Enter multiple symbols separated by commas

Outbreak of Deadly Piglet Virus Spreads to 13 States

Felbert+Eickenberg | Stock4B | Getty Images

A swine virus never been seen in North America and deadly to young pigs is spreading rapidly across the United States, and it is proving harder to control than previously believed.

The virus, with more than 100 positive cases, has spread to 13 states since it was diagnosed in the country last month, said Montserrat Torremorell, a specialist in swine health and professor at the University of Minnesota's College of Veterinary Medicine.

While the the virus has not tended to be fatal to older pigs, mortality among very young ones infected is commonly 50 percent and can be as high at 100 percent, according to veterinarians and other scientists studying the outbreak.

The strain of the virus, known as porcine epidemic diarrhea virus, that is making its way across the nation's hog farms and slaughterhouses is 99.4 percent similar in genetic structure to the PEDV that hit China's herds last year, the researchers say. First diagnosed in China in 2010, PEDV overran southern China and killed more than 1 million piglets, according to the Emerging Infectious Diseases journal of the Centers for Disease Control and Prevention.

(Read More: Sex Superbug Could Be 'Worse Than AIDS')

The virus does not pose any health risk to humans or other animals, and the meat from PEDV-infected pigs is safe for people to eat, according to federal officials and livestock economists.

No direct connection has been found between this outbreak and previous outbreaks in Asia and Europe, scientists said.

Industry fears
The U.S. pork industry had hoped the virus' spread would slow or at least plateau as the weather grew warm. But Tom Burkgren, executive director of the American Association of Swine Veterinarians, said PEDV has proved far more tolerant of heat than a more common malady, transmissible gastroenteritis.

PEDV was diagnosed earlier this month for the first time in Arkansas, Kansas and Pennsylvania. The virus had been found before that in barns in Colorado, Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio, Oklahoma and South Dakota.

(Read More: Big Pharma Exit: Who's Fighting the Superbugs?

It has been found in baby pigs, adult sows and in other hogs being fattened for slaughter, said scientists investigating the outbreak. No known cases have been reported in Canada or Mexico.

When and how PEDV arrived in the United States remains a mystery. The total number of deaths from the outbreak is not known, and the uncertainty is fueling fears among traders, meat processors and farmers about the potential impact on pork supplies later in the year.

The outbreak comes as hog and wholesale pork prices in Iowa and Minnesota have surged to nearly two-year highs. Supermarkets are racing to fill meat cases for the summer grilling season as supplies tighten, analysts said. Hog supplies were already tight after last summer's historic drought drove up feed-grain costs, which prompted a higher-than-normal slaughter rate.

The first U.S. case of PEDV was reported May 17. But researchers at the National Veterinary Services Laboratory in Ames, Iowa, and other diagnostic labs have since discovered that PEDV arrived as early as April 16, according to the American Association of Swine Veterinarians. The labs have begun testing older samples taken from seemingly unrelated cases in an effort to track the virus' first appearance here.

Investigators with the Agriculture Department and others are hunting for clues to the widening outbreak and focusing on the nation's livestock transportation system.

PEDV most commonly is spread by pigs' ingesting contaminated feces. Investigators are focused on physical transmission, perhaps equipment marred with feces, or a person with dirty boots or dirty nails.

(Read More: A Low-Wage US Contractor Just Cooked Your Burger)

"It could happen at the slaughterhouse, where you have a trailer unloading a truck of pigs that was positive," said Torremorell, who noted that diagnostic researchers at the University of Minnesota and elsewhere have tested hundreds of samples in recent weeks.

"If the person doesn't clean the trailer correctly, and then goes to load up another load of pigs that were negative for PEDV, that person could end up delivering a truck of pigs to an uninfected farm," she said.

Contact U.S. News


    Get the best of CNBC in your inbox

    Please choose a subscription

    Please enter a valid email address
    To learn more about how we use your information,
    please read our Privacy Policy.

Don't Miss

  • Why women cheat?

    Is cheating bad? Why do women cheat? The founder and CEO of affair website Ashley Madison tells all, including why he has his eye on China.

  • American Pharoah

    As American Pharoah chases the Triple Crown at the Preakness this Saturday, his earning potential can only go up.

  • Banking on your brand: Mika Brezezinski

    Mika Brezezinski, "Morning Joe" co-host, talks about giving women, entrepreneurs and millennials the tools to live and work to their full potential.

U.S. Video

  • Cramer: Here's a sign the market could rally

    Wall Street's been soaking in red, but "Mad Money" host Jim Cramer has one signal to watch for that could point to another run.

  • Burger war maneuvers

    Cramer looks at the number of company's selling burgers and tries to determine the quality names, as well as those to avoid.

  • Cramer: What's driving defense?

    Cramer says that even though President Obama has made it clear the US can no longer be the world's policeman, the country can become the world's arms dealer. Profiting from defense spending.