Vector-borne Infectious Diseases in Climate Change Investigations (VICCI):

Project 5: Study on the presence of rodent-transmitted zoonoses along a climate gradient in the Bavarian Forest National Park

Project Director

*Susanne Schex, Dr. Gerhard Dobler, PD Dr. Sandra Essbauer, *Dr. Volker Fingerle und *PD Dr.Dr. Andreas Sing
Institut für Mikrobiologie der Bundeswehr, München; * Sachgebiet Infektiologie, Bayerisches Landesamt für Gesundheit und Lebensmittlesicherheit, Oberschleißheim
In Zusammenarbeit mit Dr. Jörg Müller und Dr. Claus Bässler; Nationalpark Bayerischer Wald, Grafenau


Rodents are associated with several pathogens and transmit many zoonotic pathogens. So far in Germany there is a lack of knowledge if and how climate, micro-climate or weather can influence the dynamic of rodent populations and the transmission of its pathogens. In 2004 we investigated an unusual outbreak of hantavirus-infections in Lower Bavaria, South-East Germany. Investigations revealed that a new Puumalavirus (PUUV) strain is abundant in the regions where human cases occured.

There off a longitudinal follow-up study was initiated in order to assess the occurrence and prevalence of this pathogen in wild rodents. In the present project we focus on the prevalence of hantaviruses and rickettsiae in rodents. Rodents are captured along an altitudinal and hence a climate gradient in districts close to the 2004 outbreak. In cooperation with the Bavarian Forrest National Park we have chosen 22 locations out of 330 existing sampling sites. Sites range from 300 m up to 1400 m in altitude above sea level and have been explored intensively within the Bioklim Project with respect to flora, fauna and microclimate. Rodents are trapped with Sherman life trap. Captured rodents are screened for infection with hantaviruses and rickettsiae by PCR. Trapping site, species, sex, reproductive, physical conditions and various other variables including parasitic load are recorded for each rodent. The collected data on rodents and their pathogens are combined and statistically analysed together with data sets on temperature, water supply, soil, radiation, vegetation (moss, lichen fungi) and animals (rodents, birds, spiders, snails).

Aim of the study is to reveal by means of molecular- and sero-epidemiological methods the prevalence, species and variants of hantaviruses and rickettsiae along the climate gradient in the Bavarian Forrest National Park over a period of three years. This is– to our knowledge –the first study in Germany (Europe) where the complex interaction between rodent species, their pathogens and other factors of the ecosystem are investigated climate-dependently. These investigations are of special interest when it comes to the definition of risk areas and maps of distribution of e.g. hantavirus outbreaks.