Ask a Scientist: Can we eradicate diseases like Ebola and HIV/AIDS?

The world can be a scary place, especially when new and dangerous diseases seem to spring out of nowhere and cause enormous worldwide death tolls. Therefore, it’s no surprise that both the public and scientists are united on getting rid of these diseases as fast as possible. But what exactly is disease eradication, and are scientists even able to eradicate diseases like Ebola and HIV in the future?

Well first, according to the Centers for Disease Control and Prevention (CDC), eradication of a disease is defined as the “permanent reduction to zero of the worldwide incidence of infection”. This means that there must be zero new infections worldwide for a disease to be labeled as “eradicated”. Three guidelines are used to identify diseases that have the potential for eradication:

1) There must be an effective intervention to stop transmission of the disease. This can be a quarantine of all sick patients or administration of a vaccine to healthy people. Essentially, this is anything that will stop a new infection from occurring. 

2) There must be tools to identify when someone is infected. This is usually something like a cheek swab or a blood/urine test to determine whether someone is actually infected with the disease-causing virus or bacteria (aka pathogen).

3) The pathogen must rely on humans for its life cycle.  This means that if a pathogen can survive without a human, it cannot be eradicated.

If these three conditions are met, then a disease has the potential to be eradicated.

So how does Ebola virus measure up against these criteria?

1)    Prevention of transmission:

Although quarantines are effective in blocking human-to-human transmission, humans can also get Ebola from animals, like fruit bats. Therefore, quarantines will not be 100% effective in preventing the spread of Ebola. Another great way to stop people from getting a new infection of Ebola is a vaccine. Unfortunately, there are no vaccines available for public use, but there are many in the clinical trials pipeline. So the first condition isn’t met, but could the virus be eradicated if an effective vaccine were available?

2)    Tools for detection:

Yes! There are currently lab tests that measure infection.

3)    Dependence on humans:

Unfortunately, Ebola can survive in fruit bats without a human. Therefore, even if an effective vaccine were developed, it would be possible for a mutated form of the current Ebola virus to evolve in bats and be resistant to the developed vaccine. So unfortunately, eradication of Ebola is unlikely under the lens of these criteria.

Don’t be too discouraged, though, because eradication of HIV/AIDS is a different story. Returning to the three conditions required for eradication:

1)  Prevention of transmission:

Currently, the only interventions against HIV transmission are education and use of protection during sex. These are obviously not 100% effective to stop transmission of HIV. The creation of a vaccine would be ideal, but like Ebola, there are no currently available vaccines targeting HIV. There are a few vaccines being tested in clinical trials, however. But, when scientists are able to create an HIV vaccine, will eradication be possible? The answer is yes, because HIV meets both the second and third requirement set forth by the CDC:

2) Tools for detection:

There are tools that can accurately detect HIV infection and,

3)    Dependence on humans:

Yes! The life cycle of HIV depends on humans.

So now you know: eradication of Ebola is unlikely, while eradication of HIV/AIDS is definitely possible! However, a common theme among both of these diseases is that vaccines are desperately needed in order to be able to stop human-to-human transmission. Trust in vaccines is dwindling in today’s society, and although the safety of vaccines is a topic for another day, I will say that I fully support the creation and distribution of vaccines, new and old. They are a necessary part of our society if we want to be serious about eradicating diseases.  And I don’t know about you, but I definitely want to eradicate HIV as quickly and effectively as possible.