Crimean-Congo hemorrhagic fever is a deadly infection with the tick-borne virus called Nairovirus. Read about its transmission, symptoms, diagnosis, and treatment.
Crimean-Congo hemorrhagic fever, otherwise called CCHF, is a zoonotic viral infection caused by the virus Nairovirus, which belongs to the Bunyaviridae family and is spread by ticks. It is transmitted in humans through direct contact with infected animal tissues in slaughterhouses. It is a hemorrhagic fever, meaning the symptoms include fever and bleeding disorders, which can progress to shock and death in many patients. Outbreaks of CCHF are a potential public health risk, as it can cause epidemics, and the fatality rate can be up to 40 %.
Outbreaks are more common in hospitals and healthcare facilities and have been reported in Africa, the Middle East, Asia, and the Balkans (southeastern Europe). As this infection was first described in 1944 in Crimea, it was named Crimean hemorrhagic fever. But in 1969, scientists found that the virus responsible for this infection was the same that caused an outbreak in the Congo in 1956, so the condition was renamed as Crimean-Congo hemorrhagic fever (CCHF). No vaccine is available for humans and animals.
The spread of this infection can be prevented by following precautionary measures while treating patients and administering prophylactic therapy for healthcare workers after exposure. It is also necessary to control the population of ticks by the use of pesticides.
CCHF virus can infect various wild and domestic animals, such as cattle, goats, sheep, etc. Most birds are resistant to this infection, but ostriches can get infected, and they are the cause of many human transmissions and outbreaks. An outbreak in South Africa recently was linked to an ostrich slaughterhouse. Animals that get infected, mostly by tick bites, do not show any symptoms. The CCHF virus remains in their blood for about one week after getting infected, which can transmit to other ticks that bite the infected animal.
The virus gets transmitted to humans through tick bites or contact with blood and tissues of infected animals during and immediately after slaughter. Slaughterhouse workers, agricultural workers, and veterinarians are most susceptible. While tick is the major vector, secondary causes are commonly due to human-to-human transmission through contact with infected blood and bodily fluids. This commonly takes place among healthcare workers in hospitals. Improper sterilization of medical equipment and reusing needles can also result in hospital-acquired CCHF.
The incubation period of the CCHF virus varies based on the mode of transmission. After a tick bite, the incubation period is 1 to 3 days, which can be up to 9 days. And that after contact with infected bodily fluids and tissues is 5 to 6 days, which can take up to 13 days. Patients usually develop sudden symptoms, such as:
Muscle ache (myalgia).
Lightheadedness or dizziness.
Neck pain or stiffness.
Sensitivity to light (photophobia).
Nausea and vomiting.
Later, patients develop:
Severe mood swings.
Rapid heartbeat (tachycardia).
Enlarged lymph nodes (lymphadenopathy).
Pinpoint red spots on the mucosa and skin (petechial rash).
The petechiae can result in bigger rashes called ecchymoses.
Patients may develop hepatitis, deterioration in kidney function, liver failure, and lung failure. The fatality rate ranges from 9 to 50 %, and severely ill patients usually die in the second week of illness. Recovered patients start to feel better after the ninth or tenth day of symptoms. The long-term effects have not been well studied. Recovery takes time.
People who work closely with animals, such as herders, slaughterhouse workers, veterinarians, and livestock workers, are at risk of CCHF. Healthcare providers are also at risk. Crimean-Congo hemorrhagic fever is found in the Mediterranean, Eastern Europe (formerly the Soviet Union), northwestern China, Asia, the Middle East, southern Europe, Africa, and the Indian subcontinent.
Various lab tests are available to diagnose the CCHF virus. The tests that can be done are:
Enzyme-linked immunosorbent assay (ELISA).
Reverse transcriptase-polymerase chain reaction (RT-PCR).
Virus isolation by cell culture.
Even with severe infection, patients do not develop substantial antibody responses in the first few days of illness. So the diagnosis is made by the detection of virus or viral RNA in blood or tissue samples.
As there is no specific treatment, only supportive care is given for CCHF patients to help the body fight off the virus. The doctor will prescribe medicines to correct blood abnormalities and secondary infections. Oxygen support is provided if needed, and fluid balance is maintained. After doctors found the virus to be sensitive to the antiviral medicine Ribavirin, it is being used to treat CCHF patients.
No vaccine is available against CCHF for both animals and humans. Sticking to strict precautionary measures is the best way to prevent this infection.
Reducing the Risk of CCHF in Animals:
As animals do not show any symptoms even after getting infected, it is very difficult to identify and prevent CCHF in animals and to stop the tick-animal-tick cycle. Acaricides, chemicals used to kill ticks, can be used in livestock facilities to keep animals tick-free. In a recent outbreak in an ostrich slaughterhouse in South Africa, ostriches were held tick-free for 14 days in quarantine before slaughtering them. This drastically reduced animal to human transmission.
Reducing the Risk of CCHF in Humans:
Educating people about the way this virus spreads and what they can do to stop it is crucial. CCHF virus transmission can be prevented from animals to humans by:
Wearing long pants and trousers and other protective clothing while handling livestock.
Preferably, wear light-colored clothes, as ticks can be easily detected.
You can use Acaricides on clothes to kill ticks.
If you find ticks on your skin or clothes, remove them carefully.
Use pesticides in stables and barns.
Wear gloves while handling animals or their carcasses.
Before slaughtering an animal, keep them in quarantine for 14 days or treat them with chemicals that kill ticks.
To prevent human to human transmission:
Do not come in direct contact with CCHF patients.
If you are caring for CCHF patients, wear gloves and protective equipment.
Do not forget to wash your hands regularly after caring for ill people.
In hospitals, healthcare workers should implement infection control precautions, such as proper hand hygiene, use of PPE (personal protective equipment), and safe injection practices. For more information on Crimean-Congo hemorrhagic fever, consult a doctor online.
Last reviewed at:
08 Oct 2020 - 4 min read
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