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air pollution: twenty-four times higher than the rest of China. The population accordingly suffers from all
the classical respiratory problems (and, probably, cancers) associated with industrial smog and high sulfur
dioxide emissions.
Thanks especially to the prevalence of wet markets in the cities, the urbanization of Guangdong has
probably intensified rather than decreased microbial traffic between humans and animals. As income has
risen with industrial employment, the population is eating more meat and less rice and vegetables. The
most dramatic increase has been in the consumption of poultry, which has more than doubled since 1980.
Guangdong is one of China's three largest poultry producers and is home to more than 700 million chick-
ens. An extraordinary concentration of poultry, in other words, coexists with high human densities, large
numbers of pigs, and ubiquitous wild birds. Battery chickens, indeed, “are sometimes kept directly above
pig pens, depositing their waste right into the pigs' food troughs.” 94 Moreover, as the urban footprint has
expanded and farm acreage has contracted, a fractal pattern of garden plots next to dormitories and factor-
ies has brought urban population and livestock together in more intimate contact. Finally, Guangdong is
also a huge market for wild meat. Unlike West Africa, where subsistence demand drives the bushmeat
trade, the Chinese predilection for exotic animals stems from ancient homeopathic beliefs; the demand is
inexorable, and Laos (via Vietnam) has become a major supplier of live game. 95
From the beginning of the second wave of H5N1 in the fall of 1997, everyone in Hong Kong was
looking nervously over their shoulders at Guangdong and the rest of south China. A newspaper in Beijing
reported that there were cases of bird flu in Guangdong but then was forced to retract the story. 96 At the
WHO's urging, the CDC sent H5N1 diagnostic kits to researchers in Guangzhou (Canton) and Shenzhen
to ensure that everyone doing lab work was using the same protocols. In mid-January, after a brief scuffle
over visas, a top-level WHO team was allowed to visit Guangdong for a week. Unlike Hong Kong, with
its lively press and political opposition, Guangdong (despite a quarter-million private businesses) was still
living under the semantic Maoism of press releases that read, “Thanks to the correct line of the Chinese
Communist Party there is no avian flu in Guangdong.” Dr. Daniel Lavanchy, at that time the chief influ-
enza expert for WHO, responded in kind with praise for the “high quality of the surveillance activities
which had been implemented by the Chinese government.” The clear purpose of the mission was to build
bridges with provincial and national authorities, not to overturn rocks (or flocks) where H5N1 might be
hiding. 97
The WHO visit bore fruit with the adoption in March of an influenza surveillance plan for south China
under the administration of the Chinese National Influenza Center; health workers were asked to be par-
ticularly vigilant in reporting and monitoring cases of acute respiratory disease. No human cases of H5N1
were found, but Guangdong and the rest of the south were unexpectedly hit by a severe summer epidemic
of normal flu: H3N2. It was a dramatic reminder that influenza can circulate all year round in tropical and
semitropical latitudes. In the winter the flu moved north, producing one of the most memorable outbreaks
since 1968—in Beijing they called 1998 “the year of the flu.” 98 Flu, however, meant H3N2, not H5N1. It
was almost as if the reigning champion subtype, vintage Hong Kong 1968, had roared back in the face of
the brief challenge from the avian usurper.
In a simpler universe, as in some microbiology textbooks, each subtype would patiently await its turn
at the helm. But in late winter 1999, the new surveillance system revealed a claim-jumper: Hong Kong sci-
entists were stunned to discover H9N2 in two children in March, with five “officially unconfirmed” cases
simultaneously reported from Guangdong. Although none of the cases was life-threatening, the discovery
of another hole in the species barrier was unnerving. The new strain was very close to an H9N2 isolated
from quail the year before by Guan, Peiris, and Shortridge. But it was not the only H9 in town. Surveil-
lance of pigs in a Hong Kong slaughterhouse found animals with the quail strain as well as some with
a distinctive H9N2 derived from ducks. Genetic analysis then implicated the H9 quail strain in the viral
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