Submitted to: Medical and Veterinary Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2008
Publication Date: 2/1/2009
Publication URL: http://handle.nal.usda.gov/10113/57316
Citation: Crippen, T.L., Sheffield, C.L., Esquivel, S.V., Droleskey, R.E., Esquivel, J.F. 2009. The acquisition and internal carriage of Salmonella by lesser mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae). Vector-Borne Zoonotic Diseases. 9:65-72. Interpretive Summary: There is a need in the poultry production industry to reduce the accidental spread of pathogens amongst the birds and facilities. A thorough understanding of the sources of pathogens within the facilities is necessary so that management practices can be created to reduce this spread. The lesser mealworm beetle is a common pest in poultry litter that is reported to carry pathogens affecting both human and animal health. Current farm management practices affect the numbers of beetles on the farm and so contribute to the distribution of pathogens. To study the dispersal of bacteria by this beetle, we investigated if bacterial pathogens were taken up internally by these insects and the time and exposure levels required. Beetles were exposed to a marker Salmonella bacterium, and then their external surface was washed clean. The head, gastrointestinal tract and hemolymph of the beetle were then cultured for the presence of the Salmonella. We found that the beetles rapidly took up Salmonella from environmental sources into their gastrointestinal tract within 30 min and hemolymph within 2 hr. The lesser mealworm is a serious pest within the poultry brooder and laying industry. Because of their mobility, ravenous feeding habits, and prey potential, these beetles can, in a relatively short amount of time, become an active source facilitating the spread of Salmonella.
Technical Abstract: In poultry broiler production facilities, it is important to understand the sources and contribution of reservoir populations of pathogens to devise realistic management practices to contain the inadvertent propagation and dissemination of these pathogens. The lesser mealworm beetle, Alphitobius diaperinus (Panzer), is a common pest in poultry litter that is reported to carry pathogens affecting both human and animal health. Current farm management practices perpetuate infestations and contribute to the dissemination of beetles and pathogens. To study the dispersal of bacteria by this beetle, this study investigates whether the carriage of a bacterial pathogen occurs by the harboring of bacteria internally by these insects. Beetles exposed to a marker bacterium, Salmonella serovar Typhimurium-green fluorescent protein (ST-GFP), at concentrations up to 108 cfu ml-1 for 30 min to 12 hrs were subsequently surface disinfected and dissected. The head, gastrointestinal tract and hemolymph were cultured for the presence of ST-GFP. We found that the beetles rapidly acquired bacteria from external sources and harbored the bacteria within their alimentary canal after exposure for 30 min at 104 cfu ml-1 and within the hemolymph after exposure for 2 hr at 106 cfu ml-1. The lesser mealworm is a serious pest within the poultry brooder and laying industry. Because of their mobility, voracious feeding habits, and prey potential, these beetles can, in a relatively short amount of time, become an active source facilitating the dissemination of Salmonella.