One only needs to look at a global map of malaria outbreaks to get an accurate depiction of where the standard of living is low.
Outbreaks blanket Central Africa, India, Pakistan, and Southeast Asia.
In the Western Hemisphere, a large epidemic exists over the Brazilian rain forest. From there the disease winds its way up through Central America and into Mexico, stopping a few hundred miles south of the United States, which was also covered with the disease not more than sixty years ago. The reason malaria infects impoverished areas, Roberts asserted, has little to do with hygiene, the water supply or a bad diet. Rather, it has to do with the lack of protection impoverished people have against mosquitoes. The Anopheles mosquito breeds in standing water, is most active at night and usually bites people as they rest in their homes.