Outbreak investigation of septicemic salmonellosis in calves

Abstract

Introduction: An early and accurate diagnosis of septicemic salmonellosis is critical for implementing timely and proper treatment, prevention, and control measures. Methodology: Here, we report a study on three outbreaks of septicemic salmonellosis in calves from Midwestern Brazil. Results: the morbidity, mortality and lethality rates were of 10.55%, 2.79%, and 26.4%, respectively. Higher susceptibility was detected in Bos taurus than in Bos indicus cattle. Clinical manifestations consisted of apathy, hyperthermia, difficulty breathing and panting, and pallor of the mucous membranes. Chronic cases had necrosis of the tail tip and ears. Gross findings included enlarged liver, non-collapsed edematous lungs and diphtheritic enteritis. Significant histopathological changes included paratyphoid nodules in the liver and acute interstitial pneumonia. Salmonella enterica subsp. enterica serotype Dublin was detected by culture and by PCR from the blood of live calves, and from the spleen, liver, bile, mesenteric lymph node and lung samples of necropsied calves. Conclusions: We suggest that in clinical cases of septicemic salmonellosis, blood samples are better than fecal samples for detection of the agent, being a sound test to identify animal carriers in the herd.