A new study found that Ebola lasts much longer than previously thought in semen, in some cases lasting for a year and a half.

The study published Tuesday in the Lancet medical journal provides new evidence about the persistence of Ebola and the role of sexual transmission of the virus that killed more than 10,000 people during an outbreak that started in 2014.

Before the latest outbreak, scientists thought the virus could last for three months in semen after a man recovered from Ebola. Now the latest study shows it can last more than a year.

The study looked at preliminary results from Liberia's Men's Health Screening Program, which is the first national semen testing program for Ebola, according to the Centers for Disease Control and Prevention.

Researchers looked at 429 male Ebola survivors, 38 of whom had fragments of the virus in their semen. Of those 38 men, about 63 percent had semen samples that tested positive for Ebola a year after recovering from the disease.

The study also found that men older than 40 were more likely than younger men to have a semen sample test positive, CDC added.

Sexual transmission was attributed to a woman in Liberia contracting the disease and dying in March 2015. The only known exposure to Ebola was through unprotected sex with an Ebola survivor, CDC said.

"We now have many more Ebola survivors than ever before," said Moses Soka, coordinator of the Ebola Virus Disease Survivor Clinical Care at the Liberian Ministry of Health. "This work demonstrates the importance of providing laboratory testing and behavioral counseling to empower survivors to make informed decisions to protect their intimate partners."