The virus that causes Crimean-Congo haemorrhagic fever (CCHF) is slow moving and will not spread across the country as fast as the H1N1 swine flu virus, experts have said. However, the mortality rate among those affected by Congo virus will be far more than H1N1.
In an exclusive interview to TOI, Dr A C Mishra, director of the National Institute of Virology, Pune, said different viruses have different characteristics. Influenza viruses like H1N1 have very high transmissibility rate and could spread across a country or nations in no time. "That's not the case with the Congo fever virus. It is slow moving and can be contained within hospital or ICU settings with proper containment measures," Dr Mishra said.
"However, the CCHF virus has tremendously high pathogenecity which means mortality rate is very high among those infected. In comparison, H1N1 did not kill that many as it infected. So chances of the CCHF spreading across India from Gujarat - the place where it has infected humans for the first time - is very low," he added.
Indian Council of Medical Research ( ICMR) director general Dr V M Katoch told TOI on Sunday that it was a case of local transmission and the fact that ticks carried the virus was a very dangerous proposition.
So is there a vaccine available against CCHF? A health ministry official said, "There is no safe and effective vaccine available for human use. Ribavirine is the most effective drug and is widely available in the market as it is also used to treat Hepatitis C."
A six-member central team of experts headed by Dr Veena Mittal of National Centre for Communicable Diseases (NCDC) returned to Delhi on Sunday from Gujarat.
"It is clear that the transmission is local and has not been imported. If you see the geography of Rann of Kutch, it is clear that the virus cannot be brought into Gujarat from Pakistan. It is also not a porous border," a team member told TOI. "Now that we know that ticks carry the vHair Replacement Expert Charle Dewitt Comments on Latest Hair Loss Statisticsirus, there is no other option but to destroy them using chemicals called acarisites. This will be undertaken by the Gujarat Agricultural Institute," he added.
NIV Pune has found high quantities of CCHF virus in ticks collected from Ahmedabad. This pointed to the possibility that the virus was now openly circulating in the environment and had not been brought into India from other CCHF endemic countries. Humans may become infected from a tick bite or through direct contact with blood or other infected tissues from livestock such as cattle, sheep and goats.
Dr Katoch added, "We are not even looking at developing a vaccine. It was by chance that humans got infected in India and there is no large scale outbreak."
A particular variety of ticks, Hyalomma, has been found carrying the CCHF virus in high quantities. Hyalomma is a genus of hard-bodied ticks common in Asia. 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 development 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.
Patients with suspected or confirmed CCHF should be isolated and cared for using barrier nursing techniques. Specimens of blood or tissues taken for diagnostic purposes should be collected and handled using universal precautions. Sharps (needles and other penetrating surgical instruments) and body wastes should be safely disposed of using appropriate decontamination procedures.