A virus sweeping through the nation’s hog industry is killing piglets at an increasingly alarming rate, threatening to hamper production and lead to higher retail pork prices.

Porcine epidemic diarrhea virus (PEDv) surfaced in the United States last spring but has accelerated during the winter, notably in Minnesota. The virus often wipes out an entire barn’s young pig population, with piglets dehydrating, unable to retain nutrients from their mothers’ milk.

“I’ve never seen anything like it as far as the devastation it does to little pigs,” said Paul FitzSimmons, a 30-year industry veteran in southern Minnesota whose family business manages 16 sow farms, three of which have been stricken by PEDv. “The virus is very, very contagious.”

Minnesota is the nation’s third-largest pig producing state and home base for Hormel Foods Corp., a major pork producer, and Cargill Inc., one of the nation’s largest hog processors.

The virus could crimp the hog pipeline to meat processors. Hormel’s CEO, Jeffrey Ettinger, noted during a conference call with analysts in November that hog costs may be volatile “due to concerns in the marketplace about the PED virus affecting supply.”

Those concerns have lit a fire under hog futures on the Chicago Mercantile Exchange. The lean hog contract for June is at a 52-week high, 11 percent higher than the past year’s average price.

Premiums are built into summer hog futures as a wave of piglet deaths is expected to hurt production by then, said Justin Roelofs, a financial services officer specializing in swine for Mankato-based AgStar Financial.

“If we don’t figure out a vaccine quickly, we will likely see an increase in [pork] costs for the consumer,” he said. “It will just get passed down the line.”

PEDv poses no danger to human health, nor is it a food safety threat. When it strikes a barn, animals of all ages contract the virus. Older pigs withstand it, but among pigs in the first two weeks of life, the mortality rate is often 100 percent.

“Once a farm gets infected, it’s very hard to control the virus because it spreads very quickly,” said Albert Rovira, an assistant professor at the University of Minnesota’s Veterinary Diagnostic Laboratory in St. Paul.

To make matters worse, the virus is shed in copious amounts, in pig feces for example. “It’s just really a bad combination,” Rovira said.

The U’s veterinary diagnostic lab last summer unveiled the nation’s first rapid detection test for PEDv. Last week, it introduced a new test that tells farmers if a hog has been exposed to the virus, which could be an early alert. The quicker farmers know the presence of PEDv, the faster they can seal off a hog farm.

PEDv has been around since at least the 1970s, and has reared its head in Asia in recent years. The first cases in this country were reported in late April. The virus has since shown up in 23 states. “The big spike in ­Minnesota is going on right now,” Rovira said.

Nationwide, the number of cases is climbing steeply, too, as PEDv appears to thrive in cold weather. While there are no hard numbers on how many pigs have died, PEDv can take a big toll on production.

Once it strikes, “you’re going to lose baby pigs for a month,” said David Preisler, executive director of the Minnesota Pork Producers Association. “It takes that long for immunity to build up in the rest of the herd.”

Since there’s no vaccine, farmers let the virus run its course until sows build up antibodies, which are transmitted to piglets via milk.

But during that period, hog growers can lose about 10 percent of a farm’s annual production — a costly proposition.

FitzSimmons, whose hog operations are based south of Mankato in Mapleton, said the piglets wiped out in just one 3,000-sow farm will cost his business about $500,000. And unlike crop farmers, livestock growers aren’t protected by government-subsidized insurance. “We’re on our own,” FitzSimmons said.

As a counterweight to PEDv, hog farmers have an incentive to expand their herds these days because corn — the chief ingredient in feed — is cheap. And hog prices are strong not only due to PEDv worries, but consumer demand for pork is strong.

Analysts say the effect of PEDv is uncertain. “The main wild card in the global market this quarter is the impact of PEDv outbreaks in the U.S. and what this means to U.S. pork production this year,” according to a report last week from Rabobank. “Rabobank expects the impact to be more severe than forecast by the USDA.”

The bank’s analysts expect overall U.S. pork production to be flat to up slightly in 2014 — “well short of the 3 percent-plus growth we would have seen had PEDv not appeared.”