we investigated a tbe outbreak , comprising 6 cases , in a mountain region in western austria in july 2008 .
the index case occurred in a 43-year - old shepherd who had stayed for 24 days at his alpine pasture ( 1,564 m above sea level ) before he was hospitalized for nonbacterial urethritis and nonspecific influenza - like symptoms ( including pain in the lower abdomen and legs ) , followed by clinical signs of meningitis .
tbev infection was confirmed serologically by elisa demonstration of specific immunoglobulin ( ig ) m and igg in serum and cerebrospinal fluid .
the patient did not remember a tick bite but had eaten self - made cheese prepared from a mixture of nonpasteurized goat milk and cow milk 811 days before illness onset ; further investigation found 6 additional persons who had eaten the same cheese ( figure ) . for 5 of them ,
recent tbev infection was serologically proven ( table ) . for 3 of these persons ( 2 men , 44 and 65 years of age ; and 1 woman , 60 years of age ) ,
similar to the index patient , a typical biphasic course and symptoms of tbe ( nonspecific flu - like symptoms followed by fever , cephalea , meningism , and ataxia after 410 days ) developed and they were hospitalized .
the 2 other persons who had eaten the cheese ( female , 37 and 7 years of age ) were clinically asymptomatic .
the noninfected person had vomited shortly after eating the cheese because of a gastric banding .
time course and series of events of a tick - borne encephalitis ( tbe ) outbreak from cheese made with goat milk .
week 0 , transport of goat to high altitude ;  , onset of disease ; o 
i , hospitalization period ; tbev , tick - borne encephalitis virus ; me , meningoencephalitis . * tbev , tick - borne encephalitis virus ; nt , neutralization test ; csf , cerebrospinal fluid ; ig , immunoglobulin ; me , meningioencephalitis ; pos , positive ; bor , borderline ; na , not applicable ; neg , negative . the cheese was prepared from a mixture of fresh milk from 1 goat and 3 cows and was eaten shortly after production .
detection of tbev - specific hemagglutination inhibiting ( hi ) and neutralizing antibodies in the goat s serum proved infection in the goat ; the 3 cows were seronegative for tbev . at the time of this investigation ( 1 month after cheese production ) , tbev was already undetectable by pcr in serum and milk of the goat .
cheese from the 3 batches produced after the contaminated batch was tbev negative by pcr .
the 4 domestic pigs kept at the alpine pasture and fed with the whey and goat milk , however , were seropositive ( tbev hi- and neutralizing antibodies detected ) , which indicated tbev infection , but no clinical signs were observed .
serum samples from 105 goats from pastures in the neighborhood also were investigated for tbev - specific antibodies ; all goats were seronegative .
our analyses showed that the 6 humans and the 4 pigs were infected through the milk of 1 goat , which had been transported by car from a tbe  nonendemic valley to the alp 12 days before production of the tbev - contaminated cheese .
experiments have demonstrated that infected domestic animals ( i.e. , goats , sheep , and cows ) can excrete tbev into milk for 37 days , beginning as early as the second or third day postinfection ( 69 ) . in addition , although cheese was produced once or twice each week , only this 1-kg batch of cheese transmitted tbev . therefore , all the evidence indicates that the goat was infected at the alpine pasture at an altitude of 1,564 m. indeed , some ticks were collected from cows that had stayed at this altitude during the entire summer .
analyses of these ticks for tbev by pcr , however , yielded only negative results .
our findings provide further evidence for the expansion of tbev - endemic regions to higher altitudes in central europe .
for example , longitudinal studies in the czech republic , a country with similar climatic and ecologic conditions to those of austria , showed a shift in ixodes ricinus ticks and tbev , from 700 m in 19811983 to 1,100 m altitude in 20012005 ( 10,11 ) .
likewise , zeman and benes demonstrated that the maximum altitude at which tbev is found in the czech republic gradually moved upward during 19702000 , corresponding to the rise in temperature during the same period ( 12 ) . in scandinavia , a northward extension of the geographic range of i. ricinus ticks and tbev since the mid-1980s has also been recognized ( 1,1315 ) .
climatic changes most likely are the major driving forces for the geographic changes in the distribution of tbev and its main vector , i. ricinus , in europe .
this report also emphasizes the efficiency of oral transmission of tbev to humans and to pigs .
six of the 7 persons who ate the cheese and all 4 pigs fed residual milk or whey from the same cheese became infected .
given the excellent effectiveness of the tbe vaccine ( 2 ) , vaccination probably could have prevented all 6 human cases .
 we report transmission of tick - borne encephalitis virus ( tbev ) in july 2008 through nonpasteurized goat milk to 6 humans and 4 domestic pigs in an alpine pasture 1,500 m above sea level . 
 this outbreak indicates the emergence of ticks and tbev at increasing altitudes in central europe and the efficiency of oral transmission of tbev . 
The Study
Conclusions