Crimean-Congo fever is a viral disease that can be fatal. The viruses are mainly transmitted by Hyalomma ticks. Hyalomma ticks are originally native to warmer regions of southeastern Europe and Asia, and adult specimens have also been found in Austria for several years.

Crimean-Congo fever occurs in southeastern Europe, the Middle East, and many countries in Asia and Africa

Hosts can be migratory birds and domestic and wild animals, such as cows, sheep, camels or goats

Transmission to humans occurs through tick bites or through direct contact with blood or meat from infected animals and after contact with blood or tissue from infected patients. Nosocomial infections (infections in hospitals or care facilities) can also lead to outbreaks if hygiene is poor.

More than 80% of cases are asymptomatic. The infection can lead to high fever, chills, severe headache, muscle and joint pain, vomiting and diarrhea. General bleeding can cause life-threatening complications

The therapy exclusively combats the symptoms. In severe cases, the primary objective is to safeguard vital functions. The mortality rate is between two and 50 percent, depending on the strain of the virus and the supply situation.

A vaccine is currently not available. In affected areas, animal contact should be avoided and tick bites should be prevented as best as possible.

Human diseases with source of infection in Austria have never been documented so far. In 2018, an adult Hylomma tick was found near Melk. Although it could be ruled out that this specimen carried Crimean Congo virus, other pathogens were found.

Over 30 Hyalomma species have been identified as vectors. Hyalomma ticks are originally native to warmer regions of southeastern Europe and Asia and are mostly unable to finish developing in colder climates. However, adult specimens have also been found in Austria for several years.

Ticks change hosts twice in their lifetime. As larvae and nymphs they feed on one host, as adults on another. As the climate warms, it becomes more likely that nymphs introduced via migratory birds will develop into adults. This also increases the risk of spreading new diseases, such as Crimean-Congo fever.

Ministry of Health: Information for healthcare professionals