In 2011, nearly a decade after it was first detected in Gujarat, two people died from Crimean-Congo hemorrhagic fever in Rajasthan’s Jodhpur and Jaisalmer. The state government has sent blood samples of 134 other people to the National Institute of Virology (NIV) in Pune for examination. But the disease, which is transmitted either through the bite of a tick, or contact with blood or tissues of infected animals or humans, and has a high fatality rate (from 5% to 80%), underscores the belief that India is fast becoming a hotspot for emerging illnesses. The last decade has seen infectious diseases such as Nipah, Avian influenza, pandemic influenza, severe acute respiratory syndrome (SARS) coronavirus, and chikungunya virus emerging and re-emerging in the country.
Crimean-Congo hemorrhagic fever (CCHF) has not been reported previously from India. Initial clinical features of dengue fever and CCHF are similar and it is very difficult to differentiate and diagnose CCHF. Common clinical features of CCHF include; high-grade fever with chills, headache, body ache, myalgia, vomiting, abdominal pain, weakness, and bleeding from multiple sites. Laboratory investigations showed cytopenia, raised prothrombin time (PT) and activated partial thromboplastin time (aPTT), raised creatinine phosphokinase (CPK), and lactic dehydrogenase (LDH) as well as altered liver and renal functions. Patients with the above symptoms can rapidly progress to bleeding from multiple sites and death compared to dengue fever. It is crucial to recognize CCHF at an early stage to institute ribavirin treatment and also to prevent nosocomial spread of disease to health care workers. Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic viral disease that is asymptomatic in infected animals, but a serious threat to the health of humans. Human infections begin with non-specific febrile symptoms but progress to a serious hemorrhagic syndrome with a high case fatality rate. Although the causative virus is often transmitted by ticks, animal-to-human and human-to-human transmission also occur. CCHF affects mostly adults and is endemic in many countries in Africa, Europe, and Asia. During 2001, cases or outbreaks were recorded in Iran, Pakistan, South Africa with the latest being in India.4 It has also been found in parts of Europe including southern portions of the former USSR, Turkey, Bulgaria, Greece, Albania, and Kosovo.
In this outbreak, this rare deadly virus killed many people. The victims included an adult female, a nurse, and the doctor who treated the adult female at a private hospital in Ahmedabad. The patients died due to multiple organ failure, specifically failure of the liver and kidney. The National Institute of Virology (NIV), (Pune, India) confirmed that all three patients were infected with the CCHF virus. The NIV is testing some 50 samples from the area, and the Gujarat government, warning of a possible outbreak, has begun a screening exercise covering approximately 16,000 villagers then. The CCHF virus may infect a wide range of domestic and wild animals, with the occurrence of this virus correlated with the distribution of a particular species of tick. A number of tick genera are capable of becoming infected with the CCHF virus, but the most efficient and common vectors for CCHF appear to be members of the Hyalomma genus. Trans-ovarial (transmission of the virus from infected female ticks to offspring via eggs) and venereal transmission have been demonstrated amongst some vector species, indicating one mechanism which may contribute to maintaining the circulation of the virus in nature. Many birds are resistant to infection, but ostriches are susceptible and may show a high prevalence of infection in endemic areas. Animals become infected with CCHF from the bite of infected ticks.
However, the most important source for acquisition of the virus by ticks is believed to be infected small vertebrates on which immature Hyalomma ticks feed. Once infected, the tick remains infected through its developmental stages, and the mature tick may transmit the infection to large vertebrates, such as livestock. Domestic ruminant animals, such as cattle, sheep, and goats, are viraemic (virus circulating in the bloodstream) for around one week after becoming infected. Humans acquire CCHF in two different ways; through a tick bite or contact or by contagion. The sources of exposure include being bitten by a tick (happening, occasionally when individuals squash them between their fingers as a means of self-protection), contacting animal blood or tissues, and drinking unpasteurised milk. Human-to-human transmission can occur, particularly when the skin or mucous membranes are exposed to blood during hemorrhages or tissues during surgery. This disease is a particular threat to farmers and other agricultural workers, veterinarians, laboratory workers, and hospital personnel. Infection more commonly occurs in people who have outdoor occupations such as farmers, dairymaids, or woodsmen.
The first sign of CCHF is a sudden onset of fever and other non-specific symptoms including chills, severe headache, dizziness, photophobia, neck pain, myalgia and arthralgia, and the accompanying fever may be very high. Gastrointestinal symptoms including nausea, vomiting, non-bloody diarrhea, and abdominal pain are also common. It is followed, after several days, by the hemorrhagic phase. The average case fatality rate is 30–50%, but mortality rates from 10% to 80% have been reported in various outbreaks. The mortality rate is usually higher for nosocomial infections than after tick bites; this may be related to the virus dose. Particularly high mortality rates have been reported in some outbreaks from the United Arab Emirates (73%) and China (80%). Due to the high case fatality rates and difficulties in treatment, prevention, and control, CCHF is a disease that should be notified to the public health authorities immediately. CCHF virus is also in the list of agents for which the Revised International Health Regulations of 2005 call for the implementation of the decision algorithm for risk assessment and possible notification to the World Health Organization (WHO).
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