Crimean-Congo Hemorrhagic Fever (CCHF) is a very dangerous viral infection that belongs to a group called viral hemorrhagic fevers (VHFs). VHFs are a type of infectious disease caused by viruses that affect the body’s ability to clot blood, hence, any bleeding from the body cannot be stopped.¹ They cause severe bleeding, organ damage, and sometimes even death. VHFs include diseases like Ebola, Marburg, Lassa fever, and Dengue fever.¹

What are viral hemorrhagic fevers?

Viral hemorrhagic fevers (VHFs) are caused by different families of viruses. These viruses affect the body’s blood vessels, often leading to severe bleeding (haemorrhage), fever, and damage to organs like the liver, kidneys, and lungs. In severe cases, VHFs can cause death. Some of the most well-known VHFs include Ebola, which is caused by the Ebola virus, Marburg, caused by the Marburg virus, Lassa Fever, caused by the Lassa virus, Dengue fever, caused by the Dengue virus, and Crimean-Congo Hemorrhagic Fever, caused by Nairovirus.² Though these infections are from different viruses, they have some common features, such as affecting blood clotting and often leading to internal and external bleeding. They all have their mode of infection and are present across several regions of the world.

What causes Crimean-Congo hemorrhagic fever?

CCHF is caused by a virus known as the Nairovirus of the Bunyaviridae family, and it is mainly spread through ticks that carry this virus, in particular the Hyalomma tick.³ When humans are bitten by these infected ticks, the virus gets transmitted to them. Like other viral hemorrhagic fevers, it also spreads between people through contact with infected blood or bodily fluids, so healthcare workers and family members of infected patients are also prone to this infection.

How does CCHF compare to other VHFs?

Transmission

The primary way CCHF spreads is through tick bites. People who work on farms, in slaughterhouses, or handle livestock are at the highest risk of contracting the virus. Human-to-human transmission can occur through contact with infected blood or body fluids, which is why healthcare workers are also placed at a higher risk. Both Ebola and Marburg viruses are spread through contact with the bodily fluids (such as blood, saliva, or urine) of infected animals or humans.

Bats are thought to be the natural host of both viruses. Human-to-human transmission happens through direct contact with blood or fluids, especially during caring for sick individuals or handling dead bodies. Lassa fever is spread through contact with food or household items contaminated with rodent urine or droppings. The disease is very common in the regions of West Africa. Person-to-person transmission is possible, especially in hospitals where proper precautions aren’t followed.

Dengue is spread by mosquitoes, specifically the Aedes mosquito. It does not spread from person to person, but through mosquito bites after a mosquito bites an infected person. Unlike CCHF, which is mainly spread through ticks, Ebola, Marburg, and Lassa fever are often spread through contact with infected bodily fluids. Dengue is unique because it spreads through mosquitoes, not direct human contact.

Symptoms

Early Symptoms include fever, headache, muscle aches, fatigue, and nausea. Severe symptoms are bleeding (from the nose, gums, and internal organs), organ failure (especially liver and kidney), shock, and death in some cases. Ebola and Marburg infection also begins with fever and muscle pain, but they quickly lead to severe bleeding, vomiting, diarrhoea, and damage to the liver and kidneys.

Lassa Fever can cause hearing loss in survivors, along with fever, headache, and chest pain. Dengue Fever causes fever, joint and muscle pain, and a rash. In severe cases, it can progress to a dangerous form called dengue hemorrhagic fever, which leads to bleeding and organ failure. While all VHFs cause fever and bleeding, the severity and types of symptoms can vary. CCHF, like Ebola and Marburg, can lead to severe internal bleeding, while Dengue usually causes joint pain and only progresses to bleeding in extreme cases.

The mortality rate Crimean-Congo Hemorrhagic Fever has a higher mortality rate. It said that around 10-40% of cases end in death.⁴ Patients who are not given appropriate early treatment are more likely to die. Ebola fever is notorious for its high mortality rate, which can range between 20% and 90% depending on the species, epidemic, and treatment availability.⁵ Marburg is quite similar to Ebola, with a comparable mortality rate. Compared to Ebola and CCHF, Lassa has a lower fatality rate, with around 1% of patients dying.⁶ Pregnant women, on the other hand, are more likely to die if infected. Dengue has a substantially lower death rate than other VHFs, with the majority of patients recovering completely.

Geographical distribution

CCHF is common in Africa, the Middle East, Asia, and Eastern Europe. People living in rural regions with cattle and ticks are at a higher risk. Ebola and Marburg are primarily found in sub-Saharan Africa. Ebola outbreaks have been reported in West and Central Africa, but Marburg is more prevalent in East Africa. Lassa Fever is widespread throughout West Africa, particularly in Nigeria, Sierra Leone, and Liberia. Dengue fever is more prevalent in tropical and subtropical regions such as Southeast Asia and South America. CCHF is more widely distributed than Ebola, Marburg, or Lassa fever. Dengue fever is the most common of the VHFs, infecting vast populations in tropical areas.

Treatment

There is no specific treatment for any of the viral hemorrhagic fevers, including CCHF. Treatment is supportive, which means doctors focus on relieving symptoms and helping the body recover through hydration and rest. In CCHF, patients receive fluids, blood transfusions, and medicines to help with pain and fever. The antiviral drug ribavirin has shown some promise in treating CCHF, though it is not always effective. For Ebola and Marburg, supportive care, such as fluids and oxygen, is the main treatment. However, there are now vaccines and experimental antiviral drugs that can help reduce the severity of Ebola.

Like CCHF for Lassa fever, ribavirin can be used to treat Lassa fever if given early. There is no specific antiviral treatment for dengue. Treatment focuses on managing fever and pain, and preventing dehydration. Severe cases may require hospitalisation. While all VHFs lack a specific cure, experimental treatments and vaccines for Ebola have shown promise. Ribavirin is used for both CCHF and Lassa fever, though it is not a guaranteed cure.
 

Summary

Crimean-Congo Hemorrhagic Fever (CCHF) is one of many viral hemorrhagic fevers, a group of diseases known for causing severe bleeding, organ damage, and high mortality rates. CCHF shares many features with other VHFs like Ebola, Marburg, Lassa, and Dengue, including how it affects the body and the lack of specific cures.