The team "found that a surprisingly large fraction of 'imported'
infections --- that is, infections that are carried by people
moving from one place to another --- wind up in Nairobi, with
infected residents returning there after journeys to spots such
as Lake Victoria or the coast," the news release says. This may
lead to an increased risk of local transmission within Nairobi
and its surrounding areas, despite the lower number of
mosquitoes, or "malaria vectors," in urban areas. The research
suggests that efforts to control malaria could benefit from a
focus on "source" areas where incidence is high, rather than on
areas where fewer people are infected. Human travel patterns
mean the parasite is likely repeatedly to be carried back to
areas where it has been almost eliminated. The study advises
that on a very local scale, "hot spots of transmission can be
targeted by indoor residual spraying, vector habitat removal,
insecticides, drug administration, and bed-net use." But
attempts to control transmission by