By Betsy Todd, MPH, RN, CIC, AJN clinical editor
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. Read the rest of this entry »