More than 800 NHS staff have volunteered to help to treat those infected with Ebola in West Africa. But what kind of conditions will they find when they arrive?
A 92-bed treatment centre funded by the UK is almost ready to open in Kerry Town in Sierra Leone.
It will be run by the charity Save the Children and staffed by British volunteers, each of whom will go out for a stint of several weeks.
The working conditions in such facilities are intense, with staff wearing personal protection equipment in high temperatures.
Healthcare workers are most at risk from the virus because they are in direct contact with people in the later stages of the disease.
Rachael Cummings, a nurse and health adviser from Save the Children, has been involved in planning the Kerry Town facility.
She said screening of volunteers in the UK ensured only those who were robust enough psychologically, and had the right skills, were put forward.
"Part of Save the Children's role is to train people before deployment so they have a real understanding of how difficult the environment is going to be," she said.
Staff would be "caring for people who have a very high risk of dying" but also needed to protect themselves because those with Ebola were "very contagious", she said.
More training on arrival in Sierra Leone will follow, modelled on the experience of the charity Medecins sans Frontieres (MSF).
Ms Cummings added: "When people are working in the Ebola centre we'll have a 'buddy' system, making sure when they're tired they're rotated out, and through the decontamination area, where again you'll have that 'buddy' with you to guide you.
"We're acutely aware of the risks, and trying to mitigate all those risks."
One way in which they do that is to make sure that a volunteer is talked through each stage of the process of removing the protective suit by their "buddy".
It is one of the moments of highest risk, when concentration can easily lapse if someone is tired.
Few of the NHS volunteers will be used to working in an environment where so many of their patients die.
Save the Children hopes to help improve the survival rate, but counselling will be available for volunteers.
That is work Theresa Jones has already undertaken in Liberia, where she was a clinical psychologist when the outbreak happened.
She volunteered at a treatment centre run by MSF, and both Liberian and international staff faced daily challenges.
"A huge amount of people are coming to the gates, but we are having to turn people away.
"But also we have to treat people for a very scary, very deadly virus.
"So it's an incredibly difficult working environment."
Fear and suspicion
On Monday Ms Jones left her home in Bristol to fly back out to Liberia to begin similar work with the International Rescue Committee.
"I help people find what it that helps them keep going.
"Maybe for some people it's to reflect on their day; maybe they've made someone smile or found a toy for a child."
She says that for people working far from home, supporting each other is vital, but so is regular contact by email or phone with family and friends.
In Liberia she also hopes to work with survivors who often face fear and suspicion when returning to their communities.
Both women say celebrating those who do survive is the most important way of coping with the psychological impact of being at the heart of the Ebola outbreak.
Ebola virus disease (EVD)
- Symptoms include high fever, bleeding and central nervous system damage
- Spread by body fluids, such as blood and saliva
- Fatality rate can reach 90% - but current outbreak has mortality rate of about 70%
- No proven vaccine or cure
- Fruit bats, a delicacy for some West Africans, are considered to be virus's natural host