By CDC microbiologist Cynthia Goldsmith, a colorized transmission electron micrograph (TEM) reveals some of the ultrastructural morphology displayed by an Ebola virus virion. CDC image library.
We humans have a knack for taking any newly reported issue of legitimate concern entirely out of context, foregoing all common sense as we transform it into a danger of galactic proportions.
The current case in point is Ebola viral disease. There has been much ranting and raving about closing our borders to people with Ebola infection (as if that were possible), even some misinformed speculation that the virus has been intentionally released.
To me as a nurse epidemiologist, though, the central questions in this tragic outbreak are the same for Ebola as for any other disease:
How is the organism transmitted?
What is the risk of protected or unprotected exposure to the infected person?
Ebola is a bloodborne pathogen. It’s spread in the same way as HIV, hepatitis B, or hepatitis C: when blood or other body fluids contaminate another person’s non-intact skin or mucous membranes. None of these diseases is spread by casual contact. And unlike HIV or hep B or C, Ebola is not a chronic condition; transmission occurs during acute infection, after the fever begins and the disease progresses. It is virtually impossible to contract the virus by, say, walking past an infected person in the airport, or sharing a bus ride, or shopping in the same grocery store.
Preventing transmission. Unlike for HIV or hep B or C infection, isolation precautions are implemented to prevent transmission of Ebola. This is because bloody secretions, vomit, and diarrhea are typical symptoms as the disease progresses. Because of the resulting probability of exposure to the patient’s blood or bloody secretions/excretions, both contact and droplet precautions are used (i.e., gown, gloves, mask, and eye protection) in order to place a barrier between the infected person’s secretions and the caregivers.
Airborne transmission has not been documented—however, because of the potential for aerosolization of blood or bloody secretions/excretions, most experts recommend airborne isolation precautions as well (negative pressure room, N95 or greater respirators), if possible. (Here’s a CDC table with recommendations regarding transmission precautions for Ebola in various clinical situations.)
Why the rapid spread in West Africa? News reports of unchecked spread of the virus in West Africa have fueled global fears. However, a closer look at what’s happening makes it clear that two main groups of people have been at particular risk for Ebola infection:
close family members of those who are already infected
health care workers
There are risk factors unique to these groups in this region that have contributed to transmission.
It has been reported that many family members have continued to provide close personal care to their infected loved ones, without using any kind of protective gear. (Don’t attribute this to ignorance. If your two-year-old child were gravely ill, would you be likely to gown, glove, and mask? And even if you thought about doing so, do you have a large stash of these items at home?) Their repeated exposure to blood and body fluids inevitably leads in some cases to the contamination of mucous membranes or non-intact skin.
Postmortem care is traditionally done by families, and this also involves much intimate contact. Added to prolonged, unprotected exposure are health belief systems that can further increase risk. Reportedly, family members in some of the outbreak regions deny the possibility of Ebola infection. They see their loved one’s illness as a curse, not a virus, and believe it can only be cured by a traditional healer.
For health care workers, risk is increased by the difficulties of maintaining full isolation precautions under these particular circumstances. Have you ever complained about suiting up for isolation because the gown, mask, and gloves make you too warm, even in an air-conditioned workplace? Imagine wearing all of this gear for a prolonged period of time in a high-temperature, high-humidity environment.
Western medical professionals who have worked under these conditions have noted how easy it is to unconsciously wipe their faces with their contaminated hands, as they try to keep the sweat streaming into their eyes from blurring their vision. It’s not that personal protective equipment doesn’t work, but that difficult conditions and a high-pressure care situation can compromise the use of personal protective equipment (PPE), sometimes unnoticed.
Should we be worried in the U.S.? In this age of global travel, it is inevitable that we will eventually see cases of Ebola in the U.S. Of course the prospect is sobering; though the virus is not spread casually, the mortality rate from Ebola infection is high. (As of August 1, there had been 1603 confirmed or suspected cases in this outbreak, with 887 deaths.) However, given the infection-control resources and expertise of hospitals and health care providers, there is very little risk of the spread of Ebola in the U.S. The take-home points for health care workers are these:
This is a bloodborne pathogen. It is transmitted through contact of mucous membranes or non-intact skin with blood or body fluids.
Transmission is most likely to occur after fever develops and as the disease progresses.
If infection is suspected, ALWAYS inquire about the patient’s travel history. Ebola and other diseases don’t appear out of thin air. Look for a link to outbreak areas.
INSTITUTE ISOLATION PRECAUTIONS IMMEDIATELY. Policy in all health care organizations should specify that any clinical staff person can initiate isolation; if your policy limits isolation “orders” to physicians, change it.
Wear appropriate PPE.
Don and remove PPE as though someone’s life depends on it. Often, someone’s does. Unfortunately, we caregivers can be careless about suiting up because in most situations, we are not the people at risk. But the patient down the hall to whom you’ve just carried MRSA (because of poor hand hygiene, messy glove technique, or a sloppily tied gown) can die from MRSA bacteremia or pneumonia.
With a disease like Ebola, or any emerging infectious disease that has not yet been fully defined (e.g., MERS), a “gatekeeper” should be stationed outside of the closed door of the patient’s room. The gatekeeper’s role: to ensure that only essential personnel enter the room, and to supervise the meticulous donning and doffing of protective gear.
For details on the pathogenesis, clinical presentation, epidemiology, and treatment of Ebola virus, see this still very relevant AJN article from several years back, free until the end of September.