The federal government has given conditional approval to the first vaccine licensed to fight a deadly pig virus, and warmer weather appears to be slowing the spread of the disease that has been blamed in part for making bacon more expensive.
Porcine epidemic diarrhea has killed millions of baby pigs since it showed up in the United States last year, and pork prices have been rising for months. Bacon averaged more than $6 per pound in May, nearly 19 percent more than it did 12 months earlier, according to the U.S. Bureau of Labor Statistics.
For consumers, the worst may be yet to come because the most deaths happened last winter, and those animals would just now be reaching market weight. Prices also have risen more than economists previously predicted, and one said he doesn't expect to see them come down much even if slaughter picks up in October and November as anticipated. Strong demand for pork in the U.S. and overseas has amplified the effect of the disease, said Steve Meyer, president of Paragon Economics.
"I think it is important to know that we're not going to run out of pork," he added. "There's still going to be pork on the shelves. It will be a little pricier than before, but it's still a good value compared to beef."
Beef has become more expensive since a nationwide drought in 2012 forced ranchers to send millions of animals they couldn't feed to slaughter.
PED does not infect humans or pets but has proven deadly to young pigs. Struck with severe diarrhea, piglets dehydrate quickly and must be euthanized to end their misery. With little information on how the virus operates or spreads, farmers have struggled to get a grip on it.
The federal government gave the conditional approval last week to a vaccine produced by Iowa-based Harrisvaccines. The vaccine, which was already available on a test basis, has been used mostly to boost immunity in sows that had PED so they could better pass on antibodies to their young.
Company spokesman Joel Harris said Wednesday that one challenge with PED is that infection doesn't result in lifetime immunity, as it does for some viruses, and pigs may sicken again in a few months.
"There's something about this virus that we still need to learn," Harris said.
Another challenge has been that the virus behaves differently on different farms. In some cases, the disease kills nearly ever baby pig during an initial outbreak, but more animals survive as time goes on. But other farmers get past the first outbreak, see herds start to recover and then have a new wave of illness as deadly as the first.
Vaccines, which several companies have in development, can help farmers fight the disease, but they also need to work with veterinarians and follow tight biosecurity procedures because several diseases similar to PED have emerged, said Lisa Becton, a veterinarian with the National Pork Board.
No data exist yet on how many animals have been killed by PED or how many farms have been infected. In April, the federal government began requiring farms to report outbreaks and is working on compiling those numbers. However, test results submitted by labs where farms send tissue and fecal samples indicate that the virus, which does not do well in heat, is spreading slower than it did last winter.
Chris Pardee, a health intelligence analyst with the iJET International consulting firm, praised the federal government for approving a vaccine and committing more than $26 million to fighting PED and similar diseases.
"It shows that a country is taking this seriously, that it is doing things to address the situation and that can really mean a lot when other countries are looking at the situation in the U.S. and considering trade bans or those types of responses," Pardee said.
Countries including France have stopped importing live pigs from the U.S. in recent months.