Ticks are a common concern for outdoor enthusiasts, and Sweden is no exception. These small arachnids are present across many parts of the country, especially in areas with dense vegetation. Understanding where ticks are found and the diseases they can transmit is important for minimizing risks.
Tick Presence and Distribution in Sweden
The most common tick species in Sweden is the castor bean tick, Ixodes ricinus. This species thrives in humid, shady environments such as woodlands, tall grass, and bushes, and can even be found in urban parks and gardens. Ticks require hosts for survival and reproduction; abundant wildlife, particularly deer, provides a plentiful food source.
Ticks are most prevalent in southern and central Sweden, including coastal areas and islands like Öland and Gotland. Due to factors like climate change and increased host populations, Ixodes ricinus has expanded its range northward, now reported in northern Sweden as far as 66°N. The tick season in Sweden runs from early spring to late autumn (March to November), with peak activity in late spring and early summer (June to August). Ticks remain active when temperatures are above 4–5°C.
Key Tick-Borne Diseases in Sweden
Ticks in Sweden can transmit several pathogens, with Lyme borreliosis and Tick-Borne Encephalitis (TBE) being the main concerns. Lyme borreliosis is more common, caused by Borrelia bacteria transmitted by Ixodes ticks. Symptoms often include a characteristic expanding red rash (erythema migrans or “bullseye” rash), appearing at the bite site one to four weeks after exposure. Other early symptoms include tiredness, headache, and muscle and joint pain. Early diagnosis and antibiotic treatment, often with penicillin, are effective in preventing the infection from spreading to the nervous system, joints, or heart.
Tick-Borne Encephalitis (TBE) is a viral disease less common than Lyme borreliosis but can lead to severe neurological complications. The TBE virus is transmitted by Ixodes ricinus ticks. Initial symptoms, appearing one to two weeks after a bite, are often flu-like, including fever, headache, and muscle aches. In about a third of infected individuals, the virus can progress to affect the central nervous system, causing inflammation of the brain or its surrounding membrane. This can lead to symptoms like severe headache, dizziness, nausea, and in some cases, paralysis or long-term cognitive issues. There is no specific treatment for TBE once symptoms develop, but an effective vaccine is available as a preventative measure.
Preventing Tick Bites and What to Do After
Preventing tick bites involves several steps when spending time outdoors in Sweden. Wearing long trousers and long-sleeved tops, especially in wooded or grassy areas, minimizes skin exposure. Tucking trousers into socks or boots creates a barrier against ticks crawling upwards. Using tick repellents containing DEET or Picaridin on exposed skin and clothing deters ticks. Staying on marked paths and avoiding dense vegetation, tall grass, and shrubs where ticks reside is recommended.
After outdoor activities, perform a thorough tick check on yourself, children, and pets. Pay attention to areas such as the knees, elbows, armpits, behind the ears, and in hair. If a tick is found, remove it promptly and carefully using fine-tipped tweezers or a specialized tick remover. Grasp the tick as close to the skin as possible by its head and pull steadily upwards without twisting or jerking, which can leave mouthparts embedded. After removal, clean the bite area with antiseptic or soap and water.
Monitor the bite site for several weeks for any developing rashes or flu-like symptoms. Seek medical attention if a rash develops (especially if it expands beyond 5 cm), or if you experience fever, headache, muscle pain, or neurological symptoms after a tick bite. For those at higher risk or spending significant time in endemic areas, TBE vaccination is a preventative option.