April 25, 2015 marks World Malaria Day. The latest figures from the World Health Organization show 198 million cases of malaria in 2013 — which led to 584,000 deaths, mostly among children under age five.

One effort to combat the disease has been distributing hundreds of millions of insecticide-treated bed nets across Africa. As we reported in 2013, the nets were supposed to last from three to five years. But in Malawi, they were being compromised by growing insecticide resistance. Many families told us that their nets became tattered with large holes. The World Health Organization predicted that an additional 120,000 African kids would die each year from Malaria if insecticides in bed nets continued failing.

Listen to our story here.