A century of successes and failures to eliminate malaria
Malaria is caused by Plasmodium parasites. The parasites are spread to people through the bites of infected Anopheles mosquitoes, called "malaria vectors", which bite mainly between dusk and dawn. Approximately half of the world's population is at risk of malaria. Most malaria cases and deaths occur in sub-Saharan Africa. However, Asia, Latin America, and to a lesser extent the Middle East and parts of Europe are also affected. In 2008, malaria was present in 108 countries and territories in the world.
1900 – Role of mosquitoes in malaria transmissionconfirmed in an experiment conducted by Sir Patrick Manson, where infected mosquitoes are fed on a volunteer (his son), which subsequently falls ill.
1901 – First use of ‘physical prophylaxis’ tried in Italy through house screening. Preventing mosquitoes from biting humans at night is demonstrated to lead to a reduction of almost 90% of malaria cases.
1904 – The Panama Canal project is adopted by the Americans, after the French gave up due to the massive number of workers succumbing to yellow fever and malaria. Army surgeon William Gorgas launches a massive and integrated attack on mosquitoes and reduces deaths due to yellow fever to zero within a year, and malaria prevalence from 86 to 8% in four years.
1921 – Paris Green, an arsenic compound, is discovered by US scientists as a potent larvicide. Until then, crude oil was used for controlling larvae in breeding sites.
1934 – Chloroquine is discovered by Bayer in Germany. It would become one of the most successful anti-malarial medicines in history.
1939 – Swiss chemist, Paul Mueller, hits upon DDT as a potent adulticide for insects. DDT had been synthesised first in 1874, but its insecticidal properties only became known through Mueller.
An invasion of African malaria mosquitoes in Brazil that occurred in 1930 and spread over 54,000 km2 is eliminated mostly through larval control with Paris Green. More than 4000 workers are involved in the campaign, led by Dr. Fred Soper.
1943 – DDT and Paris Green are used in a massive campaign in Egypt, from Asyut to the border with Sudan, and leads to elimination of malaria. More than 2000 workers are involved in the campaign. Soper plays a major role in the success of the campaign.
1946 – DDT is used on an ever-larger scale to wipe out malaria. Sardinia starts its attack on an island-wide basis (24,000 km2) with more than 50,000 workers. 250 tonnes of DDT are being used. In 1946 some ten thousand Sardinians died of malaria, in 1950 the disease was eliminated. Cyprus followed in 1949.
1951 – Disaster strikes in Greece, when local malaria mosquitoes are shown to have become resistant to DDT.
1952 – Taiwan embarks on an island-wide campaign, with DDT as its main weapon. In 1958 the disease was eliminated.
1955 – In spite of hurdles and recorded resistance, the World Health Organization launches the ‘Global Malaria Eradication Campaign’. It would run until 1969.
1957 – Notwithstanding the fact that virtually all successful elimination campaigns before the 1950s were based on area-wide integrated concepts that involved larval source management, availability and success with DDT cause a shift from larval control to adult control and focus on the house rather than the environment. George MacDonald publishes ‘The epidemiology and control of malaria’ this year, furthering the focus on adult rather than larval mosquito control.
1957 – Disaster strikes again, now on the Cambodia/Thai border, where parasite resistance to chloroquine surfaces. In 1959 the same happens in Colombia.
1962 – Unbridled use of DDT in agriculture leads to public resistance against its use. Rachel Carson published her book ‘Silent Spring’ this year, heightening the debate on DDT.
1972 – DDT is banned in the USA, Europe follows shortly afterwards.
1973 – Although malaria had almost been eliminated from the island of Zanzibar it resurged to levels from before 1958.
1976 – Malaria in India surged from a mere 50,000 cases in 1961 to almost 6,5 million this year. The aftermath of unsuccessful elimination became harshly apparent.
1976 – The famous Garki project in Nigeria is completed. Massive indoor residual spraying with propoxur, combined with mass-chemoprophylaxis led to a large reduction in prevalence, but was insufficient to reach elimination. Area-wide (larval) control was not included in the campaign, it had become out of fashion at that time.
1978 – The primary health care concept was adopted at the famous Alma-Ata conference. This led to a further decentralisation of malaria control.
1985 – Synthetic pyrethroids have become available and are being used in agriculture. In West Africa, the first experiments with bednets, dipped in pyrethroids, start.
1994 – The first results of a large-scale trial with impregnated bednets is published in the Lancet, showing a 63% reduction in under-five mortality. Throughout the 1990s, large-scale bednet trials follow in other countries (Burkina Faso, The Gambia, Ghana, Kenya), all showing promising results.
1998 – The Roll Back Malaria initiative is launched.
1999 – A malaria epidemic strikes South Africa. Resistance to pyrethroids leads to renewed use of DDT.
2000 - The Millennium Development Goals are set, including the goals for malaria control (zero deaths by 2015).
2002 – The Global Fund is set up.
2004 – DDT is officially ratified for malaria control at the Stockholm Convention.
2005 – The US President’s Malaria Initiative (PMI) start. Some 17 African countries are included, and receive indoor residual spraying (incl. DDT) and treated bednets.
2007 – Bill and Melinda Gates change the field of malaria control and use the E-words again (Eradication and Elimination). A shift in mindset follows, with a renewed focus on eradication (see 1955).
2010 – The gains of a decade of global efforts to control malaria are becoming visible. Many countries have seen a reduction of malaria by more than half. Compared to 2000, malaria deaths worldwide have been reduced by almost 25%. Nearly 300 million bednets have reached African families since 2008. Ten percent of vulnerable populations in Africa were covered with Indoor Residual Spraying. The use of artemisinin-based combination therapies (ACTs) has increased by a factor 15 since 2005, now 158 million courses.
2015 - ?