What is ... Malaria?
Malaria is a serious and sometimes fatal disease caused by single-celled protozoan parasites that are transmitted through the bites of infected female Anopheles mosquitoes. There are five Plasmodium species that cause malaria in humans, and two of these species – P. falciparum and P. vivax – pose the greatest threat.
P. falciparum is the most prevalent malaria parasite on the African continent. It is responsible for most malaria-related deaths globally.
P. vivax is the dominant malaria parasite in most countries outside of sub-Saharan Africa.
What is the disease?
How dangerous is Malaria?
The different species of the malaria parasite cause varying severity of symptoms. Malaria generally causes high fevers, shaking chills, and flu-like illness. If left untreated, severe forms of the disease can be fatal.
Illness and death from malaria can usually be prevented if diagnosed and treated promptly and correctly. Nevertheless, the majority of people affected by malaria have no access to comprehensive medical care and are thus mortally threatened by the disease.
Who is at risk?
In 2016, nearly half of the world's population was at risk of malaria.
Most malaria cases and deaths occur in sub-Saharan Africa but the WHO regions of South-East Asia, Eastern Mediterranean, Western Pacific, and the Americas are also at risk. In 2016, 91 countries and areas had ongoing malaria transmission.
Infants, children under five years of age, pregnant women and patients with HIV/AIDS, as well as non-immune migrants, mobile populations and travelers are at considerably higher risk of contracting malaria, and developing severe disease, than others.
How many people are affected by Malaria?
3.2 billion people in 106 countries and territories live in areas at risk of malaria transmission.
The World Health Organization estimates that in 2016 malaria caused 216 million clinical episodes in 91 countries. This was an increase of 5 million cases compared to 2015.
Deaths caused by Malaria were estimated to be 445 000 in 2016, just a little under the 446 000 figure in 2015.
Where is Malaria found?
Where malaria is found depends mainly on climatic factors such as temperature, humidity, and rainfall. Malaria is transmitted in tropical and subtropical areas, where Anopheles mosquitoes can survive and multiply.
The WHO African Region carries a disproportionately high share of the global malaria burden. In 2016, the region was home to 90% of malaria cases and 91 percent of malaria deaths.
In many malaria-endemic countries, malaria transmission does not occur in all parts of the country. Even within tropical and subtropical areas, transmission will not occur
- at very high altitudes
- during colder seasons in some areas
- in deserts (unless there are water sources providing breeding sites for mosquitoes)
- in countries where transmission has been successfully interrupted through control/elimination programs
Generally, in warmer regions closer to the equator
- transmission will be more intense
- Malaria can be transmitted year-round
In many temperate areas, such as western Europe and the United States, economic development and public health measures have succeeded in eliminating malaria. However, most of these areas still have Anopheles mosquitoes that can transmit malaria, and reintroduction of the disease is therefore a constant risk.
How do people get Malaria?
Malaria is transmitted to people through the bites of infected female Anopheles mosquitoes.
SYMPTOMS AND COURSE
What are the signs and symptoms of Malaria?
Infection with malaria parasites may result in a wide variety of symptoms, ranging from absent or very mild symptoms to severe disease and even death.
The classical (but rarely observed) malaria attack lasts 6-10 hours. It consists of:
- a cold stage with the sensation of cold and shivering
- a hot stage with fever, headaches, vomiting, and seizures in young children
- and finally a sweating stage with sweats, return to normal temperature, and tiredness
More commonly, the patient presents with a combination of the following symptoms:
- fever Sweats
- nausea and vomiting
- general malaise
- body aches
In countries where cases of malaria are infrequent, these symptoms may be attributed to influenza, a cold, or other common infections, especially if malaria is not suspected.
Conversely, in countries where malaria is frequent, residents often recognize the symptoms as malaria and treat themselves without seeking diagnostic confirmation.
Physical findings may include:
- elevated temperatures
- mild jaundice
- increased respiratory rate
- enlarged spleen
- enlargement of the liver
Severe malaria occurs when infections are complicated by serious organ failures or abnormalities in the patient's blood or metabolism. The manifestations of severe malaria include:
- cerebral malaria, with abnormal behavior, impairment of consciousness, seizures, coma, or other neurologic abnormalities
- severe anemia due to hemolysis which is the destruction of the red blood cells
- hemoglobinuria where hemoglobin is found in the urine due to hemolysis
- acute respiratory distress syndrome (ARDS), an inflammatory re-action in the lungs that inhibits oxygen exchange, which may occur even after the parasite counts have decreased in response to treatment
- abnormalities in blood coagulation
- low blood pressure caused by cardiovascular collapse
- acute kidney failure
- hyperparasitemia, where more than five percent of the red blood cells are infected by malaria parasites
- metabolic acidosis which is excessive acidity in the blood and tissue fluids, often in association with hypoglycemia
- hypoglycemia which is low blood glucose. Hypoglycemia may also occur in pregnant women with uncomplicated malaria, or after treatment with quinine.
Severe malaria is a medical emergency and should be treated urgently and aggressively.
DIAGNOSIS AND TREATMENT
How is Malaria diagnosed?
Diagnosis of malaria depends on the microscopic demonstration of parasites in the blood. Additional laboratory findings may include mild anemia, mild decrease in blood platelets, elevation of bilirubin, and elevation of aminotransferases.
Increasingly, reference diagnostic tools like PCR are employed to confirm malaria infection and to determine definitively which parasite species are involved.
How is Malaria treated?
There are a range of drugs available for the treatment of malaria infection – the choice of which depends on the species of parasite and the likelihood of drug resistance.
WHO recommends that all cases of suspected malaria be confirmed using parasite-based diagnostic testing before administering treatment.
Treatment, solely on the basis of symptoms should only be considered when a parasitological diagnosis is not possible.
PREVENTION, CONTROL AND EDUCATION
How can infection be prevented?
There are a range of preventative antimalarial medicines available.
WHO recommends specific treatment protocols for Chemoprevention and therapy for those living in endemic areas (link to website)
Besides medical prevention the most effective way to avoid Malaria infection is to prevent mosquito bites.
- Sleep under an insecticide treated mosquito net
- Apply insect repellent to the skin and use in accordance with label instructions. Repellents containing DEET or Picaridin are generally recognized as the most effective.
- Wear clothing which reduces exposure of bare skin to mosquito bites
- If living in an area where malaria is endemic then take steps to reduce mosquito breeding (eliminate sources of standing water) and mosquito entry into domestic areas (eg. maintain screens on doors and windows). Air conditioning, if available, can also help reduce mosquito activity indoors.
TRANSMISSION, VECTOR AND VECTOR CONTROL
How is Malaria transmitted?
In most cases, the malaria parasite Plasmodium is transmitted through the bites of female Anopheles mosquitoes. There are more than 400 different species of Anopheles mosquito but only about 30 are malaria vectors of major importance. All of the important vector species bite between dusk and dawn. Female mosquitoes take blood meals because they need the protein in blood in order to develop eggs. Mosquitoes (male and female) commonly feed on plant-based sugar sources for everyday sustenance.
More in-depth information:
The parasite goes through a life-cycle change within the female mosquito and this takes time; as such it is only older female mos-quitoes which transmit malaria. Disease transmission is therefore more intense in places where there are both more mosquitoes and where conditions support a longer mosquito lifespan. Some mosquito species preferentially bite people whereas others will happily feed on both people and animals. The long lifespan and strong human-biting habit of African vector species is the main reason why nearly 90 percent of the world's malaria cases are in Africa.
Transmission also depends on climatic conditions that may affect the number and survival of mosquitoes, such as rainfall patterns, temperature and humidity. In many places, transmission is seasonal, with the peak during and just after the rainy season.
Malaria epidemics can occur when climate and other conditions suddenly favor transmission in areas where people have little or no immunity to malaria. They can also occur when people with low immunity move into areas with intense malaria transmission, for in-stance to find work, or as refugees.
Human immunity is another important factor, especially among adults in areas of moderate or intense transmission conditions.
Partial immunity is developed over years of exposure, and while it never provides complete protection, it does reduce the risk that ma-laria infection will cause severe disease. For this reason, most malaria deaths in Africa occur in young children (who have not yet acquired immunity), whereas in areas with less transmission and low immunity, all age groups are at risk.
How are the mosquito vectors commonly controlled?
Two forms of vector control – insecticide-treated mosquito nets and indoor residual spraying – are part of current WHO Policy for malaria vector control prevention.
Long-lasting insecticidal nets (LLINs) are intended to provide long term (3 year) night-time protection to those using them and when used at adequate scale can also achieve a level of community protec-tion through an overall impact on the mosquito population.
In most settings, WHO recommends LLIN coverage for all people at risk of malaria.
Indoor residual spraying (IRS) with insecticides is a powerful way to rapidly reduce malaria transmission. Its potential is realized when at least 80% of structures in targeted areas are sprayed. This can have a dramatic effect on the mosquito population.
- Some of the benefits of IRS are that it provides greater opportunity to introduce different insecticide modes of action (helping with resistance management) and also there can be greater confidence in the intervention having effect (because it does not rely on the behavioral choice of the population to use or not use their treated mosquito net.
What are the difficulties and challenges in combating Malaria?
Vector control has been highly dependent on the use of a single class of insecticide – pyrethroids - which are the only class of insecticide currently recommended for use in the treatment of LLINs. Unfortunately mosquito resistance to pyrethroids is well established in many countries and – even worse – in some areas, resistance to all four classes of insecticides used for public health has been detected.
More in-depth information:
Antimalarial drug resistance
Resistance of P. falciparum to previous generations of medicines, such as chloroquine and sulfadoxine-pyrimethamine (SP), became widespread in the 1950s and 1960s, undermining malaria control efforts and reversing gains in child survival. Therefore WHO recommends the routine monitoring of antimalarial drug resistance.
An ACT, an artemisinin-based combination therapy, contains both the drug artemisinin and a partner drug. By combining two active ingredients with different mechanisms of action, ACTs are the most effective antimalarial medicines available today.
Nevertheless in recent years, parasite resistance to artemisinin has been detected in five countries of the Greater Mekong subregion: Cambodia, Lao People’s Democratic Republic, Myanmar, Thailand and Viet Nam. Studies have confirmed that artemisinin resistance has emerged independently in many areas of this subregion.
In 2013, WHO launched the Emergency response to artemisinin resistance (ERAR) in the Greater Mekong Subregion, a high-level plan of attack to contain the spread of drug-resistant parasites and to provide life-saving tools for all populations at risk of malaria. But even as this work was under way, additional pockets of resistance emerged independently in new geographic areas of the subregion. In parallel, there were reports of increased resistance to ACT partner drugs in some settings. A new approach was needed to keep pace with the changing malaria landscape.
Consequently, WHO’s Malaria Policy Advisory Committee in September 2014 recommended adopting the goal of eliminating P. fal-ciparum malaria in this subregion by 2030. WHO launched the Strategy for Malaria Elimination in the Greater Mekong Subregion (2015–2030) at the World Health Assembly in May 2015, which was endorsed by all the countries in the subregion. With technical guidance from WHO, all GMS countries have developed national malaria elimination plans. Together with partners, WHO will provide ongoing support for country elimination efforts through the Mekong Malaria Elimination program, a new initiative that evolved from the ERAR.
Currently many countries with a high burden of malaria have weak surveillance systems and cannot assess disease distribution and trends, making it difficult to optimally respond to outbreaks.
Effective surveillance is required at all points on the path to malaria elimination and the Global Technical Strategy for Malaria 2016-2030 (GTS) recommends that countries transform surveillance into a core intervention. Strong malaria surveillance empowers programs to:
- advocate for investment from domestic and international sources, commensurate with the malaria disease burden in a country or sub-national area
- allocate resources to populations most in need and to interventions that are most effective, in order to achieve the greatest possible public health impact
- assess regularly whether plans are progressing as expected or whether adjustments in the scale or combination of interventions are required
- account for the impact of funding received and enable the public, their elected representatives and donors to determine if they are obtaining value for money
- evaluate whether program objectives have been met and learn what works so that more efficient and effective programs can be designed
INITIATIVES AND PARTNERS
What programs exist against Malaria?
Total funding for malaria control and elimination reached an estimated US$ 2.7 billion in 2016. Contributions from governments of endemic countries amounted to US$ 800 million, representing 31 percent of funding.
The WHO Global Technical Strategy for Malaria 2016-2030 – adopted by the World Health Assembly in May 2015 – provides a technical framework for all malaria-endemic countries.
The Strategy sets global targets, including:
- reducing malaria case incidence by at least 90% by 2030
- reducing malaria mortality rates by at least 90% by 2030
- eliminating malaria in at least 35 countries by 2030
- preventing a resurgence of malaria in all countries that are malaria-free.
This Strategy, developed with the participation of more than 400 technical experts from 70 Member States, is based on three key pillars:
- ensuring universal access to malaria prevention, diagnosis and treatment
- accelerating efforts towards elimination and attainment of malaria-free status
- transforming malaria surveillance into a core Intervention
The WHO Global Malaria Programme (GMP) coordinates WHO's global efforts to control and eliminate malaria by:
- setting, communicating and promoting the adoption of evidence-based norms, standards, policies, technical strategies, and guidelines
- keeping independent score of global progress
- developing approaches for capacity building, systems strengthening, and surveillance
- identifying threats to malaria control and elimination as well as new areas for action
GMP is supported and advised by the Malaria Policy Advisory Committee (MPAC), a group of 15 global malaria experts appointed following an open nomination process.
The MPAC, which meets twice yearly, provides independent advice to WHO to develop policy recommendations for the control and elimination of malaria. The mandate of MPAC is to provide strategic advice and technical input, and extends to all aspects of malaria control and elimination, as part of a transparent, responsive and credible policy setting process.
Malaria elimination is defined as the interruption of local transmis-sion of a specified malaria parasite species in a defined geographical area as a result of deliberate activities. Continued measures are required to prevent re-establishment of transmission. The certification of malaria elimination in a country will require that local transmission is interrupted for all human malaria parasites.
Malaria eradication is defined as the permanent reduction to zero of the worldwide incidence of malaria infection caused by human malaria parasites as a result of deliberate activities. Interventions are no longer required once eradication has been achieved.
In countries with high or moderate rates of malaria transmission, national malaria control programs aim to maximize the reduction of malaria cases and deaths.
As countries approach elimination, enhanced surveillance systems can help ensure that every infection is detected, treated and reported to a national malaria registry. Patients diagnosed with malaria should be treated promptly with effective antimalarial medicines for their own health and to prevent onward transmission of the disease in the community.
Countries that have achieved at least three consecutive years of zero local cases of malaria are eligible to apply for the WHO certification of malaria elimination. In recent years, seven countries have been certified by the WHO Director-General as having eliminated malaria:
- United Arab Emirates, 2007
- Morocco, 2010
- Turkmenistan, 2010
- Armenia, 2011
- Maldives, 2015
- Sri Lanka, 2016
- Kyrgyzstan, 2016
The WHO Framework for Malaria Elimination (2017) provides a detailed set of tools and strategies for achieving and maintaining elimination.
What does Bayer contribute to the fight against Malaria?
Bayer has been successfully developing vector control products for decades (see below).
During the last six years Bayer researchers have been concentrating on new mosquito control compounds that can help manage resistances as part of an integrated vector control approach: the first vector control IRS product to be based on a combination of two active ingredients, Fludora™ Fusion.
In addition, signing the ‘ZERO by 40’ declaration on World Malaria Summit 2018, Bayer committed to provide innovative vector control solutions to help eradicate malaria by 2040.
Besides this Bayer can look back on many research successes which lead to products that helped people to control mosquitos for decades:
- 1960’s: Bayer develops and launches Propoxur™ and an active ingredient which has been superceded today but which was used in indoor residual spraying campaigns in the past
- 1971: Ficam™ is developed and launched, Bendiocarb™, an indoor residual spray (IRS), is still used as an insecticide for mosquito control to this day. It represents an important mode of action for resistance management in IRS programs today.
- 1980s: Bayer launches K-Othrine™, based on the pyrethroid, deltamethrin. This insecticide is used for IRS and to impregnate mosquito nets against malaria vectors as well as in space spray products against Aedes mosquitoes.
- 2000s: K-Otab™ was launched; one of the first products for in-field treatment of mosquito nets.
- 2012: Introduction of LifeNet™. The first LLIN to be based on insecticide incorporated into polypropylene – intended to address the challenge of physical durability of nets (later withdrawn due to market conditions). Although Bayer does not produce long-lasting insecticide treated bed-nets (LLINs), we supply the active ingredients deltamethrin and permethrin to bed-net manufacturers.
- 2013: K-Othrine™ PolyZone is recommended by WHO Pesticide Evaluation Scheme (WHOPES) – a polymer enhanced formulation to give stronger residual activity for IRS programs.
- 2015: Bayer submits Fludora™ Fusion to the WHO - the first IRS product with a two-way mode of action.
What is the societal burden of Malaria?
According to the latest World Malaria Report, released in November 2017, there were 216 million cases of malaria in 2016, up from 211 million cases in 2015.
The estimated number of malaria deaths stood at 445 000 in 2016 similar to the 446 000 deaths of the previous year.
The WHO African Region continues to carry a disproportionately high share of the global malaria burden. In 2016, the region was home to 90 percent of malaria cases and 91 percent of malaria deaths.
Some 15 countries – all in sub-Saharan Africa, except India – accounted for 80 percent of the global malaria burden.
In areas with high transmission of malaria, children under five are particularly susceptible to infection, illness and death as 70 percent of all malaria deaths occur in this age group.
Although the number of under-5 malaria deaths has declined from 440 000 in 2010 to 285 000 in 2016, malaria remains a major killer of children under five years old, taking the life of a child every two minutes.
How did the history of the disease proceed?
Malaria or a disease resembling malaria has been noted for more than 4,000 years. From the Italian for “bad air,” mal’aria has probably influenced to a great extent human populations and human history.
Ancient History (2700 BCE-340 CE)
The symptoms of malaria were described in ancient Chinese medical writings. In 2700 BC, several characteristic symptoms of what would later be named malaria were described in the Nei Ching , The Canon of Medicine.
Malaria became widely recognized in Greece by the 4th century BCE, and it was responsible for the decline of many of the city-state populations. Hippocrates noted the principal symptoms. By the age of Pericles, there were extensive references to malaria in the literature and depopulation of rural areas was recorded.
In The Compendium of Susruta, a Sanskrit medical treatise, the symptoms of malarial fever were described and attributed to the bites of certain insects.
A number of Roman writers attributed malarial diseases to the swamps.
In 340 CE, the antifever properties of the plant Qinghao were first described by Ge Hong of the East Yin Dynasty. The active ingredient of Qinghao, known as artemisinin, was isolated by Chinese scientists in 1971. Derivatives of this extract, known collectively as artemisinins, are today very potent and effective antimalarial drugs, especially in combination with other medicines.
Quinine (Early 17th Century)
Following their arrival in the New World, Spanish Jesuit missionaries learned from indigenous Indian tribes of a medicinal bark used for the treatment of fevers. With this bark, the Countess of Chinchón, the wife of the Viceroy of Peru, was cured of her fever. The bark from the tree was then called Peruvian bark and the tree was named Cinchona after the countess. The medicine from the bark is now known as the antimalarial, quinine. Along with artemisinins, quinine is one of the most effective antimalarial drugs available today.
In 1880 Charles Louis Alphonse Laveran, a French army surgeon stationed in Constantine, Algeria, was the first to notice parasites in the blood of a patient suffering from malaria. This occurred on the 6th of November 1880. For his discovery, Laveran was awarded the Nobel Prize in 1907.
In 1886 Camillo Golgi, an Italian neurophysiologist, established that there were at least two forms of the disease, one with tertian periodicity, which means fever every other day, and one with quartan periodicity, which means fever every third day. He also observed that the forms produced differing numbers of new parasites upon maturity and that fever coincided with the rupture and release of these parasites into the blood stream. He was awarded a Nobel Prize in Medicine for his discoveries in neurophysiology in 1906.
In 1890 the Italian investigators Giovanni Batista Grassi and Raimondo Filetti first introduced the names Plasmodium vivax and P. malariae for two of the malaria parasites that affect humans in. Laveran had believed that there was only one species, Oscillaria malariae.
In 1897, after reviewing the subject, the American William H. Welch named the malignant tertian malaria parasite P. falciparum . There were many arguments against the use of this name; however, the use was so extensive in the literature that a change back to the name given by Laveran was no longer thought possible.
In 1922, John William Watson Stephens described the fourth human malaria parasite, P. ovale.
In 1931 P. knowlesi was first described by Robert Knowles and Biraj Mohan Das Gupta in a long-tailed macaque. The first documented human infection with P. knowlesi was in 1965.
On August 20th, 1897, Ronald Ross, a British officer in the Indian Medical Service, was the first to demonstrate that malaria parasites could be transmitted from infected patients to mosquitoes. In further work with bird malaria, Ross showed that mosquitoes could transmit malaria parasites from bird to bird. This necessitated a sporogonic cycle (the time interval during which the parasite developed in the mosquito). Thus, the problem of malaria transmission was solved. For his discovery, Ross was awarded the Nobel Prize in 1902.
Discovery of the Transmission of the Human Malaria Parasites Plasmodium (1898- 1899)
In 1898 a team of Italian investigators, led by Giovanni Batista Grassi and including Amico Bignami and Giuseppe Bastianelli, collected Anopheles claviger mosquitoes and fed them on malarial patients. The complete sporogonic cycle of Plasmodium falciparum, P. vivax , and P. malariae was demonstrated.
In 1899, mosquitoes infected by feeding on a patient in Rome were sent to London where they fed on two volunteers, both of whom developed malaria.
Between 1905 and 1910 the Panama Canal was constructed. This was only possible after yellow fever and malaria were controlled in the area. These two diseases were a major cause of death and disease among workers in the area.
In 1906, there were over 26,000 employees working on the Canal. Of these, over 21,000 were hospitalized for malaria at some time during their work.
By 1912, there were over 50,000 employees, and the number of hospitalized workers had decreased to approximately 5,600.
Through the leadership and efforts of William Crawford Gorgas, Joseph Augustin LePrince, and Samuel Taylor Darling, yellow fever was eliminated and malaria incidence markedly reduced through an integrated program of insect and malaria control.
In 1914 Henry Rose Carter and Rudolph H. von Ezdorf of the USPHS requested and received funds from the U.S. Congress to control malaria in the United States. Various activities to investigate and combat malaria in the United States followed from this initial request and reduced the number of malaria cases in the United States.
USPHS established malaria control activities around military bases in the malarious regions of the southern United States to allow soldiers to train year round.
On May 18, 1933 U.S. President Franklin D. Roosevelt signed a bill that created the Tennessee Valley Authority (TVA). The law gave the federal government a centralized body to control the Tennessee River’s potential for hydroelectric power and improve the land and waterways for development of the region.
An organized and effective malaria control program stemmed from this new authority in the Tennessee River valley. Malaria affected 30 percent of the population in the region when the TVA was incorporated in 1933. The Public Health Service played a vital role in the research and control operations and by 1947, the disease was essentially eliminated. Mosquito breeding sites were reduced by controlling water levels and insecticide applications.
Chloroquine (Resochin) (1934, 1946)
In 1934 chloroquine was discovered by a German, Hans Andersag, at Bayer I.G. Farbenindustrie A.G. laboratories in Eberfeld, Germany. He named his compound resochin. Through a series of lapses and confusion brought about during the war, chloroquine was finally recognized and established as an effective and safe antimalarial in 1946 by British and U.S. scientists.
Dichloro-diphenyl-trichloroethane (DDT) (1939)
In 1939, 65 years after the German chemistry student, Othmer Zeidler, synthesized DDT in 1874 for his thesis, the insecticidal property of the substance was discovered by Paul Müller in Switzerland. Various militaries in WWII utilized the new insecticide initially for control of louse- borne typhus.
DDT was used for malaria control at the end of WWII after it had proven effective against malaria-carrying mosquitoes by British, Italian, and American scientists. Müller won the Nobel Prize for Medicine in 1948.
Between 1942 and 1945 Malaria Control in War Areas (MCWA) was established to control malaria around military training bases in the southern United States and its territories, where malaria was still problematic. Many of the bases were established in areas where mosquitoes were abundant.
MCWA aimed to prevent reintroduction of malaria into the civilian population by mosquitoes that would have fed on malaria-infected soldiers, in training or returning from endemic areas.
During these activities, MCWA also trained state and local health department officials in malaria control techniques and strategies.
On July 1, 1947 the National Malaria Eradication Program, a cooperative undertaking by state and local health agencies of 13 Southeastern states and the CDC, originally proposed by Louis Laval Williams, commenced operations.
By the end of 1949, over 4,650,000 housespray applications had been made.
While in 1947, 15,000 malaria cases were reported, by 1950, only 2,000 cases were reported and by 1951, malaria was considered eliminated from the United States.
In 1955 with the success of DDT, the advent of less toxic, more effective synthetic antimalarials, and the enthusiastic and urgent belief that time and money were of the essence, the World Health Organization (WHO) submitted at the World Health Assembly an ambitious proposal for the eradication of malaria worldwide.
Eradication efforts began and focused on house spraying with residual insecticides, antimalarial drug treatment, and surveillance, and would be carried out in four successive steps:
Successes included elimination in nations with temperate climates and seasonal malaria transmission. Some countries such as India and Sri Lanka had sharp reductions in the number of cases, followed by increases to substantial levels after efforts ceased.
Other nations had negligible progress such as Indonesia,
Afghanistan, Haiti, and Nicaragua.
Some nations, most of them in sub-Saharan Africa, were excluded completely from the eradication campaign.
During the following decades the emergence of drug resistance, widespread resistance to available insecticides, wars and massive population movements, difficulties in obtaining sustained funding from donor countries, and lack of community participation made the long-term maintenance of the effort untenable. Completion of the eradication campaign was eventually abandoned.
The goal of most current National Malaria Prevention and Control Programs and most malaria activities conducted in endemic countries is to reduce the number of malaria-related cases and deaths. To reduce malaria transmission to a level where it is no longer a public health problem is the goal of what is called malaria “control.”
Recent increases in resources, political will, and commitment have led again to discussion of the possibility of malaria elimination and, ultimately, eradication.