treatment. in the 2000s (decade), malaria with partial resistance to artemisins emerged in southeast asia. resistance is now common against all classes of antimalarial drugs apart from artemisinins. treatment of resistant strains became increasingly dependent on this class of drugs. the cost of artemisinins limits their use in the developing world. malaria strains found on the cambodia–thailand border are resistant to combination therapies that include artemisinins, and may, therefore, be untreatable. exposure of the parasite population to artemisinin monotherapies in subtherapeutic doses for over 30 years and the availability of substandard artemisinins likely drove the selection of the resistant phenotype. resistance to artemisinin has been detected in cambodia, myanmar, thailand, and vietnam, and there has been emerging resistance in laos. resistance to the combination of artemisinin and piperaquine was first detected in 2013 in cambodia, and by 2019 had spread across cambodia and into laos, thailand and vietnam (with up to 80 percent of malaria parasites resistant in some regions). there is insufficient evidence in unit packaged antimalarial drugs in preventing treatment failures of malaria infection. however, if supported by training of healthcare providers and patient information, there is improvement in compliance of those receiving treatment. prognosis disability-adjusted life year for malaria per 100,000 inhabitants in 2004 no data <10 0–100 100–500 500–1000 1000–1500 1500–2000 2000–2500 2500–2750 2750–3000 3000–3250 3250–3500 ≥3500 when properly treated, people with malaria can usually expect a complete recovery. however, severe malaria can progress extremely rapidly and cause death within hours or days. in the most severe cases of the disease, fatality rates can reach 20%, even with intensive care and treatment. over the longer term, developmental impairments have been documented in children who have had episodes of severe malaria. chronic infection without severe disease can occur in an immune-deficiency syndrome associated with a decreased responsiveness to salmonella bacteria and the epstein–barr virus. during childhood, malaria causes anaemia during a period of rapid brain development, and also direct brain damage resulting from cerebral malaria. some survivors of cerebral malaria have an increased risk of neurological and cognitive deficits, behavioural disorders, and epilepsy. malaria prophylaxis was shown to improve cognitive function and school performance in clinical trials when compared to placebo groups. epidemiology deaths due to malaria per million persons in 2012 0–0 1–2 3–54 55–325 326–679 680–949 950–1,358 past and current malaria prevalence in 2009 relative incidence of plasmodium species by country of origin for imported cases to non-endemic countries the who estimates that in 2021 there were 247 million new cases of malaria resulting in 619,000 deaths. children under 5 years old are the most affected, accounting for 67% of malaria deaths worldwide in 2019. about 125 million pregnant women are at risk of infection each year; in sub-saharan africa, maternal malaria is associated with up to 200,000 estimated infant deaths yearly. there are about 10,000 malaria cases per year in western europe, and 1300–1500 in the united states. the united states eradicated malaria as a major public health concern in 1951, though small outbreaks persist. about 900 people died from the disease in europe between 1993 and 2003. both the global incidence of disease and resulting mortality have declined in recent years. according to the who and unicef, deaths attributable to malaria in 2015 were reduced by 60% from a 2000 estimate of 985,000, largely due to the widespread use of insecticide-treated nets and artemisinin-based combination therapies. efforts at decreasing the disease in africa since 2000 have been partially effective, with rates of the disease dropping by an estimated forty percent on the continent. malaria is presently endemic in a broad band around the equator, in areas of the americas, many parts of asia, and much of africa; in sub-saharan africa, 85–90% of malaria fatalities occur. an estimate for 2009 reported that countries with the highest death rate per 100,000 of population were ivory coast (86.15), angola (56.93) and burkina faso (50.66). a 2010 estimate indicated the deadliest countries per population were burkina faso, mozambique and mali. the malaria atlas project aims to map global levels of malaria, providing a way to determine the global spatial limits of the disease and to assess disease burden. this effort led to the publication of a map of p. falciparum endemicity in 2010 and an update in 2019. as of 2021, 84 countries have endemic malaria. the geographic distribution of malaria within large regions is complex, and malaria-afflicted and malaria-free areas are often found close to each other. malaria is prevalent in tropical and subtropical regions because of rainfall, consistent high temperatures and high humidity, along with stagnant waters where mosquito larvae readily mature, providing them with the environment they need for continuous breeding. in drier areas, outbreaks of malaria have been predicted with reasonable accuracy by mapping rainfall. malaria is more common in rural areas than in cities. for example, several cities in the greater mekong subregion of southeast asia are essentially malaria-free, but the disease is prevalent in many rural regions, including along international borders and forest fringes. in contrast, malaria in africa is present in both rural and urban areas, though the risk is lower in the larger cities. climate change further information: climate change and infectious diseases § malaria climate change is likely to affect malaria transmission, but the degree of effect and the areas affected is uncertain. greater rainfall in certain areas of india, and following an el niño event is associated with increased mosquito numbers. since 1900 there has been substantial change in temperature and rainfall over africa. however, factors that contribute to how rainfall results in water for mosquito breeding are complex, incorporating the extent to which it is absorbed into soil and vegetation for example, or rates of runoff and evaporation. recent research has provided a more in-depth picture of conditions across africa, combining a malaria climatic suitability model with a continental-scale model representing real-world hydrological processes. history main articles: history of malaria and mosquito-malaria theory ancient malaria oocysts preserved in dominican amber although the parasite responsible for p. falciparum malaria has been in existence for 50,000–100,000 years, the population size of the parasite did not increase until about 10,000 years ago, concurrently with advances in agriculture and the development of human settlements. close relatives of the human malaria parasites remain common in chimpanzees. some evidence suggests that the p. falciparum malaria may have originated in gorillas.