Preventing Epidemic by Air Travel

Preventing Epidemic by Air Travel

Aerospace Medicine / Blog / Civilian Aviation Medicine / Medical Science

Ebola Risk & Response for Airlines

WHO Ebola Fact Sheet

WHO Ebola Fact Sheet

The Centers for Disease Control (CDC) maintains a webpage dedicated to providing updated recommendations to airlines on high-interest infectious diseases.  The current website offers guidance to airlines on the measles, flu, cholera, and Middle-East respiratory syndrome (MERS).  On August 11 2014, they added airline guidance for Ebola. Ultimately, the CDC’s recommendations emphasize the fact that Ebola IS NOT spread by airborne or respiratory droplets and therefore risk of rapid global spread remains low, unlike many of the other diseases stated above.  But before going into the specific CDC guidance to airlines, it is important to understand and review the basic facts surrounding this serious and terrible disease.


The 2014 outbreak of Ebola, which started in March of this year, at the time of this writing has affected 4 West African Countries – Guinea, Sierra Leone, Liberia, and Nigeria.  As of 19 Aug 2014, the World Health Organization (WHO) has reported 2240 suspected and confirmed cases of Ebola, including 1383 laboratory-confirmed cases, and 1229 deaths (54.9% mortality).  This is not the first outbreak of Ebola.  The virus was first identified in 1976 in the Republic of Congo, gaining its name from the nearby Ebola River.  The last outbreak was in 2012 when Uganda and the Republic of Congo experienced a smaller scale epidemic, which lasted from July to December of that year.  Other outbreaks have occurred in Gabon, Sudan and the Ivory Coast and can be seen in detail by clicking the above photo. The disease currently stirring so much attention is called Ebola Hemorrhagic Fever and is caused by an RNA virus in the filovirus family.  There are 5 separate Ebola virus species.  Ebola is considered a viral hemorrhagic fever, though it is much more fatal than many other hemorrhagic fevers such as Dengue or Yellow Fever.  The pathogenesis is complex, but basically the viruses causing these diseases provoke small blood clots throughout the body, disrupt the clotting cascade and generally attack the lining of blood vessels and/or platelets.  Many of the initial symptoms of Ebola are vague and non-specific making early diagnosis difficult:

  • Fever (greater than 38.6°C or 101.5°F)
  • Severe headache
  • Muscle pain
  • Weakness
  • Diarrhea
  • Vomiting
  • Abdominal (stomach) pain
  • Lack of appetite
The Ebola Life Cycle

The Ebola Life Cycle

The incubation period for the virus is 2 to 21 days after exposure, but 8-10 days seems to be the most common incubation period prior to symptom onset.  At this point, the true reservoir for the virus is unknown, but many have speculated that bats are the likely culprit.  The virus has also been identified in non-human primates and pigs.  Once humans are infected (after likely ingesting infected animal tissue), the virus can spread from person to person by direct contact of contaminated fluids.  The Ebola virus’ ability to spread is limited:

  • Sick person’s blood or body fluids (urine, saliva, feces, vomit, and semen)
  • Contaminated objects (such as needles) with infected body fluids
  • Infected animal tissue

Because of the need for direct contact for transmission, the groups of people at biggest risk for contracting the disease are family members and healthcare workers in close proximity to infected patients and their bodily fluids.  The fact that the disease does not spread by respiratory droplets has led many public health policy makers to rank the risk of a global outbreak of ebola as quite low. Given the vague, non-specific symptoms of Ebola; diagnoses are often delayed.  The diagnosis is confirmed via lab assessment of a blood sample, by doing either viral cultures and reverse transcriptase polymerase chain reaction (PCR) to identify the virus, or enzyme-linked immunosorbent assay (ELISA) to identify antibodies. There is currently no proven antiviral treatment or vaccination for Ebola Hemorrhagic Disease.  The mainstay of current treatment is supportive therapy in the form of fluids, oxygen, and life support as required.  Several vaccinations are currently in the test phase, but none have yet proven safety and efficacy.  ZMapp, being developed by Mapp Biopharmaceutical Inc., is an experimental treatment for Ebola. It has not yet been tested in humans.  According to the manufacturer, ZMapp  is “composed of three “humanized” monoclonal antibodies manufactured in plants ” that bind to the protein of the Ebola virus.  In an incredibly rare event, the FDA has permitted this experimental drug to be used to treat Ebola in a few cases.  The two American missionary healthcare workers recently infected with Ebola were provided this new experimental drug.  According to the CDC: “This experimental treatment was arranged privately by Samaritan’s Purse, the private humanitarian organization, which employed one of the Americans who contracted the virus in Liberia. Samaritan’s Purse contacted the Centers for Disease Control and Prevention (CDC), who referred them to the National Institutes of Health (NIH). NIH was able to provide the organization with the appropriate contacts at the private company developing this treatment. The NIH was not involved with procuring, transporting, approving, or administering the experimental treatments. The two Americans who received the experimental drug seem to be improving, but a Spanish priest also provided the drug for its third use did not recover and subsequently died of the disease.

Ebola 2014 Outbreak Distribution Map

Ebola 2014 Outbreak Distribution Map

As a consequence of the significant mortality and nature of the disease, public hysteria continues to rise.   Mass quarantines are being implemented as public health and government agencies scramble to develop plans and guidance to prevent spread and respond to the disease in the event that it does extend outside West Africa.  Quarantine zones have been established in high transmission areas including the severely affected cities in Guinea, Liberia; and Sierra Leone.  Liberian soldiers along the border with Sierra Leone have been ordered to shoot anyone attempting to cross the border at night. And countries with Ebola cases have been requested to conduct an exit screening of all persons at entry/exit points of the country.  Obviously, the existence of international air travel adds a new variable in rapid disease spread that did not exist 100 years ago.


Preventing Epidemic by Air Travel

Preventing Epidemic by Air Travel

Released on 11 Aug 2014, the CDC report provides guidance to Airlines in respect to the Ebola Outbreak.  Here are some highlights:

  • Any person exposed to Ebola should not be permitted aboard commercial airliners until 21 days of observation and medical clearance by their physician.
  • Any airplane traveling to a country affected by Ebola (currently Sierra Leone, Liberia, Guinea, and now Nigeria) should have a universal precautions kit on board.
  • In addition to standard in-flight medical services, the CDC should be contacted for guidance if suspicion for an Ebola-infected passenger for any flights into the United States.
  • Treat any bodily fluids as if contaminated.  Personnel tasked to clean bodily fluids from within airlines need to wear impermeable plastic gloves and use an EPA approved cleaner.  Other specific guidance is provided.
  • Since Ebola virus is spread through direct contact of bodily fluids, cargo does not bear any risk unless soiled with blood or other infected bodily fluids.



The CDC also has a page of resources specifically drafted for healthcare workers.  For those interested, click the link above.



1. CDC Ebola Hemorrhagic Fever. Accessed 19 Aug 2014. 2. WHO Ebola Fact Sheet. Accessed 19 Aug 2014. 3. Paessler S, Walker DH. Pathogenesis of the viral hemorrhagic fevers. Annu Rev Pathol. 2013 Jan 24;8:411-40. Epub 2012 Nov 1.