Zoonotic Diseases
The Animal Factory Crucible

Zoonotic diseases are infections that can be shared or transmitted between animals and humans. 

This is no small concern and the Center for Food Security and Public Health (CFSPH) at Iowa State University has created a remarkable Zoonotic Tutorial which can be seen online.

Anyone new to the field will be astounded at the magnitude of the threat.

Although the list of zoonotic diseases referenced in the CFSPH's website documents about 70 such infectious diseases, we are only concerned with those stemming from the factory farming system of food production. 

As such the focus will be confined to the bird factories (chickens and turkeys) and the hog CAFOs.  In this context swine flu and bird flu are the culprits.

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Swine Flu

One of the particularly nasty zoonotic diseases is an influenza virus known as swine flu.  Strictly speaking, swine flu refers to influenza in pigs so what is this new virus, first found in 2009, doing in human beings? 

Named 2009 H1N1, it spreads rapidly and easily jumps from person to person.  Within just a few months of the first reported case, H1N1 related illnesses were in almost all parts of the world and increasing.  The World Health Organization then declared this strain of swine flu to be a worldwide pandemic. 

For the record, a pandemic has nothing to do with the severity of a disease, only its geographic dispersion.

With flu, mutation is the name of the game.  When an infectious organism like influenza mutates into something different than what we have been exposed to previously, a pandemic can result.  The worst H1N1 pandemic ever recorded was in 1918 when millions of people died.

The 2009 pandemic is behind us and, fortunately, it was fairly mild.  Nevertheless, we can learn a lot from the 2009 experience. 

The series of events start with two children in neighboring California counties who came down with a flu-like illness well after the flu season had passed.  The CDC determined the infectious organism to be one of the zoonotic diseases; actually a new virus that had already spread from its apparent origin in southern Mexico. 

Within a few weeks it had traveled to several sites in the U.S. and Canada.

The action then moved to Mexico and the hog farms that had sprung up in the area around Mexico City and Puebla.  It turned out that for several preceding years, U.S. hog industrialists had been setting up hog factory farms in Mexico.

These are the animal factories that squeeze thousands of hogs into closely confined quarters for their entire lives. 

As happened in the U.S., the hog CAFOs demand ever cheaper labor, cheaper feed, cheaper operating costs, cheaper everything.  The result in Mexico has mirrored the results in the U.S; namely traditional small farms driven out of business and mega sized farm factories taking over.

What is unique about pigs is that they are very efficient mixing bowls for interspecies zoonotic disease organisms.  Swine flu has contained genetic code of human influenza for years. 

After the hog factories had become widely established in North Carolina and other areas of the U.S. researchers found that genetic material from avian flu had found its way into the mix. 

Scientists around the world have feared that industrial hog factory farms could become breeding grounds for new infectious organisms that could infect humans and spread quickly throughout the general population.

It looked like their fears had come to pass in Mexico.  The new strain of swine flu that was sickening and killing people had, for the first time, components of human flu virus, bird flu and two types of swine flu virus.  CAFO workers could serve as the zoonotic disease bridge from factory farm to rural community populations and then spread throughout the country via commercial air, rail and automobile travel. 

In the 1918 worldwide pandemic, it is thought that the illness was spread when farm workers went to military training camps for World War I. 

The Mexico experience is just one chapter in what will certainly be a very long book.  Another chapter in the story concerns the antibiotics given to these tightly confined animals, without which they would not survive.

Growing antibiotic resistance due to the farm factory model is covered in succeeding pages but first let's look at the avian flu, an important component of swine flu.

The Mexican incident was covered in considerable detail by David Kirby, author of Animal Factory, in a Huffington Post article titled:

"Swine Flu Outbreak - Nature Biting Back at Industrial Animal Production?"

Avian Flu:  Zoonotic Diseases from China

In November 2010, Hong Kong recorded its first human case of the bird flu since 2003 and in typical government fashion, scrambled to reassure the public that there was no cause for alarm. 

Chinese officials said there was little risk of person-to-person transmission, after a 59-year-old woman tested positive for Influenza A (H5), a variant of bird flu. She was listed in a serious condition in a hospital isolation ward. 

Nevertheless, in an apparent contradiction, the government raised its avian influenza alert level to "serious", meaning there is a "high risk" of people contracting these potentially fatal zoonotic diseases.

When it comes to animal-to-human transmission of viral zoonotic diseases, China seems to be the "canary in the coal mine".  China is the breeding ground for animal viruses and in recent years, this is where outbreaks are most likely to appear first. 

Hong Kong recorded its last human case of bird flu in 2003, and had the world's first major outbreak among humans in 1997, when six people died of a mutation of the virus, which is normally confined to poultry. 

In the 1997 case, millions of domestic birds were killed in an attempt to contain the outbreak.  This was just a preview of things to come. 

How many remember SARS, Severe Acute Respiratory Syndrome? It is one of the respiratory zoonotic diseases in humans caused by a corona virus. These viruses are important pathogens of animals and birds which cause respiratory tract infections in humans, livestock and even pets.

Beginning in November 2002, SARS spread from the Guangdong province of China and in a matter of weeks, rapidly infected individuals in 37 countries around the world. 

Before it was contained in July 2003, there were 8,096 known infected cases and 774 confirmed human deaths, a 9.6% fatality rate.  Fortunately, SARS is considered to be a rare disease in humans.

Bird Flu in Humans

Flu infected birds spread the influenza virus through their saliva, nasal secretions, and feces.


Bird-to-bird transmission occurs when healthy birds have contact with contaminated excretions or with surfaces that are contaminated with excretions or secretions.

In the case of farm poultry or other domesticated birds, they may become infected with avian influenza virus through direct contact with migratory waterfowl, contact with material such as bedding, cages or dirt and/or from contaminated water or feed.
The good news for humans is that we are not usually infected with bird flu viruses.  Since 1997 there have only been a little over 100 confirmed cases of human acquired zoonotic diseases of bird flu. 

Most of those cases resulted from direct or close contact with infected poultry or contact with surfaces contaminated with secretions and excretions from infected birds.

The spread of zoonotic diseases of bird flu viruses from an infected person to another is rare, and, so far, the chain of infection seems to stop after the first transmission.
The greater concern with bird flu is that the flu virus is notorious for mutating and in theory could mutate into one or more zoonotic diseases in a form that is highly infectious for humans and that spreads easily from person to person.  So far this has not happened but it is the possibility that fuels the fears of a new worldwide pandemic.

What does all this have to do with poultry factory farms?  Namely the crowding and filth that characterizes the typical battery cage egg laying operation or wing-to-wing density of the floor of a broiler CAFO would be an ideal Petri dish for the incubation of avian flu.

If an avian flu virus found its way into such a facility, it is reasonable to assume that it would spread like wildfire throughout the bird population and then to the facility workers, then to their families, to their kids, the kids schoolmates and on and on. 

The perverse upside is that all the antibiotics that are fed to the captive birds just may be their salvation from a migratory flu bug, at least until it mutated to an antibiotic resistant version.

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Physiology and Naming Conventions

Type A viruses, the one that causes flu in birds, have a protein coating that surrounds their surface.  The protein coatings in these virus strains are called Hemagglutinin and Neuraminidase.

These surface proteins are the parts of a virus that can be changed when viruses mutate into new forms. This is how they change to be able to attack the cells of new hosts or in new ways in the same hosts.

They are no longer recognized as viruses that the immunological system of the host has fought before, and that allows them to mutate to forms that can evade the body's defenses again, at least for awhile but that may be all it needs to kill someone.

In the naming convention of viruses, the protein classifications become part of the name as in H1N1; H for the Hemagglutinin and N for the Neuraminidase.

Hemagglutinin binds the virus to the cell it is infecting.

Neuraminidase is an enzyme that lets the virus be released from the host carrier cell. 

Taking it a step further, the 2009 pandemic flu was officially designated A/California/7/2009(H1N1); California being where it was first reported and 7 being the specific lab that identified it.

There are different subtypes of viruses using the H and N nomenclature, for example H1N1 is the swine flu and H5N1 is the Avian (bird) flu.

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