Lung lesion score system in cattle: proposal for contagious bovine pleuropneumonia

Sero-prevalence of contagious bovine pleuropneumonia in dryland of Borana, southern Oromia, Ethiopia

Ethiopia is one of the largest African countries where livestock farming represent a relevant resource for the economy and the livelihood of the population. Contagious bovine pleuropneumonia (CBPP) is among the transboundaries animal disease that is hindering cattle farming in Ethiopia. Due to the limited resources of veterinary services, disease control and surveillance is discontinuous and occasional field investigations of target areas contribute to depict disease spreading in the country. The study was conducted to determine the seroprevalence, at herd and animal level, and identify the risk factors involved in CBPP diffusion and persistence in the Borana pastoral zone. A total of 498 serum samples were collected from 120 cattle herds and tested using competitive Enzyme-Linked Immunosorbent Assay (c-ELISA). Of 120 herds sampled, 37 (30.83%; (95% CI = 22.73-39.91%) were tested positive to CBPP antibody. Out of 498 sera samples tested 46 (9.24%; 95% CI = 6.84-12.13%) were positive. The highest prevalence was observed in Teltele (12/95; 12.90%; 95% CI = 6.7-21%) followed by Yabello (12/104; 11.54%; 95% CI = 6.1-19.3%) and Arero (10/91; 10.99%; 95% CI = 95% CI = 5.4-19.3%), whereas the lowest prevalence was observed in Gomole (5/101; 6.42%; 95% CI = 1.6-11.2%) and Dubluk (7/109; 4.95%; 95% CI = 2.6-12.8%) districts and statistically not significant (p > 0.05). Results of multivariate logistic regression analysis revealed that, age, herd movement and herd size of the animals had statistically significant effect on sero-positivity to CBPP (p < 0.05). Sex, season and body condition were not significantly (p > 0.05) associated with the occurrence of CBPP. The study confirms that CBPP is persistent in the territory and remain as a major problem that affects health and productivity of cattle. Therefore, awareness creation to the pastoralists in the study area about the effect of CBPP and designing appropriate control methods has a paramount importance to improve the health and productivity of cattle production in the area.

Bovine schistosomiasis in some selected areas of South Wollo and Oromia Zones of Amhara Region, North-East Ethiopia

A cross-sectional coprological and pathological study was conducted in five districts of South Wollo and Oromia Administrative Zones, Amhara regional state, Ethiopia from November 2020 to June 2021 to determine the prevalence and associated risk factors of Bovine Schistosomiasis and to characterize pathological lesions induced by the adult worm of Schistosoma bovis. For coprological examination, a total of 768 fecal samples were collected both from the field (384) and the abattoirs (384). An abattoir survey was carried out on 384 cattle to evaluate the performance of the sedimentation method. The risk factors were identified using multivariable mixed-effect logistic regression analyses. The diagnostic efficacy of the sedimentation technique was determined by calculating sensitivity and specificity considering postmortem examination as a reference test. The overall prevalence of bovine shistosomiasis using coprological examination was found to be 16.7% (95% CI = 14.10–19.49). The prevalence of shistosomiasis based on post-mortem examination was found to be 17.19% (95% CI = 13.55–21.34). Local cattle breed (OR = 2.44, 95%CI = 1.34–4.43), poor body condition (OR = 4.09, 95% CI = 2.45–6.83) and adult (OR = 1.78, 95% CI = 1.21–3.28) cattle are more likely to acquire shistosomiasis than crossbreed, good body condition, and young cattle. The sensitivity and specificity of sedimentation techniques, keeping postmortem examination as a reference test were 74.24% (95%CI = 61.99–84.22) and 98.11% (95%CI = 95.94–99.30), respectively. The major gross lesions were observed in the liver and intestinal tracts. In conclusion, adult local cattle with medium and poor body conditions should be prioritized for deworming and future surveillance.

Contagious Bovine Pleuropneumonia: A Comprehensive Overview

Contagious bovine pleuropneumonia (CBPP) is a respiratory disease of cattle that is listed as notifiable by the World Organization for Animal Health. It is endemic in sub-Saharan Africa and causes important productivity losses due to the high mortality and morbidity rates. CBPP is caused by Mycoplasma mycoides subsp. mycoides (Mmm) and is characterized by severe fibrinous bronchopneumonia and pleural effusion during the acute to subacute stages and by pulmonary sequestra in chronic cases. Additional lesions can be detected in the kidneys and in the carpal and tarsal joints of calves. Mmm infection occurs through the inhalation of infected aerosol droplets. After the colonization of bronchioles and alveoli, Mmm invades blood and lymphatic vessels and causes vasculitis. Moreover, Mmm can be occasionally demonstrated in blood and in a variety of other tissues. In the lung, Mmm antigen is commonly detected on bronchiolar and alveolar epithelial cells, in lung phagocytic cells, within the wall of blood and lymphatic vessels, inside necrotic areas, and within tertiary lymphoid follicles. Mmm antigen can also be present in the cytoplasm of macrophages within lymph node sinuses, in the germinal center of lymphoid follicles, in glomerular endothelial cells, and in renal tubules. A complete pathological examination is of great value for a rapid presumptive diagnosis, but laboratory investigations are mandatory for definitive diagnosis. The purpose of this review is to describe the main features of CBPP including the causative agent, history, geographic distribution, epidemiology, clinical course, diagnosis, and control. A special focus is placed on gross and microscopic lesions in order to familiarize veterinarians with the pathology and pathogenesis of CBPP.

Prevalence of Pneumonia in Sheep and Goats Slaughtered at Elfora Bishoftu Export Abattoir, Ethiopia: A Pathological Investigation

Accurate clinical diagnosis of pneumonia, the leading cause of mortality in small ruminants, is difficult and usually requires postmortem examination of the lungs. An active abattoir survey was conducted between November 2017 and April 2018 to estimate the prevalence and characterize the gross and histopathological lesions of pneumonic lungs in 864 clinically healthy young small ruminants (490 sheep and 374 goats aged 1.5 to 3 years) raised for meat in different parts of the country and slaughtered at Elfora Bishoftu export abattoir, Ethiopia. Out of the total lungs examined grossly, pneumonic lesions were found in 158 (18.29%) lungs. On histopathological examination of the lungs with gross pneumonic lesion, however, typical pneumonic lesions were diagnosed in 148 (17.13%) lungs only. No significant (p>0.05) difference was noted in the prevalence of pneumonia between sheep (17.14%) and goats (17.11%) in histopathological examination. Based on the predominant histopathological findings, the pneumonic lesions were characterized as interstitial pneumonia (41.9%), acute suppurative bronchopneumonia (25.7%), acute fibrinous bronchopneumonia (24.3%), chronic bronchopneumonia (6.1%), aspiration pneumonia (4.7%), bronchointerstitial pneumonia (3.4%), and ovine pulmonary adenomatosis (3.4%). The study further showed the spread of ovine pulmonary adenomatosis and ovine progressive pneumonia (Maedi) from the central highlands to areas that were previously free from these diseases. Due to its better diagnostic capacity, histopathology should be employed routinely as an ancillary test in the major abattoirs and regional veterinary laboratories to generate additional epidemiological data for a better disease control and prevention measures. Further studies are also recommended to identify the etiological agents of pneumonia in sheep and goats and thereby to formulate feasible and cost-effective interventions.