In one study, promoting hand-washing and giving free soap to families in impoverished settlements in Karachi, Pakistan, significantly reduced cases of infectious diarrhea in children.
In another study, treated bed nets given to families in western Kenya led to dramatic reductions in malaria-carrying mosquitoes and infant deaths over a period of about six years.
"What many people look at as just overwhelming problems of poverty" can be tackled by addressing one aspect of behavior and don't require trying to solve the more complex underlying causes of impoverishment, said Dr. Stephen Luby of the federal Centers for Disease Control and Prevention.
That doesn't mean that the underlying causes shouldn't be addressed, but rather that making a dent may not be as daunting as some people have thought, said Luby, lead author of the hand-washing study.
The studies appear in the Wednesday Journal of the American Medical Association, an issue on global health.
A journal essay says that many developing countries face a double burden of infectious disease and rising rates of heart disease, cancer, diabetes and other chronic diseases. In India, for example, infections such as diarrhea, malaria and pneumonia kill 2.5 million children each year, but the country also has the world's highest number of diabetics, according to the report by Derek Yak at the World Health Organization and colleagues.
A JAMA editorial says the bed net and soap studies are encouraging evidence of successful interventions but that more research is needed to evaluate the long-term effects.
In the soap study, 600 households received regular supplies of soap for about a year. Field workers also made weekly home visits to encourage regular hand-washing.
Children younger than 15 years had a 53 percent lower incidence of diarrhea than youngsters living in households that didn't receive the soap or hand-washing advice. Severely malnourished children under age 5 had 42 percent fewer days of diarrhea than children in households without the intervention.
The bed net study involved 130,000 residents of 221 Kenyan villages from 1997 to 2002. About half were given nets in the study's initial phase; the remainder received nets later on. Nets were periodically retreated and replaced as needed.
More than 20 percent of deaths in children under 5 in the region are attributed to malaria, which is transmitted by mosquitoes.
Less than half as many malaria cases occurred in infants whose families had the nets in the first phase than in infants in families without nets. In the first phase, there also were significantly fewer infant deaths from all causes in the bed net group. Death rates fell in the no-net group in the second phase after they received nets.
An earlier analysis determined that the program's first phase, which cost $725,700, was cost-effective given the lives saved and reduced disease burden.
CDC researcher Kim Lindblade, the lead author, said a cost-effectiveness analysis has not been done for the study's second phase.
The results show the benefits "are likely to endure if programs continue to actively supply nets and insecticide," Lindblade said.
By Lindsey Tanner