Crimean-Congo hemorrhagic fever in southeastern Europe.

Crimean-Congo hemorrhagic fever (CCHF) is an acute, tick-borne viral disease, affecting only humans and newborn mice, with hemorrhagic manifestations and considerable mortality in humans. CCHF virus circulates in nature in an enzootic tick-vertebrate-tick cycle; migrating birds and livestock transferred from endemic to non-endemic areas may carry large numbers of infected ticks thus spreading the CCHF virus into novel areas. From 2000 through 2008, the infection emerged or re-emerged in Bulgaria, Albania, Kosovo, and Turkey. It has also recently emerged in Greece, where the first human case has been recognized. This has been attributed to mild winters and to the disruption of agricultural activities, both accounting for an increased tick population, as well as to the migration or transportation of tick-infested birds or animals. CCHF cases occurring as an expected event in endemic areas should be notified to clinicians in the international neighborhood. They should be aware of the probability of importation of CCHF cases from endemic areas, of human-to-human transmission, particularly in the nosocomial setting, and of the potential transmission of the virus via tick-infested and infected imported livestock. This novel European CCHF geographic distribution is a challenge for the scientific community of medical microbiologists, epidemiologists, medical entomologists, and veterinarians that could be followed by acceleration of a European Standardized Response at the national, regional, and international level.