The eradication of infectious diseases is the reduction of the prevalence of an infectious disease in the global host population to zero.
Two infectious diseases have successfully been eradicated: smallpox in humans, and rinderpest in ruminants. , the Carter Center International Task Force for Disease Eradication has targeted two human diseases for eradication: dracunculiasis (Guinea worm), and lymphatic filariasis (elephantiasis). Other long-running eradication programs that have been attempted are polio, yaws, hookworm, yellow fever, and malaria.
The concept of disease eradication is sometimes confused with disease elimination, which is the reduction of an infectious disease's prevalence in a regional population to zero, or the reduction of the global prevalence to a negligible amount. Further confusion arises from the use of the term 'eradication' to refer to the total removal of a given pathogen from an individual (also known as clearance of an infection), particularly in the context of HIV and certain other viruses where such cures are sought.
The targeting of infectious diseases for eradication is based on narrow criteria, as both biological and technical features determine whether a pathogenic organism is (at least potentially) eradicable. The targeted pathogen must not have a significant non-human (or non-human-dependent) reservoir (or, in the case of animal diseases, the infection reservoir must be an easily identifiable species, as in the case of rinderpest). This requires sufficient understanding of the life cycle and transmission of the pathogen. An efficient and practical intervention (such as a vaccine or antibiotic) must be available to interrupt transmission. Studies of measles in the pre-vaccination era led to the concept of the critical community size, the minimal size of the population below which a pathogen ceases to circulate. The use of vaccination programs before the introduction of an eradication campaign can reduce the susceptible population. The disease to be eradicated should be clearly identifiable, and an accurate diagnostic tool should exist. Economic considerations, as well as societal and political support and commitment, are other crucial factors that determine eradication feasibility.
Eradicated diseases So far, only two diseases have been successfully eradicated—one specifically affecting humans (smallpox) and one affecting cattle (rinderpest).
Smallpox
Smallpox is the first disease, and so far the only infectious disease of humans, to be eradicated by deliberate intervention. It became the first disease for which there was an effective vaccine in 1798 when Edward Jenner showed the protective effect of inoculation (vaccination) of humans with material from cowpox lesions.
Smallpox (variola) occurred in two clinical varieties: variola major, with a mortality rate of up to 40 percent, and variola minor, also known as alastrim, with a mortality rate of less than one percent. The last naturally occurring case of variola major was diagnosed in October 1975 in Bangladesh. The last naturally occurring case of smallpox (variola minor) was diagnosed on 26 October 1977, in Ali Maow Maalin, in the Merca District, of Somalia. The source of this case was an outbreak in the nearby district of Kurtunwarey. All 211 contacts were traced, revaccinated, and kept under surveillance.
After two years' detailed analysis of national records, the global eradication of smallpox was certified by an international commission of smallpox clinicians and medical scientists on 9 December 1979, and endorsed by the General Assembly of the World Health Organization on 8 May 1980. However, there is an ongoing debate regarding the continued storage of the smallpox virus by labs in the US and Russia, as any accidental or deliberate release could create a new epidemic in people born since the late 1980s due to the cessation of vaccinations against the smallpox virus.
Rinderpest
During the twentieth century, there were a series of campaigns to eradicate rinderpest, a viral disease that infected cattle and other ruminants and belonged to the same family as measles, primarily through the use of a live attenuated vaccine. The final, successful campaign was led by the Food and Agriculture Organization of the United Nations. On 14 October 2010, with no diagnoses for nine years, the FAO announced that the disease had been completely eradicated, making this the first (and so far the only) disease of livestock to have been eradicated by human undertakings.
Global eradication underway
Poliomyelitis (polio)
+ International wild poliovirus cases by year Year Estimated Recorded 1975 — 49,293 1980 400,000 52,552 1985 — 38,637 1988 350,000 35,251 1990 — 23,484 1993 100,000 10,487 1995 — 7,035 2000 — 2,971 2005 — 1,998 2010 — 1,352 2011 — 650 2012 — 222 2013 — 385 2014 — 359 2015 — 74 2016 — 37 2017 — 22 2018 — 33 2019 — 176 2020 — 140 2021 — 62022 —302023 —122024 —992025 —40References:
A dramatic reduction of the incidence of poliomyelitis in industrialized countries followed the development of a vaccine in the 1950s. In 1960, Czechoslovakia became the first country certified to have eliminated polio.
In 1988, the World Health Organization (WHO), Rotary International, the United Nations Children's Fund (UNICEF), and the United States Centers for Disease Control and Prevention (CDC) passed the Global Polio Eradication Initiative. Its goal was to eradicate polio by the year 2000. The updated strategic plan for 2004–2008 expects to achieve global eradication by interrupting poliovirus transmission, using the strategies of routine immunization, supplementary immunization campaigns, and surveillance of possible outbreaks. The WHO estimates that global savings from eradication, due to forgone treatment and disability costs, could exceed one billion U.S. dollars per year.
The following world regions have been declared polio-free: The Americas (1994) Western Pacific region, including China (2000) Europe (2002) Southeast Asia region (2014), including India Africa (2020)
The lowest annual wild polio prevalence seen so far was in 2021, with only 6 reported cases. Only two countries remain in which poliovirus transmission may never have been interrupted: Pakistan and Afghanistan. (There have been no cases caused by wild strains of poliovirus in Nigeria since August 2016, though cVDPV2 was detected in environmental samples in 2017.) Nigeria was removed from the WHO list of polio-endemic countries in September 2015 but added back in 2016, and India was removed in 2014 after no new cases were reported for one year.
On 20 September 2015, the World Health Organization announced that wild poliovirus type 2 had been eradicated worldwide, as it has not been seen since 1999. On 24 October 2019, the World Health Organization announced that wild poliovirus type 3 had also been eradicated worldwide. This leaves only wild poliovirus type 1 and vaccine-derived polio circulating in a few isolated pockets, with all wild polio cases after August 2016 in Afghanistan and Pakistan.
Dracunculiasis
+ International Guinea worm cases by year Year Reported cases Countries 1989 892,055 16 1995 129,852 19 2000 75,223 16 2005 10,674 12 2010 1,797 6 2011 1,060 4 2012 542 4 2013 148 5 2014 126 4 2015 22 42016 25 32017 30 22018 28 32019 54 42020 27 62021 15 42022 12 32023 14 52024 15 22025 10 3References:
Dracunculiasis, also called Guinea worm disease, is a painful and disabling parasitic disease caused by the nematode Dracunculus medinensis. It is spread through consumption of drinking water infested with copepods hosting Dracunculus larvae. The Carter Center has led the effort to eradicate the disease, along with the CDC, the WHO, UNICEF, and the Bill and Melinda Gates Foundation. It is slated to be the first parasitic disease to ever be eradicated.
Unlike diseases such as smallpox and polio, there is no vaccine or drug therapy for guinea worm. Eradication efforts have been based on making drinking water supplies safer (e.g. by provision of borehole wells, or through treating the water with larvicide), on containment of infection and on education for safe drinking water practices. These strategies have produced many successes: two decades of eradication efforts have reduced Guinea worm's global incidence dramatically from over 100,000 in 1995 to just 10 cases in 2025. While success has been slower than was hoped (the original goal for eradication was 1995), as of the WHO has certified 200 countries free of the disease, leaving just six countries —South Sudan, Ethiopia, Mali, Angola, Cameroon and Chad—left to be certified free of the parasite. Nonetheless, the last 1% of the effort may be the hardest, as the worm is now understood to be able to infect dogs, domestic cats and baboons as well as humans, providing a natural reservoir for the pathogen and thus complicating eradication efforts. In response, the eradication effort is now also targeting animals (especially wild dogs) for treatment and isolation since animal infections far outnumber human infections now. WHO's goal is still to eliminate the disease by 2030.
Yaws
Yaws is a rarely fatal but highly disfiguring disease caused by the spiral-shaped bacterium (spirochete) Treponema pallidum pertenue, a close relative of the syphilis bacterium Treponema pallidum pallidum, spread through skin to skin contact with infectious lesions. The global prevalence of this disease and the other endemic treponematoses, bejel and pinta, was reduced by the Global Control of Treponematoses programme between 1952 and 1964 from about 50 million cases to about 2.5 million (a 95% reduction). However, following the cessation of this program these diseases remained at a low prevalence in parts of Asia, Africa and the Americas with sporadic outbreaks. In 2012, the WHO targeted the disease for eradication by 2020, a goal that was missed. WHO's current target for eradication is 2030.
The discovery that oral antibiotic azithromycin can be used instead of the previous standard, injected penicillin, was tested on Lihir Island from 2013 to 2014; a single oral dose of the macrolide antibiotic reduced disease prevalence from 2.4% to 0.3% at 12 months. The WHO now recommends both treatment courses (oral azithromycin and injected penicillin), with oral azithromycin being the preferred treatment.
, there were 16 countries known to be endemic for yaws. That year, 152,164 suspected cases of yaws were reported to the WHO and 996 cases were confirmed. Evidence of antibiotic resistance emerged in 2020, as has evidence that the bacterium can infect primates, which could complicate eradication efforts.
Others Malaria
Malaria has been eliminated from most of Europe, North America, Australia, North Africa and the Caribbean, and parts of South America, Asia and Southern Africa. The WHO defines "elimination" (or "malaria free") as having no domestic transmission (indigenous cases) for the past three years. They also define "pre-elimination" and "elimination" stages when a country has fewer than 5 or 1, respectively, cases per 1000 people at risk per year.
In 1955, WHO launched the Global Malaria Eradication Program. Support waned, and the program was suspended in 1969. Since 2000, support for eradication has increased, although some actors in the global health community (including voices within the WHO) thought that eradication as goal was premature and that setting strict deadlines for eradication may be counterproductive as they are likely to be missed.
According to the WHO's World Malaria Report 2015, the global mortality rate for malaria fell by 60% between 2000 and 2015. The WHO targeted a further 90% reduction between 2015 and 2030, with a 40% reduction and eradication in 10 countries by 2020. However, the 2020 goal was missed with a slight increase in cases compared to 2015.