Seroprevalence rates for immunoglobulin G (IgG) antibodies to Tahyna virus (TAHV) and Inkoo virus (INKV) were determined in sera of 1630 blood donors from North, East, and South Tyrol by immunofluorescence assays (IFAs) and confirmatory serum neutralization tests (SNTs). Ten sera (0.6%) reacted positive by TAHV IFA, five of which (0.3%) were confirmed by SNT. Eleven sera (0.7%) reacted positive in the INKV IFA; only one thereof (0.06%) was verified by subsequent SNT. To identify the source of infections, mosquitoes were trapped at 18 sampling sites in the study area, resulting in the collection of 2571 adult mosquitoes: 1254 individuals of the genus Aedes (48.8% of total) including A. albopictus, 640 Culex (24.9%), 303 Coquillettidia (11.8%), 252 Ochlerotatus (9.8%), 49 Anopheles (1.9%), and 73 mosquitoes of the genus Culiseta (2.8%). The mosquitoes were pooled according to species, trapping site, and time, and were tested by RT-PCR for the presence of California serogroup orthobunyavirus nucleic acids. PCR amplification products were obtained in five of 195 pools (2.6%), and all were identified as TAHVs by subsequent sequencing. This represents the first evidence of TAHV circulation and human exposure in the Tyrols and in the alpine region in general. Interestingly, all TAHV sequences were identified in Culex pipiens/torrentium mosquitoes. Whether other California serogroup orthobunyaviruses such as INKV are also circulating in this area is subject of further investigations on larger numbers of mosquitoes.

This study shows that Babesia spp. are present in the Tyrols, which blood donors come into serologic contact with, and that we have to consider how to sustain blood product safety concerning this new challenge. Additionally, it is the first description of B. venatorum in the Tyrols, found in one Ixodes ricinus at the Italian border.

A large majority of Austrian citizens are aware of tick-borne encephalitis (TBE), consequently reflected by a high vaccination rate of 85%. In return, risk assessment and disease mapping on human cases might be hampered due to high and inhomogeneous vaccination rates and travel habitats of humans. The roe deer was used to obtain a starting point for the integral view on the actual risk of TBE in Austria. The roe deer exhibits several attributes which makes it suitable as an indicator species: the roe deer has a restricted home range and it is known to be a heavy tick carrier. Furthermore it sero-converts after infection with TBE, but no outbreak occurs. Sera from 945 roe deer were obtained from all over Austria and screened with IFAT for the antibodies against TBE. Twenty-two positive samples, 2.4%, and 17 samples at the borderline titre of 1:16 were identified. The majority of the positive samples, 70.6%, were located in known TBE areas based on human cases. Further research is needed to confirm or reject new endemic foci of TBE transmission.

After malaria, babesiosis is the second most common transfusion-transmitted vector-borne disease. This study investigates seroprevalence rates to Babesia divergens and B. microti in the Tyrol and assesses the risk of blood products being contaminated by either agent.The area of investigation comprises the Austrian part of Tyrol. A number of 988 sera were tested for IgG antibodies against B. divergens and B. microti by in-house immunofluorescence assays (IFA). IFA-slides were tested by using commercially available hyperimmunesera.Collection of questing ticks was performed in summer 2009 by about 120 volunteers among hunters at 25 sampling sites over a period of three months by flagging.Of 988 sera, 21 (2.1%) were positive in IFA against the B. divergens-complex at titres of 1:128 or higher and 5 (0.5%) were positive in IFA against B. microti.Under the presumption of a long-lasting immune response we can expect 0.5 (±0.2, 95%) seroconversions against B. divergens per 10.000 persons per year. For B. microti the same calculation results in 0.1 (±0.08, 95%) seroconversions per 10.000 persons per year. B. divergens The risk of a blood donation being contaminated by B. divergens or B. microti is estimated to be 24.2 and 5.8 per 100,000 blood donations.The present study shows that the local population comes into seroreactive contact with at least one member of the B. divergens-complex and -to a lesser extent -B. microti. To our knowledge, it is the first demonstration of B. venatorum in the Tyrols. Thus, and as vector-borne diseases are subjected to dynamic changes, we recommend re-assessment of the risk of transfusion-mediated infections on a regular basis and to introduce PRT for blood components like platelets.

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