Salmonellosis in elephants in managed care: report of 2 cases and literature review

Abstract

In animals, salmonellosis is seen typically as enteritis and/or septicemia. Subclinical infection also occurs, and outwardly healthy animals can serve as reservoirs of infection. Reports of salmonellosis in elephants are rare, limited to a few serovars, and the gross and microscopic lesions of enteric salmonellosis in this species have not been described in detail. We present here, in 2 elephants in managed care settings, cases of salmonellosis that resulted from infection by Salmonella enterica serovar Muenchen and S. enterica serovar Montevideo, serovars that have not been described previously as the cause of salmonellosis in elephants, to our knowledge. We also review the literature on salmonellosis in elephants. Animal A, an adult Asian elephant that was euthanized because of gastrointestinal hemorrhage, had multifocal, necrotizing, suppurative enterocolitis, and necrotizing gastritis. Animal B, an adult African elephant with chronic, recurrent colic, followed by death, had necrotizing typhlocolitis. The origin of infection was not determined in either case. The animals came from different facilities and did not have a common feed source. Previously reported cases of salmonellosis in elephants were caused by Salmonella Dublin, Salmonella Typhimurium, or Salmonella Enteritidis. The definitive diagnosis of salmonellosis is made based on compatible gross and microscopic lesions, coupled with the detection of Salmonella spp. in the affected tissues. Effective biosecurity should be adopted to minimize the risk of salmonellosis in elephants in managed care.

Keywords: Salmonella enterica serovar Montevideo; Salmonella enterica serovar Muenchen; elephants; salmonellosis.

Figures 1–3.

Intestine of 2 elephants with salmonellosis. Figure 1. The mucosa of the small intestine of the Asian elephant (animal A) is covered by a yellow, velvety pseudomembrane. Figure 2. Marked submucosal edema and severe congestion of the cecal mucosa of an African elephant (animal B). Figure 3. The colonic mucosa is necrotic and inflamed in an Asian elephant (animal A). Inset: large numbers of viable and degenerate neutrophils in the affected mucosa. H&E.