Evaluation of diagnostic performance of H-based blocking ELISA for specific detection of peste des petits ruminants in domestic sheep, goats, cattle and camels.

INTRODUCTION: Peste des petits ruminants virus (PPRV) causes a highly devastating disease of sheep and goats, peste des petits ruminants (PPR), which is targeted for global control and eradication by 2030. The serological diagnostic tool kits for accurate diagnosis of PPR have inherent strengths and weaknesses that require parallel validation and optimization across animal species. Thus, the objective of this study was to evaluate diagnostic performance of haemagglutinin based PPR blocking ELISA (HPPR- b-ELISA), that was developed by Africa Union Pan African Veterinary Vaccine Center for specific detection of anti- PPRV antibodies. METHODS: In preliminarily investigation, diagnostic performance of the HPPR-b-ELISA®, commercial PPR competition ELISA (c-ELISA) and virus neutralization test (VNT) were compared for the detection of anti-PPRV antibodies in goats, sheep, cattle and camels. RESULTS: The sensitivity and specificity of HPPR- b-ELISA® were 79.55 and 99.74%, respectively, compared to c-ELISA. The HPPR- b-ELISA® was in perfect agreement (κ = 0.86) with the c-ELISA in all sera collected from goats, sheep and cattle. There was almost perfect agreement between the species of goats (κ = 0.82) and sheep (κ = 0.98), while the agreement was substantial in cattle (κ = 0.78) and no agreement was observed in camels (κ = 0.00). Similarly, the sensitivity and specificity of the HPPR b-ELISA were 80 and 96.36%, respectively compared to VNT with almost perfect agreement in goats (κ = 0.83) and sheep (κ = 0.89), moderate in cattle (κ = 0.50) and none in camels (κ = 0.00). CONCLUSION: Our study revealed that HPPR- b-ELISA is a suitable and valid method that can alternatively be used for screening and monitoring of PPR in sheep, goats and cattle except for camels.

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.

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.

Bovine trypanosomosis and its fly vectors in three selected settlement areas of Hawa-Gelan district, western Ethiopia.

A cross-sectional study aimed at investigating the species diversity of fly vectors and estimating the prevalence of bovine trypanosomosis was carried out from October 2009 to May 2010 in selected settlement areas of the Hawa-Gelan district in the western Wollega zone of Ethiopia. Standard methods of sampling and identification were employed for both entomological and parasitological examination. Three species of the genus Glossina (Glossina pallidipes, Glossina morsitans submorsitans and Glossina fuscipes) and two genera of biting flies (Stomoxys and Tabanus) were caught and identified. The overall apparent density of Glossina species caught was 10.5 flies per trap per day, with a higher proportion of female flies (57.2%). Out of a total 389 cattle examined, 42 (10.8%; 95% CI: 7.89% - 14.3%) were found infected with trypanosomes. Three trypanosome species were detected in the study area, namely Trypanosoma congolense (54.8%), Trypanosoma brucei (23.8%) and Trypanosoma vivax (21.4%). The prevalence of trypanosomosis was found to be significantly (p < 0.05) higher in cattle with poor body condition. There was an association between mean packed cell volume (PCV) and the occurrence of parasitaemia (χ2 = 49.5, p < 0.05). About 95.2% of cattle that were positive for trypanosomes had a PCV less than the lower limit for cattle. Considering the current result, bovine trypanosomosis seems to be a serious constraint for agricultural activities in the settlement areas of the Hawa-Gelan district and seems to be associated with the presence of Glossina species. Therefore, application of control methods through community involvement to reduce the Glossina species infestation level is likely to increase animal productivity.