or niche for their survival.

Epidemiology of Bovine Trypanosomosis and Vector Distribution in Didessa River Basin, Ethiopia

BACK GROUND

Tsetse-transmitted trypanosomosis much depends on the distribution and capacity of Glossina species responsible for transmission.

METHOD

A cross-sectional study based on parasitological and entomological studies was conducted from October to June 2018 to determine the epidemiology, distribution, and magnitude of the vector, the disease and Analyze associated risk factors.

RESULTS

Based on implemented entomological study, Didessa river basin has a total apparent fly density of 5.33 Fly/Trap/Day (FTD); similarly, Glossina species accounted about 4.04 and 1.29 were other biting flies (Stomoxys and Tabanus). The composition of Glossina species identified in the study were 3335 (98.56%) Glossina tachinoides and 49 (1.44%) Glossina fuscipes. Comparatively higher and lower FTD found in altitude ranges from 1317 m above sea-level Bedele District (FTD = 5.19) and 1334 m above sea-level Boracha District (FTD = 1.88). Furthermore, from the total of n = 1517, local breeds of cattle examined for the infection of parasite and 82 cattle were found infected with an overall prevalence of 5.41%. The resulted overall prevalence was composed of Trypanosome congolense and Trypanosome vivax, 59 (3.89%) and 23 (1.52%), respectively. Among studied Districts; Goma, Limukosa, Limuseka, Bedele, Boracha, and Gechi prevalence of bovine trypanosomosis was 6.56%, 6.48%, 7.56%, 3.56%, 6.71%, and 1.60%, respectively. Based on parasitological study, statistically significant prevalence was demonstrated between Districts of Limuseka 7.56% and Gechi 1.60% with highest and lowest, respectively. During the early dry season, the prevalence of Trypanosome vivax 0.53% was significantly lower than that of late rainy season 0.99%; however, the higher number of Trypanosome congolense 2.44% resulted during the late rainy season. The study also demonstrated that trypanosomosis strongly causes anemia with mean pcv of infected cattle 20.93 ± 3.93 and non-infected cattle 26.74 ± 3.81 (Mean pcv ± SD) with 95% CI, Pr (T > t) = 0.0000. Moreover, trypanosomosis-related anemia was highly associated with T. congolense with mean pcv result of 18.80 ± 4.66 [mean pcv ± SD, Pr (T > t) = 0.0000] when compared with T. vivax 27.53 ± 4.47 (Mean pcv ± SD, Pr (T > t) = 0.6222).

CONCLUSION

Finally, the research demonstrated the new local demographic occurrence of G.f. fuscipes in the Didessa river basin which was not reported by other studies so far, therefore, the current finding invites further studies and investigations.

A meta-analysis of the prevalence of bovine trypanosomiasis in some African countries from 2000 to 2018

Bovine trypanosomiasis is a disease of cattle. In sub-Saharan Africa, the disease mean prevalence estimates are unknown in most endemic countries. We therefore performed a meta-analysis with the aim of estimating national mean prevalence of bovine trypanosomiasis in endemic countries across sub-Saharan Africa. Relevant articles reporting bovine trypanosomiasis prevalence were retrieved through systematic literature search and scanning of articles reference-lists. Eligibility criteria included that articles reported sample size, prevalence, and diagnostic technique adopted. Overall, data from 180 eligible articles from 19 countries satisfied the inclusion criteria. Meta-analysis of prevalence data based on the random-effects model resulted in an overall mean prevalence of 15.10% (95% CI: 13.22-17.08). National prevalence estimates were generally high except those of Benin and Senegal where estimates ranked below 10.00%. Significant heterogeneity (I² = 98.75%. p = <0.0001) was noted between studies, and univariate meta-regression analysis identified choice of diagnostic method being major contributor to observed heterogeneity (R² = 36.37%); while country of study (R² = 9.57%) and sample size (R² = 3.47%) had marginal effect on heterogeneity. In spite of past and ongoing control activities, bovine trypanosomiasis remains highly prevalent in most endemic sub-Saharan African countries. Nevertheless, dearth of epidemiological data in some countries and the use of less sensitive diagnostic tools limit reliable estimation of the disease prevalence. Therefore, there is the need to intensify efforts in aspects of surveillance and increased application of molecular diagnostic tool(s) across endemic locations as this would raise the chances of achieving a near-accurate estimate of the disease prevalence which is the first step to attempting eradication.

Bovine trypanosomosis: changes in parasitemia and packed cell volume in dry and wet seasons at Gidami District, Oromia Regional State, western Ethiopia

BACKGROUND

Animal trypanosomosis is one of the major disease problems affecting agricultural productivity in Ethiopia. The impact of the disease is believed to vary with season and agro-ecologies in line with fly vector distribution. A cross-sectional study on bovine trypanosomosis was conducted from November 2015 to June 2016, in seven selected villages of Gidami district, Oromia Regional State, western Ethiopia. A total of 930 blood samples were collected and subjected to parasitological and hematological analysis.

RESULT

The overall prevalence of bovine trypanosomosis was 14.1%. The seasonal prevalence shows 9.06% in early dry and 18.4% in early rainy seasons. Three trypanosome species, Trypanosoma congolense, Trypanosoma vivax and Trypanosoma brucei were identified in the examined animals. T. congolense followed by T. vivax were the predominant species (respectively 59.0 and 35.9% in early dry season and 62.0 and 22.8% in early rainy season). The prevalence of T. vivax remained similar in both early dry and early rainy seasons in both lowland and midland agroecologies whereas T. congolense was more dominant in the lowland area in both seasons compared to mid land study sites. The disease was more prevalent in lowland (23.9%) compared to midland (11.1%) during early rainy season (P < 0.001) whereas no significant difference was observed between the two agroecologies during early dry season (P = 0.165). Packed cell volume (PCV) was much lower in parasitemic animals than in aparasitemic cattle whereas the mean PCV value for parasitemic animals (20.36%; 95% CI 19.56 to 21.16) in early dry season was similar to values in early rainy season (20.46%, 95% CI 18.84 to 21.08%). A similar situation was noticed for animals in both low land and mid land study sites.

CONCLUSION

Overall, the detection of trypanosomes in blood was significantly affected by agro-ecology, season and body condition of the animals. Special emphasis should be given to integrated trypanosomosis management in early rainy months where fly population is believed to start increasing.

New insights from Gorongosa National Park and Niassa National Reserve of Mozambique increasing the genetic diversity of Trypanosoma vivax and Trypanosoma vivax-like in tsetse flies, wild ungulates and livestock from East Africa

BACKGROUND

Trypanosoma (Duttonella) vivax is a major pathogen of livestock in Africa and South America (SA), and genetic studies limited to small sampling suggest greater diversity in East Africa (EA) compared to both West Africa (WA) and SA.

METHODS

Multidimensional scaling and phylogenetic analyses of 112 sequences of the glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH) gene and 263 sequences of the internal transcribed spacer of rDNA (ITS rDNA) were performed to compare trypanosomes from tsetse flies from Gorongosa National Park and Niassa National Reserve of Mozambique (MZ), wild ungulates and livestock from EA, and livestock isolates from WA and SA.

RESULTS

Multidimensional scaling (MDS) supported Tvv (T. vivax) and TvL (T. vivax-like) evolutionary lineages: 1) Tvv comprises two main groups, TvvA/B (all SA and WA isolates plus some isolates from EA) and TvvC/D (exclusively from EA). The network revealed five ITS-genotypes within Tvv: Tvv1 (WA/EA isolates), Tvv2 (SA) and Tvv3-5 (EA). EA genotypes of Tvv ranged from highly related to largely different from WA/SA genotypes. 2) TvL comprises two gGAPDH-groups formed exclusively by EA sequences, TvLA (Tanzania/Kenya) and TvLB-D (MZ). This lineage contains more than 11 ITS-genotypes, seven forming the lineage TvL-Gorongosa that diverged from T. vivax Y486 enough to be identified as another species of the subgenus Duttonella. While gGAPDH sequences were fundamental for classification at the subgenus, major evolutionary lineages and species levels, ITS rDNA sequences permitted identification of known and novel genotypes.

CONCLUSIONS

Our results corroborate a remarkable diversity of Duttonella trypanosomes in EA, especially in wildlife conservation areas, compared to the moderate diversity in WA. Surveys in wilderness areas in WA may reveal greater diversity. Biogeographical and phylogenetic data point to EA as the place of origin, diversification and spread of Duttonella trypanosomes across Africa, providing relevant insights towards the understanding of T. vivax evolutionary history.

A systematic review and meta-analysis of trypanosome prevalence in tsetse flies

Background

The optimisation of trypanosomosis control programs warrants a good knowledge of the main vector of animal and human trypanosomes in sub-Saharan Africa, the tsetse fly. An important aspect of the tsetse fly population is its trypanosome infection prevalence, as it determines the intensity of the transmission of the parasite by the vector. We therefore conducted a systematic review of published studies documenting trypanosome infection prevalence from field surveys or from laboratory experiments under controlled conditions. Publications were screened in the Web of Science, PubMed and Google Scholar databases. Using the four-stage (identification, screening, eligibility and inclusion) process in the PRISMA statement the initial screened total of 605 studies were reduced to 72 studies. The microscopic examination of dissected flies (dissection method) remains the most used method to detect trypanosomes and thus constituted the main focus of this analysis. Meta-regression was performed to identify factors responsible for high trypanosome prevalence in the vectors and a random effects meta-analysis was used to report the sensitivity of molecular and serological tests using the dissection method as gold standard.

Results

The overall pooled prevalence was 10.3% (95% confidence interval [CI] = 8.1%, 12.4%) and 31.0% (95% CI = 20.0%, 42.0%) for the field survey and laboratory experiment data respectively. The country and the year of publication were found to be significantly factors associated with the prevalence of trypanosome infection in tsetse flies. The alternative diagnostic tools applied to dissection positive samples were characterised by low sensitivity, and no information on the specificity was available at all.

Conclusion

Both temporal and spatial variation in trypanosome infection prevalence of field collected tsetse flies exists, but further investigation on real risk factors is needed how this variation can be explained. Improving the sensitivity and determining the specificity of these alternative diagnostic tools should be a priority and will allow to estimate the prevalence of trypanosome infection in tsetse flies in high-throughput.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-017-1012-9) contains supplementary material, which is available to authorized users.

Bovine trypanosomosis and vector density in Omo-Ghibe tsetse belt, South Ethiopia

African animal trypanosomosis (AAT) is a parasitic disease that causes serious economic losses in livestock from anemia, loss of condition, emaciation and death in untreated cases. It is one of the major constraints to improved livestock production and productivity in Ethiopia. Entomological and parasitological surveys were conducted in the Omo-Ghibe tsetse belt of south Ethiopia to estimate the prevalence of bovine trypanosomosis and the apparent tsetse density (AD), and identify the potential risk factors. For the parasitological study, blood samples were collected from 1508 cattle sampled from 11 districts and assayed using the buffy coat technique and Giemsa-stained thin smears. For the entomological survey, a total of 216 biconical and NGU traps were deployed in all districts. The overall animal-level prevalence of trypanosomosis was 7.8% (95% CI: 6.5, 9.3). The trypanosome species identified were Trypanosoma congolense (75.4%), T. vivax (20.3%), T. brucei brucei (1.7%) and mixed T. congolense/T. vivax (2.6%). Regarding the entomological survey result, a total of 2243 tsetse flies were captured which identified to be Glossina pallidipes (85.1%) and G. f. fuscipes (14.9%). Besides, other biting flies of the genus Stomoxys (n=146) and Tabanus (n=17) were also trapped. The AD noted in the present study was 3.5 flies/trap/day. Both the prevalence of trypanosomosis and AD of tsetse flies were significantly (p<0.05) influenced by altitude. The prevalence of trypanosomosis was also significantly (p<0.05) associated with poor body condition score, black coat color and lower mean packed cell volume while no significant prevalence difference was noted along with age and sex category. In conclusion, the present study suggested that trypanosomosis is an important disease of cattle in the Omo-Ghibe tsetse belt in dry season. The disease is mainly caused by the most pathogenic T. congolense and transmission is predominantly by tsetse flies, particularly G. pallidipes. The study warrants the need for strengthening the vector and parasite control interventions in the area.

Medical pluralism and livestock health: ethnomedical and biomedical veterinary knowledge among East African agropastoralists

BACKGROUND

Human and animal health are deeply intertwined in livestock dependent areas. Livestock health contributes to food security and can influence human health through the transmission of zoonotic diseases. In low-income countries diagnosis and treatment of livestock diseases is often carried out by household members who draw upon both ethnoveterinary medicine (EVM) and contemporary veterinary biomedicine (VB). Expertise in these knowledge bases, along with their coexistence, informs treatment and thus ultimately impacts animal and human health. The aim of the current study was to determine how socio-cultural and ecological differences within and between two livestock-keeping populations, the Maasai of northern Tanzania and Koore of southwest Ethiopia, impact expertise in EVM and VB and coexistence of the two knowledge bases.

METHODS

An ethnoveterinary research project was conducted to examine dimensions of EVM and VB knowledge among the Maasai (N = 142 households) and the Koore (N = 100). Cultural consensus methods were used to quantify expertise and the level of agreement on EVM and VB knowledge. Ordinary least squares regression was used to model patterns of expertise and consensus across groups and to examine associations between knowledge and demographic/sociocultural attributes.

RESULTS

Maasai and Koore informants displayed high consensus on EVM but only the Koore displayed consensus on VB knowledge. EVM expertise in the Koore varied across gender, herd size, and level of VB expertise. EVM expertise was highest in the Maasai but was only associated with age. The only factor associated with VB expertise was EVM expertise in the Koore.

CONCLUSIONS

Variation in consensus and the correlates of expertise across the Maassi and the Koore are likely related to differences in the cultural transmission of EVM and VB knowledge. Transmission dynamics are established by the integration of livestock within the socioecological systems of the Maasai and Koore and culture historical experiences with livestock disease. Consideration of the nature and coexistence of EVM and VB provides insight into the capacity of groups to cope with disease outbreaks, pharmaceutical use patterns, and the development of community health interventions.