House Flies (Musca domestica) Pose a Risk of Carriage and Transmission of Bacterial Pathogens Associated with Bovine Respiratory Disease (BRD).

ABSTRACT

House flies are important nuisance pests in a variety of confined livestock operations. More importantly, house flies are known mechanical vectors of numerous animal and human pathogens. Bovine respiratory disease (BRD) is an economically important, complex illness of cattle associated with several bacteria and viruses. The role of flies in the ecology and transmission of bacterial pathogens associated with BRD is not understood. Using culture-dependent and culture-independent methods, we examined the prevalence of the BRD bacterial complex Mannheimia haemolytica, Pasteurella multocida and Histophilus somni in house flies collected in a commercial feedlot from a pen with cattle exhibiting apparent BRD symptoms. Using both methods, M. haemolytica was detected in 11.7% of house flies, followed by P. multocida (5.0%) and H. somni (3.3%). The presence of BRD bacterial pathogens in house flies suggests that this insect plays a role in the ecology of BRD pathogens and could pose a risk as a potential reservoir and/or a vector of BRD pathogens among individual cattle and in their environment.