Thomas Eric Duncan, condition critical, but stable

A Liberian diagnosed with Ebola in Texas has received an experimental drug, the first time the medicine has been used to fight the deadly virus in humans, officials said Monday.

Thomas Eric Duncan is in critical but stable condition, Texas Health spokeswoman Candace White said in a brief statement to reporters.

“He is now receiving an investigational medication, brincidofovir,” she said.

The drug is made by the North Carolina-based pharmaceutical company Chimerix.

Brincidofovir is currently in phase three trials against cytomegalovirus (CMV) and adenovirus, the company said on its website.

However, for Ebola infections it has only been evaluated in test-tubes, not animals or humans, it added.

The drug “works by keeping viruses from creating additional copies of themselves,” Chimerix said.

Three American missionaries who were treated for Ebola in the United States after they became infected in Liberia were given other experimental treatments.

The supply of one promising drug, ZMapp, has run out.

US doctor Rick Sacra was treated with the Canadian firm Tekmira’s Ebola drug, TKM-Ebola, as well as serum from doctor Kent Brantly, who had Ebola and recovered.

There is no market-approved drug for treating Ebola yet, and no vaccine to prevent it.

Duncan is the first person to be diagnosed with Ebola in the United States, and is believed to have become infected while in Liberia.

His condition worsened from serious to critical over the weekend.

West Africa is currently battling the largest outbreak of Ebola in history, with more than 3,400 dead from the hemorrhagic virus since the start of the year.