Mirror of Research in Veterinary Sciences and Animals (Nov 2018)
Histopathological, Bacteriological and Molecular study of enzootic respiratory complex of Small Ruminants Slaughtered at Al Muthanna abattoir
Abstract
Small ruminants play an important role in the nutrition and income of people around the world. They serve as source of meat, milk, skin and wool. Small ruminants contribute significantly to the economy of farmers in the Iraq. The mass production of small ruminant in the country is constrained by disease, inadequate nutrition, poor genetic resources of the local stock, marketing, social factors, structural constraints. Diseases of respiratory system contributes to high morbidity and mortality rate in the sheep and goat in Iraq.This study intends to study histopathological, bacteriological and molecular study of enzootic respiratory complex of small ruminant that slaughtered in Al Muthanna province. This study was conducted in Samawah city / Al Muthanna Government during a period started from October 2017 to March 2018. A study was done as a cross sectional survey on the slaughtered sheep and goats in Al Muthanna abattoir. Before slaughtering all animals were examined for any signs of respiratory diseases. One hundred four nasal swabs were collected from nasopharyngeal area of sheep and goats that showed nasal discharge. The nasal swab from each diseases sheep and goat was analyzed using standard methods. Tissue samples were collected from animals and processed routinely for histopathological investigation. Molecular Identification was done for isolated Mannheimia haemolytica. The results of this study showed that the total number of diseased animals was 104 out of 270, in addition to the five dead animals. The percentages of the respiratory diseases were 38.51 % including 29/ 62 ( 46.77 %) and 33/62 ( 53. 22%) for male and female respectively in sheep and totally 62/107 ( 57. 94%). While, the percentages of respiratory diseases in goat were 23/42 ( 54.76%) and 19 /42 (45.23%), and totally 42/ 163 (25.76%).The aerobic isolated bacteria associated with respiratory in small ruminants were Mannheimia haemolytica, Escherichia coli, Pasteurella multocida, Klebsiella pneumoniae and Staphylococcus aureus and Streptococcus pyogenes. The gross lesions observed were majorly, suppurative pneumonia, exudative pneumonia, congestion, and various stages of pneumonia. Histologically, the following types of pneumonia was seen : suppurative bronchopneumonia necrotic bronchopneumonia, fibrinous bronchopneumonia, bronchointerstitial pneumonia, and pyogranulomatous pneumonia. The lungs diagnosed with bronchopneumonia were characterised by neutrophilic exudates were present in the alveolar spaces and lumens of the bronchioles and bronchi, and in some occasions a mixture of various amounts of cell debris, neutrophils and macrophages were observed in these areas and there are also distended interlobular space, infiltrated with inflammatory cells, distended alveoli and collapsed alveoli, while the lungs with interstitial pneumonia were characterised by interalveolar space infiltrated with predominantly polymorphonuclear cells namely lymphocytes, macrophages and a few neutrophils. Identification M. haemolytica was confirmed for all strains of by PCR analysis. The test was performed, all isolates were tested to present 16 s rDNA and 12 s rRNA genes. Hereafter, all strains were positive for all isolated bacteria and 12 s primers, they showed a specific 304 bp and 270 band respectively on agarose gel, no amplification was observed in control negative. In conclusion, this study approved the incidence of respiratory diseases in small ruminant in Al Muthanna abattoir. The study also approved the isolation of different microorgaisms that might be the cause of respiratory diseases in this study, moreover, M. haemolytica showed a positive results with PCR. The author, recommoned to consider PCR as a valuable tool for rapid detection of M. haemolytica in clinical samples from sheep and goats. In addition, it offers the opportunity to perform large scale epidemiological studies regarding the role of M. haemolytica in clinical cases of pneumonia and other disease manifestations in sheep and other ruminants, thereby providing the basis for effective preventive strategies.
