Scientists at Texas A&M College of Veterinary Medicine & Biomedical Science, working with researchers from the Swedish National Veterinary Institute and the Swedish University of Agricultural Sciences, have examined the intermittent pattern in which pigs shed Salmonella bacteria in their feces. They discovered that Salmonella may lie dormant in the host at an undetectable level as a survival strategy that prolongs the host’s infection. Furthermore, different Salmonella serotypes are shed and go dormant in different frequencies, making detection difficult at best.
This “off and on” pattern of pathogen excretion can lead to a host being misdiagnosed as clear of bacteria when it is still infected. In the “on stage”, the host sheds the bacteria in fecal material, while in the “off stage”, the pathogen is still present in the host, but not shed. Therefore, the leading method of detecting infection – fecal shedding – becomes difficult.
This study, funded by the National Science Foundation, will become a model for future studies aimed at furthering the detection capabilities and effective control for Salmonella and similar infectious agents in their animal and human host populations. Future research will investigate if the same association between this cyclic behavior and length of infection holds true in other host-pathogen models.