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ARS Home » Southeast Area » Auburn, Alabama » Aquatic Animal Health Research » Research » Publications at this Location » Publication #374657
Research Project: Integrated Research to Improve Aquatic Animal Health in Warmwater Aquaculture

Location: Aquatic Animal Health Research

Title: Three cases of acute bacterial sepsis in pygmy hippopotamus (Choeropsis Liberiensis) calves siblings

Author
item DEMAAR, THOMAS - Gladys Porter Zoo
item Lafrentz, Benjamin
item GARNER, MICHAEL - Northwest Zoopath

Submitted to: Journal of Zoo and Wildlife Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2020
Publication Date: 6/11/2021
Citation: Demaar, T.W., Lafrentz, B.R., Garner, M.G. 2021. Three cases of acute bacterial sepsis in pygmy hippopotamus (Choeropsis Liberiensis) calves siblings. Journal of Zoo and Wildlife Medicine. 52(2): 755-762. https://doi.org/10.1638/2020-0097.
DOI: https://doi.org/10.1638/2020-0097

Interpretive Summary: Streptococcus iniae is primarily considered a pathogen of fish, but there are some reports of this Gram-negative bacterium causing infections in humans and a few other animals. In this study, we report on three cases of disease in pygmy hippopotamus calves that resulted in unexpected deaths. Two of the cases were attributed to S. iniae infection, while the third was attributed to another pathogen, Escherichia coli. The S. iniae recovered from the pygmy hippos were genetically characterized and found to be quite divergent from fish and human strains of the bacterium. The results of these cases combined with a previous association of S. iniae in pygmy hippo deaths, suggest this bacterium is an especially important pathogen of the endangered pygmy hippopotamus.

Technical Abstract: A multiparous pygmy hippopotamus (Choeropsis liberiensis) dam produced three consecutive calves that died acutely at 13 to 15 weeks of age from bacterial sepsis, for which diagnostic and therapeutic intervention was not possible. Streptococcus iniae (Cases 1 and 3), Escherichia coli (Case 2), and an unidentified member of the family Pasteurellaceae (Case 1) were identified in post-mortem tissues through bacterial culture followed by standard and molecular identification methods. After the loss of two calves, a series of vaccinations were administered to the dam during the third pregnancy to enhance transplacental and colostral transfer of antibodies to the calf. The third calf did not survive, and the source of the bacterial infection in these three calves was undetermined. Prior to and after the birth of the fourth calf, nutritional and nutraceutical supplements were provided to the dam and calf. Additionally, pest control around the barn was enhanced. The fourth calf survived. Pygmy hippopotamus calves at the age of 13 to 15 weeks may have increased susceptibility to bacterial infection, possibly due to waning maternal-derived immunity. The findings in these cases, combined with a previous association of S. iniae in pygmy hippopotamus deaths, suggest that this bacterium is an especially important pathogen of the endangered pygmy hippopotamus.