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Monday, September 3, 2012

Beating Back Malaria

Last week's Republican National Convention and this week's Democratic National Convention have been located in states--Florida and North Carolina, respectively--that were characterized by fairly high rates of malaria until the 1940s, when concerted efforts to drain swamps, spray for mosquitos and other intervention methods paid off and wiped out the disease. But vigilance is always necessary in hot, humid climates where mosquitos exist. News about Sri Lanka this week reinforced that idea. In an article published in PLoS ONE the authors note that:
Malaria incidence in Sri Lanka has declined by 99.9% since 1999...Indoor residual spraying [IRS] and distribution of long-lasting insecticide-treated nets have likely contributed to the low transmission.
This is, of course, very welcome and encouraging news. But here's the rub: 
Malaria had been nearly wiped out of Sri Lanka back in 1963.A massive decline in incidence occurred in Sri Lanka, from 91,990 cases in 1953 to 17 cases in 1963. Then, as was the case for many other countries, IRS was scaled down, surveillance and control activities were relaxed, and financial support reduced. In combination with reduced rainfall in the wet zone, these actions led to a massive resurgence, with an estimated 1.5 million cases during the two-year period 1967–1968. IRS was scaled back up the next year, but the damage had already been done. Major epidemics have since occurred in Sri Lanka in the 1980s and early 1990s.
This is a story that has been repeated throughout history when it comes to diseases of all kinds--the bugs are out there waiting for us whenever we let our guard down. 


  1. Curious: Flu strains change yearly. What about malaria? I know there are different kinds in different regions, but do the strains not evolve so fast that continued spraying is effective?

  2. Malaria is a parasite and while there are variations, it mainly needs a host and a vector (the mosquito) to go from host to host, as it kills each host and needs to move on. As long as there are available hosts and vectors, malaria can continue to exist.