eradication of infectious diseases eradication of infectious diseases the eradication of infectious diseases is the reduction of an infectious disease's prevalence in the global host population to zero. a child with smallpox. in 1980, the world health organization announced the global eradication of smallpox. it is the only human disease to be eradicated worldwide. two infectious diseases have successfully been eradicated: smallpox in humans, and rinderpest in ruminants. there are four ongoing programs, targeting the human diseases poliomyelitis (polio), yaws, dracunculiasis (guinea worm), and malaria. five more infectious diseases have been identified as of april 2008 as potentially eradicable with current technology by the carter center international task force for disease eradication—measles, mumps, rubella, lymphatic filariasis (elephantiasis) and cysticercosis (pork tapeworm). 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 main article: smallpox boy with smallpox (1969). the last natural smallpox case was of ali maow maalin, in merca, somalia, on 26 october 1977. 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 food and agriculture organization 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) main article: polio eradication international wild poliovirus cases by year yearestimatedrecorded 1975—49,293 1980400,00052,552 1985—38,637 1988350,00035,251 1990—23,484 1993100,00010,487 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—6 2022 — 30