Stable fly host blood meal analysis using a multiplex polymerase chain reaction

Stable fly, Stomoxys calcitrans (L.), attacks on cattle cause decreased weight gains and milk production due to reduced feed efficiency. Stable flies also have pronounced impacts on horses and dogs, as well as humans, causing severe annoyance and irritation. Attempts by livestock producers to reduce pest populations often solely focus on the use of animal-applied insecticides. Unfortunately, this response can result in localized resistance development, increased economic losses to producers, and an over reliance on insecticides. The determination of fly breeding sources is vital if management strategies are to succeed, as has previously been shown with house flies. Blood meal analysis can be used to indirectly pinpoint sources of stable fly breeding by identifying host species that adult flies have fed upon. This is particularly true of areas where production systems of various mammal species exist. Newer molecular techniques, such as polymerase chain reaction (PCR), provide a means of discovering fly breeding sources. Because stable flies blood-feed multiple times per day and rarely to repletion, there is an increased likelihood that more than one host is attacked. This behavior was exploited using a multiplex PCR targeting the cytochrome b gene to determine the hosts recently fed on by a single stable fly. Primers specific to the horse, cow, dog, and human were designed for use in a multiplex PCR, as these hosts are commonly encountered at livestock facilities.