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ARS Home » Southeast Area » Auburn, Alabama » Aquatic Animal Health Research » Research » Publications at this Location » Publication #433888
Research Project: Reducing On-Farm Losses to Disease in Crustacean Aquaculture

Location: Aquatic Animal Health Research

Title: Is Co-Infection Of Vibrio cholerae And Aeromonas veronii Associated With Late-Term Mortality In Pacific White Shrimp (Litopenaeus Vannamei)?

Author
item Garcia, Julio
item Beck, Benjamin
item TEICHERT-CODDINGTON, D. - Greene Prairie Aquafarm
item DAVIS, D. - Auburn University
item BRUCE, T. - Auburn University
item KELLY, A. - Auburn University
item MARTIN, B. - Auburn University
item Bader, Troy
item ROY, LUKE - Auburn University

Submitted to: Annual Eastern Fish Health Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 3/9/2026
Publication Date: 3/23/2026
Citation: Garcia, J.C., Beck, B.H., Teichert-Coddington, D., Davis, D.A., Bruce, T., Kelly, A.M., Martin, B., Bader, T.J., Roy, L.S. 2026. Is Co-Infection Of Vibrio cholerae And Aeromonas veronii Associated With Late-Term Mortality In Pacific White Shrimp (Litopenaeus Vannamei)?. Annual Eastern Fish Health Workshop. ABSTRACT.

Interpretive Summary:

Technical Abstract: Pacific white shrimp (PWS), Litopenaeus vannamei, are the most popular farm-raised shrimp in the world, with international trade valued at 25.4 billion USD. In the U.S., most low-salinity shrimp production occurs in Alabama, Florida, and Texas. Since 2017, shrimp farmers have experienced production declines, with reported shrimp survival rates falling below 35%. Producers have observed mortalities in shrimp when they reach approximately 20g, between August and October. This phenomenon is known as “late term mortality”. In September 2025, we received 10 shrimp each from 4 different ponds at a shrimp farm in Alabama experiencing late-term mortality. Upon arrival, PWS were examined for clinical signs, and exhibited lesions associated with Vibriosis in shrimp. Additionally, during necropsy, it was observed that PWS exhibited a pale, watery hepatopancreas. Bacterial samples collected from the eye stalks, gills, hepatopancreas, intestines, and lesions of diseased PWS revealed the presence of Vibrio spp. in 100% of the PWS, with 43% of the PWS also testing positive for Aeromonas spp. The isolates were then characterized by biochemical, phenotypical, FAME, and 16S rRNA sequencing. The results of our characterization and identification of the isolates showed the presence of presumed Vibrio spp. and Aeromonas spp. isolates to be V. cholerae and A. veronii. To establish their pathogenicity, 12 isolates were selected for a bacterial challenge in PWS, comprised of 6 V. cholerae and 6 A. veronii isolates. Results from the challenge confirmed the pathogenicity of the isolates, with V. cholerae mortalities ranging from 30% to 90%, depending on the isolate. Additionally, mortality from A. veronii varied, with rates averaging a cumulative 46%, while one A. veronii isolate caused a 90% mortality rate. Several theories have emerged concerning the factors that may contribute to late term mortality. We hypothesize that this phenomenon may be linked to bacterial co-infections. Our findings suggest a potential association between co-infections of V. cholerae and A. veronii with late-term mortality in PWS. Future research will focus on developing challenge models utilizing different routes of delivery, conducting co-infection studies, and examining the interactions between shrimp size and bacterial infection. Results from this research will help scientists and producers develop disease management and prevention tools and improve management practices to reduce or prevent late-term mortality in shrimp.