Eradicating diseases: an "ongoing process "22.07.2020 – Louis Pasteur (1822-1895), considered a pioneer in the field of microbiology who developed, among other things, vaccines against rabies, once declared that it was within the power of mankind to banish infectious diseases from the earth. And in fact this was successful with smallpox and rinderpest. The global community is also well on its way to eradicating polio (poliomyelitis). But can all infectious diseases be eradicated??
Pox. Content Providers: CDC/James Hicks – Public Health Image Library of the Centers for Disease Control and Prevention
1980 was a special year: the World Health Organization (WHO) officially declared smallpox eradicated worldwide, the first disease ever to be eradicated. In the 20. In the nineteenth century, the virus had still claimed the lives of 300 million people. "From the development of a smallpox vaccine by Edward Jenner in 1796, it took almost two centuries before the disease was eradicated," writes a team from Oxford University led by economist Max Roser on the website "Our World in Data.". According to the report, the turning point came with the founding of the WHO in 1948, when the fight against smallpox was elevated from a national to an international agenda – u.a. with an intensified smallpox eradication program launched and funded in 1966.
To date, smallpox is the only human infectious disease that has been fully defeated. The global community only managed to do something similar with rinderpest (2011), which primarily affected cattle and buffalo. But on the occasion of the 40. On the occasion of the 50th anniversary of smallpox eradication last May, WHO chief Tedros Adhanom Ghebreyesus emphasized, "Now, as the world faces the COVID 19 pandemic, humanity's victory over smallpox is a reminder of what is possible when nations join together to fight a common health threat."He stressed to the press the importance of the availability of a vaccine and global solidarity.
Eradication: permanent& Worldwide
The next disease that could be eradicated worldwide is polio. Since the Global Polio Eradication Initiative was founded in 1988, the number of cases of the disease has fallen by over 99 percent. With the help of extensive vaccination campaigns, among other things, more than 18 million people are now able to walk "who would otherwise have been paralyzed," says WHO.
"In theory, many diseases could be eradicated," write Roser et al. On "Our World in Data.". "In reality, however, only a handful of diseases meet the criteria that make them eradicable with current knowledge, facilities and technology." Eradication resp. Eradication means that the number of new cases of the disease worldwide is permanently at zero. Once a disease, along with its pathogen, is eradicated, intervention measures – such as vaccination – are no longer necessary. The situation is different with "elimination": here, only the chain of infection in a particular region is interrupted; theoretically, it is also possible to "eliminate" a disease in humans, while the pathogen itself, however, remains in the environment. Either way, measures such as vaccination must be maintained.
Which infectious diseases can be eradicated worldwide??
Criteria for eradication to be conceivable
"You can only eradicate a disease if you can get it from other people or animals – in other words, it is infectious," states Our World in Data. "Non-contagious conditions like heart disease or cancer cannot be eradicated."There are certain metabolic diseases that could disappear from the face of the earth if everyone ate the right diet to prevent vitamin C deficiency, for example. But they are not eradicated – after all, they reappear as soon as the nutritional status changes.
Another criterion for eradication to be even conceivable: There must be some way to prevent it (prevention: z.B. vaccination) or to treat.
In addition, many other factors play a role – such as how easy it is to detect and diagnose a disease in the first place. Or whether it has already been eliminated in a particular region. Eradication efforts are also easier if there are fewer different pathogens that can cause the disease in question. Smallpox z.B. were caused by only two types of variola virus – "the same vaccine was used for prevention". There is also a better chance of success if the pathogen in question has only one host. In the case of dracunculosis – an infectious disease caused by the sog. Guinea worm is caused – the world community has been on the verge of eradication before. But then it turned out that the worm also affects animals such as dogs – and so the eradication measures must now be extended to them as well.
Eradication can also be financially rewarding
No matter how many of the above criteria are met, the pathogen itself can still be treated: If sufficient financial resources are not available or if the political situation in the affected countries is tense, the "eradication" project can quickly become an impossible undertaking. Also, the level of disease burden is relevant when deciding whether to take eradication measures.
"The immediate benefits from disease eradication are obvious: preventing suffering and saving lives," Roser and his colleagues write. But it can also be worth it financially (s. Graphic): If the global community wants to banish a disease to the history books once and for all, it will require a lot of patience and financial investment at first, to be sure. But in the long run, it can pay off – after all, persistent cases of illness place a burden on health care systems and economic productivity. That's why donor countries and private donors made pledges of about $2.6 billion in late 2019 to fund the global polio eradication plan. Goal is to vaccinate 450 million children annually against polio. But in order to achieve eradication, experts say more investment is needed. For example, the amount needed for definitive eradication is estimated at $3.2 billion.
Eradication as an "ongoing process"
Eradication is always subject to ongoing debate, note Roser and Co. Even the question of which pathogens can be eradicated in the first place has to be constantly revisited. Within the framework of the "International Task Force for Disease Eradication" of the non-profit organization "The Carter Center", founded in 1988, scientists have currently identified eradication potential for eight diseases, according to the website: Dracunculosis, Polio, Mumps, Rubella, Lymphatic Filariasis, Cysticercosis, Measles and Frambosie. This list is not set in stone. Because with each new development – such as a vaccine -. As knowledge of infectious diseases grows, the situation can change. Especially since there is no worldwide agreement on which ailments to eradicate or. eliminate are.
And even when eradication programs – such as those against polio or dracunculosis – are launched, it becomes clear that the whole thing is an "ongoing process" – an up and down process. Draculosis, for example, was originally targeted for eradication by 1995, then 2009, then 2015, 2020 and now 2030.
The microbiologist Walter R. Dowdle – once a deputy director at the U.S. Centers for Disease Control and Prevention – wrote in a 1998 WHO bulletin: "Elimination and eradication are the ultimate goals of public health. The only question is whether they can be achieved in the present or by a future generation".