Microbe of the Week: Crimean-Congo hemorrhagic fever virus (CCHFV)

Microbe of the Week is written by undergraduate researcher Maria Bergquist

Microbe of the Week: Crimean-Congo hemorrhagic fever virus (CCHFV)

 

Welcome to microbe of the week, where we break down the different disease-causing microbes that lurk inside our tick vectors! While our Microbe of the Week normally focuses on microbes in the United States, this week’s microbe is Crimean-Congo hemorrhagic fever virus (CCHFV)* found throughout Africa as well as spanning from Eastern Europe through the Middle East and into Western China.

*CCHFV describes the virus while CCHF describes the disease caused by the virus.

What is CCHFV?

Crimean-Congo hemorrhagic fever virus is a strain of Nairovirus and is the most widespread tick-borne virus in humans. CCHFV resides in domesticated farm animals such as cattle, sheep, and goats. It is transmitted to humans primarily by the Hyalomma species of ticks, though other Ixodid ticks are capable of spreading the virus. Ticks can remain infected with CCHFV for long periods of time and can even pass the virus on to their eggs. CCHFV can also be spread through the slaughtering of infected animals or person to person through infected bodily fluids.

Symptoms

According to the CDC, initial symptoms of CCHFV include headache, high fever, back pain, joint pain, stomach pain, vomiting, red eyes, a flushed face, a red throat, and petechiae (red spots) on the palate. After about the fourth day of symptoms, large areas of severe bruising, severe nosebleeds, and uncontrolled bleeding at injection sites may occur. Recovery takes about two weeks in most cases. The CDC reports mortality rates for CCHFV range from 9% to as high as 50%, but other academic articles average the rate at around 30%.

Treatments

While there is no known cure for CCHFV, there are supportive treatments available. According to the CDC and the WHO, it’s important to maintain fluid and electrolyte balance in patients with CCHF. Also, the antiviral drug Ribavirin has had some success in reducing viral replication in patients, though more research is required on actual effectiveness.

A Condensed History

• 12th Century — Severe hemorrhagic illness from ticks described in Tadjikistan. 
• 1944 — Russian research team lead by Mikhail Chumakov discovers hemorrhagic fever infecting Russian soldiers and Crimean farm workers. 
• 1956 — Hemorrhagic fever isolated by physician Ghislaine Courtois in the region now known as the Democratic Republic of the Congo. 
• 1967 — Techniques advance to cultivate virus in lab, increasing ability to research CCHFV. 
• 1969 — Researchers determine Crimean hemorrhagic fever and DRC hemorrhagic fever are caused by the same virus, coining the name Crimean-Congo Hemorrhagic Fever. 
• 1984 — First recorded case of using Ribavirin to treat CCHF during outbreak in South Africa. 
• February 5, 2020 — Most recent outbreak of CCHF occurs in Mali.