Crimean-Congo hemorrhagic fever (CCHF) is caused by infection with a tick-borne virus (Nairovirus) belonging to the Bunyaviridae family.
The disease was first characterized in the Crimea in 1944, which gave it the name of ‘Crimean hemorrhagic fever”. In 1969, it was also identified in the Congo, giving it the present name of Crimean-Congo hemorrhagic fever.
CCHF is endemic in Africa, Eastern Europe, northwestern China, central Asia, southern Europe, the Middle East and the Indian subcontinent.
- Ticks (Ixodid) is the reservoir as well as the vector for the CCHF virus. Many wild and domestic animals, such as cattle, goats, sheep and hares act as amplifying hosts for the virus.
- Animal herders, livestock workers and slaughterhouse workers in endemic areas are at occupational risk of CCHF. Similar is the case with veterinarians and healthcare workers in endemic areas, who are at risk of infection through unprotected contact with infectious blood and body fluids.
- Humans can acquire the infection through tick bites or through contact with infected animal blood or tissues during and immediately after slaughter. Human to human transmission of infection can occur via contact with infectious blood or body fluids. Other modes of transmission are improper sterilization of medical equipment, reuse of injection needles, and contamination of medical supplies.
- The incubation period following a tick bite is 1-3 days (max 9 days); the incubation period following contact with infected blood or tissues is 5-6 days (maximum 13 days).
- The onset of illness is sudden with headache, high fever, myalgia, backache, joint pain, stomach pain and vomiting, red eyes, photophobia, a flushed face, a red throat and petechiae (red spots) on the palate followed by sharp mood swings and confusion. Jaundice may also occur. Hemorrhagic manifestations become evident by the 4th day of illness as the disease increases in severity and may last up to two weeks.
- Case fatality rate in hospitalized patients is as high as 50%.
- Recovery is slow in patients who survive the illness.
- Diagnosis in suspected patients can be confirmed by antigen-capture enzyme-linked immunosorbent assay (ELISA), real time polymerase chain reaction (RT-PCR), detection of antibody by ELISA (IgG and IgM) and virus isolation.
- Treatment is mainly supportive and includes fluid and electrolyte balance, oxygenation, hemodynamic support and treatment of secondary infections. Ribavirin has been shown to have some benefit.
- The key to prevention is to avoid tick bites. This can be done by the use of insect repellent (DEET) on exposed skin, gloves and protective clothing. All healthcare workers should strictly adhere to infection control precautions when handling suspected cases. At present, there is no safe and effective vaccine available for humans.
(Source: CDC, WHO)
Links to earlier published stories on CCHF in eMedinewS