New Delhi, Nov 05: Investigations into the dengue outbreak reveal that this year's episode has been caused by two virus strains - 2 and 3 - and scientists warn that emergence of strain 3 may make the disease more dangerous in the future. The National Institute of Communicable Diseases, which investigated the strain of the virus, found that of the five samples analysed for the sequence, three were of dengue strain 3 and two were of dengue strain 2, its officials told reporters.
The dengue outbreak in 1996 was majorly of dengue strain 2, which has more chances of haemorrhage. Apparently prevalence of dengue 3 has considerably increased this year, Dr Naveen Khanna from the Recombinant Gene Lab at the International Centre for Genetic Engineering and Biotechnology (ICGEB) said.
Dengue strain 3 is believed to be a milder strain in comparison to dengue 2. But, evidence has shown emergence of a new subtype of dengue 3 - subtype III - in this part of the world, which is much more virulent resulting in more haemorrhagic fever in infected people, Khanna said.
Almost all recent severe dengue outbreaks in the subcontinent have been associated with this new subtype.
The new strain had come to light through a study by the US-based Centre for Disease Control (CDC) in Sri Lanka after incidence of hemorrahagic fever had increased there in 1990s.
By 1994, the new subtype had moved as far as Latin America, Khanna said adding the strain has been prevalent in this subcontinent and Africa.
Bureau Report