The Role of Poultry Viruses in Human Cancers

The incidence of cancers has been rising for the last half century, and the question is why? Up to 20 percent of all cancers are caused by infectious agents, chiefly viruses. We’ve known this was possible for a century, when a cancer-causing virus was discovered in chickens. The idea was considered such heresy that Dr. Peyton Rous, the man who made this landmark discovery, wouldn’t get his Nobel Prize until 55 years later.

If there are cancer-causing chicken viruses, might they have any effect on people who handle or eat poultry? Concern has been raised about the potential infectivity of cancer-causing farm animal viruses for decades. The first question was whether there was any evidence of human exposure, and, indeed, people do have antibodies to these cancer-causing chicken viruses in their bloodstream. This indicates that the virus is no stranger to our immune systems. Is there any evidence, though, that the virus itself can get into our blood? There wasn’t any such evidence…until 2001.

As I explain in my video The Role of Poultry Viruses in Human Cancers, there is a cancer-causing herpesvirus in poultry, but does it pose a public health hazard? Researchers used DNA fingerprinting techniques to test the blood of 202 people and found that 20 percent, or one in five individuals, had viral DNA in their bloodstream. Testing positive for avian herpesvirus doesn’t mean these diseases can necessarily infect human cells, however. But, as it turns out, they can indeed.

But do they cause human disease? How can that be figured out? Since we can’t just inject people, researchers looked at poultry workers, which is the way we figured out how other farm animal diseases, such as brucellosis and anthrax, jumped to humans. In fact, studying workers is also how we discovered the carcinogenic nature of things like asbestos and benzene. If the poultry workers, who are exposed day in and day out, don’t have higher cancer rates, then presumably the viruses are harmless. Unfortunately, they do have higher rates. In fact, those with high exposure to cancer-causing poultry viruses have “increased risk of dying from several cancers.”

As such, “the relative ease” with which some of the viruses can infect human cells, as well as infect and cause tumors in primates in laboratories, “may be of public health significance, particularly because of the…increased risk of cancer in meat workers” and the evidence that we may become infected with these viruses. However, even if poultry workers are at risk, it doesn’t mean people who merely eat chicken or eggs are. For example, workers who kill chickens were found to be six times more likely to die from brain cancer compared to workers who do not kill poultry, but the slaughterers have live birds flapping in their faces. The “intensity of exposure to these viruses in the general population cannot be expected to be as high as those experienced by poultry workers…[but] the general population is nevertheless widely exposed” to the viruses simply because we eat so many chickens and eggs.

This is supported by data showing that it’s not only the factory farm workers who are at higher risk for brain tumors, but also butchers and meat cutters who have no exposure to live birds, particularly those who don’t wear gloves and frequently have cuts on their hands. These workers are at higher risk for other cancers, as well.

Those who handle meat for a living also have higher rates of non-cancer mortality, such as increased death from heart disease and other health concerns outlined at 3:32 in my video. Some of the poultry viruses not only cause cancer in chickens, but also atherosclerosis. Indeed, that cancer-causing poultry herpesvirus also triggers the buildup of cholesterol crystals in chickens. But, what about in people? “Because chickens infected with Marek disease virus, a herpesvirus, develop atherosclerotic lesions after infection, [researchers] looked for the presence of herpesvirus or parts thereof in human artery wall tissue…” Evidence of the virus was found, though any role they play in human heart disease remains speculative.

“Considerable attention has been paid to substances present in animal food before and after cooking as risk factors for human diseases such as heart disease, diabetes, and various cancers…[and] exposures have included heme [iron], fat or cholesterol, dioxins,” and the cooked meat carcinogens. We didn’t think, however, about the animal viruses, which “are important not only for supermarket workers and other workers in the meat and poultry industries, but also because the general population is exposed.” Indeed, the study that found chicken virus DNA circulating in people’s bloodstreams also found about the same rates in office workers as they did in chicken slaughterhouse workers.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations—2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not to Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

Related on Care2:

63 comments

Jack Y
Jack Y14 days ago

thanks

SEND
Jack Y
Jack Y14 days ago

thanks

SEND
John J
John J15 days ago

thanks for sharing

SEND
John J
John J15 days ago

thanks for sharing

SEND
 .
.2 months ago

I am so happy, i never believe i will be this happy again in life, I was working as an air-hoster ( cabby crew ) for 3 years but early this year, i loose my job because of this deadly disease called Herpes virus (HSV), I never felt sick or have any symptom, till all workers were ask to bring their doctors report, that was how i got tested and i found out that am HSV positive that make me loose my job, because it was consider as an STD and is incurable disease, i was so depress was thinking of committing suicide, till i explain to a friend of mine, who always said to me a problem share is a problem solved, that was how she directed me to Dr Peterwise, that was how i contacted him and get the medication from this doctor and i got cured for real, I just went back to my work and they also carry out the test to be real sure and i was negative. Please contact this doctor if you are herpes positive or any STD diseases his email is: peterwisespellhome@gmail.com or you can call or whatsApp his mobile number on +2349051208634

SEND
Anna Ballinger
Anna Ballinger3 months ago

Thank you for sharing.

SEND
Marija M
Marija M3 months ago

tks for sharing

SEND
Lorraine Andersen
Lorraine A3 months ago

Thanks for sharing

SEND
Alexandra Richards
Alexandra Richards3 months ago

Thank you.

SEND
Richard B
Past Member 3 months ago

Thank you

SEND