With the recent global attention on the Zika virus (we won’t say emergence, as Zika virus itself is not new), public health programs focused on controlling the mosquito vector enter a debate with its own long and storied past.
Pick up any early 20th century book on infectious disease management and you’ll find confident statements assuring the victory of humans over illness and death. One text from 1909 called Mosquito or Man? speaks of this inevitable triumph over disease with an air of colonial domination, stating:
The tropical world is today being steadily and surely conquered…The campaigns show that the three great insect-carried scourges of the tropics–the greatest enemies that mankind has ever had to contend with, namely Malaria, Yellow Fever, and Sleeping Sickness–are now fully in hand and giving way, and with their conquest disappears the depression which seems to have gripped our forefathers. Now the situation is full of hope. The mosquito is no longer a nightmare; it can be got rid of.
Most European and U.S. medical attention in diseases of the “tropical world” peaked only after these conditions negatively impacted colonial interests. For example, the deaths of tens of thousands of workers from yellow fever or malaria infections (from the then-unknown mosquito vector) contributed to the failure of the 19th century French attempt to construct a canal through Panama. To create such a canal—an infrastructure project which would accelerate trade and establish imperial power—required “the economic control or eradication of the disease-conveying species…that affect personal comfort or real estate value” (LePrince and Orenstein 1916, p. 3).
Man using a knapsack carrier to spray larvicide or oil in a ditch, 1916.
By the time, the United States began their own efforts to build the Panama Canal in 1904, U.S. public health officials had already instituted extensive sanitation projects informed by new epidemiological and entomological discoveries. These measures included draining stagnant water, controlling insect-breeding areas by spraying oil and larvicide or introducing larva-eating fish, fumigating buildings, and installing mosquito netting and window screens. Although canal laborers experienced less mortality from disease than their predecessors working for the French endeavor, medical staff continued to treat thousands of cases of mosquito-borne illnesses.
The hard fought results from these projects came with their own costs. Draining wetlands and adding larvicides (a combination of resin, carbolic acid, and sodium hydroxide) and crude oil into the remaining standing water wrecked havoc on the local ecology (Becker et al. 2013, p. 408). During mosquito control efforts in Panama, mosquito brigades poured an estimated 160,000 gallons of oil poured into the water in a single year of construction (Canfield 1908). Meanwhile, the time and money required for mosquito control campaigns could not be permanently sustained, making the comparative ease of mosquito eradication through DDT a welcome alternative. Mosquito resistance to insecticides has renewed interests in vector control, but today’s program developers are additionally informed by the historical challenges of managing mosquitoes.
Left: A mosquito breeding ground: shaded wetlands surrounded by brush. Right: The brush-free ditch dug to drain the area. 1922
Gone is the easy confidence that mosquitos “may be destroyed” (Howard 1902). Today’s public health officials instead advise people living in mosquito-endemic areas to make difficult sacrifices to preserve their health. Although an absolute victor in the “mosquito or man” competition is both ridiculous and unlikely, it is tempting to view recent events placing mosquitoes firmly in the lead. We should remember that government officials, scientists, and physicians actually made these bold claims in a time immense of suffering and death from mosquito-transmitted diseases. Perhaps a bit of this early conviction in success (sans colonialism, of course) is necessary to fuel large-scale projects and innovation, so we can live with, rather than against, this historic foe.
Applying a layer of oil to a ditch using a horse drawn cart. Panama, 1916.
References:
- Becker, N., Zgoma, M., Petric, D., Dahl, C., Boase, C., Lane, J., & Kaiser, A. 2013. Mosquitoes and their Control. New York, NY: Springer Science+Business and Media.
- Boyce, R. 1909. Mosquito or Man? The Conquest of the Tropical World. London, UK: John Murray.
- Canfield, H. 1908. Oil and Mosquitoes: Why the sanitary department used 3,200 barrels of oil or about 160,000 gallons during the last fiscal year. The Canal Record, Volume 1, p. 3.
- Hardenburg, W.E. 1922. Mosquito Eradication. New York, NY: McGraw Hill Co.
- Howard, L.O. 1902. Mosquitoes: How They Live, How They Carry Disease, How They are Classified, How They may be Destroyed. New York, NY: McClure, Phillips, & Co.
- LePrince, J.A. & Orentstein, A.J. 1916. Mosquito Control in Panama: Eradication of Malaria and Yellow Fever in Cuba and Panama. New York, NY: G.P. Putnam’s Sons.
- Nuttall, G.H, Cobbett, L., & Strangeways-Pigg, T. 1901. Studies in relation to Malaria. Journal of Hygiene 1, 4-77.