Pune: The chikungunya surge in the city and surrounding areas has been caused by the Indian Ocean lineage of the virus, a known culprit that has triggered large outbreaks in the past, scientists from National Institute of Virology have said. The announcement is based on analysis of patient samples and preliminary genome sequencing data. NIV director Dr Naveen Kumar told TOI the virus appears to "cluster" with previous circulating strains found in India, indicating it is not a new strain, but "a resurgence of one previously seen".
The term "clustering" refers to the genetic similarity between the current virus strain and those detected in past outbreaks in India. It suggests the virus shares a lineage with older strains and is not significantly different in its core structure. The 'Indian Ocean strain' of the chikungunya virus first emerged in investigations into mass outbreaks on islands in the Indian Ocean, in 2006.
That year, the island of Reunion, one of the worst hit, recorded 45,000 cases within a week. Doctors in Pune city said it would also be a good time to look for mutations in the virus, given the seriousness of symptoms they've seen in patients. "Though the virus belongs to a known lineage, the large number of severe cases, including neurological complications, makes it crucial for us to determine if there mutations present," said Dr Ameet Dravid, an infectious disease expert from Noble Hospital.
He said: "We've had respiratory pneumonitis in some chikungunya patie.