Crimean-Congo Hemorrhagic Fever Virus in Asia, Africa and Europe

Abstract

The global spread of ticks and various tick-borne viruses (TBVs) suggests the possibility of new tick-borne diseases emerging. Crimean-Congo hemorrhagic fever virus (CCHFV) is an emerging TBV of the Nairoviridae family that causes serious disease that can be fatal in humans. CCHFV endemic foci can be found in Africa, Asia, the Middle East, and South-Eastern Europe, and has spread to previously unaffected regions and nations, such as Spain, over the last two decades. In this review, we discuss the current situation of CCHFV in Asia, Africa and Europe based on existing knowledge, and we discuss driving factors in the distribution and transmission of the virus, such as the spread of tick vector species and host reservoirs.

Crimean–Congo Hemorrhagic Fever Virus Past Infections Are Associated with Two Innate Immune Response Candidate Genes in Dromedaries

“…Given the relatively high tick burden in the study population, we suspect that repeated exposure occurs, particularly in livestock markets when animals are concentrated and tick control measures are not robust. Though we cannot confirm that all sampled animals have been exposed, we suspect that it is highly likely due to similar serosurvey reports in other countries showing high ratios of seroconversion that increases with age but never reaches 100% in a study population [ 10 , 35 , 36 , 37 , 38 ]. Similarly, in our cohort, we noted an age-associated increase in seroprevalence, but the highest ratio of seropositivity never reached 100% despite a relatively high tick burden on all animals.…”

A Historical Review of Military Medical Strategies for Fighting Infectious Diseases: From Battlefields to Global Health

“…The infection may run asymptomatic in a large percentage of cases, up to 90% in hyperendemic areas [ 485 ]; however, symptomatic cases may be severe with high mortality of up to 40% [ 484 ]. First described during WWII in Soviet military personnel in Crimea [ 486 ] and in 1956 in Congo (hence the name), CCHF is now present in Asia, Africa, and Eastern and Southern Europe, including Spain [ 484 , 487 ]. There is no therapy nor available vaccine, even though in Bulgaria, an inactivated vaccine from suckling mouse brain was licensed and used for at-risk categories of workers, including the military.…”

“…However, the etiologic agent was only identified in the 1980s, whereas the new world type was only identified in 1993 [ 489 ]. The viruses are present in rodents and are transmitted to humans by aerosol of contaminated biological fluids or feces, a condition which may induce consideration of hantaviruses as potential biological weapons, for easy dissemination, high clinical severity and lethality, lack of therapy and vaccine [ 487 , 492 ]. The military seems to be particularly exposed, due to the easier contact with rodents, which is associated with the disruption of the rodent habitat linked to the war and with the operational training in the field [ 493 ].…”

Virome of Giant Panda-Infesting Ticks Reveals Novel Bunyaviruses and Other Viruses That Are Genetically Close to Those from Giant Pandas

“…For example, Crimean-Congo hemorrhagic fever virus (CCHFV, genus Orthonairovirus , family Nairoviridae ) can circulate in nature in vertical and horizontal transmission cycles between ixodid ticks and animal hosts and develop viremia in infected hosts ( 13 ). When transmitted to humans, this virus can lead to a highly lethal hemorrhagic fever with a high case fatality ratio (up to 40%) ( 13 – 15 ). In recent years, the increased prevalence of tick-borne encephalitis virus (TBEV, genus Flavivirus , family Flaviviridae ) has caused great concern ( 16 ).…”