Crimean–Congo Hemorrhagic Fever

There are many viral hemorrhagic fevers whose presentations range from febrile hemorrhagic disease with capillary fragility to acute, severe shock leading to death. The causative agents include arthropod-borne and rodent-associated viruses. The latter do not require an arthropod vector but are transmitted directly via aerosols or through contact with infected excreta or body secretions of the rodents. Still, there are viruses such as the African hemorrhagic fever viruses, Marburg and Ebola, whose reservoirs and modes of transmission remain undetermined. Many viruses cause human hemorrhagic fever, including yellow fever, Dengue hemorrhagic fever, Lassa fever, Marburg and Ebola disease, Crimean–Congo hemorrhagic fever (CCHF), Kyasanur forest disease (KFD), Omsk hemorrhagic fever, Rift Valley fever, Hemorrhagic fever with renal syndrome due to Hantaan virus, and Hemorrhagic fevers named after Africa, Brazil, Venezuela, Argentina, and Bolivia. They are afflicting mankind in different parts of the world. The hemorrhagic fevers constitute a distinct entity characterized by viral replication in lymphoid cells. KFD is found in a limited area of Karnataka State, India. Dengue has been reported across the country in recent years. There is serological evidence of Hantavirus, particularly the Tottapalayam strain, in North Arcot, Tamil Nadu, and reports of Hantavirus infection in India. Other viral diseases are not encountered in India. In early January 2011, an unusual viral fever was reported from Sanad, Gujarat. Three people, including a doctor and a nurse who had attended the patient, died from the mysterious fever in the village of Kolat, 30 km from Ahmedabad. Another patient, the husband of the deceased, was treated for febrile illness, recovered, and the condition was recognized to be due to CCHF virus.[1] In 2012, there were 2 deaths from the same condition in Gujarat. The condition has occurred as a nosocomial infection in India.[2] It has been noted sporadically since then. During 2015, CCHF was reported from Amreli and Kutch in Gujarat and from Jaisalmer, Rajasthan. In 2019, 34 cases of CCHF were reported in Gujarat, with a case fatality of 50%.[3] Mourya and colleagues have highlighted the endemicity of the condition in Gujarat and Rajasthan and the role of animals such as cattle, buffalo, and goats as reservoirs of the virus.[4] In 2023, three cases were reported from Gujarat, of which two died.[3] A 26-year-old adult from Gandhinagar district, Gujarat, was shown to be positive for CCHF in January 2026.[5] The Public Health authorities have alerted about the condition. The CCHF virus infection is prevalent in Africa, the Middle East, Turkey, Pakistan, and Eastern European countries. Hemorrhagic fever was first recognized in 1944 in Crimea, a former Soviet region, and was named after that place. A similar illness was recognized in 1967 in Congo, and Congo’s name was added to it. Later, the causative virus, a Drosdov strain, was isolated in Moscow. CCHF is caused by an orthovirus belonging to the family Nairovirus of the order Bunyaviridae. Hantavirus also belongs to the same family. Nairovirus comprises 7 species with 34 strains. CCHF virus is a spherical, enveloped RNA virus. The virus is spread by infected Ixodid (soft) or Argasid (hard) ticks. A softwood tick bite can also cause KFD. CCHF is primarily found in regions where the hard ticks of the genus Hyalomma are present. The virus is maintained among domestic livestock such as cattle, goats, and sheep, and certain wild mammals through ticks, and, peculiarly, the animals do not manifest any signs of illness. However, they exhibit viraemia. The virus is more active during dry weather conditions. A person acquires the disease through a tick bite or while crushing infected ticks. In addition, the infection spreads through direct contact with the blood or tissues of viraemic animals or humans.[3] The infection can be community-acquired or nosocomially acquired. The disease is endemic in Africa and is predominantly encountered in rural areas, especially among the poverty-stricken lower socioeconomic groups. CCHF has been reported from the Middle East, Eastern Europe, Russia, and China. Ticks feed on domestic livestock, and humans can be bitten by them. The condition affects all age groups and both sexes. Those working as animal herders, livestock workers, and slaughterhouse workers are at risk of acquiring the disease. Medical personnel are also at high risk due to the frequent spread in hospitals from infected human blood and tissues. The virus affects the reticuloendothelial system and activates cytokines. It causes endothelial dysfunction and capillary fragility, resulting in a “leaky capillary syndrome” as seen in dengue hemorrhagic fever. This leads to bleeding. The condition is further aggravated by thrombocytopenia. There is oozing of blood and petechiae, hypovolemia, and shock. After an incubation period of 3–12 days, the condition has a sudden onset and presents with nonspecific features, including high-grade fever, malaise, sore throat, and severe headache. These features are common to most viral diseases. Fever is continuous but may be remittent. Examination often reveals bradycardia, conjunctivitis, throat congestion, hypotension, and a palpable, tender liver. Jaundice may be present in some cases. Hemorrhagic manifestations appear late in the course of the disease. A petechial rash is noted on the trunk, limbs, and oral cavity. There may be epistaxis, hematemesis, melena, and uterine bleeding. Blood examination reveals thrombocytopenia. Leukocytosis is present, unlike leukopenia seen in many viral illnesses.[6] Urine examination may show proteinuria and hematuria. Some cases show elevated bilirubin, alanine aminotransferase, aspartate aminotransferase, and lactic dehydrogenase. The virus is isolated during the 1st week of illness. Antibodies are demonstrable by immunofluorescence and enzyme-linked immunosorbent assay in surviving patients. There is a fourfold increase in antibody levels between the initial stage of illness and 3 weeks later. Patients may report travel to endemic regions in Africa. Such an exposure history was not reported in Gujarat. Diagnosis is made by excluding all other viral diseases responsible for hemorrhagic fever. Malaria, typhoid, and respiratory illness should also be considered in the differential diagnosis. Generally, the flu-like manifestations of the illness resolve after 1–10 days. Asthenia persists for a month or longer. Recovery is generally complete. Severe thrombocytopenia, raised levels of alanine and aspartate aminotransferase, lactate dehydrogenase and creatinine phospokinase (CPK), and prolonged prothrombin time and activated partial thromboplastin time (aPTT) are associated with poor prognosis.[7] The condition, especially in those presenting with hemorrhagic manifestations, disseminated intravascular coagulation, and multi-organ failure, carries a high mortality varying from 15 to 75 per cent. The patient is managed in isolation, and treatment is essentially symptomatic. Health care personnel caring for the patient should wear protective clothing. The patient should be closely monitored, and fluid and electrolyte replacement should be undertaken. Hematocrit should be tested frequently, and blood should be transfused to those with decreased hematocrit values. Ribavirin has been used successfully in the management of CCHF. However, there are no controlled trials confirming its usefulness. Ribavirin should be initiated at the onset of illness.[8] It is administered intravenously at a dose of 100 mg/kg body weight. The dose is then reduced to 25 mg/kg body weight and administered for 3 days. The dose is further halved to 12.5 mg/kg body weight and given for 4 days. The drug is also used prophylactically for those who have been in close contact with the patient. Ribavirin is also available in oral form as tablets containing 200 mg. There is no specific vaccine. The disease is not contagious. Environmental hygiene must be maintained to contain the spread of the disease. Protection against tick bites is essential. Care should be taken when handling the blood and tissues of sick livestock. Veterinary sero-surveys should be conducted to monitor virus circulation in the region. Because the condition resembles many other febrile illnesses, diagnosing CCHF is difficult in non-endemic regions. It is necessary for physicians to keep CCHF in mind when dealing with febrile hemorrhagic disorders in our country, as the condition is highly infectious and carries a high mortality. Author contributions PSS is the sole author of this article and involved in the concept, design and writing the manuscript.