WASHINGTON (Reuters) - Leaders of the U.S. House Energy and Commerce Committee on Tuesday asked the Food and Drug Administration about the potential threat to the U.S. heparin supply due to the outbreak of African swine fever in China.

FILE PHOTO: Police officers and workers in protective suits are seen at a checkpoint on a road leading to a farm owned by Hebei Dawu Group where African swine fever was detected, in Xushui district of Baoding, Hebei province, China February 26, 2019. Picture taken February 26, 2019. REUTERS/Hallie Gu/File Photo

Heparin is currently on the FDA’s drug shortage list.

Energy and Commerce chairman Frank Pallone, a Democrat, and its top Republican, Greg Walden, and four other bipartisan leaders said in a letter seen by Reuters that they seek information on “any contingency plans in the event of a serious shortage” and a briefing from FDA on its plans to address it.

About 60 percent of the crude heparin used to make finished heparin in the United states is sourced from China, the letter said.

The FDA said it has been monitoring the issue since 2018 “and has followed up with heparin suppliers. At this time we do not anticipate supply issues.”

In March 2018, the FDA said it encouraged the reintroduction of alternative sources of heparin. Until the 1990s, the United States used sources of heparin produced from bovine sources until concerns were raised about “Mad Cow” disease.

“The FDA has been in contact with several companies, both domestic and foreign, regarding reintroduction of bovine heparin to the U.S. market. The details of those conversations are confidential,” the agency said on Tuesday.

Heparin, which the letter said is the only anticoagulant drug used in the United States for open heart surgeries and kidney dialysis, is derived from pig intestines.

African swine fever, for which there is no cure and no vaccine, kills almost all infected pigs but does not harm people. The virus is similar to the strain found in recent years in Russia, Georgia and Estonia.

As many as half of China’s breeding pigs have either died from African swine fever or been slaughtered because of the disease, industry insiders estimate. The World Organization for Animal Health said in May it will take years for China, the world’s biggest pork producer, to contain the virus.

The United States has previously had heparin shortages, as recently as when Baxter International Inc.’s supply was impacted by the effect of Hurricane Maria on its manufacturing facilities in Puerto Rico.