<P> The high rate of deaths among workers on the Panama Canal due to disease was the source of a great deal of controversy in the United States . Newspapers, such as The Independent, frequently reported on the poor conditions workers in the Canal Zone experienced, including the rampant disease . Poultney Bigelow wrote an article in The Independent in 1906 critiquing the work on the Panama Canal, which was highly influential with the American public . Among other topics, Bigelow brought attention to the poor living conditions of the workers, including pools of standing water where mosquitoes could breed and spread disease from . </P> <P> It was clear to organizers of the American effort that previous disease control efforts had been largely ineffective, as the causes of the two main diseases were unknown, but in 1897 it was proved by Britain's Ronald Ross in India that malaria was spread by mosquitoes . </P> <P> The Canal Commission appointed Colonel William Crawford Gorgas in March 1904 as head of hospitals and sanitation . Under his leadership, many new departments of sanitation were founded, covering different aspects of the sanitation problem . Commissions were also formed to look after the basic welfare of laborers . </P> <P> The sanitation work included clearing land and establishing quarantine facilities . The most ambitious part of the sanitation program, though, was undoubtedly the effort to eradicate the mosquitoes Aedes aegypti and Anopheles, the carriers of yellow fever and malaria, respectively, from the canal zone . There was initially considerable resistance to this program, as the "mosquito theory" was still considered controversial and unproven . However, with the support of chief engineer John Frank Stevens, who took over the post on July 26, 1905, Gorgas was finally able to put his ideas into action . </P>

Who discovered a way to treat yellow fever so the panama canal could be built