SciTech

Ebola outbreak leads to new drug development initiatives

Transmission electron micrograph of the RNA filovirus that causes Ebola hemorrhagic fever.
 (credit: Phil Moyer via Flickr) Transmission electron micrograph of the RNA filovirus that causes Ebola hemorrhagic fever. (credit: Phil Moyer via Flickr)

The whole world has been gripped by the recent Ebola virus outbreak, with multiple countries attempting to establish effective practices to prevent the spread of the pathogen. In addition to the active battle against the virus, there is a newfound interest in fully understanding the virus to determine why it is so pernicious.

The scientific community has known about the Ebola virus since the first reported outbreak in 1976. The virus is not always around but emerges in outbreaks. The largest previous outbreak occurred in 2000 and affected 425 people with a fatality rate of 53 percent according to the World Health Organization (WHO). Currently, the world is experiencing the largest outbreak to date with recent statistics by the Centers for Disease Control (CDC) reporting a total of 10,141 cases with 4,922 deaths.

However, when compared to the leading causes of death, the Ebola virus doesn’t even compare to the number of cases and deaths for other diseases such as cancer, HIV/AIDS, or even influenza (the flu). Ebola has garnered a notorious reputation because it can be spread through bodily fluids and has been characterized by the WHO as “a severe, often fatal illness with an average fatality rate of 50 percent.” Additionally, there are currently no approved treatments or vaccines.

A recent survey by the Harvard School of Public Health reported that in the United States alone, 40 percent of Americans believe that there will be a large outbreak of Ebola, and 25 percent believe that someone in their immediate family will be affected. A lot of these fears are far from reality since many experts believe that an Ebola outbreak of that scope in the U.S. is near impossible. Ebola can be prevented with effective practices and a strong medical infrastructure.

One important question scientists are trying to answer is why this outbreak has been the deadliest to date. The origin of the virus this year has been traced back to Guéckédou, a small town that is in the southern corner of Guinea. Its location near the borders of Liberia and Sierra Leone allowed the virus to spread in these countries, which are ranked as three of the poorest in the world. Their lack of medical expertise and corrupt governments without proper infrastructure has caused the death toll to escalate.

Like most viruses, the various strains of the Ebola virus all rely on the host for their survival and replication. Once in the body, the virus inserts its genetic material into our cells and uses our cells’ machinery to replicate itself. Once producing progeny, the virus will cause the infected cell to explode, releasing the newly constructed virus. This cycle continues as the virus spreads to multiple organ systems. As cells die, more complications arise.

The first symptoms are the sudden onset of fever, fatigue, muscle pain, headache, and sore throat. This is followed by vomiting, diarrhea, rash, symptoms of impaired kidney and liver function, and in some cases, both internal and external bleeding.Everyday we are exposed to a variety of pathogens such as bacteria and viruses, but our body has a powerful immune system that protects us from getting sick.

The cells of the immune system that travel through the bloodstream are able to differentiate the proteins on the outer surfaces of foreign particles and the proteins found on normal body cells. While identifying a pathogen, the immune system produces antibodies that can bind to and target the pathogen. The killer cells of the immune system identify this antibody and engulf and destroy the pathogen.

In the case of Ebola, the virus is adept at infecting the cells of the immune system, reducing their count in the bloodstream and thus limiting the immune system’s effectiveness.
This allows the virus to propagate in the body and overcome the immune system.

Scientists do not lack treatments or vaccines because the Ebola virus is too scientifically complex to treat. The fault can be put on drug companies that ignored developing Ebola drugs because of the small subset of people that were actually being infected. Their priority is to focus on diseases which affect a large population so that, in the end, they make more revenue.

The recent Ebola outbreak has led to a renewed interest in developing a drug. The fundamental tenet of general virus treatments and vaccines is the enhancement of the body’s immune system to be better fitted to kill the disease. A vaccine works by exposing the body to a harmless version of the same virus so that the body recognizes it and creates antibodies against the virus. The body’s immune system has the ability to remember pathogens that have infected it so if the virus ever enters the body, its response will quickly and efficiently destroy the virus before symptoms arise.

Vaccines can only help to prevent a disease but will not be useful for those who are already infected. BioCryst Pharmaceuticals is currently developing a drug that directly targets the virus’s ability to replicate.

The company has seen success in treating similar symptoms in monkeys. Another company, Tekmira Pharmaceuticals, is developing a treatment using a new technique in biotechnology that involves encapsulating RNA molecules in fats and lipids. The RNA specific for the virus has the ability to enter the infected cells and bind to the virus RNA, preventing it from replicating itself.

Many of the details of these treatments are kept secret as these companies are competing to develop the most efficient drug.

After developing a viable treatment plan, it takes an extended period of time to conduct the necessary clinical trials and get FDA approval before the drug can be mass produced and administered. In the case of Ebola, the Food and Drug Administration is trying to speed up trials to get the treatments out into the public. GlaxoSmithKline is already in the first phase of clinical trials and estimate that they will have a drug sometime in 2015.

Still, the only thing medical professionals can currently do is provide Ebola patients with basic supportive care such as maintaining hydration. They must also ensure that their interaction with others is limited to prevent transmission.