This progress - which compares favorably with other WHO regions - is the result of ongoing prevention and control efforts in malaria-endemic countries carried out by governments with support from the Pan American Health Organization (PAHO) and other international partners.
In 2000, more than 1 million cases of malaria were reported in the Region of the Americas. By 2011, the number had dropped to below 490,000. Malaria deaths declined from 439 to 113 during the same period. Nevertheless, some 30% of the population in 21 endemic countries of the Americas remains at risk of contagion, and 8% is considered at "high risk."
Of the 21 countries in the Western Hemisphere where malaria is endemic, 18 are considered to be on track to achieve the Millennium Development Goal (MDG) related to malaria, which calls for a 75% reduction in cases between 2000 and 2015. This target has already been met in 13 of the region's countries: Argentina, Belize, Bolivia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Honduras, Mexico, Nicaragua, Paraguay and Suriname. Six of these - Argentina, Costa Rica, Ecuador, El Salvador, Mexico and Paraguay - are considered in the pre-elimination phase.
Three other countries - Colombia, Panama and Peru - have reduced cases by more than 64% and are therefore on track to achieve the MDG by 2015. Brazil is projected to achieve a reduction of between 50% and 75% by 2015. Countries that face greater challenges in achieving the 75% reduction in cases by 2015 are Guyana, the Dominican Republic, Venezuela, and Haiti (where data limitations make it difficult to assess trends over time).
"Between 2005 and 2011, the Dominican Republic achieved a very significant reduction in cases - from 3,837 to 1,616," noted Dr. Keith Carter, PAHO/WHO senior advisor on malaria. "The number of cases in 2011 would have been lower than the number in 2000 [1,233 cases] if the country had not received imported cases from Haiti as a consequence of the 2010 earthquake." According to official data from the Dominican Republic, 577 of the 1,616 cases recorded in 2011 were imported.
"The Dominican Republic is on track to reach the MDG target for malaria," added Dr. Carter.
In Guyana, malaria cases declined between 2000 and 2010 but increased in 2011. Cases also increased in Venezuela.
"Countries should continue to invest efforts and resources to achieve further reductions in cases and deaths," said Dr. Carter.
The 2012 World Malaria Report estimates that some US$5.1 billion annually will needed between 2011 and 2020 to achieve universal access to malaria interventions in the 99 countries with ongoing transmission. In 2011, only US$2.3 billion was available, less than half of the amount needed.
The report summarizes data received from 104 malaria-endemic countries and territories. In 99 of these countries, malaria transmission is ongoing.
Malaria is caused by the parasite Plasmodium, which is transmitted through the bites of infected mosquitoes. In the human body, the parasites multiply in the liver and then infect red blood cells. In the Americas, Plasmodium vivax causes approximately 70% of all cases, with Plasmodium falciparum causing a majority of the rest, and Plasmodium malariae responsible for a small number of cases.
Symptoms of malaria include fever, headache, and vomiting, and usually appear between 10 and 15 days after the mosquito bite. If not treated, malaria can quickly become life-threatening by disrupting the blood supply to vital organs. In many parts of the world, the parasites have developed resistance to a number of malaria medicines.
Key interventions to control malaria include: prompt and effective treatment with artemisinin-based combination therapies wherever P. falciparum is resistant to other drugs; use of insecticidal nets by people at risk; and indoor residual spraying with insecticide to control the vector mosquitoes.
Malaria in numbers
- In 2010 there were an estimated 219 million cases of malaria worldwide and an estimated 660,000 deaths due to the disease, most of them in children under 5.
- In 2010, 673,723 cases were reported in the Americas, or about 3% of total cases worldwide.
- Africa is the most affected continent: about 90% of all deaths from malaria occur there.
- Of the 50 countries in the world that are on track to meet the goal of reducing malaria cases by 75% by 2015, 18 are in the Americas.
- An estimated 1.1 million lives have been saved globally over the past decade thanks largely to scaled-up malaria-control efforts.
- The burden of malaria is concentrated in 14 endemic countries where an estimated 80% of all malaria deaths occur.
- An estimated US$ 5.1 billion will be needed every year between 2011 and 2020 to achieve universal access to malaria interventions in the 99 countries with ongoing transmission of the disease.
- The number of rapid diagnostic tests delivered to endemic countries increased from 88 million in 2010 to 155 million in 2011.