Detection of Zoonotic Bacteria and Paragonimus kellicotti in Red Swamp Crayfish (Procambarous clarkii) and The Assessment of Traditional Crayfish Boils

Studies on red swamp crayfish ( Procambarus clarkii ) outside of the United States confirm a variety of zoonotic pathogens, but in the $200 million dollar US commercial crayfish industry it is unknown if these same pathogens occur, demonstrating a need to evaluate this consumer commodity. The study objectives were to evaluate specific zoonotic pathogens present on red swamp crayfish ( P. clarkii ) from two United States southeastern states, Alabama and Louisiana, and to determine the effectiveness of traditional food preparation to reduce pathogens. Experiment A evaluated the presence of Escherichia coli, Salmonella, Staphylococcus aureus, and Vibrio spp . in crayfish and environmental samples over a two-month collection period (May-June 2021). Crayfish sampling consisted of swabbing the cephalothorax region and submitting 15 samples testing for E. coli, Salmonella, and S. aureus , and an additional 15 samples testing for vibrio spp. detection. Additionally crayfish shipping materials were sampled. In experiment B, 92 crayfish were evaluated for Paragonimus kellicotti . Experiment C compared the presence of Vibrio spp . between live and boiled crayfish. In experiment A & B, 100% (60/60) of crayfish samples and 81.25% (13/16) of environmental samples returned characteristic growth of  Vibrio spp.. A total of 5% (3/60) samples returned E. coli growth with no statistical difference ( p =0.5536) between farms. Paragonimus kellicotti, Salmonella, and S. aureus were not recovered from any samples. In experiment C, 100 % (10/10) of the live pre-boiled crayfish samples returned characteristic growth, while 10% (1/10) of samples of crayfish boiled in unseasoned water returned growth for Vibrio ( p <.0001). These results confirm that Vibrio spp . and E. coli may be present on US commercial crayfish and care should be taken when handling any materials that live crayfish come into contact with as they can potentially be contaminated.