Editor 's Note : Tachi Yamada is the President of the Global Health Program at the Bill & Melinda Gates Foundation . He writes for CNN 's Vital Signs about how the island of Zanzibar has virtually eliminated the disease over the past five years . ZANZIBAR , Tanzania -- I recently accompanied Margaret Chan , Director General of the WHO , and Ray Chambers , U.N. Special Envoy for Malaria , on a trip to Africa to see firsthand the region 's fight against malaria . A hospital ward on the Tanzanian island of Zanzibar stands empty . The single most memorable image of the trip was from a pediatric hospital ward on the Tanzanian island of Zanzibar : a dozen beds and not a single patient in them . Imagine that . I have searing memories of visiting wards much like this elsewhere in the world where there were as many as three children to a bed and more sleeping on the floor , deathly ill with malaria . Where have all the patients gone ? After all , malaria is a big killer in much of the developing world . It is probably the most prevalent disease that mankind has ever suffered . Each year , there are over 250 million cases and almost one million deaths -- most of them young children , and the vast majority in Africa . But in many countries , malaria is also a success story . Since 2000 , the number of reported malaria cases , deaths , or both has declined by at least half in 25 countries . Zanzibar -- a relatively small but striking example -- has virtually eliminated the disease over the past five years . These successes show what a combination of political will , technical resources , and financial commitment can do when applied to a strategy that works . There is no question that leaders and health officials in sub-Saharan Africa and other parts of the world recognize the horrible toll of malaria . In fact , Uganda 's Minister of Health told us that he himself has suffered from malaria three times this year . This understanding of the problem and the availability of tools to address it led the Bill & Melinda Gates Foundation in 2005 to fund the Malaria Control and Evaluation Program in Africa , which focused on malaria control in Zambia . Our investment was relatively small , but it helped Zambia create a comprehensive and aggressive national plan to fight malaria . With funding from the President 's Malaria Initiative , the World Bank , and the Global Fund to Fight AIDS , Tuberculosis , and Malaria , Zambia greatly expanded the use of proven tools to prevent and treat the disease , such as the use of indoor spraying with insecticides , distribution of bednets , and effective malaria treatment in government clinics . As a result , in three short years , the malaria incidence in Zambia declined by more than 50 percent , and child mortality from all causes , including malaria , declined by 30 percent . Zambia , Zanzibar , and other success stories provide a beacon of hope for the dream of a world free of malaria , articulated by Bill and Melinda Gates in 2007 when they put out a call to eradicate the disease . Today , there are a number of outspoken people who question the value and true impact of development assistance . The example of malaria shows that with political will , advice on planning , funds to purchase sound , scientifically validated tools , and the courage to measure results objectively , development assistance can have an enormous impact in a short period of time . Where have all the patients gone ? Home , where they can live happier , healthier lives . Let them be the retort to the skeptics of development assistance .
Yamada : The number of malaria cases has declined by at least half in 25 countries . Zanzibar has virtually eliminated the disease over the past five years . Zambia expanded the use of insecticides , bednets , and appropriate treatment . Bill & Melinda Gates Foundation helps funding a malaria control program .