Ronan Kelly
Retired 2020
Mumbai under attack of 3 influenza viruses
Sumitra Deb Roy, TNN, Aug 11, 2010, 04.42am IST
MUMBAI: Three types of influenza viruses are circulating in Mumbai's air, with the most "potent and predominant" H1N1 affecting people even more than the seasonal flu, experts told TOI, providing a possible explanation for the deluge of fever and cold complaints at city hospitals.
The observation about the three strains was made by virologists working with Haffkine Research Institute, who, between June and August this year, studied 500 patients admitted for influenza-related ailments in various hospitals.
Of the 500 patients studied, the institute found that about 23 % tested positive for H1N1, while about 11 % were positive for the seasonal flu. Surprisingly, 8% of the samples tested positive for influenza B, a relatively less virulent influenza strain that did not surface in Mumbai last year.
In the last 10 days, about 99 people have tested positive for H1N1 in the city, while about 500 had tested positive in July. "Three virus types are circulating in Mumbai air, but so far there are fortunately no cases where one person is suffering from any two types together," said Dr Abhay Chaudhary, director, Haffkine Research Institute. "Influenza H1N1 is undoubtedly the most predominant virus in the air now and it will continue to be so for some time."
Chaudhary added that the H1N1 virus has surpassed the seasonal flu in afflicting the wider public, a finding echoed by the National Institute of Virology (NIV) in Pune.
Speaking to TOI, the director of NIV, Dr A C Mishra, said that samples tested at the laboratory were primarily testing positive for H1N1. "As much as 40% of the samples are testing positive for the pandemic virus, whereas just about 10% are found to be affected by the seasonal flu," Mishra said, adding that traces of influenza B type were also found in Pune's air.
Virologists said they were surprised that the milder B type has managed to affect people. "It is amazing that B type has actually managed to find its place amidst stronger strains like the pandemic and seasonal one," added Chaudhary. In 2008, incidentally, influenza B was the more dominant strain to affect Mumbai.
But does that mean that influenza B has gained in potency? Infectious diseases expert Dr Om Srivastava said: "Clinical features of virus types are undergoing tremendous change. Even influenza B can have crippling effects, but it still remains milder than the other influenza types."
Some experts differ with Chaudhary and Mishra about H1N1's dominance. Dr Jayanthi Shastri, the head of BMC's PCR lab at Kasturba Hospital, said, "The magnitude of the pandemic virus cannot be judged as only those who are hospitalised are getting tested".
Shastri added that there is no community sampling to deduce such a conclusion.
Mishra, however, countered that in Pune even outdoor patients were tested. "Our deduction can easily be upheld as indicative of the entire community," he said.
Read more: Mumbai under attack of 3 influenza viruses - Mumbai - City - The Times of India http://timesofindia.indiatimes.com/...viruses/articleshow/6289980.cms#ixzz0wGF53vK0
Sumitra Deb Roy, TNN, Aug 11, 2010, 04.42am IST
MUMBAI: Three types of influenza viruses are circulating in Mumbai's air, with the most "potent and predominant" H1N1 affecting people even more than the seasonal flu, experts told TOI, providing a possible explanation for the deluge of fever and cold complaints at city hospitals.
The observation about the three strains was made by virologists working with Haffkine Research Institute, who, between June and August this year, studied 500 patients admitted for influenza-related ailments in various hospitals.
Of the 500 patients studied, the institute found that about 23 % tested positive for H1N1, while about 11 % were positive for the seasonal flu. Surprisingly, 8% of the samples tested positive for influenza B, a relatively less virulent influenza strain that did not surface in Mumbai last year.
In the last 10 days, about 99 people have tested positive for H1N1 in the city, while about 500 had tested positive in July. "Three virus types are circulating in Mumbai air, but so far there are fortunately no cases where one person is suffering from any two types together," said Dr Abhay Chaudhary, director, Haffkine Research Institute. "Influenza H1N1 is undoubtedly the most predominant virus in the air now and it will continue to be so for some time."
Chaudhary added that the H1N1 virus has surpassed the seasonal flu in afflicting the wider public, a finding echoed by the National Institute of Virology (NIV) in Pune.
Speaking to TOI, the director of NIV, Dr A C Mishra, said that samples tested at the laboratory were primarily testing positive for H1N1. "As much as 40% of the samples are testing positive for the pandemic virus, whereas just about 10% are found to be affected by the seasonal flu," Mishra said, adding that traces of influenza B type were also found in Pune's air.
Virologists said they were surprised that the milder B type has managed to affect people. "It is amazing that B type has actually managed to find its place amidst stronger strains like the pandemic and seasonal one," added Chaudhary. In 2008, incidentally, influenza B was the more dominant strain to affect Mumbai.
But does that mean that influenza B has gained in potency? Infectious diseases expert Dr Om Srivastava said: "Clinical features of virus types are undergoing tremendous change. Even influenza B can have crippling effects, but it still remains milder than the other influenza types."
Some experts differ with Chaudhary and Mishra about H1N1's dominance. Dr Jayanthi Shastri, the head of BMC's PCR lab at Kasturba Hospital, said, "The magnitude of the pandemic virus cannot be judged as only those who are hospitalised are getting tested".
Shastri added that there is no community sampling to deduce such a conclusion.
Mishra, however, countered that in Pune even outdoor patients were tested. "Our deduction can easily be upheld as indicative of the entire community," he said.
Read more: Mumbai under attack of 3 influenza viruses - Mumbai - City - The Times of India http://timesofindia.indiatimes.com/...viruses/articleshow/6289980.cms#ixzz0wGF53vK0