More than 400 healthcare workers have contracted Ebola – and 58% percent of those have died – according to a report from the World Health Organisation.

A breach in safety protocol at a Dallas Hospital in the US has caused a female healthcare worker to become infected with Ebola after having extensive contact with Ebola patient Thomas Eric Duncan. The development – the first known case of the deadly disease transmitted in the US – stunned health officials who had not included the woman in the group of 48 people being monitored for the disease because she was thought to be of low risk for infection as she had worn protective equipment while caring for Duncan.

But the woman developed symptoms, and preliminary diagnostic tests came back positive – a reminder of the risk that nurses, doctors and other hospital workers face treating Ebola patients.

To date, more than 400 healthcare workers – the vast majority in West Africa – have contracted Ebola. 58% eight percent of those have died, according to the most recent report from the World Health Organisation.

Dr Tom Frieden, director of the US Centres for Disease Control and Prevention (CDC), said the CDC must still confirm the diagnosis, but that there was little doubt that there had been a failure of the supposedly rigid precautions health workers are to take when caring for patients with the highly contagious disease.

“We don’t know what occurred in the care of (Duncan), but at some point, it was a breach in protocol and that breach in protocol resulted in this infection,” says Dr Frieden in a briefing. “If this individual was exposed, which they were, it is possible that other individuals were exposed.” All healthcare workers who treated Duncan are now being monitored for possible infection.

Previously, those monitored included family members and others who had come into contact with Duncan before he was hospitalised on Sept 28. Four family members are being checked twice a day and are being guarded to ensure they remain isolated. The 21-day incubation period for most of the 48 ends today.

As the epidemic has swept the West African nations of Liberia, Guinea and Sierra Leone, healthcare workers, unaware that they were treating people with the disease, are thought to have played a role in its spread.

Texas officials say only one person is believed to have had contact with the new Dallas patient after she began to show symptoms. That person will now be monitored for 21 days.

Diagram of safety procedures for healthcare workers in contact with Ebola.

The CDC is now recommending that the Dallas hospital, Texas Health Presbyterian, keep the number of workers treating possible Ebola patients to an “absolute minimum”, says Dr Frieden. The agency also wants the hospital to provide a full-time infection control officer to ensure that safety measures are followed with Ebola patients.

Meanwhile, the hospital has announced that its emergency department had stopped accepting patients brought by ambulance until further notice “because of limitations in staffed capacity”, a step known as “diversion”.

“While we are on diversion, we are also using this time to further expand the margin of safety by triple-checking our full compliance with updated CDC guidelines,” says the hospital. “We are also continuing to monitor all staff who had some relation to Mr Duncan’s care, even if they are not assumed to be at significant risk of infection.”

The infected woman sought care immediately after her symptoms developed and was placed in isolation at the hospital, says Dr Frieden. He added that the worker had extensive contact on multiple occasions with Duncan during his care, but currently had a low level of the virus.

In light of the likely breach, US President Barack Obama has asked federal authorities take more steps to ensure that hospitals and healthcare providers are ready to follow proper procedures in dealing with Ebola patients. The White House also says Obama has asked the CDC to move as quickly as possible in investigating the apparent breach of procedures. 

The CDC is investigating whether the new infection occurred during kidney dialysis or respiratory intubation procedures that Duncan underwent “as a desperate measure to try to save his life”, says Dr Frieden. “Both of those procedures may spread contaminated materials and are considered high risk,” he says. Duncan died of complications from Ebola on Oct 8.

The CDC is recommending that the hospital perform only “essential procedures” on Ebola patients to limit workers’ possible exposure to the virus. Under that guideline, Duncan would not have received the kidney dialysis and respiratory intubation treatments.

Officials will also examine whether the infection occurred during the removal of the worker’s protective equipment. The full-body suits, gloves and masks worn by Ebola caregivers are designed to protect them from infected body fluids that spread the disease. But removing the gear is a “major potential area of risk”, says Dr Frieden.

Map and chart showing cases of Ebola outbreak as of October 11, 2014. – MCT

If done improperly, a person could accidentally put their skin in contact with soiled or contaminated protective equipment, leaving them potentially exposed to the virus. Dr Frieden says proper equipment removal to avoid infection is “critically important and not easy to do right”.

“It requires meticulous and scrupulous attention to infection control,” he says. “And even a single, inadvertent, innocent slip can result in contamination.” For that reason, “putting more on isn’t always safer,” Dr Frieden said. “It may make it harder to provide effective care.”

A nursing assistant in Madrid, Spain, who became infected after treating Ebola patients, has suggested her infection may stem from hand-to-face touching as she removed her protective equipment. Spanish authorities are monitoring 16 people who came in contact with the nursing assistant, who is in critical condition.

The CDC will examine the use of protective equipment and will look to develop better guidelines to assure its proper use, says Dr Frieden.

Because the newly infected woman was thought to be at low risk for infection, like other healthcare workers who treated Duncan after he was placed in isolation on Sept 28, she was self-monitoring her condition when she developed Ebola symptoms.

A hazardous materials crew from Fort Worth, Texas, arrived on Oct 18 to begin decontaminating the worker’s apartment. Brad Smith with Fort Worth-based CG Environmental Cleaning Guys says a crew of about 15 on Sunday was to start scrubbing the exterior of the apartment building. Smith says he expects to begin work inside on Monday.

His company decontaminated the Dallas apartment where Duncan stayed before he was hospitalised, and also cleaned parts of the hospital where he was treated. Dallas County officials hurried early on Oct 18 to reassure residents that they were not in danger.

“While this was obviously bad news, it is not news that should bring about panic,” says Dallas County Judge Clay Jenkins at a morning news conference at the hospital. “That healthcare worker is a heroic person,” says Jenkins. “Let’s remember that as we do our work that this is a real person who is going through a great ordeal, and so is that person’s family.”

Ebola problems

The new infection is the latest in a series of problems at the hospital since Duncan first showed up for care on Sept 24. After telling hospital staff he had recently traveled from Liberia, where Ebola is raging, Duncan was sent home that day with only antibiotics after doctors failed to properly screen him as a possible Ebola patient.

After Duncan returned four days later and was placed in isolation with the disease, the hospital offered several different accounts about why Duncan was initially released. At first, it said nurses didn’t provide Duncan’s travel history to other staffers. Then, it blamed a computer glitch for the error. 

The hospital later retracted that account, saying the information was available to all Duncan’s caregivers. No further explanation has been provided.

Dr Daniel Varga, chief clinical officer of Texas Health Resources, which oversees the hospital, declined to place blame for whatever lapse that led to the new infection. “This individual was following full CDC precautions,” he says. “Gown, glove, mask and shield.”

Asked how concerned he was that even after those precautions, the worker tested positive, his reply: “We’re very concerned.” – McClatchy Washington Bureau/McClatchy-Tribune Information Services