Isolation and Identification of Pasteurella multocida and Mannheimia haemolytica from Pneumonic Small Ruminants and Their Antibiotic Susceptibility in Haramaya District, Eastern Ethiopia.

Background: Pasteurella species are frequently encountered as serious diseases in small ruminants. It is the main cause of respiratory pasteurellosis in sheep and goats of all age groups. Methods: The cross-sectional study was conducted from December 2022 to April 2023 in Haramaya district, eastern Ethiopia, to isolate and identify Pasteurella multocida and Mannheimia haemolytica and estimate their prevalence, associated risk factors, and antimicrobial sensitivity of isolates in small ruminants using a purposive sampling method. A total of 384 samples (156 nasal swabs from clinic cases and 228 lung swabs from abattoir cases) were collected. STATA 14 software was used to analyze the data. In addition, multivariable logistic regression analysis was performed to assess an association of risk factors. Results: Out of the 384 samples examined, 164 were positive for pasteurellosis, resulting in a 42.70% prevalence. Similarly, 63 (38.4%) of the 164 positive results were from nasal swabs, while 101 (61.6%) came from lung samples. M. haemolytica accounted for 126 (76.82%) of the isolates, while P. multocida accounted for 38 (23.17%). Of the 63 nasal swab isolates, 33 (37%) were from goats and 30 (42.8%) were from sheep. And 17 (10.89%) and 46 (29.58%), respectively, were P. multocida and M. haemolytica. Of the 46 (40%) of the 101 (44.3%) isolates of the pneumonic lung, samples were from goats, while 55 (48.47%) were from sheep. In this study, the risk factors (species, age, and body condition score) were found to be significant (p < 0.05). Pasteurella isolates evaluated for antibiotic susceptibility were highly resistant to oxacillin (90.90%), followed by gentamycin (72.72%), and penicillin (63.63%). However, the isolates were highly sensitive to chloramphenicol (90.90%), followed by tetracycline (63.63%), and ampicillin (54.54%). Conclusion: This study showed that M. haemolytica and P. multocida are the common causes of mannheimiosis and pasteurellosis in small ruminants, respectively, and isolates were resistant to commonly used antibiotics in the study area. Thus, an integrated vaccination strategy, antimicrobial resistance monitoring, and avoidance of stress-inducing factors are recommended.

Prevalence, seasonal dynamics and associated variables of ixodid tick cattle infestation in Gondar, northwestern Ethiopia.

Ticks are ectoparasites that impact the health and productivity in farm animals. They are also important vectors for pathogens transmitted to animals and humans. A cross-sectional study was conducted from November 2018 to April 2019 with the objectives of determining the prevalence, identifying genera and seasonal dynamics of adult ixodid ticks infesting cattle in and around Gondar, northwestern Ethiopia. Pearson Chi-square Test was used to evaluate the association of tick prevalence with explanatory variables. One way analysis of variance was used to compare mean tick density of cattle with the explanatory variables. The overall prevalence of cattle ixodid tick infestation was found to be 65.8% (95% CI = 60.0-71.2%). The effect of breed, sex, age and body condition score on tick prevalence was investigated. However, only the body condition score of study animals was found to have statistically significant effect on the prevalence of tick infestation. Monthly analysis of tick infestation showed statistically significant variation (χ2 = 36.17, p = 0.00) during the study period (November 2018 - April 2019). The highest monthly prevalence was recorded in March (85.0%), and the least in February (42.0%). A comparison of the tick prevalence across seasons showed statistically significant differences (χ = 34.10, p = 0.00), being highest (82.5%) during the short rainy season. During the study period, a total of 3796 adult ixodid ticks were collected from different body regions of the study animals. Three ixodid tick genera were identified, with the genus Rhipicephalus being the most prevalent (n = 2122 (55.9%) of the total adult ticks (3796). The overall mean tick density per host for all genera was 12.78 ticks, with a marked difference in tick density during the three study seasons. The highest MTD was recorded during the short rainy season (MTD = 18.58), (F = 19.71, p < 0.05). The present study has shown that ticks are highly prevalent in the study area. Therefore, an appropriate tick control program should be designed and implemented.