Given the lack of an epidemiological linkage and no apparent genetic relatedness of these two samples, epidemiologists considered these cases to likely not be part of an outbreak. While the true source of infection for these cases could not be determined, interviews helped elucidate possible exposure routes of infection, including contact with undercooked meat or environmental exposure to surfaces contaminated by raw meat. Given its rarity, E. rhusiopathiae cases should be studied when they occur to establish greater epidemiological and molecular evidence to support future outbreak investigations of the pathogen.
Schenk et al. (Tue,) studied this question.