Edge of the Abyss - The Monster at Our Door: The Global Threat of Avian Flu - page 50

splendid view of the wiring, but only a fragmentary concept of its purpose. They knew that GenZ, the sole
survivor of a marathon competition between more than a dozen H5N1 genotypes, was a superfit strain,
and was evolving rapidly as it passed back and forth between different populations and species. (Other
studies would show that GenZ was far more environmentally stable than the 1997 strain and that it was
becoming progressively more skillful in infecting mammals.) 209 They also knew that natural selection,
horrifyingly, seemed to favor increased virulence in humans, but they were unable to nail down the mo-
lecular determinants of the human infections in Vietnam and Thailand or, for that matter, explain why
H5N1 had not yet acquired pandemic transmissibility. The researchers noted potentially synergistic muta-
tions at strategic sites in the H5 molecule as well as in proteins (PB2 and NSI) involved with replication
and immune suppression, but they refrained from speculating how these variations were choreographed
in avian or human infections. 210
Gen Z, in other words, was not giving away any secrets. Although leading researchers would presum-
ably all concur with evolutionary biologist Simon Levin that “influenza presents a [evolutionary] system
that is second to none in terms of complexity,” there had been considerable optimism that a “smoking
gun” of some kind would emerge from the high-powered research teams doing parallel work on H5N2
and the resurrected genome of the 1918 virus—science seemed tantalizingly close to unlocking the secret
of why some influenzas were such vicious killers. The team working on recovered fragments of the 1918
genome, led by Jeffery Taubenberger, Ann Reid, and Thomas Fanning at the Armed Forces Institute of
Pathology in Maryland, had made breathtaking progress in unraveling the molecular structure of H1N1/
1918, but they had failed to resolve the central question of the source of its pathogenicity. Indeed, their
research to date has only reframed the essential mysteries of the great pandemic, offering “no definite clue
to [its] exceptional virulence,” while casting doubt on the traditional hypothesis that it originated either in
swine or ordinary waterfowl. 211
By the summer of 2004, in other words, the world's elite influenza researchers had reached the sober-
ing consensus that avian influenza would neither go away nor allow itself to be easily understood. (“It's
troubling to me,” leading CDC researcher Keiji Fukuda confided to the New York Times in fall 2004, “that
we still don't know much more about this virus than we did in 1997.”) 212 Many also had begun to worry
that the virus might bypass the textbook requirement to reassort with a human influenza and simply evolve
on its own to the pandemic stage by the simple accumulation of a few more mutations. “Mutation during
human infection,” the WHO had cautioned in April, “is a second mechanism for improving transmissib-
ility; scientists believe that only a small number of mutational changes in the virus may be needed.” 213
In August Western scientists were shocked to discover that a team of Chinese virologists from the Harbin
Veterinary Research Institute had published a paper in January in which they reported that H5N1 was
widespread in swine in southeast China and urged utmost “pandemic preparedness.” That such an import-
ant report should have passed unnoticed for months by the WHO and FAO hardly inspired confidence in
global influenza surveillance. 214
Just as researchers feared, GenZ came creeping back at the end of spring, infecting a mixed flock of
chickens and waterfowl at a university research farm in Thailand in late May; by July there were wide-
spread outbreaks in Vietnam, central Thailand, and China's Anhui province. Thai officials again respon-
ded by blaming foreign birds and ordered crews to exterminate open-bill storks and chop down the trees
they nested in. (An ornithologist despaired: “I've never seen anything like it. Birds had become the en-
emy.”) 215 In mid-August veterinary officers discovered Malaysia's first case of H5N1 in a pair of fighting
cocks returned from a match in Thailand: troubling evidence that the prized sporting birds were now a
vector of infection. Vietnam then shattered hopes with a belated announcement that three people, includ-
ing two young sisters, had died between 30 July and 3 August in Hau Giang province, southwest of Ho
Chi Minh City. 216