Back in September, I wrote a blog that included a report from India suggesting that mutations in the H1N1 pandemic virus were causing rapid death. Now, a new report from India, also suggests that the virus is becoming more virulent.
From DNA, October 28, 2009
Pathologists at the state-run Sassoon General Hospital in Pune took tissue samples from the bodies of the deceased to study the effect of the virus that attacks the respiratory tract. “Our doctors have concluded that the virus has undergone some genomic changes,” said Dr Arun Jamkar, dean, BJ Medical College, Pune. A key discovery is that the virus, which was initially causing a bacterial infection, is now causing a more potent viral infection.
“The viral is now leading to a condition called hyalinisation of alvelar membrane, or thickening of the lung wall by deposition of proteins. Due to this, oxygen supply is severely affected, and even ventilators have been of little help,” said Dr Pravin Shingare, joint director, Directorate of Medical Education and Research (DMER).
The state experts have found that the deaths between August 3 and 25 were largely due to formation of pus on the membrane lining the lungs. “During that period, deaths were caused mostly due to a secondary bacterial infection,” said a professor who was involved in the study. But the deaths caused thereafter were the result of deposition of proteins on the membrane. “The deposition is more severe in the case of recent deaths. It leads to the thickening of the membrane, and therefore oxygen cannot not pass into the body at all,” the professor said.
An alteration in the pathology caused by the virus is significant and deserving of notice. This is demonstrable based on the studies done. However, the investigators go on to speculate:
This finding has led experts to conclude that the virus has indeed undergone some changes and its anti-antigenicity is changing.
Not everyone agrees.
But, the National Institute of Virology (NIV) in Pune has a different opinion. Director of NIV, Dr AC Mishra, said that his team is yet to record any change in the behaviour of the virus. “We still cannot say conclusively that the virus has mutated,” he added.
To conclude that mutations are responsible for changes in pathology, it is necessary to actually sequence the viruses and show an association between specific sequences and specific pathology. This has apparently not yet been done.
The Indian investigators also report another puzzling result:
Jamkar said that another interesting finding of the state experts has been that two-thirds of the influenza H1N1 patients who died actually tested negative for the virus. “As many as 36 suspected cases who died were later found negative for the virus,” he said.
There are lots of viruses that cause respiratory symptoms. However, relatively few of them kill people. This suggests one of two possibilities, either there is a new mystery virus that is killing people in India or the assays the investigator are using are incapable of detecting a mutated form of pandemic H1N1.
These two possibilities can be distinguished by unbiased sequencing. Samples are taken and everything within the samples is sequenced. This would allow investigators to determine whether a mutated H1N1 or a novel virus was causing the mystery deaths in India.