Broiler Explosion

Broiler explosion8As early as the 1820s, high-pressure engines [on the Mississippi River] were technologically residual; they were dirtier and more dangerous than the low-pressure engines that were employed on steamboats elsewhere. They could, however, generate more power than low-pressure engines; they made it possible to run boats faster and harder–over sandbars, against the current, past the competition, and so on. They were also cheaper…That high-pressure engines were more likely to explode and faster boats more likely to sink when snagged were known risks, deliberately taken. Competition in the steamboat business spurred technological degradation rather than technological innovation. Danger was built into the boats. –Walter Johnson (2013)

A new influenza has spilled over from poultry in and around Shanghai. As of April 15, Chinese authorities have reported 60 human cases of H7N9 and 13 deaths. The most serious cases have suffered fulminant pneumonia, respiratory failure, acute respiratory distress syndrome, septic shock, multiorgan failure, rhabdomyolysis, and encephalopathy.

Virologist Richard Webby reports molecular adaptations suggesting the new variant is evolving toward human specificity. “This thing doesn’t any longer look like a poultry virus,” Webby said, “It really looks to me like it’s adapted in a mammalian host somewhere.”

Recombinomics’ Henry Niman identifies several of H7N9’s amino acid replacements, including those which have accrued over the course of the outbreak. The neuraminidase Q226L replacement previously documented in ferret transmission studies proved absent in the first reported case of H7N9, evolving only subsequently. Niman reports two other mammal-specific replacements, hemagglutinin D225G and E627K on PB2. Rongbao Gao and colleagues, the Chinese team that first published on the new variant, describe a R292K replacement in neuraminidase associated with Tamiflu resistance.

The virus has been isolated in several birds, perhaps marking a pre-spillover epizoology, but to CIDRAP’s Mike Osterholm a pig intermediary remains a possibility. In early March 16,000 dead pigs were found in tributaries leading into Shanghai’s Huangpu River.

Whatever the source of infection, the speed at which human cases are accumulating, including within families, belies official denials H7N9 hasn’t gone at least sporadically human-to-human. It’d be astonishing if 60 separate spillover events took place from bird to human.

Low-pathogenic H7N9 has long been reported in waterfowl across the globe. As in H5N1’s evolution, however, the new variant is characterized by a novel combination of genomic segments. Gao’s team identify the H7 and N9 phylogenetically closest to waterfowl H7N9 and all six internal segments to poultry H9N2, several variants of which have long circulated in China. It’s an important distinction CDC’s Timothy Uyeki and Nancy Cox fail to make in their accompanying commentary, pinning the H7N9/H9N2 split to differences in “avian” taxa alone.

Contrary to several reports, this is not the first time H7 has been found in China. Several studies have reported multiple H7 reassortants long circulating in East Asia, including China. For H7 strains found in poultry farms in Italy and around China’s Poyang Lake 1999-2005, a stone’s throw from Shanghai, Laura Campitelli and colleagues found a similar split in the phylogenies of hemagglutinin and those of the internal proteins, albeit while looking across H7 reassortants and not just within a single outbreak,

[The] H7 haemagglutinin genes were all closely related to each other, whereas the remaining genes could be divided into two or more phylogenetic groups [indicating reassortment]. Almost each year different H7 reassortant viruses were identified and in at least two different years more than one H7 genotype co-circulated [across Eurasia].

Meanwhile Hye-Ryoung Kim and colleagues may have taken a snapshot of the evolution leading up to, or alongside, the Shanghai H7N9 in what in phylogeny qualifies as real time,

The N2 gene of the A/duck/Korea/A349/09 (H7N2) strain was related to that of the LPAI H5N2 and H9N2 strains that were recently isolated from poultry and wild birds in South Korea and China (data not shown). These data suggest that the various NA genes of the H7 viruses have originated from the gene pool of AIV in poultry and wild birds in Eurasia.

Note the H9N2 admixture, which, on the other hand, could be only one of several H7/H9 experiments underway.

H7 outbreaks have been accumulating worldwide in poultry since at least the mid-1970s, including outbreaks in which infections evolved into greater pathogenicity. Repeated H7 spillovers into poultry workers have concomitantly been documented.

In other words, despite the breathless coverage, this H7N9 is part of a long and involved agroevolutionary trajectory.


Leave it to the business press to focus in on what’s most important about the outbreak. One Forbes headline reported, “H7N9 Bird Flu Cases Rise To 33, Deaths Reach Nine in China; KFC Sales Slump”.

“The public should somewhat restrain their anxieties to avoid this becoming a disaster for the whole poultry industry,” the Global Times editorialized. Shirking one’s patriotic duty would be “unfair to farmers”.

Gallows humor aside, there is an element of truth here one won’t find in the biomolecular reports or the news briefings the World Health Organization conducts stage-managing the outbreak. Nary a word has been or will be offered about the agroeconomic context out of which this next in a long line of isolated incidents emerged, save the obligatory and, given the virus’s asymptomatic clinical course in birds, impotent calls for increased biosecurity.

In a critical sense, it doesn’t matter which genomic segments matched up with which other. Causality may not be found so much in the object as in the field–the context in which the various segments can be traded so far and wide and across so many host species. The molecular alphanumerics are a useful distraction from the broader processes and players that produced human infections H1N1 (2009), H1N2, H3N2v, H5N1, H5N2, H6, H7N1, H7N3, H7N7, H9N2, and now H7N9.

What many know, but few will publicly discuss, is the role agribusiness innovations have played in facilitating the emergence of myriad novel influenzas. The resulting industrial accidents are discussed as if, like earthquakes and tsunamis, they too carry an ‘Act of God’ indemnification, a mistake easy to make when one is professionally obligated to view capitalism as the natural order of things.

Pathogens, however, arise out of anthropogenic circumstances, specific to conditions and place. Spatial modeling by FAO’s Vincent Martin and colleagues shows bird flu risk attached to particular agroecologies and extends well beyond the Pearl River delta on which attention was initially focused.

Even if the reassortment roulette taking place across East Asia is accompanied by an obvious element of chance, the nature of the agroecological complex embedded within Shanghai’s commodity field, extending as far as Poyang Lake and beyond, may tilt the odds toward spillover influenzas. “In Southern China a large potential zone of virus persistence extends from south of the Yangtze River,” Martin’s team writes,

This area hosts the vast majority of the Chinese duck population comprising birds for meat or egg production. This area can be subdivided into three areas: I-a) an area which extends from the provinces of Jiangsu, Anhui, Hubei, Jiangxi, Hunan, Guangxi autonomous region down to Guangdong province. This might be one of the most important ecological zones where key epidemiological drivers for emergence, persistence and spread are present, including a huge reservoir population, traditional farming system, a high animal and human population density, some major wild bird congregation sites such as the Poyang lake located in Jiangxi province and an important North – South gradient of poultry trade which crosses this region…. I-b) A coastal area stretching from Jiangsu to Guangdong provinces with a risk hotspot in Guangdong province along the Pearl River delta. This strip of coastal land also hosts the typical duck pond system where the risk of infection and disease is present. I-c) Few isolated areas within this geographical zone displaying an increased risk located in Yunnan, Guangxi autonomous region, Guizhou, Sichuan and Chongqing provinces which have experienced either outbreaks in the past (Guangxi autonomous region and Yunnan) or only reported viral circulation (Sichuan and Chongqing provinces).

The extent and complexities of China’s integrated bird flu agroecology have been captured by phylogeographies since at least 2008, connecting Shanghai to provinces north and south. As the Martin group writes, the system’s mechanisms are now being traced,

[The] different regions of China are not independent and are possibly epidemiologically linked through poultry trade and likely also through wild bird migrations. High production-demand discrepancies lead to long-distance trade of poultry products (e.g. chicken from the north exported to southern provinces, or duck meat exported from the south to the north). In addition, areas such as the Poyang lake, where a large population of domestic waterfowl is raised in close proximity to thousands of over-wintering wild waterfowl, could favour the transmission between wild and domestic waterfowl and lead to long-distance transmission of the virus….[The] 2006 [HPAI H5N1] Shanxi strain also grouped into the clade 7 cluster present in North-Central China has been found in Jiangsu province in South Eastern China. There is a complex pattern of links that exists between these different ecological regions that offers hiatuses for viruses to escape their reservoir areas and invade others.

A team of which I was a part characterized this geographic complexity as historically contingent, melding ancient (rice), modern (duck), and neoliberal (poultry intensification) into dynamic geo-specific composites,

The agro-ecological conditions found in southern China today arise from an amalgam of historical innovations and circumstances some of which are still in operation in one form or another today. Intensive duck farming relies in part on agro-ecosystems dating back at least 500 years. In some areas, the more traditional techniques of duck husbandry remain in practice. The elements of eras past and present interact to such an extent that they are effectively contemporaneous, in what Althusser (1965/2009) defined as the ‘historical present’…[S]outhern China’s role as a primary influenza epicentre is far from inherent, instead arising from a contingent confluence of factors in a Harvey-esque (1982/2006) ‘active moment’ in spatial configuration…

What we find in southern China today is neither effortlessly remade independent of history nor enslaved to a static past. The region has neither been unconnected from the rest of the world nor had its specificities erased by a wave of recent generic globalisation. The socioecological environment in which influenzas are evolving there is the complex and layered product of past and present, of global and local. The causes of emerging influenzas in southern China today are threads which may bind many places, peoples, and times together, though never evenly, and in a place-specific way.

Indeed, Shanghai’s influenza agroecology appears vibrant, connected to local and global alike.

Qiaoyang Teng and colleagues found a series of novel avian reassortants in Shanghai’s poultry markets, including H3N2, H4N2, and H11N2. Jin-Ping Zhou and colleagues found multiple H9N2 reassortants circulating across Shanghai live-poultry markets, fair-trade markets and poultry farms. Fe-Fe Gei’s team discovered a series of H9/H5 reassortants across Shanghai’s poultry markets.

In the face of the interventions that quash individual outbreaks, influenza’s evolution apparently marches on. Pinghu Zhang’s team followed H9N2 outbreaks over five years in a single broiler chicken operation in Shanghai. Virus across all outbreaks in the plant appeared related to that of the first outbreak despite vaccination efforts. The H9N2 isolates, with internal loci that arose via local reassortment with H5N1, showed evolution by antigenic drift across the study period.

We are early in the H7N9 investigation and the data are presently unavailable for identifying the phylogeographic source of this particular reassortant. In some sense, where exactly doesn’t matter, so much as the underlying regional processes delivering so many novel influenzas quite literally to our plates.

For instance, Jiangxi Province’s Poyang Lake, to which Martin’s team alluded and where Laura Campitelli’a group found a variety of H7 reassortants, plays home to an extraordinary melange of wild migratory birds and poultry. Preliminary work by Xiangming Xiao’s international team shows there is a very fine line indeed between ‘wild’ and ‘domestic’ birds at Poyang. Xiao’s team found an extraordinary array of farmed waterfowl: Swan Geese, Greylag Geese, Mallards, the Spot-billed Duck, the Northern Pintail, the Eurasian Wigeon, the Common Teal, the Garganey, and the Ruddy Shelduck.

Echoing 19th century accounts of duck husbandry in China, some of the migratory species allow themselves to be intermittently semi-domesticated in return for supplementary grain. A large majority of the Poyang farms surveyed host free-range ducks that commute to the the lake’s open waters and wetlands in the morning, returning on their own to their host farms at dusk.

Xiao’s team is also tracking what is an increasingly commercialized poultry and egg commodity chain around and out of Poyang. It found 31% of farms surveyed have repeat customers inside and outside the province and 69% of the farms market outside the province, delivering birds to Shanghai, yes, but also Beijing, Fujian, Guangdong, Hunan, Jiangsu, Shangdong, Shanxi and Zhejiang. As far away as 1500 km.


Our influenzas, then, H7N9 included, aren’t divorced from civilization. Indeed, like climate change, they are best cataloged as anthropogenic. But what of this third layer that so characterizes much of modern agriculture? How has intensification on the industrial model more specifically affected influenza’s spread and evolution?

A burgeoning body of research we review here is beginning to describe the mechanisms by which confined animal feedlot and barn operations associated with intensive husbandry select for and spread virulent strains:

Confined poultry and livestock are characterized by little or declining genetic diversity, offering fewer immune firebreaks against outbreaks. And immune systems can be depressed under commercial densities and housing conditions, increasing transmission and pathogen load. Industry scientists openly discuss these complications, if only in the technical literature.

Mathematical modeling and serial passage studies meanwhile suggest increases in transmission rate reduce the evolutionary costs of pathogen virulence. A high turnover rate—the duration from birth to slaughter has been reduced to 40 days in chickens—may select for virulent strains that must reach their transmission threshold before their cohort is harvested. By increasing the throughput speed, and reducing the age of food animals at slaughter, the livestock industry may also be selecting for strains able to transmit in the face of younger, more robust immune systems, including, should spillover occur, in humans.

‘Biosecurity’–a tautological exculpation as there ever was one–appears little but the wood of the powder keg. Violations in biosecurity and biocontainment are routine. Spread off-site can take place by way of commuting farm workers, livestock transport, animal waste, and environmental contamination. The widespread engagement of smallholder contractors for raising juvenile poultry and livestock means the violation in biosecurity is built into the industrial model.

Even should biosecurity measures block outbreaks where they are implemented, these sites can still be sources of infection, spreading pathogens to other production systems, including smallholder operations. As OIE’s hypothesis China’s vaccination campaign against H5N1 may have facilitated H7N9’s emergence instantiates, the absence of persistent outbreaks on intensive farms isn’t synonymous with an inert epidemiology.

Geography plays its part in other ways. Subnational regions hosting farms for one type of livestock often host other types too, permitting greater reassortment of influenza’s genomic segments across host species. In shipping livestock across greater geographic extents influenzas can overlap and trade what were previously isolated genomic segments.

In geographically expanding, intensive agriculture destroys wetlands on which many waterfowl typically stop over during migration. Waterfowl instead now migrate to where the food is located, including the very farms that replaced their traditional habitats. The resulting agroecologies expand the epidemiological interfaces wild birds and livestock share, increasing opportunities for reassortment and host switching.

The increases in influenza’s standing genetic diversity—by accumulating point mutations and repeated transcontinental reassortment across subtypes—act across these mechanisms as the fuel for the virus’s natural selection, including for greater transmissibility and virulence in humans.


These aren’t the full story, however. The means and modes such pathogens prosper extend into the very economic structure of the sector.

Agribusinesses are moving operations to the global South to take advantage of cheap labor, cheap land, weak regulation, and domestic production hobbled in favor of heavily subsidized agroexporting. The kind of structural adjustment that favors such practices also undercuts national animal health infrastructures.

But companies are also engaging in sophisticated corporate strategy. Agribusinesses are spreading their production line across much of the world. For example, the CP Group, now the world’s fourth largest poultry producer, has poultry facilities in Turkey, China, Malaysia, Indonesia, and the USA. It has feed operations across India, China, Indonesia, and Vietnam. It owns a variety of fast food chain restaurants throughout Southeast Asia.

Vertical multinationalism cushions companies from the consequences of their own mistakes. First, economies of scale can price unprotected local companies out of business—the Walmart effect. Consumers have nowhere else to go to subsequently punish corporate blunders.

Second, by threatening to move operations abroad multinationals can control local labor markets; hobbling unions, blocking organization drives, and setting wages and working conditions. Trade unions are an important check on production practices that affect not only workers and consumers, but both directly and by proxy the animals involved in production.

Third, vertical agribusiness acts as both poultry supplier and retailer. The CP Group, for instance, owns a number of fast food chains in a number of countries selling, what else, CP chicken. In short, fewer independent retailers exist to play suppliers off each other in a way that assures demands for better treatment of farm animals are met.

In operating factories across multiple countries, multinationals can hedge their bets in a variant of David Harvey’s spatial fix. The CP Group operates joint-venture poultry facilities across China, producing 600 million of China’s 2.2 billion chickens annually sold. When an outbreak of bird flu occurred in a farm operated by the CP Group in Heilongjiang Province, Japan banned poultry from China. CP factories in Thailand filled the market gap by increasing exports to Japan.

A supply chain arrayed across multiple countries increases the risk influenza can spread even as it also allows companies the means by which to compensate for the resulting interruptions in business.


Saving its own economic skin isn’t agribusiness’ only objective. It aims to remove nature itself as competition.

For instance, the kind of immune resistance we might expect in those poultry which survive an outbreak–the silver gut lining–is now near-nowhere to be found.

In intensive poultry, breeding doesn’t take place in the field. It’s all done at the grandparent level in labs abroad. Indeed, as a result of a wave of consolidation, nearly three-quarters of the world’s poultry production are in the hands of a few multinationals. The primary breeders, who engineer the first three generations of broiler lines commercial multipliers market, declined from eleven companies in 1989 to four in 2006. The ten companies producing layer lines in 1989 were consolidated to two by 2006: the Erich Wesjohann Group and Hendrix Genetics.

The value of the products these primary breeders provide is biologically ‘locked’ by offering multiplier companies only the males of the male lines and females of the female line. As a result, batches of hybrid chickens—trade secrets—must be continuously purchased. By this industrial cascade a single source male chicken can generate millions of broiler progeny, largely bred for morphometric characteristics alone.

The practice in effect removes natural selection as a self-correcting (and free) ecological service. Any culling upon an outbreak or by farmers in reaction to an outbreak has no bearing on the development of immunity to the pathogens identified, as these birds—broilers and layers alike—are unable to evolve in response. In other words, the failure to accumulate natural resistance to circulating pathogens is built into the industrial model before a single outbreak occurs.

Stripping out natural immunity in favor of capital-intensive ceuticals favors influenza. Virulence, transmissibility and spillover aren’t the simple single-gene phenotypes such interventions routinely address. Despite their unsustainability, biotech interventions only the largest operations can afford are increasingly set as national biosecurity standards. Small farmers are thereby boxed out by a solution to a problem their bigger competitors’ largely caused.


The array of diversifying poultry influenzas spilling over into human populations–each outbreak the epizootic equivalent of one of Walter Johnson’s boiler explosions–are being driven by a protein bubble. However extensive the spatial fixes and commoditizable the biology of the birds, production margins driving expected earnings and stock prices are routinely under strain.

Much as the Mississippi steamboats Johnson describes, poultry markets jostling across the globe are selecting for just-in-time practices that reduce input costs, speed up throughput, extend commodity chains, externalize diseconomies of scale, and monetize the kinds of health services nature once provided for free. As a result, broiler explosions–H7N9 only the latest–are increasing in number and magnitude.

In this context, the birds’ defining virtue, their bioeconomic pliability, shaped primarily for markets rather than for nature or even food, is helping produce the deadliest of diseases (and other environmental catastrophes). If this were a free market, internalizing such costs back onto company balance sheets would mark the end of the poultry industry as we know it.

As no bear market bites back and, at this stage in neoliberalism a virtual impossibility, no real governmental intervention is pursued, the emergence of a doozy of a bug–or two or three at this pace–is nigh-on inevitable. However much CDC or WHO flaps its wings or beats its chest. If not influenza, then Nipah, Q fever, or another monstrosity presently percolating across some globally integrated livestock backwater could kill a billion people.

The organizing principle here has little to do with agriculture or animals or farmers or food. This is, after all, an industrial sector that over history has shown itself well acquainted with the moral hazards of expropriation whatever and wherever the food commodity, perfectly comfortable rolling over capital with African slaves and colonial wars.

A billion deaths that can be easily pinned on a virus? By comparison, that’s bottled water off a duck’s back.

4 Responses to “Broiler Explosion”

  1. Thanks! (I guess…). One more stone rolling down the hill! And only minor victories and never enough. A judge has just blocked levels 3 and 4 of a ‘secure’ biolab that Boston University has been trying to get up and running for almost a decade – next to a major low income serving medical center and a low income community, of course. Only eight feet above present sea level in between two lobes of Boston harbor.

    Keep up the good work – this is my first blog visit, I see your postings on spiritof1848.

    Seemingly unrelated, but not, look up poet Kay Ryan’s “Dutch.”

  2. farmingpathogens Says:


    Much of life
    is Dutch

    in which
    legions of
    big robust
    people crouch

    badly cracked
    dike systems

    by the thumbs

    their wide
    balloon-pantsed rumps
    up-ended to the
    northern sun

    while, back
    in town, little
    tulip magnates
    stride around.

    Kay Ryan (2000)

  3. Rodrick Wallace Says:

    At CDC they appear to have their thumbs up their asses… The US sees 50K new HIV infections a year, and there is no effective national control strategy… Even now, Congress has forbidden CDC from conducting gun violence research. God forbid CDC should inconvenience the poultry industry…

  4. […] I read the posts of Rob Wallace (e.g.,, I get a strong sense of someone who can trace connections and has a sense of where to look […]

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