Basic Information on Crimean Congo Hemorrhagic Fever

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Crimean Congo hemorrhagic fever is a common infectious disease in developing countries.

Infectious Agent:

Nairovirus group, Bunyaviridae family

Mode of transmission:

Tick-borne (Hyalomma genus); also direct contact with blood/ tissue of infected people, blood/ tissue of infected domestic animals (butchering) or the grinding of infected ticks.

Image courtesy of CDC/Dr. B.E. Henderson

Incubation period:

Incubation period is usually 1 to 3 days, with a maximum of 9 days. The incubation period following contact with infected blood or tissues is usually 5 to 6 days, with a documented maximum of 13 days.

Case Definition:

Suspected Cases:
Patient with sudden onset of illness with high-grade fever over 38.5°C for more than 72 hrs and less than 10 days, especially in CCHF endemic areas and among those in contact with sheep or other livestock (shepherds, butchers, and animal handlers). Note that fever is usually associated with headache and muscle pains and does not respond to antibiotic or anti-malarial treatment.

Probable case:
Suspected case with acute history of febrile illness 10 days or less, and any two of the following:

Thrombocytopenia less than 50,000 /mm3,
Petechial or purpuric rash,
Epistaxis,
Haematemesis,
Haemoptysis,
Blood in stools,
Ecchymosis,
Gum bleeding,
Other haemorrhagic symptoms

and no known predisposing host factors for haemorrhagic manifestations.

Confirmed case:
Probable case with positive diagnosis of CCHF in blood sample, performed in specially equipped high bio-safety level laboratories. Positive diagnosis includes any of the following:

Confirmation of presence of IgG or IgM antibodies in serum by ELISA or any method.
Detection of viral nucleic acid by PCR in specimen or isolation of virus.

Management:

A suspected case of CCHF should be managed by diagnosing and treating for other likely causes of fever. If there is no response to anti-malarial and antibiotic treatment, the patient’s platelet count should be checked and examined in view of the criteria mentioned above for “probable CCHF”. All specimens of blood or tissues taken for diagnostic purposes should be collected and handled using universal safety precautions.

If the case meets the criteria for probable CCHF, begin isolation precautions, alert health facility staff, report the case immediately, draw blood samples for CCHF diagnostic confirmation, and start treatment protocol below without waiting for confirmation. Patients with probable or confirmed CCHF should be isolated and cared for using barrier-nursing techniques – masks, goggles, gloves, gowns and proper removal and disposal of contaminated articles. Specimens of blood or tissues of probable CCHF cases should be tested only in high-level bio-safety laboratory.

Treatment Protocol:

General supportive therapy is the mainstay of patient management in CCHF. Intensive monitoring to guide volume and blood component replacement is recommended. If the patient meets the case definition for probable CCHF, oral ribavirin treatment protocol needs to be initiated immediately with the consent of the patient/ relatives and strictly in consultation with the attending physician.

Oral Ribavirin: 2 gm loading dose, 4 gm/day in 4 divided doses (6 hourly) for 4 days, 2 gm/day in 4 divided doses for 6 days. Please note that pregnancy should be absolutely prevented (whether female or male partner) within six months of completing a course of ribavirin.

Prophylaxis Protocol:

In case of known direct contact with the blood or secretions of a probable or confirmed case such as needle stick injury or contact with mucous membranes such as eye or mouth, do baseline blood studies and start the person on the ribavirin protocol above in consultation with physician.

Household or other contacts of the case who may have had the same exposure to infected ticks or animals, or who recall indirect contact with case body fluids should be monitored for 14 days from the date of last contact with the patient or other source of infection by taking the temperature twice daily. If the patient develops a temperature of 38.5° C or greater, headache and muscle pains, he/she would be considered a probable case and should be admitted to hospital and started on ribavirin treatment as mentioned above.

Prevention and Control:

Educate public about the mode of transmission through tick bites, handling ticks, and handling and butchering animals, and the means for personal protection.·

Tick control with acaricide (chemicals intended to kill ticks) is a realistic option for well-managed livestock production facilities. Animal dipping in an insecticide solution is recommended.

Persons who work with livestock or other animals in the endemic areas should take practical measures to protect themselves. They include the use of repellents on the skin (e.g. DEET) and clothing (e.g. permethrin) to prevent tick bites and wearing gloves or other protective clothing to prevent skin contact with infected tissues or blood.

In case of death of CCHF patient, family should be informed to follow safe burial practices. Please see EIC Publication: Guidelines for Management, Prevention and Control of CCHF.

Hospitals should maintain stock of Ribavirin; in Pakistan it is available in the market as Ribazole®.

Bio-safety is the key to avoiding nosocomial infection. Patients with suspected or confirmed CCHF should be isolated and cared for using barrier-nursing techniques to prevent transmission of infection to health workers.

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The writer enjoys medical education and has special interest in community medicine.