Crimean-Congo hemorrhagic fever or CCHF is a viral disease transmitted by a tick from animals to humans. During the Crimean war, the disease was known as Crimean fever. In 1944 the Soviet scientists identified the disease and labeled it as Crimean hemorrhagic fever. In 1967, the virus was isolated and was named as Congo virus. Because bleeding and fever are major manifestations of the disease, the term hemorrhagic fever is used.
Ticks are infected by the virus, which remains attached to domestic animals like sheep, goats, cows, and buffalos. Humans become infected when the infected tick detaches from the animal and bites a human. Thus, butchers are mostly infected and the disease may become epidemic in the month of Eid-ul-Adha (the Muslim festival of sacrifice). in addition to butchers, other groups of people at risk for getting Crimean-Congo hemorrhagic fever are agricultural workers, individuals in rural areas who are in close contact with animals, veterinarians, leather factory workers in the area with high tick density, campers and hikers, hunters, soldiers and Healthcare workers.
Signs and symptoms of Crimean-Congo hemorrhagic fever
It takes 1 to 3 days for the person to develop symptoms after a tick bite and 3 to 7 days when exposed to blood and body fluids.
Symptoms are sudden onset of high-grade fever with a headache, malaise, muscle pains, sore throat, dizziness, red eyes, abdominal pain, nausea, and vomiting. These are all non-specific symptoms and may be confused with any viral fever. Hemorrhagic fevers are suspected when the patient starts bleeding. Patients may have bleeding from nose, gums, in vomitus, cough or in stools. furthermore, patients may bleed from cannula sites and bleeding may be life-threatening especially when it occurs in the lungs and brain.
Any patient who developed sudden onset of high-grade fever and bleeding from any site after animal exposure needs immediate medical attention.
Diagnosis of Crimen-congo hemorrhagic fever patients.
Congo fever should be suspected in all at-risk person with high fever, systemic toxicity, and bleeding manifestations.
Laboratory investigations may reveal normal/ low platelets count with abnormal coagulation profile, raised liver enzymes, muscle enzymes and azotemia. Labs may suggest disseminated intravascular coagulation as evidenced by raised D-dimers and fibrinogen degradation products with low fibrinogen.
Confirmatory blood tests include congo serology by ELISA and polymerase chain reaction.
Treatment of Crimean-congo hemorrhagic fever patients.
Management of Congo hemorrhagic fever includes supportive care and specific antiviral therapy.
Supportive management includes fluid administration and antipyretics. Paracetamol is used for pain and fever. Avoid aspirin and ibuprofen and other NSAID as it may adversely affect normal clotting.
Platelet transfusion is warranted to maintain platelets count of more than 50000 in a patient who is bleeding or a patient who is having a platelet count less than 20000 without bleeding. Similarly, patients in disseminated intravascular coagulation require the transfusion of fresh frozen plasma.
Specific therapy includes the administration of the antiviral agent – Ribavirin. It is given in a loading dose of 30 mg/kg followed by 15 mg/kg four times a day for four days and then 7.5 mg/kg thrice daily for another 6 days. Thus, the total duration of antiviral therapy lasts about ten days. Side effects of Ribavirin include flu-like symptoms, muscles pain, low platelets count, and anemia.
Prognosis of Crimean-congo hemorrhagic fever patients and our experience at PIMS hospital
Up to 30% of patients die from Crimean-Congo hemorrhagic fever. In our experience at PIMS hospital, diagnosis of CCHF was like a death sentence to the patient, since survival rate remained less than 10% in the past. The poor survival rates could be attributed to late arrivals and referrals, late diagnosis, hospital-acquired infections and comorbid illnesses. In the last few years, the survival rate has improved to more than 90%. These high survival rates have been achieved with the use of high dose methylprednisolone for 3 – 5 days along with ribavirin.
Controlling the spread of infection.
Patients with suspected or confirmed Crimean-Congo hemorrhagic fever should be treated in the isolation rooms. Contact precautions include appropriate personal protective equipment such as a gown. Gloves, mask and eyes and face protection. An N95 mask is having a good aerosol protection.
Managment of exposed individuals.
1. Immediately wash the affected skin surface with soap and water.
2. The mucous membranes such as conjunctiva should be irrigated with a copious amount of water.
3. Exposed person should be medically evaluated. Exposed individuals including healthcare workers with high-grade fever should be admitted and treated as a case of Crimean-Congo hemorrhagic fever. Monitoring temperature, vital signs and urine output, platelets and coagulation profile should be a routine in these patients.
4. Exposed individuals including healthcare workers who are otherwise asymptomatic should be isolated and post-exposure prophylaxis should be immediately started in the high-risk groups.
5. Contact tracing and follow up of family, friends, and co-workers and other patients who may have been exposed to the virus through close contact with the infected health workers is essential.
High-risk individuals who require post-exposure prophylaxis
Post-exposure prophylaxis should be considered for those exposed to Lassa fever or Crimean-Congo hemorrhagic fever. This should be limited to high-risk close contacts of the patient and laboratory and health care workers. High-risk exposure is defined as any one of the following;
- Penetration of the skin by a contaminated sharp instrument.
- Exposure of mucous membrane or broken skin to blood or bodily secretions.
- Participation in the emergency procedure without appropriate personal protective equipment.
- Prolong and continuous contact in a closed space with an infected person without appropriate personal protective equipment.
Prophylaxis dose of ribavirin should be used in all these high-risk patients.
The recommended dose of oral ribavirin is
35 mg/kg loading dose with a maximum of 2.5 gm followed by
15 mg/kg with a maximum of 1 gm every 8 hours for 10 days.
Prevention from acquiring CCHF
1. Avoid tick exposure and avoiding contact with animals body fluids.
2. The use of 20 to 30 % N, N-diethyl-m-toluamide repellant for skin provides some protection and permethrin treated clothes also help to prevent tick bites.
3. Grassy areas should be avoided in warm season when ticks are most active.
4. Ticks should not be handled with bare hands and should be crushed or squeezed.
5. Skin and especially clothes should be examined for ticks.
6. Restricted areas should be established for slaughtering and butchers should be educated to take preventive measures.
7. No FDA approved vaccine is currently available.