Congo Virus or Crimean-Congo Haemorrhagic fever (CCHF) is a tick-borne viral disease that infects wild and domestic animals, including livestock. Humans can contact this disease by getting bitten by an infected tick living on the host animal or meeting the blood, tissues or fresh meat of the infected animal. Human-to-human transmission is also possible in case of close contact with the organs, blood or other secretions and bodily fluids of the infected person.
Congo virus does not survive high temperatures, and well-cooked meat does not pose any risk of transmission of the virus. The mortality rate from CCHF is approximately 30%, with death occurring in the second week of illness. In patients who recover, improvement generally begins on the ninth or tenth day after the onset of illness.
Symptoms:
Onset of symptoms is sudden and include:
• Fever
• Body aches, headache and abdominal pain.
• Dizziness and Nausea
• Neck pain and stiffness
• Sore eyes and throat
• Photophobia (sensitivity to light)
• Followed by followed by sharp mood swings and confusion
After two to four days, the agitation may be replaced by sleepiness, depression and tiredness, and the abdominal pain may localize to the upper right side of the body with detectable hepatomegaly (liver enlargement).
Other clinical signs include:
• Fast heart rate
• Enlarged lymph nodes
• A rash caused by bleeding into the skin, mouth and throat. The rash may also get severe up to a level that it causes bleeding from the upper bowel, passed as altered blood in the feces, blood in the urine, nosebleeds and bleeding from the gums
There is usually evidence of hepatitis, and severely ill patients may experience quick kidney decline, sudden liver failure or pulmonary failure after the fifth day of illness.
Causes:
CCHF is caused by virus. Since it is enveloped virus, it can be readily inactivated. CCHF virus is stable for up to 10 days in blood kept at 400 C.
CCHF virus may infect a wide range of wild animals and domestic animals such as hares, rats, camel, cattle, sheep and goats. It can transfer from animals to humans as well through a Vector (living organisms that can transmit infectious diseases between humans or from animals to humans) – The common vector of CCHF is a type of tick which is member of Hyalomma genus, the family Ixodidae. These are hard ticks and suck blood from animals and humans. Both male and female ticks can act as a vector for disease transmission.
Environmental factors: Ecological changes, poverty, social instability, poor health services, and absence of standard infection control practices have contributed to increased transmission of the CCHF virus.
Diagnosis
• CCHF virus infection can be diagnosed by several different laboratory tests:
• Enzyme-Linked Immunosorbent Assay (ELISA)
• Antigen detection
• Serum neutralization
• Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)
• Virus isolation by cell culture
• Patients with fatal disease, as well as in patients in the first few days of illness, do not usually develop a measurable antibody response and so diagnosis in these individuals is achieved by virus or RNA detection in blood or tissue samples.
• Tests on patient samples present an extreme biohazard risk and should only be conducted under maximum biological containment conditions. However, if samples have been inactivated (e.g. with virucides, gamma rays, formaldehyde, heat, etc.), they can be manipulated in a basic biosafety environment.
Treatments:
General supportive care with treatment of symptoms is the main approach to managing CCHF in people.
The antiviral drug ribavirin has been used to treat CCHF infection with apparent benefit. Both oral and intravenous formulations seem to be effective.
