This year marks a century since the official opening of the Panama Canal, one of the most iconic structures, one of the greatest engineering feats of all times, a symbol of technological prowess and ingenuity, and a testament of the sheer determination of the human spirit. While commemorating the monumental accomplishment embodied in this gigantic undertaking, we should take a pause to remember the thousands of lives lost during its construction to accidents and mosquito-borne diseases.
Besides the sheer magnitude of the project, one of the greatest challenges the builders of the Panama Canal faced was dealing with mosquito-borne diseases common to the area. When the United States took over construction of the Panama Canal on May 4, 1904, the Isthmus of Panama was under the firm control of tropical diseases. By then, approximately 12,000 workers had perished during the construction of the Panama Railway and over 22,000 during the French attempt to build the canal. Many of these deaths were due primarily to yellow fever and malaria. In fact, construction of the Panama Railway was stopped several times due to the lack of healthy workers. American project managers quickly realized that previous disease control efforts were ineffective and something had to be done. Armed with the information provided by Sir Ronald Ross in India in 1897 that malaria was spread by mosquitoes, mosquito control methods were implemented as part of the Panama Canal construction project...
In March of 1904, the Canal Commission appointed Colonel William Crawford Gorgas to head all hospital and sanitation operations. He quickly created a number of new departments of sanitation that covered a wide range of problems and looked after the basic welfare of laborers. The sanitation plans he created included clearing land and establishing quarantine facilities, but his main goal was the eradication of Aedes aegypti and anopheles mosquitoes from the canal zone. Gorgas faced significant resistance as many considered the “mosquito theory” controversial and unproven. It was not until July 26, 1905, when John Frank Stevens took over as chief engineer and gave Gorgas his full support that Gorgas’ sanitation and environmental management plan was fully implemented.
To accomplish his task, Dr. Gorgas divided Panama City and Colón –on the Atlantic coast- into districts. In each district, teams of inspectors searched houses and buildings for mosquito larvae. If larvae were found, workers were dispatched to eliminate objects or places where stagnant water could collect. By eliminating standing water where possible and by spreading larviciding oil on the surface of any remaining pools, mosquito larvae were eliminated.
Gorgas also organized a program to drain and fill swamps and wetlands around the Canal Zone. Many miles of ditches were dug, and grass and brush were cut back over wide areas. Workers with sprayers were sent to spray oil on standing pools. Small streams were tackled by placing cans dripping larviciding oil over them. In addition to larviciding, Gorgas implemented adult mosquito control methods as another step to eradicate mosquitoes. To do this, residences of confirmed cases of yellow fever were fumigated by placing pans containing two pounds of sulfur or Pyrethrum per thousand cubic feet in the rooms. The pans were sprinkled with wood-alcohol and ignited. When the effectiveness of this procedure was realized, fumigation was extended to all of Panama. Within a year of Stevens’ appointment, every building in Panama had been fumigated, using up the entire US supply of sulfur and Pyrethrum. By 1906, only one case of yellow fever was reported, and until the end of the Panama Canal’s construction, there were zero.
Gorgas’ final means of attack on disease was to quarantine individuals infected with Yellow fever or malaria from the rest of the workforce. Those who were diagnosed with either disease were put into “Portable Fever Cages,” easily transportable screened structures used to prevent mosquitoes from biting an infected person and carrying the disease to others. Gorgas also had canal workers sleep in screened verandas, as the mosquitoes that spread malaria are nocturnal and would infect the most people at night.
Colonel Gorgas’ sanitation plan for the Panama Canal Commission was one of the first truly integrated mosquito control programs. His health measures included general health care, development of an extensive health infrastructure, and a systematic approach to mosquito control aimed at eradicating mosquitoes from the area. His actions were instrumental to the success of the Canal’s construction. By 1906, yellow fever was virtually wiped out in the Canal Zone, and the number of deaths caused by malaria was significantly reduced. (It is worth noting that the accomplishments of Dr. Gorgas sanitation teams were reached well before the advent of satellite imagery, remote sensing, cell phones, any mention of a malaria vaccine, computers, etc.)
Today, the Panama Canal area continues to be free of yellow fever and malaria, provides a significant source or revenue for Panama and is an enviable standard of living to the many people who live and work there.
Construction of the Panama Canal without Gorgas’ health and sanitation teams would have resulted in several thousand additional deaths, additional costs and/or yielded similar results to the French attempts of years earlier. Unfortunately, though vector control was instrumental in the completion of the Panama Canal, many of today’s agencies and organizations funding malaria control interventions oppose implementing Gorgas-style vector control operations under the argument that they are expensive and complex operations. This argument continues in spite of current expenditures of somewhere around a billion US dollars per year during the past decade or so that place little to no credence to vector control interventions beyond mosquito nets and indoor residual spraying.
Money is really not the problem. What is lacking is will. The world needs to get serious about addressing malaria as a vector-borne disease, give it the funding it requires and provide a career path for public health entomologists and field technicians in the affected countries.
The World Health Assembly Resolution No. 15.13 of the Fiftieth World Health Assembly of 1996 declared the mosquito as Public Enemy Number One and asked member States to promote integrated pest-management approaches. Unfortunately, the current approach to malaria control is nowhere close to what WHA Resolution 15.13 intended. Moreover, there is a marked dearth in technical expertise pertaining to mosquito population suppression tools beyond IRS and LLINS in almost every national malaria control program around the globe.