In 1110 AD, a mediaeval physician described a hemorrhagic illness after a tick bite, which occurred in Tadzhikistan. The description was very suggestive of Crimean-Congo Hemorrhagic Fever (CCHF). At present Crimean-Congo Hemorrhagic Fever occurs throughout Africa, in Asia, in the former USSR and also in Eastern Europe, the Balkans (Kosovo, Albania), the Middle East Oman, the United Emirates including Pakistan, India and Afghanistan. The virus that causes the infection belongs to the family of the Bunyaviridae, genus Nairovirus. It was originally isolated in 1944-45 in the Crimean peninsula in the north of the Black Sea, during an outbreak in Soviet military personal. This disease first diagnosed in Pakistan in 1976.

Crimean Congo hemorrhagic fever (CCHF) is a zoonotic viral disease, it is one of the severe forms of hemorrhagic fever endemic in Africa, Asia, Eastern Europe and the Middle East with a near fatal mortality rate.

Four stages are included (egg-larvae-nymph-adult) in its development. In the majority of species, the ticks drop off the host animal between stages (exceptions are one-host ticks that remain on the same animal through all stages). Larvae (seed ticks) hatch from the eggs and attach to vegetation to come into contact with passing animals. Attraction to the host is due to heat and carbon dioxide concentration. Once on the new host, they attach and feed on blood.

The geographic range of Crimean-Congo Hemorrhagic Fever virus is the most extensive one among the tick-borne viruses that affect human health, and the second most widespread of all medically important arboviruses, after dengue virus. Since its discovery in 1944, nearly 140 outbreaks involving more than 5,000 cases have been reported all over the world. A total of 52 countries have been recognized as endemic or potentially endemic regions, reporting substantial number of cases every year.

The pathogenesis of Crimean-Congo Hemorrhagic Fever is not well understood. A common pathogenic feature of hemorrhagic fever viruses is their ability to disable the host immune response by attacking and manipulating the cells that initiate the antiviral response. This damage is characterised by rapid replication of the virus along with dysregulation of the vascular system and lymphoid organs. As seen in other viral hemorrhagic fevers, damage to the endothelium plays an important role in Crimean-Congo Hemorrhagic Fever pathogenesis. This further leads to hemostatic failure by stimulating platelet aggregation and degranulation, with subsequent activation of the intrinsic coagulation cascade.

The Crimean-Congo Hemorrhagic Fever virus is transmitted to people either by tick bites or through contact with infected animal blood or tissues during and immediately after slaughter. The majority of cases have occurred in people involved in the livestock industry, such as agricultural workers, slaughterhouse workers and veterinarians.

Human-to-human transmission can occur resulting from close contact with the blood, secretions, organs or other bodily fluids of infected persons. Hospital-acquired infections can also occur due to improper sterilization of medical equipment, reuse of needles and contamination of medical supplies.

The typical course of Crimean-Congo Hemorrhagic Fever infection has four distinct phases—incubation period, prehemorrhagic phase, hemorrhagic phase, and convalescent phase.

Onset of symptoms is sudden, with fever, myalgia, (muscle ache), dizziness, neck pain and stiffness, backache, headache, sore eyes and photophobia (sensitivity to light). There may be nausea, vomiting, diarrhea, abdominal pain and sore throat early on, followed by sharp mood swings and confusion. After two to four days, the agitation may be replaced by sleepiness, depression and lassitude, and the abdominal pain may localise to the upper right quadrant, with detectable hepatomegaly (liver enlargement).

Other clinical signs include tachycardia (fast heart rate), lymphadenopathy (enlarged lymph nodes), and a petechial rash (a rash caused by bleeding into the skin) on internal mucosal surfaces, such as in the mouth and throat, and on the skin. There is usually evidence of hepatitis, and severely ill patients may experience rapid kidney deterioration, sudden liver failure or pulmonary failure after the fifth day of illness.

The mortality rate from Crimean-Congo Hemorrhagic Fever 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.

The general approach in treatment of patients with Crimean-Congo Hemorrhagic Fever viral infection depends on the severity of the clinical manifestation and is done by managing fluid and electrolyte imbalances. The early diagnosis and supportive care in the form of blood, platelet, and plasma replacement has proven to be life-saving.

In endemic regions, prevention depends on avoiding bites from infected ticks. Measures to avoid tick bites include tick repellents, environmental modification (brush removal, insecticides), avoidance of tick habitat and regular examination of clothing and skin for ticks. Clothing should be chosen to prevent tick attachment; long pants tucked into boots and long-sleeved shirts are recommended. Acaricides can be used on livestock and other domesticated animals to control ticks, particularly before slaughter or export.

Contact with infected blood or tissues should also be avoided. Protective clothing and gloves should be worn whenever skin or mucous membranes could be exposed to viremic animals, particularly when blood and tissues are handled. Unpasteurized milk should not be drunk. In meat, the virus is usually deactivated by post-slaughter acidification. It is also killed by cooking.

Strict universal precautions are necessary when caring for human patients. These recommendations include barrier nursing, isolation and the use of gloves, gowns, face-shields and goggles with side shields. Prophylactic treatment with ribavirin has occasionally been used after high-risk exposures. Safe burial practices, including the use of 1:10 liquid bleach solution as a disinfectant, have been published. Laboratory workers must follow stringent biosafety precautions.

Crimean-Congo Hemorrhagic Fever Virus can be inactivated by disinfectants including 1% hypochlorite and 2% glutaraldehyde. It is also destroyed by heating at 56°C (133°F) for 30 min.

Special precautions need to be taken before Eid-ul-Azha. Animals bring from infested areas should be treated at “Entry Points” through direct application of insecticides (acaricides) to bodies of domestic animals through spraying and dusting with insecticides. The heavy application of dusting should be avoided and should not be allowed to get into the eyes, nostrils and mouths of animals. It is particularly important to treat the back, neck, belly, and back of the head. Insecticides treatment should be 12-15 days before slaughtering of animals.

The treatment of animal keeping houses and sheds should include the spray of residual insecticides on floor (also lower areas of walls) of animal houses and associated porches, verandas, and also other places where domestic animals rest or sleep. For better control of hiding ticks, inject liquid formulation of insecticides in cracks and crevices by using syringe (Spot Treatment). Two applications of acaricides and weedicides per season directly on/in their natural habitats like grasses and other vegetation close to animal shed will be adequate to control ticks in around houses.

There is currently no safe and effective vaccine widely available for human use. In the absence of a vaccine, the only way to reduce infection in people is by raising awareness of the risk factors and educating people about the measures they can take to reduce exposure to the virus.

The World Health Organisation (WHO) is working with partners to support surveillance, diagnostic capacity and outbreak response activities in Europe, the Middle East, Africa and Asia.

WHO also provides documentation to help disease investigation and control, and has created an aide–memoire on standard precautions in health care, which is intended to reduce the risk of transmission of bloodborne and other pathogens.