A new study suggests that darkling beetles and their larvae can transmit harmful food-borne pathogens to chicks in broiler houses in successive rearing cycles.
The researchers are from Wageningen University, Wageningen, The Netherlands and Research Centre, Lelystad, The Netherlands.
Salmonella and Campylobacter are two main sources of human food-borne disease and many of the reported cases can be directly linked to the handling or consumption of contaminated chicken meat. Although exact contamination routes of broiler flocks are not fully understood, certain insects that are persistent in these environments are common reservoirs of zoonotic bacteria such as Salmonella and Campylobacter.
The darkling beetle (Alphitobius diaperinus) and its larvae are known to inhabit broiler houses and are believed to survive between rearing cycles by eating their way into insulation materials and hiding under floors. In the study researchers artificially contaminated several groups of beetles and their larvae with a mixture of Salmonella enterica Serovar Paratyphi B Variant Java and three Campylobacter jejuni strains and fed them to housed chicks either the day of inoculation or one week following to mimic an empty week between rearing cycles.
All the broiler chicks that were fed insects contaminated on the same day showed Campylobacter and Salmonella colonization levels of 50 to 100%. Insects that were fed a week after infection resulted in transfer of both pathogens as well, but at lower levels. Naturally infected insects collected at a commercial broiler farm and fed to chicks also resulted in colonization but at lower levels.
"In conclusion, the fact that Salmonella and Campylobacter can be transmitted via beetles and their larvae to flocks in successive rearing cycles indicates that there should be intensive control programs for exclusion of these insects from broiler homes," say the researchers.
- W.C. Hazeleger, N.M. Bolder, R.R. Beumer, W.F. Jacobs-Reitsma. Darkling beetles (Alphitobius diapernus) and their larvae as potential vectors for the transfer of Campylobacter jejuni and Salmonella enterica Serovar Paratyphi B Variant Java between successive broiler flocks. Applied and Environmental Microbiology, 74. 22: 6887-6891
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