Experts latest theory links the Ebola outbreak in West Africa to a December case of a 2-year-old boy.

According to The New York Times, the outbreak has already officially become the worst on record, already having claimed 961 lives out of the 1,779 reported cases.

Doctors now speculate that the virus originated in the village of Guéckédou in Guinea, which borders both Sierra Leone and Liberia. After the 2-year-old died on December 6, his mother, sister and grandmother all shortly followed. Sadly, experts suggest that the virus spread to the villages of funeral guests, who contracted the sickness at the service.

The viruses ability to penetrate borders early on in addition to preexisting political instability in the region makes containing the outbreak difficult. News24 reports that Nigeria appealed for volunteers on Sunday, a day after the World Health Organization declared an international health emergency.

Officials in the hardest hit countries have opted against border closings as a means of containing the virus, and are instead focused on addressing the shortage of medical personnel and equipment. Other countries such as India have taken measures to restrict entry for people from infected areas, and opened up an emergency hotline.