So how did the uproar over “swine flu” get started?

Dr. James Lowe, a swine veterinarian at the University of Illinois College of Veterinary Medicine in Urbana, recently offered a brief primer on influenza as well as some background on the 2009 flu outbreak. Food animal veterinarians play an important role in protecting public health by ensuring a safe food supply, but influenza is not a disease that is spread by eating meat, so worries connecting pork and flu are entirely unfounded.

“The virus that causes influenza is genetically unstable, meaning it evolves rapidly,” says Dr. Lowe. “The influenza virus changes so quickly that scientists who develop vaccines must race to try to keep ahead of it.”

Whereas vaccines developed to prevent tetanus and measles remain effective for years because the infective agents that cause these diseases change little, the flu vaccine must be updated every year. Flu shots are designed to protect against a few strains of the influenza virus that are predicted to be common in a given flu season.

“Most mammals and birds are affected by influenza,” says Dr. Lowe. “Scientists categorize influenza A strains according to two proteins found on the surface of the virus: hemagglutinin—hence the “H”—which has 17 variations, and neuraminidase—“N”—with 9 variations. The structure of these proteins differs from strain to strain because of rapid genetic mutation.”

Strains of the influenza virus affect various species differently. For example, people are usually only affected by the H1, H2, and H3 and the N1 and N2 strains. Some of these variations also affect birds and pigs. Strains arising in different species can combine to form novel strains that may affect more than one species.

There are three strains of influenza now circulating in U.S. pigs that also affect people: H1N1, H1N2, and H3N2. The flu is spread primarily by exposure to the virus through coughs and sneezes. It is just as possible for people to give the flu to pigs as it is for pigs to give the flu to people.

Pigs and people experience much the same manifestations of flu: runny noses, cough, and high fevers. The deadly aspect of influenza occurs if it damages the airways, allowing secondary infections to set in.

For people, key strategies for keeping flu-free are washing hands and staying home if infected. For pigs, modern farms have very stringent biosecurity protocols that prevent people from bringing pathogens in or out of the farm.

Although it was called “swine flu,” H1N1 is historically a human flu. It was the culprit in the 1918 pandemic Spanish Flu.

The H1N1 flu outbreak of 2009 originated in Mexico. Ironically the first cases of the 2009 outbreak that affected U.S. pigs were traced to sick farm workers who had contracted the illness from schoolchildren.

Despite dire warnings in the media and a fearful public, the number of U.S. deaths attributed to the pandemic H1N1 outbreak between April 2009 and April 2010 was estimated by the Centers for Disease Control and Prevention to fall between 9,000 and 18,000—well below the 40,000 U.S. deaths attributed to seasonal flu in a typical year.

The influenza virus is a frustrating virus to deal with, even when it is not deadly. It causes major economic losses in people and pigs: people lose productivity and incur medical bills, and pigs don’t grow well so farmers lose income.

The truth is, new strains of the virus will continually appear, and from time to time a new strain will cause more severe illness than is typical. But there is no true “swine flu,” and certainly not one that is guaranteed to be deadly in people.

It is simply the flu, we can all get it, and we all try our best to avoid it.

If you have questions about infectious diseases that pass between people and animals, your local veterinarian can be an excellent resource.

Andrea Lin is an Information Specialist at The University of Illinois at Urbana-Champaign College of Veterinary Medicine.

The Truth About “Swine Flu” The Saturday Evening Post

What would Ben Franklin say about the notion that colds come from exposure to wetness?

Here’s what Franklin did say: “The disorder we call a cold … can never by a little addition of moisture hurt a body filled with watery fluids from head to foot.”

During Franklin’s era, it was almost universally believed that cold damp air caused the condition we call a cold, a belief that persists to the present. Indeed, the name “cold” derives from that concept. Towards the middle of the 18th century, when Franklin was at the peak of his influence, a number of thinkers, Franklin among them, concluded that colds and influenza were contagious diseases, similar to smallpox, malaria, and other maladies that swept through colonial North America from time to time.

We have to remember that the notion that germs cause diseases hadn’t yet been proposed in Franklin’s lifetime, even though some experimenters had seen such tiny organisms with primitive microscopes developed in the late 1600s.

As for the notion that dampness caused colds, Franklin pooh-poohed this idea in a 1773-letter to Dr. Benjamin Rush—a prominent Philadelphia physician and signer of the Declaration of Independence. Rush strongly believed that dampness somehow led to colds. Franklin explained to Rush why he didn’t accept this concept. Instead, he concluded that colds were transmitted from one person to another. He said, “I have long been satisfy’d from Observation, that besides the general Colds now termed Influenza’s, which may possibly be spread by Contagion as well as by a particular Quality of the Air, People often catch Cold from one another when shut up together in small close Rooms, Coaches, and so forth, and when sitting near and conversing so as to breathe in each others Transpiration …”

As for the notion that one could catch a cold by becoming wet, Franklin told Dr. Rush:

“Travelling in our severe Winters, I have suffered Cold sometimes to an Extremity only short of Freezing, but this did not make me catch Cold. And for Moisture, I have been in the River every Evening two or three Hours for a Fortnight together, when one would suppose I might imbibe enough of it to take Cold if Humidity could give it; but no such Effect followed: Boys never get Cold by Swimming. Nor are People at Sea, or who live at Bermudas, or St. Helena, where the Air must be ever moist, from the Dashing and Breaking of Waves against their Rocks on all sides, more subject to Colds than those who inhabit Parts of a Continent where the Air is dryest.”

Furthermore, Franklin was convinced that a person’s physical condition was even more important than exposure to the expired breath of others. Here’s how he put it:

“From these Causes, but more from too full Living with too little Exercise, proceed in my Opinion most of the Disorders which for 100 Years past the English have called Colds.”

Catching Colds The Saturday Evening Post

What would Ben Franklin say about individuals who decline inoculation?

Here is what he did say about the subject: “As the practice of Inoculation always divided people into parties, some contending warmly for it, and others as strongly against it. …” It was necessary to have a strict and impartial enquiry into the inoculation and death rates during epidemics.

Few people alive today are old enough to remember the 1918 influenza pandemic, an event that killed tens of millions of people. Ben Franklin, however, lived in an era where contagious epidemics—yellow fever, malaria, smallpox, typhus, influenza—were common. Since the germ theory of disease had not yet been proposed during Franklin’s lifetime, people had no idea about what caused such deadly assaults on the population. The most commonly accepted explanation involved divine visitation, presumably as punishment to an entire population for sinful conduct.

Edward Jenner’s discovery of the smallpox vaccine did not occur until several years after Franklin died. During Franklin’s lifetime, inoculation against smallpox was performed by exposing a person to scabs taken from the skin of somebody with the disease. Usually, the inoculation process produced a mild smallpox infection; survival meant lifetime immunity. Occasionally, however, the inoculation would lead to a progressive form of the disease, which would kill the patient. For this reason, many feared inoculation, although Franklin favored it.

When Ben Franklin was a young printer in Philadelphia, he lost the only son he had with his wife to a smallpox epidemic. The lad was 4 years old at the time. Franklin had planned to have the boy inoculated, but never got around to it.

Ben Franklin never forgave himself for the loss. Like many parents who nowadays create a foundation in the memory of a child who died so that others might benefit from research into the illness that took away their loved one, Franklin started collecting smallpox inoculation statistics. He soon realized that the risk of inoculation was small compared to the risk of acquiring a smallpox infection in what he referred to as the “usual way.”

When Franklin was in England in 1759, he persuaded a famous physician to write a pamphlet for distribution in British North America favoring the smallpox inoculation. Franklin himself penned the pamphlet’s preface. In it, he presented his statistical results, hoping to persuade parents that their children would benefit from inoculation. Likewise, he found it necessary to overcome theological resistance to inoculation. Certain men of the cloth, it turns out, were convinced that any attempt to reduce the impact of a divinely ordained plague would go against God’s will. Franklin found it necessary, therefore, to point out that God gave mankind the capacity to discover a method that reduced the impact of a contagious illness.

Here’s how Franklin combined his analysis of smallpox statistics with his response to those who found inoculation somehow unholy:

“If the chance were only as two to one in favour of the practice [of inoculation] among children, would it not be sufficient to induce a tender parent to lay hold of the advantage? But when it’s so much greater, as it appears to be by these accounts (in some even as thirty to one) surely parents will no longer refuse to accept and thankfully use a discovery GOD in his mercy has been pleased to bless mankind with.”

Influenza Pandemic The Saturday Evening Post

Schools across the country are reporting their first cases of the newly identified H1N1 flu (earlier called the “swine flu”). And every state will likely see sporadic to widespread cases before the typical flu season winds down sometime next spring.

How can you minimize your risk? Leading experts from the Centers for Disease Control and Prevention, the National Institutes of Health, and the Food and Drug Administration offer the following advice for fighting H1N1 and seasonal flus.

Avoid flu viruses.
DO keep your hands away from your eyes, nose, and mouth. If you are ill, this helps prevent infecting others. If you’re healthy, it helps you stay that way. H1N1 and seasonal flu viruses may live for hours on hard surfaces such as doorknobs, phones, and computer keyboards.

DON’T depend on wearing a facemask for complete flu protection. In general, the use of facemasks is not recommended in community and home settings.

Follow vaccine recommendations.
DO consider flu shots. Nearly everyone is advised to get the seasonal flu shot. Exceptions may include those with an egg allergy or a history of Guillain-Barre Syndrome. People who are ill should usually delay vaccination until they recover. About 45 million doses of the H1N1 vaccine (from five manufacturers) are expected by mid-October, with up to 195 million doses by year’s end. Target groups for vaccination focus on those at most risk of infection and severe disease, including pregnant women, children and young adults ages 6 months through 24 years, and people 25 to 64 with medical conditions that predispose them to complications of the flu. Health care workers and emergency medical service workers, as well as those who care for infants not yet old enough to be vaccinated, are also encouraged to receive the H1N1 vaccine.

DON’T assume that flu vaccines provide immediate and full protection. Remember to wash hands frequently with soap and water, cover your cough, and stay home if you are sick. When possible, avoid being within about six feet of a person with influenza-like illness.

Stay informed.
DO watch for new reports about emerging trends and prevention strategies. Study findings expected in mid-September will indicate whether one or two doses of the H1N1 vaccine provide adequate immunity against the novel virus.

DON’T let your guard down. Influenza is unpredictable. Current levels of flu activity in the United States are low. But any influenza at this time of year is unusual—and most of the confirmed cases are the H1N1 flu.

H1N1: Can You Minimize Your Risk? The Saturday Evening Post