Thu 5 Jan, 2006 09:09 am
NPR news this morning (1.5.06) told of an article in the January '06 _American Journal of Tropical Medicine_:
Amy Yomiko Vittor, Robert H. Gilman, James Tielsch, Gregory Glass, Tim Shields, Wagner Sanchez Lozano, Viviana Pinedo-Cancino, and Jonathan A. Patz
"The effect of deforestation on the human-biting rate of Anopheles darlingi, the primary vector of falciparum malaria in the Peruvian Amazon"
I can't get to the text of the entire article, but I'm curious.
A relative who studied ecology and worked in tropical South America has said yellow fever became a problem in lumbered areas because a yellow-fever bearing mosquito variety bred in droplets lodged between leaf-stem and branches high in the trees. They bit random monkeys living in the layer as they moved around. Never had to seek ground or ponds. When the trees hit the ground, they thumped free the mosquitos who then bit people. The mosquitos were dislodged from their normal habitat layer. If so, why not spray the trees before cutting?
Research method: The story said researchers used soda-straw gizmos to suck anopheles in whenever they lit on bare human legs (thus biting rate). It said they didn't collect from the air since some species don't bite humans. That is apparently how/why they refer to "human-biting rate."
The assumption mentioned in the news report about the article said mosquitos (generic?) like to live in ponds and don't like the forest, thus clearing trees increases malaria by creating open area. Thus, deforestation creates more clear ground and therefore more malaria.
I am wondering this: Is the biting rate a good measure? Did felling trees increase the population of biters on-ground by bringing down mosquitos that live (and normally stay) on higher eco-layers in the trees? Is the clear-ground/pond habitat assumption merited here?
I just checked a few websites. Although on <http://www.cdc.gov/malaria/biology/mosquito/> for example, the article says the mosquitos like open areas, it also said some bred in "leaf axels."
"The larvae occur in a wide range of habitats but most species prefer clean, unpolluted water. Larvae of Anopheles mosquitoes have been found in fresh- or salt-water marshes, mangrove swamps, rice fields, grassy ditches, the edges of streams and rivers, and small, temporary rain pools. Many species prefer habitats with vegetation. Others prefer habitats that have none. Some breed in open, sun-lit pools while others are found only in shaded breeding sites in forests. A few species breed in tree holes or the leaf axils of some plants."