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THE response of the authorities was rapid enough once it was known that it was an outbreak of H5N1 infection in Navapur. However, there certainly was a failure in early detection. The report submitted to the World Organisation for Animal Health after laboratory confirmation of H5N1 on February 18, has placed the onset date as January 27, a gap of nearly three weeks.
It was indeed chance that led to the detection of H5N1 infection among the dying chickens in 16-odd large commercial farms, housing several lakh chickens and spread across an area within a raidus of about 3 km. Even though there were reports of chickens dying for a couple of weeks, was a local news report on February 8, of a truck driver throwing away chickens from a moving truck that alerted the Maharashtra Animal Husbandry Commissioner Vijay Kumar. Until then it was assumed that the deaths were owing to Newcastle or Ranikhet disease virus.
This triggered the government machinery into quick response mode and samples collected on February 9 reached the High Security Animal Disease Laboratory in Bhopal on February 11. The first positive result showed up on February 15 based on multiple diagnostic tests which included the haemagglutinin inhibition (HI) test, the neuraminidase inhibition (NI) test, the Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and real-time RT-PCR. Compared to RT-PCR, real-time RT-PCR is much more sensitive in that it can detect even a few viral particles as compared to hundreds in the former. By February 18, the laboratory had three virus isolates, four positive by RT-PCR and eight positive by real-time RT-PCR from tissue samples and three positive serum samples by RT-PCR, after which the Central government made the official announcement.
Even as the first indications were coming in from Bhopal by February 15 about the presence of H5N1 in one of the 12 samples sent, the Action Plan drawn up by the Centre in November 2005 was put in place.
Like the influenza virus, which is an Orthomyxovirus, NDV is also an RNA virus and belongs to the Paramyxovirus family. NDV also carries haemagglutinin protein on its surface like the influenza virus but the corresponding genes would be different, which can be distinguished only by RT-PCR. When the HI test is run, by inoculating nine-to-eleven days-old embryonated chicken eggs, NDV too will produce a clumping of the red-blood corpuscles.
But to distinguish it from other viruses, the inhibition test should be run to completion by inhibiting its activity using an NDV-specific serum. Because there had been evidence only for NDV until now, this important verification was apparently not done assuming that the infection was NDV. The big mistake seems to lie here. Given the imminent threat of bird flu and the central DAH's notification and Action Plan of November 2005, the laboratory should have forwarded the samples to HSADL. But State Animal Husbandry Minister Anees Ahmad has gone on record as saying that even when deaths were unusually large in number and did not decline, the farms tried to hide the situation by not reporting the deaths to the authorities.
This raises a serious question about the reporting system of notified diseases that is in force in the State. The Centre can act only on the basis of information from the State government, which conveyed the seriousness of the chicken deaths only on February 10, it appears.
But the more serious problem is the complete control over the farming operations by the major hatcheries, for which the farmers operate on contract. The contractors function as `integrators' in that they provide (day-old) chicks, feed, health cover and insurance among other things for the layer birds. The saving grace is that the farms in Navapur do not deal in broiler chicken.
Of course, droppings by chicken on eggs would have carried the infection out during the 12-day delay period because the virus can survive in the faeces for six days at 30{+0} Celsius. This could have serious consequences if H5N1 has got transmitted out of the infection region. But more important, because of fortress-like operations by the farms, government inspectors can never get the right information from them about the prevailing conditions. In fact, post-infection culling operations have reportedly proved difficult. The decision to cull all the birds in the entire 10-km-radius from `ground zero' was a wise move.
R. Ramachandran
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