Eradication of infectious diseases
There are four ongoing programs, targeting the human diseases poliomyelitis (polio), yaws, dracunculiasis (Guinea worm), and malaria.
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.
Economic considerations, as well as societal and political support and commitment, are other crucial factors that determine eradication feasibility.
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.
[citation needed] 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 WHO estimates that global savings from eradication, due to forgone treatment and disability costs, could exceed one billion U.S. dollars per year.
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.
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 less than 100 cases since 2015.
While success has been slower than was hoped (the original goal for eradication was 1995), the WHO has certified 180 countries free of the disease, and in 2020 six countries—South Sudan, Ethiopia, Mali, Angola, Cameroon and Chad—reported cases of guinea worm.
[47] 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.
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.
Studies have demonstrated that transmission of the infection can be broken when a single dose of combined oral medicines is consistently maintained annually for approximately seven years.
[81] The WHO set a goal to control morbidity of schistosomiasis by 2020 and eliminate the public health problems associated with it by 2025 (bringing infections down to less than 1% of the population).
Despite the United States declaring that it had eliminated hookworm decades ago, a 2017 study showed it was present in Lowndes County, Alabama.
[90] However, while eradication in the Americas was certified in 2015, the certification was lost in 2018 due to endemic measles transmission in Venezuela and subsequent spread to Brazil and Colombia;[91][92][93] while additional limited outbreaks have occurred elsewhere as well.
[94] Europe had set a goal to eliminate measles transmission by 2010, which was missed due to the MMR vaccine controversy and by low uptake in certain groups,[which?]
[86] By the end of 2021, WHO's European regional office considered the endemic measles eliminated in 33 out of 53 member states, with the transmission interrupted in one more and re-established in five others.
[86] European countries with endemic Rubella in 2018 were: Belgium, Bosnia and Herzegovina, Denmark, France, Germany, Italy, Poland, Romania, Serbia, Turkey and Ukraine.
[114] On 29 July 2013, the Pan American Health Organization (PAHO) announced that after 16 years of efforts, Colombia had become the first country in the world to eliminate the parasitic disease onchocerciasis.
[119][120] Following the ongoing eradication effort, only seven cases of bovine spongiform encephalopathy were reported worldwide in 2013: three in the United Kingdom, two in France, one in Ireland and one in Poland.
[130] In 2017 the WHO declared that Antigua and Barbuda, Saint Kitts and Nevis and four British Overseas Territories—Anguilla, Bermuda, Cayman Islands, and Montserrat—have been certified that they have ended transmission of mother-to-child syphilis and HIV.
The WHO aims to eliminate transmission of the Trypanosoma brucei gambiense parasite by 2030, though it acknowledges that this goal "leaves no room for complacency.
[135] However, some researchers have argued that total elimination may not be achievable due to human asymptomatic carriers of T. b. gambiense and non-tsetse modes of transmission.
[139] The use of SIT in Zanzibar proved effective in eliminating the entire population of tsetse flies but was expensive and is relatively impractical to use in many of the endemic countries afflicted with African trypanosomiasis.
Many island nations, including Iceland, Ireland, Japan, Malta, and the United Kingdom, managed to eliminate rabies during the twentieth century,[141] and more recently much of continental Europe has been declared rabies-free.
[144][145] The success of the treatment has prompted the WHO in 1991 to set a target of less than one case per 10,000 people (eliminate the disease as a public health risk) which was achieved in 2000.
[145] However, a lack of understanding of the disease and its transmission, and the long incubation period of the M. leprae pathogen have so far prevented the formulation of a full-scale eradication strategy.
[148][149] PPR is a highly contagious viral disease of goats and sheep characterized by fever, painful sores in the mouth, tongue and feet, diarrhea, pneumonia and death, especially in young animals.
[149] The World Organisation for Animal Health (WOAH) prioritises African swine fever, bovine tuberculosis, foot and mouth disease, and PPR.
