By Dr. Jonn Matsen

Fifty percent of flight attendants are off sick at least two weeks per year and they have twice the long-term disability rate of nurses, even though they do not have to lift patients as nurses do. However, like nurses, flight attendants are exposed to infectious diseases.

In her thoroughly documented book, Broken Wings, former flight attendant Nattanya Andersen quotes Harvard professor of environmental health, Dr Harriet Burge:

“There are many episodes of infectious diseases that could, if you took the trouble, be directly traced to travel on aircraft. It is also possible that if someone on the flight has an active case of an infectious disease like influenza, then other people on board will also have that disease by the end of the flight.”

This is why I have long recommended that patients take propolis before, during and after a flight because of its direct antiviral properties. However, cold and flu viruses aren’t the only diseases spread from passengers to flight attendants (and perhaps vice versa), as tuberculosis and measles have also been documented to spread on airplanes. It’s been proposed that the air in the plane is the root of the problem. In Andersen’s book, a member of the American Flight Attendant Union explains that modern planes use 50% new air and 50% recycled air, whereas planes used to use 100% fresh air. In modern planes, the air isn’t completely changed for seven minutes or longer.

A Harvard research team, commissioned by the American Broadcasting Company, found airplanes’ air contaminants to include not only microorganisms, such as viruses and bacteria, but high levels of dust mites as well. The researchers also found carbon dioxide and aromas from perfumes, aftershaves, cooking, fuel, de-icing chemicals, cleaning fluids, carpeting adhesives, upholstery finishes, ethanol, benzene and pesticides. Any of these can trigger allergy or asthma attacks in sensitive individuals.

Engineers have added filters to the air recirculation systems of some planes that remove up to 99.99% of airborne contaminants larger than 0.5 microns. The problem is that most common cold, flu and pneumonia viruses are smaller than this, so they aren’t effectively eliminated by filtration.

While chronic viral infections might be common to air travelers, it is unlikely that this alone is the root of the high numbers of chronically disabled flight attendants. There are other factors, such as exposure to high altitude radiation and frequent time zone changes, which have to be considered, though these would be difficult to change. However, there is another potential cause that could be readily changed, and that is exposure to insecticides.

After it was documented years ago that commercial aircraft traveling to Europe from tropical countries had transported malaria-carrying mosquitoes, it became mandatory practice in 18 countries to spray planes leaving tropical countries with insecticides. This became known as disinsection and the insecticide first chosen was pyrethrum, a natural insecticide extracted from chrysanthemum flowers and generally considered harmless to humans. However, the insecticides used on airplanes today are synthetic versions called pyrethroids. The World Health Organization states:

“Given the understanding of the mode of action of pyrethroids and low exposure from aircraft disinsection it is unlikely that this procedure will precipitate or influence any pre-existing disease in passengers or crew.”

This broad acceptance of synthetic pyrethroids has been proven wrong by a recent investigation into acute illness in flight attendants following exposure to pyrethroids. The State of California’s Department of Health Services published results of a study on October 23, 2003, after investigating 12 flight attendants reporting acute illness following work exposure to pyrethroids. They concluded that “…one or both of the WHO’s assumptions about the human health impacts of residual disinsection are not valid.”

Synthetic pyrethroids are also used widely in home insecticides for killing a wide range of bugs, from wasps and hornets to ants, ticks, roaches, fleas, mosquitoes, etc. A study by H. Muller-Mohnssen published in Toxicology Letters (1999, Volume 107: pages 161-175) looked at home exposure to synthetic pyrethroids as the likely cause of the dramatic increase in multiple chemical sensitivities in Germany in the past 10 years.

Muller-Mohnssen concludes that the basic therapy is “elimination of the causative agent” which means stopping the use of synthetic pyrethroids in the home. The use of pyrethroids in airplanes will be more difficult to stop; however, since the insects travel mainly in the baggage compartment, the use of toxic chemicals in the passenger compartment may be unnecessary.

For those already sensitive to chemicals, it’s crucial to avoid any planes that have been sprayed with synthetic pyrethroids. The only way to know for sure if your plane has been sprayed is to ask the airline. Healthy individuals about to undergo a trip that might include exposure may wish to begin a detoxification program at least three days before the flight (longer would be better). Taking milk thistle herb extract (at least 250 mg per day) and selenium (200 mcg per day) would be a good starting point.

Until the use of synthetic pyrethroids is banned, keep an eye on your flight attendants, as they are they canaries in the modern mineshafts called airplanes.