Open Outbreak

Crimean-Congo haemorrhagic fever

Also known as: CCHF, Crimean-Congo hemorrhagic fever

Crimean-Congo haemorrhagic fever, or CCHF, is a viral disease that mainly spreads from infected ticks and from contact with the blood or tissues of infected animals or people. It is one of the more widely distributed serious tick-borne viral diseases, with reports across parts of Africa, the Balkans, the Middle East, and Asia. Illness often starts suddenly with fever, muscle pain, headache, vomiting, and diarrhoea. Some patients go on to develop bleeding and organ failure. Severity varies by outbreak. In a WHO-reported outbreak in Iraq in 2022, 13 of 97 laboratory-confirmed patients died. There is no widely available approved vaccine for people in the sources used here. Care is mainly supportive, meaning treatment of dehydration, bleeding, and organ problems. Ribavirin has been used, but WHO noted in 2022 that randomized clinical trials had not shown it to be effective. Public-health concern is highest where people are exposed to Hyalomma ticks, livestock, or blood from infected patients without strong infection control.

Key facts

TransmissionTick bites, crushing infected ticks, contact with blood or tissues from viraemic livestock, and direct contact with blood or tissues from infected people during the acute phase.
Incubationunknown
Case fatalityVaries by outbreak; WHO reported 13% (13/97) among laboratory-confirmed cases in Iraq in 2022, and 39% (13/33) among confirmed cases in Iraq in 2021. A single overall figure is unknown from the sources used here.
Reproduction numberunknown
VaccineNo vaccine available for people or animals was reported by WHO in 2022.
TreatmentMainly supportive care. Ribavirin has been used, but WHO reported no evidence from randomized clinical trials showing effectiveness.
ReservoirThe virus circulates between ticks, especially Hyalomma species, and several vertebrate hosts including livestock without causing obvious disease in those animal hosts.
Endemic regionsAfrica, the Balkans, the Middle East, and parts of Asia, including countries south of the 50th parallel north; the 2020 review also notes the Indian subcontinent.

Transmission

CCHF usually reaches people in three main ways. First, infected ticks can transmit the virus when they bite. Second, people can be exposed while handling livestock or animal tissues if those animals are carrying the virus in their blood. Third, spread can happen from person to person through direct contact with blood or other body fluids during the acute phase of illness. WHO’s 2022 report from Iraq said that most confirmed patients had direct contact with animals and many were livestock breeders or butchers. That fits the wider review evidence, which describes CCHF as a tick-borne infection linked especially to Hyalomma ticks. The same review also notes transmission after crushing infected ticks and during close contact with infected patients. For ordinary casual contact, the sources used here do not show transmission as a main route. Risk is highest where tick exposure, animal slaughter, or unprotected care of sick patients occurs.

Symptoms and severity

CCHF often starts suddenly. The overview source lists fever, muscle pains, headache, vomiting, diarrhoea, and bleeding into the skin as possible symptoms. Complications can include liver failure. Illness does not look the same in every patient. Some people recover in about two weeks after symptoms begin, while others become severely ill and need intensive supportive care. The sources used here do not provide one reliable global fatality figure, so it is safer to describe severity as variable. WHO’s Iraq outbreak report gives one clear recent example: among 97 laboratory-confirmed cases reported from 2022-01-01 to 2022-05-22, 13 people died, a case fatality ratio of 13%. The same WHO report also noted that Iraq had reported 33 confirmed cases with 13 deaths in 2021, a much higher proportion that year. These figures show why CCHF is taken seriously, even though outcomes differ between places and outbreaks.

Treatment and vaccines

Treatment for CCHF is mostly supportive care. In plain language, that means treating the patient’s problems while the body fights the infection: fluids, careful monitoring, blood products when needed, and treatment for organ failure or shock. WHO’s 2022 outbreak report says that human cases are mainly treated with general supportive care. The same report says ribavirin, an antiviral drug, has been used in both oral and intravenous form. However, WHO also says that randomized clinical trials have not shown ribavirin to be effective for treating CCHF. That means it may still be used in some places, but the evidence base is limited. On vaccines, the sources used here are clear: WHO reported in 2022 that there was no vaccine available for people or animals. For the public, this means prevention still depends mostly on avoiding tick exposure, reducing risky contact with animal blood or tissues, and using strong infection-control measures in health care.

Where it occurs

CCHF has a wide geographic range compared with other serious tick-borne viral diseases. The 2006 Lancet review says it had been described in about 30 countries and that its distribution closely matches the known range of Hyalomma ticks. A 2020 One Health review says the virus is widespread across Europe, Asia, Africa, the Middle East, and the Indian subcontinent. WHO’s 2022 outbreak report gives a similar regional picture, saying the disease is endemic in Africa, the Balkans, the Middle East, and Asian countries south of the 50th parallel north. Iraq is specifically described by WHO as an endemic country. In the WHO report, cases from 2022 were spread across multiple Iraqi governorates, with a large share in Thiqar. The practical meaning is that CCHF is not confined to one country or one short-lived hotspot. It persists where the tick vector and animal hosts are established, especially in areas with livestock farming and regular human exposure to ticks or animal blood.

Recent history

On this site’s archive, Crimean-Congo haemorrhagic fever appears in 9 WHO-related event notices since 1996. The history results show notices from South Africa in 1996, Afghanistan and Pakistan in 1998, the Russian Federation in 1999, Kosovo in 2001, Mauritania in 2003, Turkey in 2006, Pakistan again in 2010, and Iraq in 2022. That pattern suggests repeated, scattered events rather than one single global wave. The most detailed recent WHO notice available here is Iraq on 2022-06-01. WHO reported 212 cases from 2022-01-01 to 2022-05-22, including 97 laboratory-confirmed cases and 27 deaths overall. WHO also said this was much higher than in 2021, when 33 confirmed cases were recorded in Iraq. In its risk assessment, WHO linked the rise in concern to livestock exposure, seasonal and holiday slaughter, and possible cross-border spread with population movement and animal trade. Recent history therefore points to recurring outbreaks, often tied to rural livestock settings.

What to watch

Several signals would make CCHF more concerning. One is spread into new regions, especially where Hyalomma ticks were not previously established. Reviews of emerging tick-borne diseases warn that tick ranges can shift, and WHO already describes CCHF as having a broad endemic zone. A second warning sign is more efficient person-to-person spread, especially in hospitals or households, because current evidence emphasizes blood and tissue contact rather than easy everyday transmission. A third is any stronger evidence that treatment options are failing or that ribavirin is being relied on despite weak trial evidence. A fourth is vaccine progress stalling, since WHO reported no vaccine available for people or animals. WHO’s Iraq assessment also highlights periods of increased animal movement and slaughter, which can amplify exposure and raise the chance of cross-border spread. In short, watch for new geography, healthcare-associated transmission, pressure on diagnostics and protective equipment, and any change that increases exposure around livestock handling or slaughter.

Updated