Identification of factors influencing the Puumala virus seroprevalence within its reservoir in aMontane Forest Environment.

Puumala virus (PUUV) is a major cause of mild to moderate haemorrhagic fever with renal syndrome and is transmitted by the bank vole (Myodes glareolus). There has been a high cumulative incidence of recorded human cases in South-eastern Germany since 2004 when the region was first recognized as being endemic for PUUV. As the area is well known for outdoor recreation and the Bavarian Forest National Park (BFNP) is located in the region, the increasing numbers of recorded cases are of concern. To understand the population and environmental effects on the seroprevalence of PUUV in bank voles we trapped small mammals at 23 sites along an elevation gradient from 317 to 1420m above sea level. Generalized linear mixed effects models(GLMEM) were used to explore associations between the seroprevalence of PUUV in bank voles and climate and biotic factors. We found that the seroprevalence of PUUV was low (6%-7%) in 2008 and 2009, and reached 29% in 2010. PUUV seroprevalence was positively associated with the local species diversity and deadwood layer, and negatively associated with mean annual temperature, mean annual solar radiation, and herb layer. Based on these findings, an illustrative risk map for PUUV seroprevalence prediction in bank voles was created for an area of the national park. The map will help when planning infrastructure in the national park (e.g., huts, shelters, and trails)

Nagetier-übertragene Zoonosen: Beispiele aus Untersuchungen in Süd- und Westdeutschland

Zusammenfassung Nagetiere und andere Kleinsäuger können eine Vielzahl von Krankheitserregern, RNA- und DNA-Viren, Bakterien und Parasiten, auf den Menschen übertragen, die teilweise lebensbedrohliche Erkrankungen hervorrufen. In der folgenden Übersicht soll erstmals ein Überblick über Ergebnisse aus drei Untersuchungen in Deutschland gegeben werden: eine Studie in drei Landkreisen Bayerns von 2001-2004, Untersuchungen in einem Freilandgehege im Rahmen eines Tularämieausbruchs in Niedersachsen im Jahr 2005, und schließlich im Jahr 2007 eine Untersuchung an einem Truppenübungsplatz in Baden-Württemberg. Es wurde dabei exemplarisch die Verbreitung von Zoonoseerregern in Nagetieren und anderen Kleinsäugern näher untersucht, von drei Viren (Hantaviren, Kuhpockenvirus, Frühsommer- Meningo-Enzephalitis-Virus) und vier Bakterien (Leptospiren, Francisellen, Borrelien und Rickettsien). Die hier zusammengefassten Erkenntnisse sind ein erster wichtiger Schritt auf dem Weg zur Erstellung von Verbreitungskarten für die genannten humanpathogenen Zoonoseerreger in ihren Reservoirwirten und der Definition von entsprechenden Risikogebieten. Diese Arbeit soll zudem einen Beitrag leisten, einen Anstoß zu verstärkter Zusammenarbeit von Zoologen, Ökologen, Virologen, Human- und Veterinärmedizinern, Mikrobiologen, Parasitologen, Genetikern, Epidemiologen, Forstwissenschaftlern und Klimaforschern zu geben

High prevalence of Rickettsia helvetica in wild small mammal populations in Germany

Since the beginning of the 21st century, spotted fever rickettsioses are known as emerging diseases worldwide. Rickettsiae are obligately intracellular bacteria transmitted by arthropod vectors. The ecology of Rickettsia species has not been investigated in detail, but small mammals are considered to play a role as reservoirs. Aim of this study was to monitor rickettsiae in wild small mammals over a period of five years in four federal states of Germany. Initial screening of ear pinna tissues of 3939 animals by Pan-Rick real-time PCR targeting the citrate synthase (gltA) gene revealed 296 rodents of seven species and 19 shrews of two species positive for rickettsial DNA. Outer membrane protein gene (ompB, ompAIV) PCRs based typing resulted in the identification of three species: Rickettsia helvetica (90.9%) was found as the dominantly occurring species in the four investigated federal states, but Rickettsia felis (7.8%) and Rickettsia raoultii (1.3%) were also detected. The prevalence of Rickettsia spp. in rodents of the genus Apodemus was found to be higher (approximately 14%) than in all other rodent and shrew species at all investigated sites. General linear mixed model analyses indicated that heavier (older) individuals of yellow-necked mice and male common voles seem to contain more often rickettsial DNA than younger ones. Furthermore, rodents generally collected in forests in summer and autumn more often carried rickettsial DNA. In conclusion, this study indicated a high prevalence of R. helvetica in small mammal populations and suggests an age-dependent increase of the DNA prevalence in some of the species and in animals originating from forest habitats. The finding of R. helvetica and R. felis DNA in multiple small mammal species may indicate frequent trans-species transmission by feeding of vectors on different species. Further investigations should target the reason for the discrepancy between the high rickettsial DNA prevalence in rodents and the so far almost absence of clinical apparent human infections

Phylogenetic analysis of Puumala virus strains from Central Europe highlights the need for a full-genome perspective on hantavirus evolution

Puumala virus (PUUV), carried by bank voles (Myodes glareolus), is the medically most important hantavirus in Central and Western Europe. In this study, a total of 523 bank voles (408 from Germany, 72 from Slovakia, and 43 from Czech Republic) collected between the years 2007-2012 were analyzed for the presence of hantavirus RNA. Partial PUUV genome segment sequences were obtained from 51 voles. Phylogenetic analyses of all three genome segments showed that the newfound strains cluster with other Central and Western European PUUV strains. The new sequences from Šumava (Bohemian Forest), Czech Republic, are most closely related to the strains from the neighboring Bavarian Forest, a known hantavirus disease outbreak region. Interestingly, the Slovak strains clustered with the sequences from Bohemian and Bavarian Forests only in the M but not S segment analyses. This well-supported topological incongruence suggests a segment reassortment event or, as we analyzed only partial sequences, homologous recombination. Our data highlight the necessity of sequencing all three hantavirus genome segments and of a broader bank vole screening not only in recognized endemic foci but also in regions with no reported human hantavirus disease cases.status: publishe