Doctors think the deadly Ebola outbreak in West Africa might have been triggered by a two-year-old in a village in Guinea.
Their findings, published in the New England Journal of Medicine, show the toddler was suffering from a fever and vomiting before the child's death in December 2013. The patient's 3-year-old sister, mother and grandmother died with the same symptoms not long after.
The child who doctors believe to be Patient Zero lived in the village of Guéckédou in Guenia. It is believed the virus might have started to spread after two of the people who traveled to the grandmother's funeral became infected and took the virus back to their home village.
It continued to snowball from there through health care workers and family members.
It is not clear how the toddler originally contracted the disease. The World Health Organization says Ebola is transferred from animals to humans through fluids or tissue.
Rural areas in West Africa typically lack the health care resources to properly handle this sort of outbreak, which has helped spread the virus.
Cultural traditions could also be partly to blame. Time spoke to a regional expert who used Liberia as an example: "Liberia is full of cultural practices that propagate the spread of the disease, the biggest being the veneration of the dead, including washing and kissing the corpse.”
The New York Times writes that people in those areas blame health care workers for the spread of the disease. So, many don't immediately go in for treatment. In one instance, a local gang of youths stopped workers from entering a village to treat the sick.
The Centers for Disease Control and Prevention insists the outbreak is not a threat to the U.S., and it can eventually be contained and controlled in West Africa. But it could take several months.
This is the largest outbreak of Ebola in recorded history with more than 1,700 people infected.
This video contains images from the European Commission DG ECHO.