Temporal Variation in Individual Factors Associated with Hantavirus Infection in Bank Voles During an Epizootic: Implications for Puumala Virus Transmission Dynamics

Abstract

Puumala virus (PUUV), the causal agent of nephropathia epidemica in humans, is one of the many hantaviruses included in the list of emerging pathogens. Hantavirus infection is not distributed evenly among PUUV reservoir hosts (i.e., bank voles [Myodes glareolus]). Besides environmental factors and local population features, individual characteristics play an important role in vole PUUV infection risk. Identifying the relative importance of these individual characteristics can provide crucial information on PUUV transmission processes. In the present study, bank voles were monitored during the nephropathia epidemica outbreak of 2005 in Belgium. Vole sera were tested for presence of immunoglobulin G against PUUV, and a logistic mixed model was built to investigate the temporal variation in individual characteristics and their relative importance to PUUV infection risk in bank voles. Relative risk calculations for individual vole characteristics related to PUUV infection in the reservoir host show that reproductive activity dominates infection risk. The gender effect is only found in reproductively active voles, where reproductively active males have the highest infection risk. Results also revealed a clear seasonal variation in the importance of reproductive activity linked to PUUV infection. In contrast to the main effect found in other trapping sessions, no difference in infection risk ratio was found between reproductively active and nonactive voles in the spring period. Combined with increased infection risk for the reproductively nonactive group at that time, these results indicate a shift in the transmission process due to changes in bank vole behavior, physiology, or climate conditions. Hence, our results suggest that mathematical models should take into account seasonal shifts in transmission mechanisms. When these results are combined with the seasonal changes in population structure during the epizootic period, we identify vole reproductive activity and length of the breeding season as potential drivers of PUUV epizootics in west-central European regions.

Environmental Change and Disease Dynamics: Effects of Intensive Forest Management on Puumala Hantavirus Infection in Boreal Bank Vole Populations

“…This result is consistent with other studies where hantavirus prevalence was negatively correlated with diversity [53]–[55], presence [56], or proportion [19], [57] (but see [52]) of non-host small mammals. However, we observed that an increasing number of non-host small mammals reduced the likelihood of a bank vole being infected when host density was constant (Table 2, Figure 3C).…”

“…This result implies that transmission increases with bank vole density, either between infected and susceptible individuals or between susceptible individuals and an infectious environment. Several studies focusing on the PUUV hantavirus and bank voles have addressed the association between infection prevalence and host density [12], [19], [22], [37], [38], [51], [52], but positive relationships have only been found occasionally, and in most cases without time lags [12], [22], [52].…”

Dangerous liaisons: the predation risks of receiving social signals

“…Although we are not aware of any studies which have examined this hypothesis directly, higher infection rates have been seen in old, breeding males (e.g. Tersago et al 2011), a pattern that would be predicted in species with male territorial dominance and associated high rates of scent marking and investigation. Continued, deliberate exposure to infected social signals may therefore be another factor behind the male-biased parasitism seen in some species (e.g.…”

Lymphocytic choriomeningitis, Ljungan and orthopoxvirus seroconversions in patients hospitalized due to acute Puumala hantavirus infection

“…The main host of PUUV is the bank vole (Myodes glareolus), and the virus is predominantly transmitted horizontally to humans via exposure to contaminated vole excreta [13,39,42]. Human infection is characterized by sudden onset of fever, head and backache, vomiting, and abdominal pain often accompanied by visual disturbances [24].…”