HEALTH: Malaria-Carrying Mosquitoes Travel by Airplane

By Gustavo Capdevila Reprint | | Print |

Gustavo Capdevila

GENEVA, Aug 22 2000 (IPS) - Malaria, a mosquito-transmitted disease that afflicts the human populations of Africa and other developing regions, is also found near airports in industrialised countries as the disease-carrying insects find their way aboard commercial aircraft.

The differences between the North and South are still vast as far as the effects of malaria, with a million deaths in 1999 attributed to the disease, the overwhelming majority occurring in Africa. Meanwhile, the industrialised North has recorded just 87 deaths in the last 30 years from what has been dubbed “airport malaria.”

But the problem has caught the attention of World Health Organisation (WHO) experts as these infectious agents – known for ignoring national borders – increasingly find their way into European territory.

Diseases like malaria that depend on insects for transmission are especially difficult to trace back to their origins, says a study led by Norman Gratz, former director of the WHO’s Division of Vector Biology and Control.

The problem deepens, achieving global dimensions, when the insects are capable of being transported by aircraft and surviving in a new environment. Mosquitoes are a notorious example of this, especially if they carry malaria parasites, the dengue virus or yellow fever.

Other disease-carrying insects have also been found aboard airplanes, including tsetse flies (vectors of African trypanosomiasis or sleeping sickness) and sandflies (leishmaniasis).

From 1969 to 1999, 87 cases of malaria were reported in 12 industrialised countries, affecting people who lived near airports. Five of the cases proved fatal.

France topped the list with 26 cases, followed by Belgium, which recorded 16, and Great Britain, with 14. The study related the phenomenon to the relatively high number of flights between the major air terminals in these countries and airports in central and western Africa.

Malaria-carrying mosquitoes may enter the passenger cabin of an aircraft before take-off or during stopovers, and are thought also to survive in the checked baggage compartments.

Regardless of how they travel, malaria occurring through this process is more frequently fatal because of late diagnosis, as doctors in industrialised countries do not necessarily have the training to recognise the patient’s symptoms of the disease.

In addition to airport malaria, other cases of the disease occur in the North as people travel to regions where the mosquitoes are present. In 1999, there were 2,000 recorded cases of Europeans infected during trips overseas.

The cost of treating malaria victims in industrialised countries averages 2,700 dollars each.

This sum far exceeds the cost of periodically applying a residual insecticide in airplanes, such as permethrin, plus spraying an aerosol insecticide prior to passenger embarkation or before take-off.

But the bigger picture of Africa poses greater challenges. The sub-Saharan region of the continent would require approximately one billion dollars annually to confront the disease, which claims 900,000 lives there each year.

This investment could provide benefits worth three to 12 billion dollars yearly because controlling the disease would provide a boost to the combined gross domestic product (GDP) of the countries in the region, states the WHO report.

The United Nations agency’s study also points out that the type of mosquito that transmits malaria first arrived in Brazil in 1930, most likely aboard a ship, not an airplane.

At the time, the epidemic in the South American country affected 300,000 people, leaving 16,000 dead.

The definitive eradication of the vector meant Brazil had to launch a costly campaign, warned the WHO as it strongly recommended that airport authorities around the world follow its instructions for disinfection.