Malaria's impact is widespread. Although eradicated almost 60 years ago in the United States, malaria remained a serious problem in 109 countries in 2008. Malaria is a disease caused by a parasite that is transmitted to a person through the bite of a particular mosquito. It can lead to fever, muscle aches, and, without effective treatment, sometimes death. Globally, an estimated 247 million people become ill due to malaria every year; of these, nearly 1 million die, mostly children younger than five years old. Approximately 40% of the world's population is at risk of malaria, but most cases and deaths are in sub-Saharan Africa. In the past decade, the U.S. government and international community have increasingly recognized malaria prevention, treatment, and control as a fundamental factor in community health and economic growth in developing countries. Despite global efforts to eradicate malaria in many regions in the 1950s and 1960s, the 1990s saw a resurgence of the disease after national and international investments in malaria research and control declined. Many leaders expressed their growing concern about the negative impact of high rates of malaria infection and death on many developing countries during high-level meetings and summits, including the United Nations (U.N.) General Assembly. Many U.S. policymakers have, likewise, demonstrated a strong interest in combating malaria. In recent years, Congress has passed legislation that states that a major objective of the U.S. foreign assistance program is to provide aid for the prevention, control, and cure of malaria; required the development of a U.S. global malaria strategy; and appropriated increased funding for U.S. programs that fight the disease globally. At the same time, the U.S. government reorganized many U.S. malaria programs and changed program policies to emphasize funding for commodities (such as antimalarial drugs and mosquito nets), their effective distribution and implementation, and monitoring and evaluation activities. This report provides background on malaria's cause, consequences, and impact as well as key interventions for its prevention, control, and treatment. It examines congressional activities related to global malaria, and then it describes U.S. programs through the U.S. Agency for International Development (USAID) and the Centers for Disease Control and Prevention (CDC) that address the disease internationally. The report describes U.S. funding for these activities. It also raises possible issues for Congress related to U.S. funding levels, U.S. program priorities and strategies, access to and effectiveness of commodities, and oversight of U.S. programs. Except for CDC operational and applied research, this report does not describe U.S. government activities related to malaria research. Appendix A provides a glossary of acronyms and abbreviations used in the body of this report. Appendix B lists additional key books, articles, and reports on malaria. Malaria is a complex disease that has been successfully eradicated in some parts of the world, including the United States. However, in other areas, eradication efforts have failed or not been attempted at all. Experts agree that it is important to understand not only the disease and its impact but also the recent history of international malaria efforts if ongoing efforts are going to succeed in controlling malaria where past programs did not. Malaria is caused by Plasmodium parasites, which are transmitted to humans through the bite of infected female A nopheles mosquitoes. First, these parasites multiply in the liver; then they infect red blood cells. A week or two after someone is bitten by an infected mosquito, initial symptoms appear, including fever, shivering, headache, nausea, vomiting, muscle aches and fatigue. Without effective treatment, these symptoms may rapidly progress to include organ failure, delirium, convulsions, coma, and sometimes death. Malaria infects people of all ages, but some groups — pregnant women, infants and young children, and people living with HIV/AIDS — are more vulnerable to the disease. Most cases and deaths, including more than 9 out of 10 child deaths from malaria, are in sub-Saharan Africa, but other regions of the world, including parts of Asia, Latin America, the Middle East and Europe, are also affected (see Figure 1 ). Those countries that have a fairly constant number of cases throughout the year are considered malaria endemic countries. In 2008, 109 countries were considered malaria endemic; of these, 45 were in sub-Saharan Africa. The incidence of malaria appears to correlate to many other factors affecting the health, economic development, and social well being of people and communities in many developing countries. High rates of malaria in a developing country may negatively affect economic growth and demand a great proportion of public health resources. In 2003, 25-40% of all outpatient clinic visits and 20-50% of hospital admissions in malaria endemic countries in Africa were for malaria. With the scale-up of malaria programs in many malaria endemic countries, some countries report fewer malaria-related hospital admissions. Often, poor or marginalized populations are disproportionately affected by malaria. While experts debate whether poverty leads to malaria or malaria leads to poverty, some suggest that high rates of malaria can continue the cycle of poverty by draining financial resources and contributing to absenteeism from schools or the workplace. Additionally, many malaria deaths in Africa occur among populations affected by conflicts, which may experience malaria outbreaks due to disruptions in healthcare and malaria control efforts as well as exposure to different malaria transmission patterns. Experts agree that preventing malaria infections as well as accurately diagnosing and treating malaria quickly are essential to control the spread of malaria. Four key strategies for combating malaria are: Effective Treatment with ACTs: Treating malaria early and with effective drugs shortens its duration and prevents complications and most malaria-related deaths. Several drugs are used to treat malaria, and they vary in cost, availability, and effectiveness. In most areas, donors or Ministries of Health prefer to use artemisinin-based combination therapies (ACTs), which succeed generations of antimalarial drugs, including chloroquine, that have become less effective in fighting the malaria parasite due to increased drug resistance. ACTs are made up of an artemisinin drug and one or more additional antimalarial drugs; using antimalarial drugs in combination rather than singly reduces the likelihood that the malaria parasite will develop resistance to a drug. IPTp: In many malaria-endemic areas, women may be given intermittent preventive treatment of malaria during pregnancy (IPTp) — spaced doses of the drug sulfadoxine-pyrimethamine (SP) — in order to reduce the rates of malaria-related low birth weights in newborn babies and malaria-related anemia in pregnant women. IRS: Another way of reducing the transmission of malaria is through indoor residual spraying (IRS) — spraying the inside walls of houses with a long-acting insecticide. By controlling the presence of malaria-infected mosquitoes through IRS, malaria transmission can be reduced or interrupted. Several types of insecticides are used in the environment to control mosquitoes, and, like antimalarial drugs, they vary in cost, availability, and effectiveness. ITNs: The use of insecticide-treated mosquito nets (ITNs) is another strategy to prevent malaria-infected mosquitoes from biting people and transmitting the disease. These nets protect individuals or families from malaria when people sleep under nets hung over their beds. The nets also kill the mosquitoes. These nets usually retain their insecticidal properties for up to six months, depending on how frequently they are washed, without re-treatment. Some long-lasting insecticidal nets (LLINs) have insecticide incorporated into their fibers and last for up to 3 years. However, the appropriate mix of prevention and treatment interventions may vary according to local conditions, including the presence of parasite resistance to antimalarial drugs (including ACTs and SP) and mosquito resistance to insecticides. USAID's selected interventions in a country also vary based on the pattern of disease transmission, the age and pregnancy status of infected persons, and whether activities are feasible and sustainable. Malaria prevention, treatment, and control, which is increasingly recognized as a fundamental component of community health and economic growth in developing countries, has re-emerged as a major international concern in the past decade. In the 1950s and 1960s, multilateral efforts to eradicate malaria globally and in specific countries increased; some programs experienced setbacks or failure while others had more success. However, sub-Saharan Africa was largely excluded from these efforts. Reasons given for this vary: the region's high malaria infection rates; the costs associated with trying to eradicate malaria in many countries; and that the region included "areas inhabited by populations with primitive tribal organizations incapable of supporting complex administrative structures and high costs of malaria eradication campaigns." Many experts in the 1960s believed that malaria in many areas might be eradicated in coming years, but after investments in malaria research and control declined from previous levels and little attention was paid to sub-Saharan Africa, the 1990s saw the resurgence of the disease. Several high-level meetings and summits have addressed the malaria problem in recent years, reflecting growing political interest in and public recognition of the negative economic and social impacts of malaria on affected regions. For example, in 1995, the U.N. General Assembly expressed concern about malaria's detrimental effects on many developing countries in light of increasing malaria infection rates. The Pan-Africa Malaria Summit of 1997 culminated in the Harare Declaration on Malaria Prevention and Control in the Context of African Economic Recovery and Development. In the Harare Declaration, many African heads of state invited "governments and other partners including multilateral and bilateral agencies to participate actively in a vigorous coordinated effort to control malaria in Africa" and pledged their commitment to the African Plan of Action against malaria described in the declaration. A few years later, many African heads of state agreed to the Abuja Declaration on Roll Back Malaria in Africa, which set targets for reducing malaria's impact in Africa.