The risk of an Ebola outbreak in the United States is very low. However, “I’ve been hearing loud and clear from healthcare workers from around the country that they're worried,” says Thomas Frieden, MD, director of the Centers for Disease Control and Prevention (CDC).1
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| The Ebola virus. Photo: CDC/Frederick A. Murphy |
Being concerned and cautious is one thing—but being worried is another. To prevent worry, yet inform you of appropriate precautions and safeguards, here are some FAQs about Ebola just for eye care professionals.
• Can Ebola be transmitted through tears or contact lenses?
Possibly, perhaps probably, but it’s not yet conclusively known whether the tears (or tear fluid on a contact lens) can carry the virus.
Ebola is transmitted between humans by direct physical contact with infected bodily fluids (the most infectious being blood, feces and vomit, as well as breast milk, urine and semen). But the studies implicating saliva and tears “were extremely limited in sample size and the science is inconclusive,” according to the World Health Organization (WHO).2 “In studies of saliva, the virus was found most frequently in patients at a severe stage of illness. The whole live virus has never been isolated from sweat.”
Ebola is not spread through water or food.
• Can Ebola be transmitted through the air?
Ebola could potentially be an aerosol-transmissible disease, but the information is inconclusive at this time.3 Anecdotal and experimental evidence suggests that Ebola can be transmitted by the aerosol route, although direct exposure—via a skin break or mucous membrane—is the most efficient way for Ebola to be transmitted.3
The CDC and WHO recommend the use of facemasks for health care workers providing routine care to patients with Ebola virus disease and respirators when “aerosol-generating” procedures are performed.3
• Can the virus spread while the infected patient is asymptomatic?
No. The WHO says, “The incubation period, or the time interval from infection to onset of symptoms, is from two to 21 days. The patients become contagious once they begin to show symptoms. They are not contagious during the incubation period.”4
Typical signs and symptoms include sudden-onset fever, intense weakness, muscle pain, headache and sore throat. This is followed by vomiting, diarrhea, rash, impaired kidney and liver function, and in some cases both internal and external bleeding.4
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What Precautions and Practices Should be Performed In-office?
• If you or one of your staff is sick, stay at home. Likewise, ask patients to inform you if they are sick, and reschedule the appointment if it’s not essential.8
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Because symptoms take up to three weeks to appear, be sure to ask patients if they have traveled internationally in the past month. Further, display signage in your office prompting recent international travelers to inform you or a staff member.
In the extremely unlikely event that you encounter a patient who may have been exposed to Ebola virus, you are required to contact local, state and federal health authorities ( www.cste.org/?page=StateEpi).
• How long does the virus live on surfaces?
Ebola virus can survive on dried-on surfaces, such as doorknobs and countertops, for several hours; however, in bodily fluids (such as blood), the virus can survive up to several days at room temperature, the CDC says.5 Take note that this information comes from one experimental study “performed under environmental conditions that favor virus persistence,” according to the CDC.6 “This study found that under these ideal conditions, Ebola virus could remain active for up to six days.”6
However, “in the only study to assess contamination of the patient care environment during an outbreak, conducted in an African hospital under ‘real world conditions,’ virus was not detected by either nucleic acid amplification or culture in any of 33 samples collected from sites that were not visibly bloody,” the CDC reports.4 With consistent daily cleaning and disinfection practices, “the persistence of Ebola virus in the patient care environment would be short—with 24 hours considered a cautious upper limit,” the CDC estimates.6
• What disinfectants can kill the Ebola virus?
Ebola virus is susceptible to 3% acetic acid, 1% glutaraldehyde, alcohol-based products and dilutions (1:10 to 1:100 for ≥10 minutes) of 5.25% household bleach and bleach powder.7
Ebola also can be inactivated by heating for 30 to 60 minutes at 60°C (140°F), boiling for five minutes or gamma irradiation (1.2 x106 rads to 1.27 x106 rads) combined with 1% glutaraldehyde. Ebola virus is also moderately sensitive to UVC radiation.7
• What precautions and practices should be performed in-office?
—If you or one of your staff is sick, stay at home. Likewise, ask patients to inform you if they are sick, and reschedule the appointment if it’s not essential.8
—Wear gloves when touching bodily fluids, blood, excretions or mucous membranes.
—Wear eye protection during patient examination.
—Wear a facemask for close encounters.
—Cover your mouth when coughing or sneezing; ask staff and patients to do the same.
—Routinely disinfect instruments and surfaces that patients touch or use.
—Use special care when handling needles, scalpels and other sharp instruments or devices.
—Wash your hands frequently with soap and water for at least 20 seconds, or generously apply an alcohol-based hand sanitizer.
—Provide hand sanitizer at the front desk and post infection control posters in the waiting area.
• Last but not least, maintain perspective.
For comparison, keep in mind that 5% to 20% of the US population comes down with the flu each year.9 More than 200,000 Americans are hospitalized from seasonal flu-related complications, and flu-associated deaths each year in the US range from a low of about 3,000 people to a high of about 49,000, the CDC estimates.9
So, if nothing else, go get a flu shot—and have your staff get them, too.
1. Johns Hopkins Bloomberg School of Public Health Expert Available Re: Healthcare Workers’ Possible Fears Over Ebola. Newswise. Oct 15, 2014. Available at:
www.newswise.com/articles/johns-hopkins-bloomberg-school-of-public-health-expert-available-re-healthcare-workers-possible-fears-over-ebola.
2. What we know about transmission of the Ebola virus among humans. World Health Organization website. Oct 6, 2014. Available at:
www.who.int/mediacentre/news/ebola/06-october-2014/en/
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3. Brosseau LM, Jones, R. Commentary: Health workers need optimal respiratory protection for Ebola. Center for Infectious Disease Research and Policy website. Sep 17, 2014. Available at:
www.cidrap.umn.edu/news-perspective/2014/09/commentary-health-workers-need-optimal-respiratory-protection-ebola.
4. Frequently asked questions on Ebola virus disease. World Health Organization website. Aug 8, 2014. Available at:
www.who.int/csr/disease/ebola/faq-ebola/en/.
5. Q&As on Transmission. Centers for Disease Control and Prevention website. Oct 17, 2014.
www.cdc.gov/vhf/ebola/transmission/qas.html.
6. Interim guidance for environmental infection control in hospitals for Ebola virus. Centers for Disease Control and Prevention website. Oct 17, 2014. Available at:
www.cdc.gov/vhf/ebola/hcp/environmental-infection-control-in-hospitals.html.
7. Ebolavirus: Pathogen Safety Data Sheet - Infectious Substances. Public Health Agency of Canada website. Aug 2014. Available at:
www.phac-aspc.gc.ca/lab-bio/res/psds-ftss/ebola-eng.php.
8. Interim Infection Prevention and Control Guidance for Care of Patients with Suspected or Confirmed Filovirus Haemorrhagic Fever in Health-Care Settings, with Focus on Ebola. World Health Organization website. Sep 2014. Available at:
www.who.int/csr/resources/publications/ebola/filovirus_infection_control/en/.
9. Seasonal Influenza Q&A. Centers for Disease Control and Prevention website. Aug 15, 2014. Available at:
www.cdc.gov/flu/about/qa/disease.htm.
