Who is patient zero? In epidemiological investigations, doctors often use the term to refer to the first documentated case. According to CNN Health and The New England Journal of Medicine, patient zero of the recent Ebola outbreak was a young villager from Guinea.

First identified in equatorial areas of Sudan and Zaire in 1976, the deadly Ebola virus has identified itself once again in a new location: Senegal, the epicenter for international transit.

Despite strict quarantines on Ebola outbreaks, research scientists across the world believe that it is impossible to prevent the spread of fever in such a short period of time. Scientists at Harvard University, in conjunction with the Centers for Disease Control and Prevention, were able to map out the genomes of infected patients.

An Al Jazeera article written by Digital News Producer Renee Lewis, “Scientists Map Ebola Virus Genome in Quest for Treatment” reported the analysis of over 99 Ebola virus genomes, which supported the understanding of how the virus was transmitted and evolved up until this time.

Ebola Hemorrhagic Fever, a zoonotic pathogen, is passed through various rodents and monkeys that carry the infection. Moreover, recent publications in peer-reviewed journal Emerging Infectious Diseases state that “3.5 percent of bats were positive for antibodies against Ebola Zaire and Reston viruses,” which alludes to EHF wildlife reservoirs.

“Ebola viruses, members of the filovirus family, have been found mostly in Africa,” said Daniel Christen, visiting assistant professor of chemistry, who specializes in Medicinal chemistry and history of diseases. “Among humans, the most common route of transmission is through direct contact with a symptomatic patient, bodily fluids from a patient or a diseased patient.”

The Ebola virus is caused by filoviruses that encrypt their genome into single-stranded negative-sense RNA. The Ebola virus evolves with formation of virions, filamentous infectious viral particles, which consequently infuse into receptors of the cell’s surface to release the virus into the cell. The result is evasion of the immune system.

“In order for viruses to infect and multiply, they need to gain entry into host cells,” said Michele Malotky, department chair and associate professor of biology. “Once they have gained entry, they hijack the cell’s machinery and reprogram the cells to become viral factories.   There are currently a number of labs striving to identify these cellular receptors and generate antibodies that block the ability of the virus to bind and enter.”

Meanwhile, EHF epidemiological studies have traced the Ebola virus back to patient zero of 2014 to suggest that it was a two-year-old boy from the village Gueckedou in Guinea who started the chain reaction of events that led to the spread of Ebola throughout the region. After suffering for four days, the boy consequentially infected his family, who then infected other villages in Guinea, which finally led to the spread of Ebola in the nations of Sierra Leone and Liberia.

With an unusual 2014 index case, the Ebola virus became unprecedented when the death toll in West Africa reached 2,097 out of 3,944 present cases. Since, the spread of EHF has prompted international airlines, border stations and ports to take measures to avoid possible contagion.

Scientists still do not understand how Ebola zoonotic pathogens were transmitted from animals to humans. As a result, the zoonotic pathogens now jump from human to human as they spread across the globe.