Rates of tick-borne encephalitis in Sweden are now well beyond those of surrounding countries, and have been increasing significantly since 2000. [1,2] See graph

(outline of Gideon Graph module – see http://www.GIDEONonline.com/wp/wp-content/uploads/Gideon-Graphs.pps )

References:
1. Berger SA. Infectious Diseases of Sweden, 2011. 427 pp, 133 graphs, 1346 references. Gideon E-books, http://www.gideononline.com/ebooks/country/infectious-diseases-of-sweden/2. Berger SA. Tick-borne Encephalitis: Global Status, 2011. 54 pp, 44 graphs, 314 references. Gideon E-books, http://www.gideononline.com/ebooks/disease/tick-borne-encephalitis-global-status/

Note discussed in ProMED

Prior to the institution of mass vaccination in 1981, Austria reported the highest rates of Tick-borne encephalitis in Western Europe. Currently, highest rates are reported in Germany and the Czech Republic. [1,2] see graph -

References:
1. Berger SA. Infectious Diseases of Austria, 2011. 399 pp, 108 graphs, 1187 references. Gideon e-books, http://www.gideononline.com/ebooks/country/infectious-diseases-of-austria/
2. Berger SA. Tick-borne Encephalitis: Global Status, 2011. 54 pp, 44 graphs, 314 references. Gideon e-books, http://www.gideononline.com/ebooks/disease/tick-borne-encephalitis-global-status/

Update:
Reported on ProMED

Although recent reports of Tick-borne encephalitis (TBE) in Croatia belie the fact that this disease has been steadily declining for five decades, the impact of TBE in Croatia is comparable to that of the main form of arthropod-borne encephalitis in the United States. See graph

TBE was first reported in Croatia in 1953, and mandatory reporting was instituted in 1987. There is only one natural focus in the northern part of the country, between the Sava and Drava Rivers. Alleged cases in Zadar and Pula, have not been certified. 75% of cases occur from May to July.

Approximately 20 cases per year are reported in Koprivnica-Krizevci County, characterized by a relatively mild illness without neurological residua.

References:
1. Berger SA. Infectious Diseases of Croatia, 2010. 356 pp. Gideon e-book series. http://www.gideononline.com/ebooks/country/infectious-diseases-of-croatia/
2. Berger SA. Tick-borne Encephalitis: Global Status, 2010. 52 pp. Gideon e-book series. http://www.gideononline.com/ebooks/disease/tick-borne-encephalitis-global-status/

Recent reports highlight the fact that Sweden has the highest rate of Tick-borne encephalitis (TBE) in Scandinavia, exceding even those of Russia in 2008. [1,2]

The following background data on TBE in Sweden are abstracted from Gideon. Primary references are available on request.

Time and Place:
Disease rates peak during July to August.
- Natural foci are found throughout the southern and middle parts of Sweden up to the counties of Varmland and Dalarna and further north along the Baltic sea.
- Cases are identified on the Stockholm archipelago, the middle and eastern parts of lake Malaren close to Stockholm, the coastal area of the Baltic sea from Stockholm further south to the city of Kalmar and the islands of Oland and Gotland.
- Highest incidence is found on the East Coast, (particularly on the Stockholm archipelago), the eastern region of Lake Malaren and the Gotland Island region.
- The first cases in Skane were reported in 2001. Six cases were reported in the region to 2006.
- 65.3% of cases reported during 1992 to 1996 were acquired in Stockholm, 15.2% in Sodermanland, 6% from Ostergotland or Gotland, and 4.9% from other countries (primarily Finland).
- 402 cases of TBE were registered during 1955 to 1993, with a case/fatality rate of 0.5%. During this period, the disease rate in Stockholm County was 3.4 per 100,000 per year.
- 71% of cases in 2001 were reported from Stockholm, Uppsala and Sodermanland.
- 56% of cases in 2003 were from Stockholm, 15% from Sodermanland and 6% from Uppsala.
- In 2007, TBE virus was the most common agent of viral meningitis in Sweden, accounting for 37.4% of cases.

The male/female ratio among TBE patients is is 2.1/1; and the median patient age is 41.5 years.

Exported cases:
Tick-borne encephalitis was documented in a Swedish national in England (1991 publication).
An American traveler acquired Tick-borne encephalitis in Sweden in 2006.

Prevalence surveys:
21% of adult aseptic meningitis in Northern Stockholm (1999 and 2004)

Seroprevalence surveys:
4% to 22% in endemic areas, and 5% Stockholm
3.5% on the island of Asp (Southeast Sweden) in 1991; 12% in 2002
0.8% of persons in northeastern Skane are seropositive.

Tick-borne encephalitis virus has been identified in Ixodes ricinus found on migrating passerine birds.

References:

1. Berger SA. Infectious Diseases of Sweden, 2010, 417 pp. Gideon e-book series http://www.gideononline.com/ebooks/country/infectious-diseases-of-sweden/

2. Berger SA. Tick-borne Encephalitis: Global Status, 2010, 52 pp. Gideon e-book series http://www.gideononline.com/ebooks/disease/tick-borne-encephalitis-global-status/

Highest rates of Tick-borne encephalitis in Central Europe are reported in Slovenia and the Czech Republic. Rates in Austria are similar to most other countries in the area. Most cases are encountered in Vienna, Upper and Lower Austria, Burgenland, Styria, Carinthia and northern Salzburg province – with highest rates in Karnten and Steiermark.
- During 2005 to 2006, TBE emerged in the upstream valleys of Inn and Isel, and in Ziller valley and Voralberg (Feldkirch region).
- During the pre-vaccination era, Austria had the highest incidence of TBE in Europe, with up to 700 hospitalized cases annually. TBE accounted for over 50% of all viral meningoencephalitis cases in the eastern and southern regions of the country.
- 139 cases were reported among children in Styria during 1980 to 2003 7 ; 116 during 1981 to 2005
- No fatal cases were reported in 1989; 0 in 1991; 1 in 1992; 2 in 1993
- 66 cases were reported in Tyrol during 2000 to 2006.

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