First Expert Elicitation of Knowledge on Possible Drivers of Observed Increasing Human Cases of Tick-Borne Encephalitis in Europe.

Tick-borne encephalitis (TBE) is a viral disease endemic in Eurasia. The virus is mainly transmitted to humans via ticks and occasionally via the consumption of unpasteurized milk products. The European Centre for Disease Prevention and Control reported an increase in TBE incidence over the past years in Europe as well as the emergence of the disease in new areas. To better understand this phenomenon, we investigated the drivers of TBE emergence and increase in incidence in humans through an expert knowledge elicitation. We listed 59 possible drivers grouped in eight domains and elicited forty European experts to: (i) allocate a score per driver, (ii) weight this score within each domain, and (iii) weight the different domains and attribute an uncertainty level per domain. An overall weighted score per driver was calculated, and drivers with comparable scores were grouped into three terminal nodes using a regression tree analysis. The drivers with the highest scores were: (i) changes in human behavior/activities; (ii) changes in eating habits or consumer demand; (iii) changes in the landscape; (iv) influence of humidity on the survival and transmission of the pathogen; (v) difficulty to control reservoir(s) and/or vector(s); (vi) influence of temperature on virus survival and transmission; (vii) number of wildlife compartments/groups acting as reservoirs or amplifying hosts; (viii) increase of autochthonous wild mammals; and (ix) number of tick species vectors and their distribution. Our results support researchers in prioritizing studies targeting the most relevant drivers of emergence and increasing TBE incidence.

Correction: Indirect Immunofluorescence Assay for the Simultaneous Detection of Antibodies against Clinically Important Old and New World Hantaviruses.

[This corrects the article DOI: 10.1371/journal.pntd.0002157.].

Dynamics of Puumala hantavirus outbreak in Black Sea Region, Turkey.

BACKGROUND: Some of the hantavirus species in Euro-Asia cause haemorrhagic fever with renal syndrome (HFRS) in humans. The first documented human hantavirus infection in Turkey was diagnosed in 2009. This report describes the dynamics of the first hantavirus outbreak that emerged in humans in the Western Black Sea Region of Turkey. METHODS: All the suspected cases of hantavirus infection were admitted to the Infectious Diseases and Clinical Microbiology Department at the Zonguldak Bülent Ecevit University Hospital in Zonguldak, Turkey. The patients were carefully interviewed, examined and evaluated using routine laboratory tests and hantavirus diagnostic tools. Hantavirus-reactive antibodies (IgM and IgG) in serum samples were detected via enzyme immune assay (EIA) and immunofluorescence assay (IFA) in the acute and convalescence stages of the disease. The presence of hantavirus ribonucleic acid (RNA) was analysed via reverse transcription polymerase chain reaction (RT-PCR) in serum and urine samples. A focus reduction neutralization test (FRNT) was performed to confirm specific hantavirus serotypes. In addition, a case-control study was conducted to identify possible risk factors for hantavirus transmission in the outbreak area. A control group was composed of asymptomatic individuals who were seronegative for hantavirus IgM and IgG and living in the outbreak area. RESULTS: A total of 55 suspected cases of hantavirus infection were admitted to the inpatient clinic between February and June of 2009. Twenty-four patients were diagnosed with acute HFRS via EIA or IFA. In 22 of the 24 infected patients, Puumala virus (PUUV) was identified as the causative hantavirus type by detecting IgM in the acute stage and an increase in the IgG level in follow-up serum samples. PUUV was also verified as the infecting agent by FRNT in two of the 24 cases. Among the 24 laboratory-confirmed HFRS cases, 21 (87.5%) were males and 3 (12.5%) were females, and the mean age was 45.92 years (standard deviation ± 16.90 years). Almost all these individuals were living in villages or rural areas. The 24 HFRS cases were matched with 26 healthy controls for statistical analyses and according to binary logistic regression analysis, and dealing with rodent control activities in gardens or in annexes of their homes (p = 0.021 and Odds ratio [OR] = 17.11) and being male (p = 0.019 and OR = 22.37) were detected as statistically significant risk factors for hantavirus infection. The most commonly observed clinical complaints were fatigue (95.8%), shivering (91.7%), fever (87.1%), headache (70.8%) and nausea (70.8%). Haemodialysis was required for four patients (16.7%). Except for the first case diagnosed with acute hantavirus infection, no patient died. The mean delay time to hospital admission from initiation of symptoms was 5.3 days, the mean duration of febrile days was 2.6 days, and the mean duration of hospital stay was 8.5 days. CONCLUSION: Hantaviruses are circulating in Turkey and causing sporadic or epidemic infection in humans. Additional investigations are needed to better understand the dynamics of hantaviruses in this country.

Detection of pathogens in Dermacentor reticulatus in northwestern Europe: evaluation of a high-throughput array.

BACKGROUND: The geographic distribution of Dermacentor reticulatus is expanding in Europe. Surveillance of this tick species and its pathogens is desirable, as it transmits pathogens of public and veterinary importance. A high-throughput real-time PCR-based array was used to screen 1.741 D. reticulatus ticks from Belgium, Germany, The Netherlands, and Great Britain for the presence of 28 tick-borne bacteria and twelve protozoan parasites. The presence of pathogen DNA was confirmed by conventional PCR followed by sequencing. RESULTS: The array detected the presence of DNA from Borrelia spp. (7%), B. afzelii (0.1%), B. garinii (0.1%), B. spielmanii (0.1%), B. miyamotoi (0.2%), Anaplasma marginale (0.1%), A. phagocytophilum (0.1%), Ehrlichia canis (2%), Rickettsia helvetica (0.2%), spotted fever group Rickettsia (9.6%), Francisella tularensis or Francisella-like endosymbionts (95%), Coxiella burnettii (0.1%), Babesia divergens (0.2%), B. canis (0.9%) B. vogeli (5.6%), and Theileria equi (0.1%). Only the presence of B. canis and spotted fever group Rickettsia could be confirmed by conventional PCR and sequencing. The spotted fever Rickettsia-positive samples were all identified as R. raoultii. CONCLUSIONS: We successfully detected and determined the prevalence of B. canis and R. raoultii in D. reticulatus. An high-throughput array that allows fast and comprehensive testing of tick-borne pathogens is advantageous for surveillance and future epidemiological studies. The importance of thorough validation of real-time PCR-based assays and careful interpretation is evident.

Prevalence of Leptospira spp. and Seoul hantavirus in brown rats (Rattus norvegicus) in four regions in the Netherlands, 2011-2015.

BACKGROUND:   Brown rats (Rattus norvegicus) may carry pathogens that can be a risk for public health. Brown rats in the Netherlands were tested for the zoonotic pathogens Leptospira spp. and Seoul hantavirus (SEOV), in order to obtain insight in their prevalence. METHODS AND RESULTS:   Cross-sectional studies were performed at four locations from 2011 to 2015. The rats were tested for Leptospira spp. using real-time PCR and/or culture resulting in a prevalence ranging between 33-57%. Testing for SEOV was done through an adapted human Seoul hantavirus ELISA and real-time RT-PCR. Although at several locations the ELISA indicated presence of SEOV antibodies, none could be confirmed by focus reduction neutralization testing. CONCLUSION:   The results indicate a widespread presence of Leptospira spp. in brown rats in the Netherlands, including areas with a low leptospirosis incidence in humans. No evidence for circulation of SEOV was found in this study.

The English Sweating Sickness: Out of Sight, Out of Mind?

In this paper we aim to add additional knowledge regarding the occurrence, origin and epidemiological features of the English sweating sickness. The English sweating sickness raged in five devastating epidemics with mortality rates between 30 and 50% between 1485 and 1551 throughout England, and on one occasion also affected mainland Europe, in 1529. The Picardy sweat, generally considered as the English sweating sickness' lesser deadly successor, flared up in France in 1718 and caused 196 localized outbreaks with varying severity all over France and neighboring countries up to 1861. The English sweating sickness has been the subject of numerous attempts to define its origin, but so far all efforts have failed due to lack of material, DNA or RNA, that - using modern techniques and knowledge - could shed light on its cause. Although the time frame in which the English sweating sickness occurred and the geographical spread of the outbreaks is generally known, we will demonstrate here that there was more to it than meets the eye. We found reports of cases of sweating sickness in years before, after and between the 1485, 1508, 1517, 1529 and 1551 epidemics, as well as reports of sweating sickness in Italy and Spain. CONCLUSION: In spite of the fact that the English sweating sickness apparently has not caused casualties for a more than a century now, we suggest that -given the right circumstances- the possibility of re-emergence might still exist. The fact that up until today we have no indication concerning the causal pathogen of the English sweating sickness is certainly not re-assuring.

Seroprevalence of Borrelia burgdorferi, Anaplasma phagocytophilum, and Francisella tularensis Infections in Belgium: Results of Three Population-Based Samples.

To estimate the seroprevalence of Borrelia burgdorferi (Bb), Anaplasma phagocytophilum (Ap), and Francisella tularensis (Ft) in Belgium, we tested sera from three population-based samples in which exposure to pathogen is assumed to vary: 148 samples from workers professionally exposed, 209 samples from rural blood donors, and 193 samples from urban blood donors. Sera were tested using ELISA or the immunofluorescence assay test. The seroprevalence of Bb was 5.4% in workers professionally exposed, 2.9% in rural blood donors, and 2.6% in urban blood donors, which is similar to other studies. The fraction of negative results decreases significantly from urban blood donors and rural blood donors to workers. Regarding the seroprevalence of Ap, the cutoff titer of 1:64 recommended by the manufacturer may be set too low and produces artificially high seroprevalence rates. Using a cutoff titer of 1:128, the seroprevalence of Ap was estimated at 8.1% for workers professionally exposed, 6.2% for rural blood donors, and 5.7% for urban blood donors. Tularemia sera confirmed the presence of the pathogen in Belgium at 2.0% for workers and 0.5% for rural and urban blood donors. Our study is one of the few providing an estimation of the seroprevalences of Bb, Ap, and Ft in three different populations in Belgium, filling the gap in seroprevalence data among those groups. Our findings provide evidence that the entire Belgian population is exposed to Bb, Ap, and Ft infections, but a higher exposure is noticed for professionals at risk. Education on the risk factors for tick bites and preventive measures for both professionals exposed and the general population is needed.

Analysis of delayed TBE-vaccine booster after primary vaccination.

An open, uncontrolled single centre study was conducted in the Travel Clinic at the Military Hospital, Brussels. Eighty-eight subjects were recruited who had a primary series of tick-borne encephalitis (TBE) vaccine more than 5 years ago and who never received a booster dose afterwards. Response rate after booster vaccination was very high: 84 out of 88 subjects (95.5%) had neutralizing antibodies on plaque reduction neutralization test and all (100%) had IgG antibodies on ELISA, on Day 21-28 after booster vaccination. This study adds valuable information to the common situation of delayed booster interval. The results of our study indicate that in young healthy travellers (<50 years), one booster vaccination after a primary series of TBE vaccine in the past is sufficient to obtain protective antibodies, even if primary vaccination is much longer than the recommended booster interval of 5 years.

Serologic screening for 13 infectious agents in roe deer (Capreolus capreolus) in Flanders.

INTRODUCTION: In order to investigate the role of roe deer in the maintenance and transmission of infectious animal and human diseases in Flanders, we conducted a serologic screening in 12 hunting areas. MATERIALS AND METHODS: Roe deer sera collected between 2008 and 2013 (n=190) were examined for antibodies against 13 infectious agents, using indirect enzyme-linked immunosorbent assay, virus neutralisation, immunofluorescence, or microagglutination test, depending on the agent. RESULTS AND DISCUSSION: High numbers of seropositives were found for Anaplasma phagocytophilum (45.8%), Toxoplasma gondii (43.2%) and Schmallenberg virus (27.9%), the latter with a distinct temporal distribution pattern following the outbreak in domestic ruminants. Lower antibody prevalence was found for Chlamydia abortus (6.7%), tick-borne encephalitis virus (5.1%), Neospora caninum (4.8%), and Mycobacterium avium subsp paratuberculosis (4.1%). The lowest prevalences were found for Leptospira (1.7%), bovine viral diarrhoea virus 1 (1.3%), and Coxiella burnetii (1.2%). No antibodies were found against Brucella sp., bovine herpesvirus 1, and bluetongue virus. A significant difference in seroprevalence between ages (higher in adults >1 year) was found for N. caninum. Four doubtful reacting sera accounted for a significant difference in seroprevalence between sexes for C. abortus (higher in females). CONCLUSIONS: Despite the more intensive landscape use in Flanders, the results are consistent with other European studies. Apart from maintaining C. abortus and MAP, roe deer do not seem to play an important role in the epidemiology of the examined zoonotic and domestic animal pathogens. Nevertheless, their meaning as sentinels should not be neglected in the absence of other wild cervid species.

Circulation of four Anaplasma phagocytophilum ecotypes in Europe.

BACKGROUND: Anaplasma phagocytophilum is the etiological agent of granulocytic anaplasmosis in humans and animals. Wild animals and ticks play key roles in the enzootic cycles of the pathogen. Potential ecotypes of A. phagocytophilum have been characterized genetically, but their host range, zoonotic potential and transmission dynamics has only incompletely been resolved. METHODS: The presence of A. phagocytophilum DNA was determined in more than 6000 ixodid ticks collected from the vegetation and wildlife, in 289 tissue samples from wild and domestic animals, and 69 keds collected from deer, originating from various geographic locations in The Netherlands and Belgium. From the qPCR-positive lysates, a fragment of the groEL-gene was amplified and sequenced. Additional groEL sequences from ticks and animals from Europe were obtained from GenBank, and sequences from human cases were obtained through literature searches. Statistical analyses were performed to identify A. phagocytophilum ecotypes, to assess their host range and their zoonotic potential. The population dynamics of A. phagocytophilum ecotypes was investigated using population genetic analyses. RESULTS: DNA of A. phagocytophilum was present in all stages of questing and feeding Ixodes ricinus, feeding I. hexagonus, I. frontalis, I. trianguliceps, and deer keds, but was absent in questing I. arboricola and Dermacentor reticulatus. DNA of A. phagocytophilum was present in feeding ticks and tissues from many vertebrates, including roe deer, mouflon, red foxes, wild boar, sheep and hedgehogs but was rarely found in rodents and birds and was absent in badgers and lizards. Four geographically dispersed A. phagocytophilum ecotypes were identified, that had significantly different host ranges. All sequences from human cases belonged to only one of these ecotypes. Based on population genetic parameters, the potentially zoonotic ecotype showed significant expansion. CONCLUSION: Four ecotypes of A. phagocytophilum with differential enzootic cycles were identified. So far, all human cases clustered in only one of these ecotypes. The zoonotic ecotype has the broadest range of wildlife hosts. The expansion of the zoonotic A. phagocytophilum ecotype indicates a recent increase of the acarological risk of exposure of humans and animals.

Dobrava virus carried by the yellow-necked field mouse Apodemus flavicollis, causing hemorrhagic fever with renal syndrome in Romania.

Hemorrhagic fever with renal syndrome (HFRS) has been confirmed by serological methods during recent years in Romania. In the present study, focus-reduction neutralization tests (FRNT) confirmed Dobrava hantavirus (DOBV) as the causative agent in some HFRS cases, but could not distinguish between DOBV and Saaremaa virus (SAAV) infections in other cases. DOBV was detected by a DOBV-specific TaqMan assay in sera of nine patients out of 22 tested. Partial sequences of the M genomic segment of DOBV were obtained from sera of three patients and revealed the circulation of two DOBV lineages in Romania. Investigation of rodents trapped in Romania found three DOBV-positive Apodemus flavicollis out of 83 rodents tested. Two different DOBV lineages were also detected in A. flavicollis as determined from partial sequences of the M and S genomic segments. Sequences of DOBV in A. flavicollis were either identical or closely related to the sequences obtained from the HFRS patients. The DOBV strains circulating in Romania clustered in two monophyletic groups, together with strains from Slovenia and the north of Greece. This is the first evidence for the circulation of DOBV in wild rodents and for a DOBV etiology of HFRS in Romania.

Were the English sweating sickness and the Picardy sweat caused by hantaviruses?

The English sweating sickness caused five devastating epidemics between 1485 and 1551, England was hit hardest, but on one occasion also mainland Europe, with mortality rates between 30% and 50%. The Picardy sweat emerged about 150 years after the English sweat disappeared, in 1718, in France. It caused 196 localized outbreaks and apparently in its turn disappeared in 1861. Both diseases have been the subject of numerous attempts to define their origin, but so far all efforts were in vain. Although both diseases occurred in different time frames and were geographically not overlapping, a common denominator could be what we know today as hantavirus infections. This review aims to shed light on the characteristics of both diseases from contemporary as well as current knowledge and suggests hantavirus infection as the most likely cause for the English sweating sickness as well as for the Picardy sweat.

Vector-borne disease intelligence: strategies to deal with disease burden and threats.

Owing to the complex nature of vector-borne diseases (VBDs), whereby monitoring of human case patients does not suffice, public health authorities experience challenges in surveillance and control of VBDs. Knowledge on the presence and distribution of vectors and the pathogens that they transmit is vital to the risk assessment process to permit effective early warning, surveillance, and control of VBDs. Upon accepting this reality, public health authorities face an ever-increasing range of possible surveillance targets and an associated prioritization process. Here, we propose a comprehensive approach that integrates three surveillance strategies: population-based surveillance, disease-based surveillance, and context-based surveillance for EU member states to tailor the best surveillance strategy for control of VBDs in their geographic region. By classifying the surveillance structure into five different contexts, we hope to provide guidance in optimizing surveillance efforts. Contextual surveillance strategies for VBDs entail combining organization and data collection approaches that result in disease intelligence rather than a preset static structure.

Ticks and associated pathogens collected from dogs and cats in Belgium.

BACKGROUND: Although Ixodes spp. are the most common ticks in North-Western Europe, recent reports indicated an expanding geographical distribution of Dermacentor reticulatus in Western Europe. Recently, the establishment of a D. reticulatus population in Belgium was described. D. reticulatus is an important vector of canine and equine babesiosis and can transmit several Rickettsia species, Coxiella burnetii and tick-borne encephalitis virus (TBEV), whilst Ixodes spp. are vectors of pathogens causing babesiosis, borreliosis, anaplasmosis, rickettsiosis and TBEV. METHODS: A survey was conducted in 2008-2009 to investigate the presence of different tick species and associated pathogens on dogs and cats in Belgium. Ticks were collected from dogs and cats in 75 veterinary practices, selected by stratified randomization. All collected ticks were morphologically determined and analysed for the presence of Babesia spp., Borrelia spp., Anaplasma phagocytophilum and Rickettsia DNA. RESULTS: In total 2373 ticks were collected from 647 dogs and 506 cats. Ixodes ricinus (76.4%) and I. hexagonus (22.6%) were the predominant species. Rhipicephalus sanguineus (0.3%) and D. reticulatus (0.8%) were found in low numbers on dogs only. All dogs infested with R. sanguineus had a recent travel history, but D. reticulatus were collected from a dog without a history of travelling abroad. Of the collected Ixodes ticks, 19.5% were positive for A. phagocytophilum and 10.1% for Borrelia spp. (B. afzelii, B. garinii, B. burgdorferi s.s., B. lusitaniae, B. valaisiana and B. spielmanii). Rickettsia helvetica was found in 14.1% of Ixodes ticks. All Dermacentor ticks were negative for all the investigated pathogens, but one R. sanguineus tick was positive for Rickettsia massiliae. CONCLUSION: D. reticulatus was confirmed to be present as an indigenous parasite in Belgium. B. lusitaniae and R. helvetica were detected in ticks in Belgium for the first time.

Spatial disaggregation of tick occurrence and ecology at a local scale as a preliminary step for spatial surveillance of tick-borne diseases: general framework and health implications in Belgium.

BACKGROUND: The incidence of tick-borne diseases is increasing in Europe. Sub national information on tick distribution, ecology and vector status is often lacking. However, precise location of infection risk can lead to better targeted prevention measures, surveillance and control. METHODS: In this context, the current paper compiled geolocated tick occurrences in Belgium, a country where tick-borne disease has received little attention, in order to highlight the potential value of spatial approaches and draw some recommendations for future research priorities. RESULTS: Mapping of 89,289 ticks over 654 sites revealed that ticks such as Ixodes ricinus and Ixodes hexagonus are largely present while Dermacentor reticulatus has a patchy distribution. Suspected hot spots of tick diversity might favor pathogen exchanges and suspected hot spots of I. ricinus abundance might increase human-vector contact locally. This underlines the necessity to map pathogens and ticks in detail. While I. ricinus is the main vector, I. hexagonus is a vector and reservoir of Borrelia burgdorferi s.l., which is active the whole year and is also found in urban settings. This and other nidiculous species bite humans less frequently, but seem to harbour pathogens. Their role in maintaining a pathogenic cycle within the wildlife merits investigation as they might facilitate transmission to humans if co-occurring with I. ricinus. Many micro-organisms are found abroad in tick species present in Belgium. Most have not been recorded locally but have not been searched for. Some are transmitted directly at the time of the bite, suggesting promotion of tick avoidance additionally to tick removal. CONCLUSION: This countrywide approach to tick-borne diseases has helped delineate recommendations for future research priorities necessary to design public health policies aimed at spatially integrating the major components of the ecological cycle of tick-borne diseases. A systematic survey of tick species and associated pathogens is called for in Europe, as well as better characterisation of species interaction in the ecology of tick-borne diseases, those being all tick species, pathogens, hosts and other species which might play a role in tick-borne diseases complex ecosystems.

Indirect immunofluorescence assay for the simultaneous detection of antibodies against clinically important old and new world hantaviruses.

In order to detect serum antibodies against clinically important Old and New World hantaviruses simultaneously, multiparametric indirect immunofluorescence assays (IFAs) based on biochip mosaics were developed. Each of the mosaic substrates consisted of cells infected with one of the virus types Hantaan (HTNV), Puumala (PUUV), Seoul (SEOV), Saaremaa (SAAV), Dobrava (DOBV), Sin Nombre (SNV) or Andes (ANDV). For assay evaluation, serum IgG and IgM antibodies were analyzed using 184 laboratory-confirmed hantavirus-positive sera collected at six diagnostic centers from patients actively or previously infected with the following hantavirus serotypes: PUUV (Finland, n=97); SEOV (China, n=5); DOBV (Romania, n=7); SNV (Canada, n=23); ANDV (Argentina and Chile, n=52). The control panel comprised 89 sera from healthy blood donors. According to the reference tests, all 184 patient samples were seropositive for hantavirus-specific IgG (n=177; 96%) and/or IgM (n=131; 72%), while all control samples were tested negative. In the multiparametric IFA applied in this study, 183 (99%) of the patient sera were IgG and 131 (71%) IgM positive (accordance with the reference tests: IgG, 96%; IgM, 93%). Overall IFA sensitivity for combined IgG and IgM analysis amounted to 100% for all serotypes, except for SNV (96%). Of the 89 control sera, 2 (2%) showed IgG reactivity against the HTNV substrate, but not against any other hantavirus. Due to the high cross-reactivity of hantaviral nucleocapsid proteins, endpoint titrations were conducted, allowing serotype determination in >90% of PUUV- and ANDV-infected patients. Thus, multiparametric IFA enables highly sensitive and specific serological diagnosis of hantavirus infections and can be used to differentiate PUUV and ANDV infection from infections with Murinae-borne hantaviruses (e.g. DOBV and SEOV).

Factors driving hantavirus emergence in Europe.

Hantaviruses cause hemorrhagic fever with renal syndrome (HFRS) in Eurasia. In Europe both the amplitude and the magnitude of outbreaks of HFRS have increased. The mechanisms that drive the incidences are complex and multi-factorial and only partially due to increased awareness and improved diagnostic tools. Risk determinants include reservoir ecology, virus ecology and anthropogenic factors. The dogma of one specific rodent species as primordial reservoir for a specific hantavirus is increasingly challenged. New hantaviruses have been discovered in shrews, moles and bats and increasing evidence points at host-switching events and co-circulation in multiple, sympatric reservoir species, challenging the strict rodent-virus co-evolution theory. Changing landscape attributes and climatic parameters determine fluctuations in hantavirus epidemiology, for instance through increased food availability, prolonged virus survival and decreased biodiversity.

Human puumala and dobrava hantavirus infections in the Black Sea region of Turkey: a cross-sectional study.

This study was carried out to better understand the epidemiology of hantaviruses in a province of Turkey (Giresun) where human hantavirus disease has recently been detected. In this cross-sectional study, a total of 626 blood samples from healthy people aged 15 and 84 years old were collected both in urban and rural areas in 2009. The sera were tested by enzyme-linked immunosorbent assay (ELISA), immunoblotting assay, and the focus reduction neutralization test (FRNT). We screened the samples by an ELISA and found that 65/626 samples reacted positively for the presence of hantavirus-reactive immunoglobulin G (IgG). Twenty of the 65 ELISA-positive samples could be confirmed by an immunobloting assay, and the overall seroprevalence was thereby calculated to 3.2% (20/626). The seroprevalence of the people living in wood areas or adobe houses 9/17 (52.9%) was significantly higher than among people living in concrete houses 10/47 (21.3%) (p=0.014). Finally, 3 of the 20 immunoblot-positive sera were confirmed as specific for the Puumala hantavirus serotype by FRNT, 1 serum was confirmed as Dobrava virus-specific, whereas 1 serum was found to be equally reactive to Dobrava and Saaremaa viruses. We will now focus on further investigations of the ecology and epidemiology of hantaviruses in humans and their carrier animals in Turkey, studies that have already been started and will be further intensified.

Complex evolution and epidemiology of Dobrava-Belgrade hantavirus: definition of genotypes and their characteristics.

Dobrava-Belgrade virus (DOBV) is a human pathogen that has evolved in, and is hosted by, mice of several species of the genus Apodemus. We propose a subdivision of the species Dobrava-Belgrade virus into four related genotypes - Dobrava, Kurkino, Saaremaa, and Sochi - that show characteristic differences in their phylogeny, specific host reservoirs, geographical distribution, and pathogenicity for humans.

Spatiotemporal dynamics of Puumala hantavirus in suburban reservoir rodent populations.

The transmission of pathogens to susceptible hosts is dependent on the vector population dynamics. In Europe, bank voles (Myodes glareolus) carry Puumala hantavirus, which causes nephropathia epidemica (NE) in humans. Fluctuations in bank vole populations and epidemics in humans are correlated but the main factors influencing this relationship remain unclear. In Belgium, more NE cases are reported in spring than in autumn. There is also a higher incidence of human infections during years of large vole populations. This study aimed to better understand the link between virus prevalence in the vector, vole demography, habitat quality, and human infections. Three rodent populations in different habitats bordering Brussels city, Belgium, were studied for two years. The seroprevalence in voles was influenced first by season (higher in spring), then by vole density, vole weight (a proxy for age), and capture site but not by year or sex. Moreover, voles with large maximal distance between two captures had a high probability for Puumala seropositivity. Additionally, the local vole density showed similar temporal variations as the number of NE cases in Belgium. These results showed that, while season was the main factor influencing vole seroprevalence, it was not sufficient to explain human risks. Indeed, vole density and weight, as well as the local habitat, were essential to understanding the interactions in these host-pathogen dynamics. This can, in turn, be of importance for assessing the human risks.