The next contagion

Updated - November 16, 2021 08:15 pm IST

Published - April 05, 2013 12:26 am IST

The influenza A(H7N9) virus, a novel bird flu strain that emerged in China, has infected nine people and already killed three. Unlike the H5N1 virus that is widely endemic in poultry in Asia, this strain is unique in several ways. The most important among them is that it has turned out to be lethal; the virus is capable of killing people within a very short span of time after infection. In the case of the first two victims, the time from infection to death was less than two weeks. The third person who died on March 27 lived the longest — 18 days. It also appears to have the same lethal effect on elderly and young people. While the first person to die was an 87-year-old man in Shanghai, the other two were young adults, aged 27 and 35 respectively. Human-to-human transmission has not been found so far but that’s of cold comfort: Unlike the H5N1 strain, H7N9 infection in animals will go unnoticed as the virus does not cause serious disease in birds. This is quite troubling, as researchers and health workers will be unaware of when infection sets in and silently spreads among birds. Culling poultry to halt the spread, which is one of the methods used when ‘traditional’ bird flu strikes, is therefore completely ruled out. This may have long-term implications — the birds will become viral reservoirs and there is a greater possibility of the virus getting established in birds. Genome sequencing of the virus has revealed that it is a product of reassortment — when gene swapping occurs between two or more viruses present at the same time in a host — of three avian influenza virus strains that “infect only birds.”

The sudden emergence of a deadly virus turns the spotlight on the major controversy that surrounded the laboratory research conducted by two teams to create lethal strains of H5N1. In December 2011, the American government “recommended” that Nature and Science journals publish only a redacted version of their research papers. The work dealt with adaptations to the avian flu virus to increase its transmissibility and lethality. The “recommendation” was borne out of misplaced concern that the information contained in the papers may be used by people to engage in bioterrorism. The importance of informing the public and allowing stakeholders to be prepared for such a strain was completely ignored. Scientists ended their moratorium this January on any work related to engineering virulent strains of H5N1 after the authorities were convinced that the risk exists of a transmissible strain emerging. In the end, crucial time was wasted. Much would have been learnt if such essential research was allowed to continue last year.

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