SARS, Influenza and Meat?

Severe Acute Respiratory Syndrome has been a major topic in the news recently, which means it was also an opportunity for animal rights groups and individuals to spread the usual nonsense and lies about zoonosis (diseases that humans may acquire from animals).

One of the major errors concerns the 1918 influenza pandemic. For such a major event with plenty of books, articles and web pages available, you’d think they could at least get this right, but alas, no.

Michael Greger, MD, weighed in with this bit of outdated information,

Animal agriculture is not just a public health hazard for those that consume meat. In fact, the single worst epidemic in recorded history, the 1918 influenza pandemic, has been blamed on the livestock industry. In that case, the unnatural density and proximity of ducks and pigs raised for slaughter probably led to the deaths of 20 to 40 million people. . . . All of these influenza strains seem to have arisen in the same region of southern China where intensive systems of animal agriculture have become a breeding ground for new killer viruses.

PETA chimes in claiming that,

The influenza epidemic of 1918 originated in pigs.

But these claims are completely dishonest distortions of what is known about the 1918 epidemic.

The 1918 influenza pandemic did not originate in Asia. The first known cases of the disease, in fact, occurred Kansas in May 1918. Five hundred soldiers became infected with a mysterious new disease, and 48 of them died. It is most likely the disease originated either in Europe or the United States — soldiers traveling both ways across the Atlantic would have quickly spread the virus.

Did the disease arise from animal agriculture? To answer that question, first consider one of the more astounding aspects of the 1918 influenza pandemic — we actually have samples of the disease that were preserved (in some cases because the bodies of victims were buried in places like Alaska, where the ground remained frozen) and have been partially sequenced.

As far as ducks are concerned, a study of waterfowl from the Smithsonian Institution’s collection found that this was unlikely. The Smithsonian has a huge collection of liquid-preserved waterfowl from which it extracted genetic material. The genetic material was tested for a specific gene that made the 1918 influenza strain so deadly. Researchers who studied the genetic material concluded that (emphasis added), “Comparisons of this sequence with that of the 1918 pandemic virus suggest that the pandemic viral HA gene was not derived directly from an avian source.”

But did the disease spread from pigs to humans? The short answer is that nobody knows, and that it is just as likely that the disease spread from human beings to pigs.

The 1918 strain could definitely infect both humans and pigs, but the 1918 pandemic was the first time that swine influenza was recognized as a disease — this was something entirely new for both pigs and human beings. The swine influenza was isolated in 1930 and human form of the disease in 1933, and they were similar enough for researchers to conclude that they were essentially the same virus.

Dr. Richard D. Slemons, DVM at Ohio State University, writes of the question of how the pandemic started,

Since swine flu was reported as a new disease entity in pigs in 1918, it was further believed that the agent was originally transmitted from humans to pigs and subsequently became established in pigs. Retrospective serologic investigations provided further data supporting the belief that the same agent was responsible for the 1918 influenza outbreaks in humans and pigs. However, these data did not provide insight into whether the virus went from humans to pigs or vice versa. The question as to whether the virus originated in humans or pigs, or even another species and then jumped to both pigs and humans, remains unanswered.

Why can’t groups like PETA ever get even basic facts right?


SARS: Another deadly virus from the meat industry. Michael Greger, April 13, 2003.

SARS Epidemic Caused by Meat?. People for the Ethical Treatment of Animals, April 2003.

Influenza: Past Clues Guide Future Defense. PulmonaryReviews.Com, January 2002.

History, Structure, and Function of Swine Influenza Virus. Richard D. Slemons.

Seeking the 1918 Spanish Influenza Virus. Jeffery K. Taubenberger, American Society for Microbiology, July 1999.

Origin and evolution of the 1918 “Spanish” influenza virus hemagglutinin gene. Reid AH, Fanning TG, Hultin JV, Taubenberger JK, Proc Natl Acad Sci U S A 1999 Feb 16;96(4):1164-6.

1918 Human Influenza Epidemic No Longer Linked to Birds. Smithsonian Institution, Press Release, August 2, 2002.