role of aircraft in the international transmission of disease, The

Journal of Multicultural Nursing & Health, Winter 2000 by Neff-Smith, Martha, Spencer, Gale A, Williams, Richard S, O'Donnell, Charles R, Riley-Eddins, Essie A

In the past, geographical features such as deserts, oceans and mountain ranges limited human and with it the transmission of disease. With the development of vessels of transportation and trade, disease began to spread, often with disastrous consequences. With the advent of air travel, the speed of this transmission increased significantly. Due to intercontinental jet travel, the wold has become immediately linked as a community. The use of aircraft has increased the danger that travelers will transmit disease once thought only to afflict those in distant countries.

KEY WORDS: Aircraft; Disease; Transmission.

Diseases have been spread by man in vessels of transportation throughout recorded history. Movements of populations due to military and political conflict have traditionally been associated with disease. Armies were (and are) composed of large numbers of individuals susceptible to disease and often operate in conditions of environmental extremes and poor hygiene. This has fostered the spread of a variety of diseases among armies and has facilitated transmission of these same diseases to the civilian population. The mobile nature of armies caused diseases endemic to a particular locale to be introduced to the inhabitants of other regions. Population migration, which is often associated with military activity, has accounted for the spread of disease in much the same way. History is replete with demonstrations of this phenomenon, with resurgence of malaria in the United States following the return of troops from Southeast Asia a recent example.

One of the earliest efforts toward military public hygiene occurred in 630 AD, when Gallus established a sanitary zone about the diocese of Cahors, placing armed guards at each point of entry to prohibit movement. The first quarantine in recorded history was adopted by the knights templars of the Order of St. John of Jerusalem. The length of the quarantine was set at forty days because that was the amount of time Christ spent in the wilderness. The notion was perpetuated by the Venetians in 1348 AD, where vessels, crews and passengers were held for forty days to guard against plague. The practice continued throughout sixteenth and seventeenth century Europe and was termed "quarantine" from the Italian word "quanta", which means forty.

Epidemics of cholera accompanied the rapid increase in travel with the development of steamships and railroads. The magnitude of these epidemics necessitated international cooperative efforts to effect control. The First International Sanitary Conference was held in Paris in 1851, and was attended by one physician and one diplomat from Sicily, Spain, the Papal States, France, Great Britain, Greece, Portugal, Russia, Sardinia, Tuscany, and Turkey. It was agreed that quarantine was largely ineffective, and rules of international hygiene and sanitation in international commerce were adopted. The International Office of Public Health was formed in Paris in 1907 after nine more International Sanitary Conferences. This Office antedated the League of Nations Health Office, which eventually evolved into the World Health Organization. The treaty, signed by sixtyfive countries at the Thirteenth International Sanitary Conference in 1926, is the basis for our modern international health laws.

The extensive use of the airplane as available means of international travel prompted concern about potential disease transmission, and the first sanitary convention for aerial navigation was held in 1933. Existing international maritime laws were used as a model, modified to suit the state of aviation in 1933. Medical inspection and control of infectious diseases were topics of discussion of the convention. Yellow fever was targeted as a disease of particular interest, and detailed methods to eliminate the vector, the mosquito Aedes aegypti, were proposed. The 1933 convention was the progenitor of the World Health Organization Committee on Hygiene and Sanitation in Aviation. The committee is the current agency responsible for protecting the international community from the spread of disease by military or civilian aircraft.

Impact of Air Travel on Disease Transmission

In times past, incubation of most communicable diseases was shorter than transit times, allowing symptoms of disease to arise prior to arrival at the destination. This facilitated identification of and control of diseases at ports of entry. In today's environment of jet travel, infected individuals often manifest disease after arrival, magnifying the potential for epidemic spread.

Currently, nearly any area on earth can be reached in twenty-four hours by jet travel. This has greatly reduced the effectiveness of geographic separation as a barrier to disease transmission. Infectious diseases of almost every kind have been spread in some way by air travel. Vectorborne diseases are particularly important, since vectors and susceptible populations for many of these diseases are found in areas regularly served by scheduled air carriers. Diseases transmitted by person-to-person contact are an obvious air travel concern. Food is often moved by aircraft and insect infestation of cargo also present potential threats.