3rd Paper

Ebola Virus, a Very Real Threat

There are thousands of infectious diseases found around the world. Some pose little or no threat, others create opportunities for death to occur, and others outright kill. Ebolavirus is the genus of a group of viruses that kill mercilessly. The virus is more commonly known as Ebola, Ebola virus or Ebola HF (hemorrhagic fever). The disease is feared world wide for its quick, efficient killings, with low survivability and even fewer treatments. It has been the focus of novels and movies as a relentless killer that is stopped by nothing except containment; sparing only a few lucky individuals along the way. Ebola virus is a danger that needs to be stopped before it finds a way to reach the whole world.

The Facts:

Ebola virus is named for the Ebola River in Zaire or the Democratic Republic of Congo. The virus and its forms are generally contracted by apes first, from an unknown reservoir or source, and then spread to humans through contact with infected apes.[1] Ebola virus is actually at least five distinct species of the virus; Zaire (DRC), Sudan, Reston, Tai (Ivory Coast) and Bundibugyo (Uganda District). All five of the viruses vary in intensity and whether they infect humans or not. The Zaire strand is highly lethal in humans in comparison to the Reston strand that seems to be lethal only to non-human primates.(Iden) The viruses are labeled as a level 4 Biosafety agent. Level 4 indictates that the virus causes severe - fatal results in humans and has no treatment or vaccine. A Hazmat suit with a self contained oxygen system is required when working with the virus. Upon entering or exiting a lab with these virulent agents a person must pass through multiple showers, a vacuum room, a UV room all designed to destroy all possible traces of the virus.[2]These drastic measures are only used when the most virulent diseases are dealt with. To put it in prespective, HIV is only considered a level 2 Biosafety agent. [2]

The Symptoms and Methods of Infection:

Ebola virus is extremely severe and more often than not fatal disease discovered in all primates. The path of infection is unknown, but generally suspected to be from infected animal to human. The pathogen has not yet been readily transferred in the air, but rather contact with an infected patient’s fluids, direct, or indirect via needles or other such items is the primary method of transfer. Medical procedures are not very sterile in many countries, with the re-use of needles and the treatment of infected patients without preventative clothing. Once infected the virus has a varied incubation period of 2-21 days. The symptoms of Ebola are rather sudden and consist of fever, headache, joint and muscles pains, weakness, and a sore throat. Those preliminary symptoms are immediately followed by diarrhea, vomiting, stomach pain, internal and external bleeding, rashes, red eyes and the hiccups. [3]

The Details and Possible Treatments/Preventions:

Ebola, like some other viruses, has genetic material coded in negative stranded RNA, it codes 3’ to 5’ instead of the other way. This RNA strands possessions seven genes. They code for a nucleoprotein, matrix proteins VP40 and VP35, glycoprotein, viral proteins VP30 and VP 24 and RNA polymerase. All of the proteins play an important role in the life cycle and replication of Ebola. Having knowledge of the genetic coding of Ebola and the function of the proteins coded for enables potential treatments. One of the most interesting discoveries comes from the understanding of Tsg101 protein. This protein is partly responsible for the movement of proteins in and out of the cell. Both HIV-1 and Ebola have been shown to utilize this protein as a means for leaving the cell.[4] The viruses both contain an L-domain, which promote the release of the virus from the cell and the production of viral particles capable of infection.[4] The function of the L-domain has been proven dependent upon the presence of Tsg101 by using double stranded RNA to interfere with the Tsg101 and L-domain function.[4] Without the Tsg101 the virus is not capable of leaving the host cell.[4] This is very promising considering that as of this point treatment involves only supportive care involving fluids and comfort.

There are also methods of prevention to go along with the newly established treatments. Resistance to the lethal effects of Ebola can be achieved in an animal if it is injected with plasmids encoding viral proteins.[5] These plasmids, specifically the glycoprotein, were introduced to a guinea pig which elicited an a cell-mediated response in addition to an antibody response.[5] This provides potential for application in humans. Another method of treatment involves a potential vaccine. A new vaccine has provided immunity, after one shot, from Ebola for non-human primates.[1] This vaccine was generated form the glycoproteins of Ebola.[1] The mediated response that was generally seen was T-cell response from CD4⁺ and CD8⁺ that corresponded directly with the glycoprotein.[1] Unfortunately there was no cross protection amongst the various forms of Ebola virus. This vaccine presents a glimmer of hope, but also demonstrates just how far people have come in about 30 years of work on prevention of this terrible disease.

The potentials for Ebola treatment and prevention are increasing every day. On January 21^st, 2008 scientists released that the removal of one gene negates the strand of Ebola by making it unable to replicate and therefore safer to study. With Ebola having to be studied in level 4 Biosafety environments it posses a problem for the continued study of the virus to find treatments and cures. The new ability to manipulate the virus in such a manner to make it unable to replicate removes the necessity of such extreme Biosafety requirements. With less threat posed by the virus under study, more intimate contact can be made in regards to finding a way to create a vaccine or treatment that can negate the virus before or after an infection. This is a very important step in towards a cure seeing as Ebola is a very real and imminent threat to Africa and other nations alike.

Areas to Avoid/Recent Outbreaks:

As recently as August 20^th 2007 yet another outbreak of Ebola started. This time the majority of the infection took place in the Bundibugyo region of Uganda. In this most recent outbreak there are upwards of 100 infected individuals with over 20 deaths confirmed to be due to Ebola virus. This just serves to put the issue right in the worlds face. Ebola is not a disease of the past, it is alive and evolving. Different strands of the virus are showing up in various areas around Africa. Another case of Ebola recently appeared in the DRC where over 30% of those infected have died as a result of contracting the disease at the time of the report. This recent episode also may have provided a clue to reservoir of Ebola virus. It is proposed that Ebola moves through an area in a sort of wave. It does not remain dormant in any one species, but is transferred from one species to another killing sporadically. This means that many areas around past outbreak zones may be potential locations of new or continued outbreaks and caution should be taken when visiting any areas in the region of an outbreak.

How to Protect Yourself:

Ebola is one of the most deadly diseases of this century. It is a relentless killer, halting only when quarantined effectively enough to limit outside exposure. The disease, as to date, has no cure for humans and only case specific treatments for non-human primates. The disease holds the ability to completely destroy a human in less than a week. In some descriptions it has been said to liquefy the internal organs and sometimes patients will vomit a black mass of blood and disintegrated organs. In less than a weeks time the patient ca n go from mild pains and fever to extensive fluid loss due to vomiting, diarrhea, and bleeding. It is an extremely scary and dominating force that is very difficult to survive from. However, if you are in a region with an outbreak do not come in contact with any other person’s fluids and stay away from any potential infected items (needles, syringes, waste materials, etc). This rule alone will decrease the likeliness of infection. This simple method of avoidance combined with continued progress in the area of treatments and preventions will allow Ebola to be managed in the years to come.

1. Baize, S., A single shot against Ebola and Marburg virus. Nat Med, 2005. 11(7): p. 720-1.

2. OHS, C.a. BMBL Section II

Principles of Biosafety. 1999 June 17, 1999 [cited 2008 4/1]; Available from: http://www.cdc.gov/od/ohs/biosfty/bmbl4/bmbl4s2.htm.

3. CDC, Ebola Hemorrhagic Fever Information Packet. 2002.

4. Luban, J., HIV-1 and Ebola virus: the getaway driver nabbed. Nat Med, 2001. 7(12): p. 1278-80.

5. Xu, L., et al., Immunization for Ebola virus infection. Nat Med, 1998. 4(1): p. 37-42.