Correction: An earlier version of this article omitted the first name of the first lady of Sierra Leone. She is Sia Nyama Koroma. This version has been corrected.

As the worst Ebola outbreak in history unfolds in West Africa, The Post's Joel Achenbach explains how the deadly virus wreaks havoc on the human body. (Davin Coburn/The Washington Post)

As the number of lives claimed by the Ebola epidemic in West Africa rises above 1,000, the rate of infection among women is outpacing that among men because women are the caregivers, nurses and cross-border traders, health officials report.

Outbreaks are thought to originate through contact with infected forest animals, often making men who hunt for bushmeat or handle the meat the first targets of infection.

But as an outbreak progresses, women tend to be disproportionately affected. Women account for 55 to 60 percent of the deceased in the current epidemic in Liberia, Guinea and Sierra Leone, according to UNICEF.

“Women constitute a large section of the health workers and are on the frontlines of this crisis,” Sia Nyama Koroma, first lady of Sierra Leone, said in a telephone interview.

At a task force meeting in Liberia a few weeks ago, health teams reported that 75 percent of those who were infected or died from Ebola were women, said Julia Duncan-Cassell, Liberia’s minister for gender and development.

“Women are the caregivers — if a kid is sick, they say, ‘Go to your mom,’ ” she said in an interview. “The cross-border trade women go to Guinea and Sierra Leone for the weekly markets, [and] they are also the caregivers. Most of the time when there is a death in the family, it’s the woman who prepares the funeral, usually an aunt or older female relative.”

Women also are the traditional birth attendants, nurses and the cleaners and laundry workers in hospitals, where there is risk of exposure.

Pregnant women are at high risk because of increased contact with health services and health workers. Two of the three largest outbreaks of Ebola involved transmission of the virus in maternity settings, according to the World Health Organization.

“When a family member is sick and is tended at home, women cook and serve food to the sick, clean after them and wash their clothes,” said Suafiatu Tunis, a spokesperson for Community Response Group, a grass-roots initiative to combat Ebola in Sierra Leone and a leader of the Social Mobilization Committee on Ebola that reports to the National Task Force. “This role is extended to the medical field, where women are mostly nurses and cleaners at hospitals and do not get the same support and protection as doctors, who are predominantly men.”

She said that one woman contracted Ebola when she went to care for her mother-in-law in another village, and the wife of a chief in the Kailahun district, an epicenter of the Ebola epidemic in Sierra Leone, was infected while caring for people at a local hospital. She then transmitted the virus to her child.

Understanding the role gender plays in an Ebola epidemic is crucial so that communication and intervention strategies can be targeted, health experts say. Women play a major role as conduits of information in their communities, and therefore they are being enlisted as leaders in campaigns to spread awareness about the disease. A government task force in Liberia is providing training for women’s groups.

“By reaching the women, they are reaching those who can best protect their families, and their own health,” said Maricel Seeger, a WHO spokeswoman who is in Monrovia, Liberia.

As the deadliest Ebola outbreak ever unfolds in West Africa, two American missionaries continue to recover in Atlanta after receiving an experimental drug called ZMapp. An Ebola expert explains how ZMapp is derived and how it fights the deadly virus. (Gillian Brockell and Pamela Kirkland/The Washington Post)

From “mamie queens,” traditional female leaders in Sierra Leone, to housewives and grandmothers, women are helping to inform other women about how to protect themselves and their communities.

Liberia has a history of women’s movements driving social change, notably the role the women’s peace movement had in helping to end the civil war of 1999-2003. “Women have taken the lead in informing the community,” Duncan-Cassell said.

Now spanning four countries — Liberia, Sierra Leone, Guinea and Nigeria — the worst outbreak of the Ebola virus on record is following the trend of previous outbreaks.

During the 2000-2001 Ebola outbreak in Gulu, Uganda, the number of women infected exceeded that of men throughout. The tradition of the paternal aunt or another female relative washing the body before burial — a practice that also is common in West Africa — likely contributed to the high rate of infection in women.

In a 1979 Ebola outbreak in Sudan, 69 percent of those affected were women, according to a 2007 report by WHO.

The impact on women has economic implications. In rural areas, where the majority of smallholder farmers are women, food production could be affected, said Koroma, Sierra Leone’s first lady. She added that border restrictions will affect traders, the majority of whom are women, making it difficult for them to provide for their families.