Thorax injury lowers resistance to infection in Drosophila melanogaster

The route of infection can profoundly affect both the progression and outcome of disease. We investigated differences in Drosophila melanogaster defense against infection after bacterial inoculation into two sites--the abdomen and the thorax. Thorax inoculation results in increased bacterial proliferation and causes high mortality within the first few days of infection. In contrast, abdomen inoculation results in minimal mortality and lower bacterial loads than thorax inoculation. Inoculation into either site causes systemic infection. Differences in mortality and bacterial load are due to injury of the thorax and can be recapitulated by abdominal inoculation coupled with aseptic wounding of the thorax. This altered resistance appears to be independent of classical immune pathways and opens new avenues of research on the role of injury during defense against infection.