The scale of the world’s worst Ebola outbreak has been concealed by families hiding infected loved ones in their homes and the existence of “shadow zones” that medics cannot enter, the World Health Organisation (WHO) said yesterday.

The UN agency issued a statement detailing why the outbreak in West Africa had been under­estimated, following criticism that it had moved too slowly to contain the killer virus, now spreading out of control.

Independent experts raised similar concerns a month ago that the contagion could be worse than reported because suspicious local inhabitants are chasing away health workers and shunning treatment.

More than 1,300 people have died from the disease and many experts do not expect the epidemic to be brought under control this year.

Under-reporting of cases is a problem especially in Liberia and Sierra Leone. The WHO said it was now working with Medecins Sans Frontières (MSF) and the US Centres for Disease Control and Prevention to produce “more realistic estimates”.

Passengers are screened as they arrive at Bangkok’s Suvarnabhumi Airport yesterday. Asian nations are using thermal imaging cameras and posting doctors at airports to screen out sick travellers as health authorities scramble to control further spreading of the Ebola virus. Photos: Reuters

The head of MSF, which has urged the WHO to do more, told Reuters in an interview on Thursday that the fight against Ebola was being undermined by a lack of international leadership and emergency management skills.

The stigma surrounding Ebola poses a serious obstacle to efforts to calibrate the outbreak in Liberia, Sierra Leone, Guinea and Nigeria, which has claimed far more victims than any other episode of the disease that was first discovered nearly 40 years ago in the forests of central Africa.

Some believe infected loved ones will be more comfortable dying at home

“As Ebola has no cure, some believe infected loved ones will be more comfortable dying at home,” the WHO statement said.

“Others deny that a patient has Ebola and believe that care in an isolation ward – viewed as an incubator of the disease – will lead to infection and certain death. Most fear the stigma and social rejection that come to patients and families when a diagnosis of Ebola is confirmed.”

Corpses are often buried without official notification, the WHO said, while an additional problem is the existence of numerous “shadow zones”, or rural villages where there are rumours of cases and deaths that cannot be investigated because of community resistance or lack of staff and transport.

In other cases, where treatment is available, health centres are being immediately overwhelmed with patients, suggesting there is an invisible caseload of patients that is not on the radar of the official surveillance systems.