Umeå University's logo

The knowledge of viral shedding patterns and viraemia in the reservoir host species is a key factorin assessing the human risk of zoonotic viruses. The shedding of hantaviruses (familyBunyaviridae) by their host rodents has widely been studied experimentally, but rarely in naturalsettings. Here we present the dynamics of Puumala hantavirus (PUUV) shedding and viraemia innaturally infected wild bank voles (Myodes glareolus). In a monthly capture–mark–recapturestudy, we analysed 18 bank voles for the presence and relative quantity of PUUV RNA in theexcreta and blood from 2 months before up to 8 months after seroconversion. The proportion ofanimals shedding PUUV RNA in saliva, urine and faeces peaked during the first month afterseroconversion, but continued throughout the study period with only a slight decline. The quantityof shed PUUV in reverse transcription quantitative PCR (RT-qPCR) positive excreta was constantover time. In blood, PUUV RNA was present for up to 7 months but both the probability of viraemiaand the virus load declined with time. Our findings contradict the current view of a decline in virusshedding after the acute phase and a short viraemic period in hantavirus infection – anassumption widely adopted in current epidemiological models. We suggest the life-long sheddingas a means of hantaviruses to survive over host population bottlenecks, and to disperse infragmented habitats where local host and/or virus populations face temporary extinctions. Ourresults indicate that the kinetics of pathogens in wild hosts may differ considerably from thoseobserved in laboratory settings.