Houses with screens, rainwater-collection systems and cement floors could be a powerful tool in the fight against childhood diseases in Africa. Children living in these specially designed houses in Tanzania had fewer cases of malaria, diarrhea and respiratory diseases than those in traditional mud and thatched homes, researchers report April 21 in Nature Medicine . “Small improvements in design, such as cross-ventilation, mosquito screening, self-closing doors, clean water harvesting, improved pit latrines are likely to make a major health impact,” the researchers write. About 2.5 million children in sub-Saharan Africa die each year before turning 5. Data from the United Nations Children’s Fund indicate that malaria, diarrhea and lower respiratory infections such as pneumonia are the leading causes of mortality among children ages 1 month to 5 years in the region. Researchers wondered if housing could make a difference.…