Which diseases have been eradicated

It can lead to serious issues, like paralysis of the hands and feet. Polio still exists in several countries outside the U. In places where not everyone gets the vaccine, it can spread before doctors have a chance to contain it. Because polio affects your brain, it can be life-threatening or cause long-term problems, like paralysis. Another disease from Middle Ages, gout is a form of very painful arthritis.

Being very overweight doubles the chances of getting it. And high blood pressure also contributes to its onset. Gout often starts with serious pain in the big toe, but can begin in any joint, like the knee or elbow. Have you ever heard of ricketts? Caused by a lack of vitamin D, this leads to soft bones. The uptick in recent years partly comes from two causes: breastfeeding only and fear of skin cancer. That can be a problem because sunlight helps your body make vitamin D.

Not quite. Scurvy is still with us today. Scurvy can be easily treated with vitamin C supplements. Diseases Thought To Have Been Eradicated, Still Around Diseases thought to have been long eradicated or brought under control are surprisingly still around. Diseases: Measles Measles can be life threatening. Smallpox eradication was accomplished with a combination of focused surveillance—quickly identifying new smallpox cases—and ring vaccination.

The last case of wild smallpox occurred in Somalia in Smallpox was a good candidate for eradication for several reasons. First, the disease is highly visible: smallpox patients develop a rash that is easily recognized. Workers from the World Health Organization found smallpox patients in outlying areas by displaying pictures of people with the smallpox rash and asking if anyone nearby had a similar rash.

Second, only humans can transmit and catch smallpox. Some diseases have an animal reservoir, meaning they can infect other species besides humans.

Yellow fever, for example, infects humans, but can also infect monkeys. If a mosquito capable of spreading yellow fever bites an infected monkey, the mosquito can then give the disease to humans.

So even if the entire population of the planet could somehow be vaccinated against yellow fever, its eradication could not be guaranteed. The disease could still be circulating among monkeys, and it could re-emerge if human immunity ever waned.

The discovery of an animal reservoir for yellow fever was in fact what derailed a yellow fever eradication effort in the early s. Smallpox, however, can infect only humans. In effect, aside from the human population, it has nowhere to hide. Equally important is the ability to protect individuals against infection.

People who survived smallpox naturally developed lifelong immunity against future infection. For everyone else, vaccination was highly effective. WHO trained vaccinators quickly, and they could immunize large groups of people in a short time. The eradication of smallpox raised hopes that the same could be accomplished for other diseases, with many named as possibilities: polio, mumps, and dracunculiasis Guinea worm disease , among others.

Malaria has also been considered, and its incidence has been reduced drastically in many countries. It presents a challenge to the traditional idea of eradication, however, in that having malaria does not result in lifelong immunity against it as smallpox and many other diseases do.

It is possible to fall ill with malaria many times, although individuals may develop partial immunity after multiple attacks. In addition, although promising steps have been made, no effective malaria vaccine yet exists. Other diseases present additional challenges. Polio, though it has been reduced or eliminated in most countries through widespread vaccination, still circulates in some areas because among other reasons many cases do not present easily recognizable symptoms.

As a result, an infected person can remain unnoticed, yet still spread the virus to others. Measles is problematic in a similar way: although the disease results in a highly visible rash, a significant period of time elapses between exposure to the virus and the development of the rash. Patients become contagious before the rash appears, and can spread the virus before anyone realizes they have the disease.

Guinea worm disease is likely on the verge of eradication. Only 30 cases were reported in , from just 2 countries Chad [15 cases], Ethiopia [15 cases]. The Carter Center International Task Force for Disease Eradication has declared six additional diseases as potentially eradicable: lymphatic filariasis Elephantiasis , polio, measles, mumps, rubella, and pork tapeworm.

At the time, smallpox was endemic in 12 countries or territories in eastern and southern Africa, 11 in western and central Africa, seven in Asia, and Brazil in the Americas. The WHO program designated two main components to its eradication plan: mass vaccinations using freeze-dried vaccine material of carefully monitored quality, and the development of a system to detect, monitor, and investigate smallpox cases and contain outbreaks.

WHO efforts came under criticism from some health workers and human rights advocates. Some public health administrators charged that campaign workers at times bent WHO and local regulations. Some human rights advocates objected to the search and quarantine aspects of the program. Later, some critics claimed that physicians used coercion to ensure vaccination of quarantined individuals.

The following examples illustrate the point:. While ITFDE has placed seven diseases on its eradicable diseases list, the WHO currently suggests that polio and Guinea worm disease are eradicable while lymphatic filariasis, cysticercosis, measles, mumps and rubella could be eliminated from some parts of the world.

Even for diseases where possibility of eradication has been agreed upon, the date when it will happen remains a moving target. The timeline for Guinea worm disease eradication was first set for , then moved to , then to , then to and is currently set for Global Malaria Eradication Program was established in to eradicate malaria, but it was abandoned in All these examples illustrate that disease eradication is an ongoing process. As science discovers new facts about diseases and researchers invent new ways to tackle them the world has to change its perspective on which goals are feasible now and which ones are not yet.

We are also getting closer to eradicating polio and Guinea worm disease. But can we eradicate all infection from the world? For a disease eradication to be feasible and an option worth considering it needs to meet certain criteria. Below we highlight some of these criteria. Notably, these criteria are not set in stone.

Eradication of diseases is an ongoing process, as we learn more about diseases and find new ways to treat them we may find that some of these criteria become obsolete or that disease that were once considered not to fulfill any of these requirements begin to tick all the boxes. There are several required aspects of a disease that need to be fulfilled in order for a disease to be considered eradicable:.

Non-infectious diseases, such as heart disease or cancer, cannot be eradicated. Without an effective treatment against a disease there is no possibility of eradicating it. The treatment can be either preventative, such as vaccination, or curative, such as drugs that can completely eliminate the pathogen that causes the disease from its host.

In addition the the key requirements there are many other aspects of the disease that should be considered in the efforts to eradicate it:. The more pathogens cause the disease the more difficult it will be to eradicate. If a disease is caused by a limited number and closely related pathogens then often same tools and approaches can be used in eradication efforts.

For example, smallpox was caused by two types of variola virus and the same vaccine was used to prevent it. Contrast this to a disease such as pneumonia , which is caused by multiple pathogens — from bacteria to viruses — each of which requires a different treatment.

Diseases with multiple hosts are difficult to target for eradication because it often means that the disease will have to be eradicated in all of them. But single-host pathogens are generally an exception rather than a rule.

Case-in-point, the eradication target for Guinea worm disease had to be postponed, because we learned about high-rates of transmission of the Guinea worm between dog populations, which may be a source for new human infections. Some diseases are not easy to detect in the first place. For other diseases even when symptoms may be visible or detectable, the stigma surrounding the disease may limit our ability to treat it.

Hepatitis C is a disease that fits most eradication criteria, however, because the disease has a high prevalence among drug users, there is a stigma attached to being identified as an infected individual, making it difficult to identify all the cases. Disease eradication is usually achieved one step at a time. A proof-of-concept eradication in one region is a positive indicator that eradication at a larger scale is possible. Once the disease elimination has been achieved on a smaller scale, a greater support for the feasibility of elimination elsewhere can be gathered.

The perceived burden of a disease, the estimated cost of eradication, and the political stability of affected countries are further factors that determine the eradicability of diseases.

Polio is a good example here. Polio eradication efforts illustrate the powerful impact of both a unified international effort and a local political support. In , the Global Polio Eradication Initiative was set-up to provide a large-scale continued support for the eradication of polio. Since then, the number of paralytic polio cases has been greatly reduced such that in it was considered endemic in only three countries: Pakistan, Afghanistan, and Nigeria.

But polio also illustrates that positive developments might reverse. But eradicating a disease can also have significant economic benefits. Simply controlling a disease can be more expensive because of the continued burden a disease poses on a healthcare system and the lost productivity of a sick population. How much we should spend on eradicating a disease?

There will always be other good causes we can spend money on. These include non-health causes, health causes with greater burden, eradication of different diseases, and even research into more cost effective treatments instead of eradication.

The scenario or intervention which brings the highest benefit needs to be assessed for each disease separately. As a classical paper by Walter R. The last recorded case of smallpox occurred in in Somalia.

The disease was officially declared eradicated by the World Health Organization in From the invention of vaccine against smallpox by Edward Jenner in , it took almost two centuries to eradicate the disease.

It was only with the establishment of the World Health Organization in the aftermath of World War II that international quality standards for the production of smallpox vaccines were introduced and the fight against smallpox moved from national to an international agenda. Shown in the chart are the number of reported smallpox cases from until the last case in Even though smallpox had high visibility and should therefore have been relatively easy to document, the lack of an international organization dedicated to global health means the number of cases was likely much greater.

The world map illustrates the year the variola virus the virus that caused smallpox was no longer endemic in a country. You can find out more about the disease and its history in our much more comprehensive Smallpox entry. Rinderpest is the only animal disease that has been eradicated so far. Rinderpest outbreaks in cattles used to cause devastating losses for animal farmers.

The eradication efforts began in the s before the vaccine against the rinderpest virus was even available. Measures such as animal quarantine and slaughter were used to contain the disease. The map here shows the last year in which cases of rinderpest were reported in a country. In an English veterinary scientist Walter Plowright has developed a vaccine against rinderpest, which finally led to its eradication.

You can read more about the history of rinderpest eradication in our post here. Polio, short for poliomyelitis, is a disease that is caused by the poliovirus. Jonas Salk and Albert Sabin invented two polio vaccines in and , respectively, which eliminated polio from the United States and Canada in and rapidly lead to a large reduction of the disease in the Western Europe.