In the past year, the U.S. saw the death of up to seven million pigs due to Porcine Epidemic Diarrhea virus, frequently referred to as PEDv. With recent reports of a second U.S. outbreak, farmers throughout the country are growing more discouraged with the USDA’s inability to find the virus’ original source.

PEDv

PEDv is a viral disease that causes severe diarrhea and vomiting in pigs. It largely affects young piglets and has a mortality rate of nearly 100 percent, Vice News reported. In the past, PEDv outbreaks have occurred in Europe and Asia, but the first outbreak to occur on U.S. soil was observed last spring. Although the virus cannot be spread to humans, there are concerns that other more dangerous diseases may be brought to the U.S through the same mysterious pathway that PEDv entered. "I know that people are concerned about the pathways and feel like we haven't done enough," John Clifford, the USDA's chief veterinary officer, told Reuters. "It's hard. It's like looking for a needle in a haystack."

Same Viral Strain

Genetic sequencing has found that the outbreaks from 2013 and 2014 were caused by the same exact strain of the virus, which appears to be related to a strain found in China in 2012. The U.S. National Board Pork Board does not consider PEDv to be a trade restrictive virus. Still, Russia announced last week it was suspending U.S. imports of live pigs effective May 30. China has also done the same.

Took Too Long to Report

The USDA is currently facing criticism for taking nearly a year to require farmers to report the the outbreaks to the government. Eric Neumann, a veterinarian studying the transmission of the disease, believes that earlier reporting of the outbreak may have led to better tracking of PEDv’s spread. "USDA deserves some very fair criticism that they did not put a more visible effort into investigating what the original source of the virus was," Neumann said to Reuters. At this point, the virus has already spread to 30 states and many fear it’s too late to trace its origins.

Unknown Source

The USDA has currently tracked down seven feed-related risk factors that may be led to the entry of PEDv in the U.S. However, this is still unconfirmed. Others believe that the virus may have had a human carrier, seeing that it is unlikely to have survived in feed for long lengths of time or in harsh environments, such as those found on cargo ships. One popular theory is that the virus was brought to the U.S. on the bottom of someone’s shoe. An amount of infected feces small enough to be on the bottom of a shoe of a truck tire is strong enough to infect an entire herd of pigs.