Impact of Puumala Virus Infection on Maturation and Survival in Bank Voles: A Capture-Mark-Recapture Analysis

Abstract

ABSTRACT:Many zoonotic diseases are caused by rodent-borne viruses. Major fluctuations in the transmission of these viruses have been related to large changes in reservoir host population numbers due to external factors. However, the impact of the pathogen itself on the demography of its reservoir host is often overlooked. We investigated the impact of Puumala virus (PUUV) on survival and reproductive maturation probability of its reservoir host, the bank vole (Myodes glareolus). Three years (2004-06) of data from nine independent sites in southern Belgium were collected and analyzed with a capture-mark-recapture (CMR) method that includes statistical correction for the variation in capture probability of voles. A multistate model based on four states of reproductive activity and PUUV immunoglobulin G (IgG) antibody status was used to estimate survival and probability of transition from one reproductive or infection state to another. Although survival estimates for reproductively active voles were similar between infected and noninfected individuals, PUUV infection in reproductively inactive voles decreased mean monthly survival by 14%. PUUV infection was associated with a threefold increase in the probability of reproductive maturation in bank voles. Moreover, the probability of PUUV IgG seroconversion was three times higher for reproductively active voles compared to reproductively inactive voles. Our model indicates that PUUV infection may alter bank vole population dynamics by affecting both survival and maturation in its host. Additional studies, using CMR methodology with shorter time intervals between trapping sessions and possibly a longer duration, are needed to confirm these findings.

No measurable adverse effects of Lassa, Morogoro and Gairo arenaviruses on their rodent reservoir host in natural conditions

“…Such complex relationships between parasite infection and host fitness were indeed observed in other rodent-borne diseases. For example, infection of Puumala hantavirus in bank voles ( Myodes glareolus ) was initially assumed to be asymptomatic [51–53] but recent long-term field studies observed negative effects on the survival probability and an equivocal impact on the fecundity of females [36, 54, 55]. An important difference between Old World arenaviruses and hantaviruses, however, is that the latter causes persistent infections in their reservoir hosts [56], while the former infects their hosts mainly acutely [29, 43].…”

Immunogenetic Factors Affecting Susceptibility of Humans and Rodents to Hantaviruses and the Clinical Course of Hantaviral Disease in Humans

“…Selection acting on Tnf promoter could therefore be linked to PUUV, either indirectly, or potentially directly. Indeed, several ongoing studies are providing evidence of negative effects of PUUV on different components of vole fitness, including survival [28,29,71] . …”

“…In rodents, which are the reservoirs of pathogenic hantaviruses, infection is persistent [26,27] and mainly asymptomatic but see [28,29,30]. Nevertheless rodents differ in their probability of being infected with their associated hantavirus e.g., [31].…”

Life-long shedding of Puumala hantavirus in wild bank voles (Myodes glareolus)

“…Inhalation of aerosolized rodent excreta is also considered the main route of infection to humans (Hjelle & Glass, 2000;Vapalahti et al, 2010). No apparent symptoms have been reported in rodent hosts due to hantavirus infection, but it may impair host survival in nature (Kallio et al, 2007;Luis et al, 2012;Tersago et al, 2012). The hantavirus infection induces a life-long antibody response where IgG appears in the bloodstream 2 to 3 weeks after infection, but viral RNA and/or infectious virus is found in various tissues, especially in the lungs of chronically infected animals (Botten et al, 2003;Hardestam et al, 2008;Meyer & Schmaljohn, 2000;Schountz et al, 2012).…”