Apex Centre for Animal Disease Investigation, Monitoring and Surveillance, College of Veterinary and Animal Science, Rajasthan University of Veterinary and Animal Sciences, Bikaner-334 001
Online published on 19 December, 2013.
An investigation was made to diagnose a disease causing regular mortality for last one year in weanling sheep and goats at an organized farm during April 2013. During the investigation, history was collected regarding herd composition, management, type of feed, feeding and watering schedule, time of onset, pattern and duration of disease, age of the affected animals, treatment done etc. At the farm the overall management of animal population was good and the weaning was being practiced at three months of age. The animals were vaccinated against ET, sheeppox and PPR and being dewormed regularly as per standard schedules. From sick animals whole blood was collected for culture and haematological examination, smears were prepared for bacterioscopy, sera for estimation of cortisol levels and nasal swabs were collected for microbiology. Two sick animals were sacrificed and impression smears from various organs were made for bacteriological examination and swabs were collected for microbiological investigations in laboratory. Various tissue samples (Lung, liver, heart, kidney, spleen, trachea, lymph nodes) were collected for histopathological examination.The clinical signs exhibited by affected animals included dullness, depression, anorexia, high rise of body temperature (up to 106°C or more), nasal discharge, dry muzzle, respiratory distress, soft faeces in some animals etc. The death of the affected animals was reported to be over variable period of time but within one week. During past one year many hundred animals died. On post-mortem examination it was recorded that in both the carcasses the trachea were congested with accumulation of froth, there was tonsillitis, the lungs were severely congested, edematous and showed red hepatization and consolidation at places. The mesenteric lymph nodes were severely congested and edematous. The small intestines were haemorrhagic in one carcass. Bacterioscopy of blood smears revealed presence of pleomorphic rods similar to pasteurella organisms in most of the smears. The impression smears prepared from heart, lung and liver from sacrificed animals also showed presence of these organisms. The organisms isolated and identified in nasal swabs from sick live animals and swabs from heart, trachea and lung from sacrificed animals as P. haemolytica. Histopathological examination of lungs was suggestive of pneumonia. The serum cortisol levels as determined by Radioimmunoassay were highly increased raging between 120.00 -130.00 nmol/L suggesting stress to the animals.On the basis of epidemiological observations, clinical examination, postmortem findings and laboratory analysis of various samples the disease was diagnosed as Pasteurella haemolytica infection. Further, appropriate measures and line of treatment was adopted and mortality was immediately controlled.
