First molecular evidence for Puumala hantavirus in Slovakia

First molecular evidence for Puumala hantavirus in Poland

Puumala virus (PUUV) causes mild to moderate cases of haemorrhagic fever with renal syndrome (HFRS), and is responsible for the majority of hantavirus infections of humans in Fennoscandia, Central and Western Europe. Although there are relatively many PUUV sequences available from different European countries, little is known about the presence of this virus in Poland. During population studies in 2009 a total of 45 bank voles were trapped at three sites in north-eastern Poland, namely islands on Dejguny and Dobskie Lakes and in a forest near Mikołajki. S and M segment-specific RT-PCR assays detected PUUV RNA in three animals from the Mikołajki site. The obtained partial S and M segment sequences demonstrated the highest similarity to the corresponding segments of a PUUV strain from Latvia. Analysis of chest cavity fluid samples by IgG ELISA using a yeast-expressed PUUV nucleocapsid protein resulted in the detection of two seropositive samples, both being also RT-PCR positive. Interestingly, at the trapping site in Mikołajki PUUV-positive bank voles belong to the Carpathian and Eastern genetic lineages within this species. In conclusion, we herein present the first molecular evidence for PUUV in the rodent reservoir from Poland.

Serological evidence of hantavirus infection in farm and abattoir workers in Trinidad--a preliminary study

Hantaviruses are established causative agents of hemorrhagic fevers and renal diseases amongst other clinical manifestations in humans, with most diagnosis based on serological assays. The disease, which is rodent-borne, has been reported in numerous countries worldwide but information about the disease is scanty in the Caribbean. The objective of this investigation is to determine the frequency of exposure to hantaviruses in a selected apparently healthy human population associated with abattoirs and livestock farms in Trinidad using a hantavirus immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA). Of a total of 236 individuals tested, 27 (11.4%) were seropositive for hantavirus infection. Amongst abattoir workers the frequency of infection was 9.4% (6 of 64) compared with seropositivity rate of 12.4% (18 of 145) and 11.1% (3 of 27) amongst livestock farm workers and office workers and other individuals with minimal animal contact respectively. The differences were, however, not statistically significant (p > .05; χ(2) test). Age, gender, and race did not significantly affect the infection rate by hantavirus in the workers studied. This is considered the first documented evidence of hantavirus infection in Trinidad and Tobago. It is imperative for local physicians to consider hantavirus as a differential diagnosis in patients with hemorrhagic fever and renal diseases, since there may be a number of undiagnosed cases of hantavirus disease in the human population in the country.

Hantaviruses and their hosts in Europe: reservoirs here and there, but not everywhere?

Five hantaviruses are known to circulate among rodents in Europe, and at least two among insectivores. Four (Dobrava, Saaremaa, Seoul, and Puumala [PUUV] viruses) are clearly associated with hemorrhagic fever with renal syndrome (HFRS). PUUV, the most common etiological agent of HFRS in Europe, is carried by the bank vole (Myodes glareolus), one of the most widespread and abundant mammal species in Europe. This host-virus system is among hantaviruses also the most studied one in Europe. However, HFRS incidence varies throughout the continent. The spatial as well as temporal variation in the occurrence of HFRS is linked to geographic differences in the population dynamics of the reservoir rodents in different biomes of Europe. While rodent abundance may follow mast seeding events in many parts of temperate Europe, in northern (N) Europe multiannual cycles in population density exist as the result of the interaction between rodent populations and specialist predator populations in a delayed density-dependent manner. The spatial distribution of hantaviruses further depends on parameters such as forest patch size and connectivity of the most suitable rodent habitats, and the conditions for the survival of the virus outside the host, as well as historical distribution patterns (phylogeographies) of hosts and viruses. In multiannually fluctuating populations of rodents, with population increases of great amplitude, one should expect a simultaneous build-up of recently hantavirus-infected (shedding) rodents. The increasing number of infectious, virus-shedding rodents leads to a rapid transmission of hantavirus across the rodent population, and to humans. Our review discusses these aspects for PUUV, the only European hantavirus for which there is a reasonable, yet still far from complete, ecological continental-wide understanding. We discuss how this information could translate to other European hantavirus-host systems, and where the most important questions lie for further research.

Network "Rodent-borne pathogens" in Germany: longitudinal studies on the geographical distribution and prevalence of hantavirus infections

Hantavirus infections are known in Germany since the 1980s. While the overall antibody prevalence against hantaviruses in the general human population was estimated to be about 1-2%, an average of 100-200 clinical cases are recorded annually. In the years 2005 and 2007 in particular, a large increase of the number of human hantavirus infections in Germany was observed. The most affected regions were located in the federal states of Baden-Wuerttemberg, Bavaria, North Rhine Westphalia, and Lower Saxony. In contrast to the well-documented situation in humans, the knowledge of the geographical distribution and frequency of hantavirus infections in their rodent reservoirs as well as any changes thereof was very limited. Hence, the network "Rodent-borne pathogens" was established in Germany allowing synergistic investigations of the rodent population dynamics, the prevalence and evolution of hantaviruses and other rodent-associated pathogens as well as their underlying mechanisms in order to understand their impact on the frequency of human infections. A monitoring of hantaviruses in rodents from endemic regions (Baden-Wuerttemberg, Bavaria, North Rhine Westphalia, Lower Saxony) and regions with a low number of human cases (Mecklenburg Western-Pomerania, Brandenburg, Saxony, Saxony-Anhalt) was initiated. Within outbreak regions, a high prevalence of Puumala virus (PUUV) was detected in bank voles. Initial longitudinal studies in North Rhine Westphalia (city of Cologne), Bavaria (Lower Bavaria), and Lower Saxony (rural region close to Osnabrück) demonstrated a continuing presence of PUUV in the bank vole populations. These longitudinal studies will allow conclusions about the evolution of hantaviruses and other rodent-borne pathogens and changes in their distribution, which can be used for a risk assessment of human infections. This may become very important in order to evaluate changes in the epidemiology of rodent-borne pathogens in the light of expected global climate changes in the future.

Hantavirus disease outbreak in Germany: limitations of routine serological diagnostics and clustering of virus sequences of human and rodent origin

In Europe, hemorrhagic fever with renal syndrome results mainly from infection with Puumala virus (PUUV) or Dobrava virus. For 31 patients from a hantavirus disease outbreak in Lower Bavaria, a district in southeast Germany, serodiagnosis was undertaken by enzyme-linked immunosorbent assay, immunofluorescence assay, and immunoblot analysis. In a few of these cases, however, PUUV-specific typing of antibodies by these standard assays failed and a virus neutralization assay under biosafety level 3 conditions was required to verify the infection by this virus type. PUUV RNA was amplified by reverse transcription-PCR from acute-phase sera of three patients and was found to be very closely related to virus sequences obtained from bank voles (Clethrionomys glareolus) trapped in the same area. These findings link the outbreak with a novel PUUV lineage, "Bavaria," circulating in the local rodent population. The Bavaria lineage associated with the outbreak is only distantly related to other PUUV lineages from Germany.