Rapid application of long-acting ceftiofur can prevent death losses associated with Streptococcus equi subspecies zooepidemicus in pigs

Authors: Hau, Samantha; Buckley, Alexandra; Brockmeier, Susan

Submitted to: Swine Health and Production
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2022
Publication Date: 9/1/2022
Citation: Hau, S.J., Devries, A.C., Brockmeier, S. 2022. Rapid application of long-acting ceftiofur can prevent death losses associated with Streptococcus equi subspecies zooepidemicus in pigs. Swine Health and Production. 30(5):292-297. https://doi.org/10.54846/jshap/1298.
DOI: https://doi.org/10.54846/jshap/1298

Interpretive Summary: Streptococcus equi subspecies zooepidemicus (SEZ) is a bacterium that causes severe disease in pigs. In a naïve herd, it rapidly causes death of 30-50% of animals. This results in large herd losses that are financially devastating to producers. No studies have evaluated treatments for SEZ infection in pigs. Our goal was to develop a treatment strategy to reduce SEZ losses. We tested treating sick animals with long-acting ceftiofur. We compared signs of disease and survival between treated and untreated animals. Most animals (>90%) improved after ceftiofur treatment, while most non-treated animals did not. The duration of effect was not long enough, and 2-3 treatments were needed to fully control disease. Antibiotic treatment gave animals enough time to develop an immune response to SEZ and control the infection. This work provides producers with an effective treatment strategy to control disease and prevent high death losses with SEZ.

Technical Abstract: Objective: Introduction of Streptococcus equi subspecies zooepidemicus (SEZ) strains into naïve populations results in field mortality rates of 30-50% over 5-10 days. Because of the rapid progression of disease, our goal was to determine whether antibiotic intervention can control SEZ disease in a group of animals following development of clinical signs. Materials and methods: Thirty-two pigs were challenged with SEZ. Following the development of clinical signs 16 were treated with long acting, injectable ceftiofur. Seven unchallenged pigs served as controls. Clinical signs were monitored following challenge and survival was compared between groups. Antibody titers were measured on day 0 and day 30 post-challenge. On day 30 post-challenge, 3 contact pigs were commingled with 2 treated animals to evaluate SEZ transmission. Results: Ceftiofur treatment eliminated clinical signs in 15/16 animals; however, multiple treatments were required to control disease in treated animals (2-3 doses providing 12-18 days of coverage). Antibody titers to SEZ increased in challenged animals treated with ceftiofur, indicating sufficient exposure for immune stimulation. No contact pigs developed clinical signs of SEZ following exposure. Implication: Rapid application of injectable antibiotics is a viable method to reduce losses due to the introduction of SEZ into a naïve group of pigs and may help prevent transmission to contact animals following recovery.