Flies (Diptera: Muscidae) that breed in faeces and other organic refuse (filth flies) have been implicated as vectors of pathogenic bacteria including Escherichia coli O157:H7, which cause haemorrhagic colitis in humans, and Campylobacter, which is the principal causative agent of human enteritis. The potential role of filth flies in the epidemiology of these pathogens in the United States was investigated by examining the prevalence of Campylobacter spp. and E. coli O157:H7 from two Arkansas turkey facilities. Polymerase chain reaction was conducted on DNA extractions of individual Musca domestica Linnaeus, Stomoxys calcitrans (Linnaeus), Hydrotaea aenescens (Wiedemann), Adia cinerella Fallen and turkey faecal samples using primers specific for E. coli H7, O157 and Campylobacter spp. Culturing verified that the flies were carrying viable Campylobacter spp. and E. coli O157:H7. Results from this study indicated that M. domestica, S. calcitrans, H. aenescens and Anthomyids are capable of carrying Campylobacter in North American poultry facilities and that the E. coli O157:H7 is carried by house flies and black dump flies associated with poultry. This PCR method provided a rapid and effective method to identify Campylobacter spp. and E. coli O157:H7 directly from individual filth flies.

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The reservoir competence of the lesser mealworm, Alphitobius diaperinus (Panzer) is reported for Salmonella typhimurium (Loeffler) relative to broiler chicken production. Salmonella typhimurium was isolated from feces of the adult lesser mealworm at least 28 d after feeding for 24 h on 1 g of chicken feed inoculated with 3 x 10(8) bacteria/ml. All larvae fed S. typhimurium ceased voiding the bacteria in their feces before pupal molt, except one. One beetle continued to void S. typhimurium after it emerged as an adult, providing evidence that transstadial transmission of S. typhimurium may occur. The bacteria were found both on the external body surface and inside the body of surface-sterilized adults and larvae during 16 d of exposure. Salmonella-positive cloacal swabs were obtained from 1-day-old broiler chicks within 24 h after eating one infected lesser mealworm adult or larva.

Larval and adult lesser mealworms, Alphitobius diaperinus (Panzer), were found to harbor a Congo red-binding strain of Escherichia coli (Migula) Castellani & Chalmers both on the external surface of their body and internally for 12 d. Thereafter, E. coli was not detected, even though the beetles were exposed continuously to a food source inoculated with the bacteria. Lesser mealworm larvae and adults discharge E. coli bacteria in their feces for up to 6 and 10 d, respectively. However, bacteria were no longer detected in their feces after larvae underwent a single molt to the next larval stage. This indicated there was no transstadial transmission of this strain of E. coli. Consumed infected larvae were found to cause more 1-d-old chicks to have positive cloacal swabs for Congo red-binding E. coli than consumed infected adults. The data indicated that the lesser mealworm may play a role in the direct transmission of E. coli and contribute to the spread of this bacteria in broiler production systems. This may be achieved by beetles being directly consumed by chickens or indirectly by spread of the bacteria throughout the broiler house by lesser mealworm feces.

Infectious bursal disease virus (IBDV) was isolated from adult lesser mealworms, Alphitobius diaperinus (Panzer), up to 14 d after exposure, but isolation of the virus was erratic over this period of time. The virus was undetected after 24 h in beetle larvae. Virus was isolated from the adult beetle's mouth parts, foregut, midgut, hindgut, and blood 24 h after they fed on feed inoculated with IBDV. Ten days after exposure, virus was isolated from the foregut but not the blood, mouth parts, or remaining digestive tract of the adult beetles. The adult lesser mealworm is capable of serving as a reservoir for IBDV, rather than a fomite, between broiler growouts.