Ebola has caused its first death in several months in Liberia, which was declared free of the viral disease in September. A 15-year-old boy has died of Ebola, according to Liberia's chief medical officer.
The boy had tested positive for Ebola last week and died on Monday in Paynesville, a town near Monrovia, the capital. His father and brother are also being treated for Ebola, officials said.
Health officials in Liberia have placed 153 people who may have come into contact with the boy under surveillance. In addition, 25 healthcare workers are being monitored. Ten of them are considered to be at high-risk, according to Liberia's chief medical officer Francis Kateh.
The source of the virus is being investigated and Liberia has requested the assistance of two experts from the U.S. Centers for Disease Control and Prevention. It is not known how the boy came to be infected with the virus. People who have survived Ebola can carry the virus in certain tissues in the body, including the eye, semen, and in cerebrospinal fluid.
Liberia has been declared to be free of Ebola twice now. The World Health Organization declared it free of the virus on May 9 and again on Sept. 3. Liberia's last previous Ebola death was in July. Sierra Leone was declared Ebola-free on Nov. 7 and Guinea started its countdown to being free of the virus on Nov. 16. A country has to go 42 days without a new confirmed case of Ebola to be declared virus free.
Since the outbreak started in March 2014, more than 11,300 people have died of the virus in West Africa. Of the three main countries affected, Over 4,800 people have died of Ebola in Liberia, according to WHO.
Liberia is working on a protocol to test a vaccine against Ebola with international partners including the WHO. The vaccine may be administered to people who might have been exposed to the boy who died. Trials of this Ebola vaccine have proven effective in Guinea and Sierra Leone, he said.