Tick-Borne Disease Part II: Crimean-Congo Hemorrhagic Fever

This story is Part II of a series on tick-borne disease. Here we discuss the severity and spread of Crimean-Congo Hemorrhagic Fever, the only hemorrhagic fever transmitted by ticks.

At present there is a serious outbreak in Iraq of Crimean-Congo Hemorrhagic Fever, a rare but deadly tick-borne disease. This is not the first time, as it is endemic to many parts of Africa and the Middle East, but this outbreak is more severe than is usually seen. The World Health Organization received reports from Iraq of 212 cases, 46% of which were laboratory confirmed. There have been 27 fatalities so far, and the death toll is expected to continue to rise.

As of 2020 there were at least 27 tick-borne diseases recognized around the world. Nicknamed the “Nose-Bleed Fever,” Crimean-Congo Hemorrhagic Fever has been around for a long time but is now spreading on multiple continents, including through Europe. Carried and transmitted most frequently by ticks of the genus Hyalomma, Crimean-Congo Hemorrhagic Fever (CCHF) carries a mortality rate often as high as 40%. There is currently no known specific vaccine or treatment. Cases have been documented in many different parts of the world, including Africa, Asia, the Middle East, Russia, and the Balkans. Recent and more frequent outbreaks have occurred in Western Europe, leading the World Health Organization to categorize CCHF as a priority pathogen.

From the family Nairoviridae and order Bunyavirales, Crimean-Congo Hemorrhagic Fever virus has a circular, negative-sense, single-stranded RNA genome. There are three segments, Small (S), Medium (M), and Large (L), each of which encodes different aspects of the virion. The L segment, the biggest, encodes the RNA polymerase, the M segment encodes the glycoproteins, and the S segment encodes the nucleocapsid protein.


Originally published on Forbes on June 3, 2022.

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© William A. Haseltine, PhD. All Rights Reserved.