Abstract:
Pneumonic pasteurellosis is one of the economically important infectious diseases affecting
sheep and goats in Ethiopia. A cross-sectional study was conducted from January 2019 to
May 2019 to investigate the major bacterial pathogens associated with small ruminant’s
pneumonic pasteurellosis in Adea, Liben-chukala and Gimbichu districts of central Ethiopia.
A total of 173 animals were randomly examined for clinical signs of pneumonic pasteurellosis.
In addition, 185 individuals in the districts were interviewed through a structured
questionnaire to assess the possible risk factors for pneumonic pasteurellosis. Nasal swab
samples were collected from 73 (42.2%) animals with evidence of pneumonic pasteurellosis
and subjected for bacterial culture. The isolates were then processed for phenotypic and
genotypic characterization using microbiological, biochemical and PCR assay. Additionally,
disc diffusion method was used to evaluate the isolates for their resistance against selected
antimicrobials. A total of 18 (24.7%) clinically affected animals were positive for pathogens of
pneumonic pasteurellosis, with 15(20.54%) M. haemolytica and 3(4.1%) P. multocida. The
occurrence of bacterial pathogens was higher in sheep (28.9%) than goats (18.5%). The result
showed that 15 of the M. haemolytica isolates were positive for the PHSSA gene. But, only one
M. haemolytica isolates was positive for both PHSSA and Rpt2 genes at about 325bp and
1022bp, respectively. The PCR product showed that three of the P. multocida isolates have
KMT gene with 460bp amplicon size. All (100%) of the tested isolates were resistant to
ampicillin whereas they were susceptible to tetracycline, chloramphenicol, and gentamicin.
Management system, season and grazing system were the major predisposing factors for the
occurrence of the disease in the study districts. Generally, the study revealed that M.
haemolytica is the major causative agent of pneumonic pasteurellosis in the study district. So,
an integrated application of vaccination and overall management measures should be
implemented to prevent and control the disease in study areas.
