ZKEA

Biological Warfare : Biological Terrorism : Emerging Diseases

Ebola, Marburg

Ebola was named after the Ebola River in Zaire. It was in this region that the first epidemics occurred in the 1970s. Ebola is thus a classic "emerging disease" - one which has only recently entered the human ecology. Emerging diseases are becoming increasingly common as human populations swell, the environment is degraded and the climate warms.

Today's tip: you really don't want to get Ebola. It's a nightmare become real. The first symptoms are a low-grade headache. This quickly progresses to a debilitating fever and muscle pain. Then things get truly bad as the major organs, the digestive tract, the skin, the eyes, the gums, all begin to break down and bleed. The body begins to dissolve. Blood pours out of body orifices while the victim writhes in pain. Death usually comes from systemic shock and blood loss. Researchers were shocked when they first autopsied people who died from these fevers. Their insides had literally melted into a necrotic mess of black fluid.

Because of the particular brutality and lethality of this disease, it causes instant panic whenever it occurs. Towns and villages in affected regions have quickly emptied whenever a case appears.

It's not definitely known where Ebola resides in the ecology. Recent research indicates that some species of fruit bats harbor the virus, but its not known if these bats are responsible for spreading the disease to humans. Nor is it clear if there are other natural hosts in addition to fruit bats.

The initial means of transmission (from animal or insect to human) are also unclear. However, once a person has contacted Ebola, it's believed that the virus isn't particularly contagious. Close personal contact appears to be the only avenue for transmission. Therefore, because the virus is so deadly, it often kills the victim before spreading. In this fashion Ebola epidemics tend to "burn out" very quickly. In a perverse way, this is rather fortunate. Otherwise Ebola would be a good candidate for an apocalyptic pandemic.

Marburg is another member of this class of mysterious viruses. It's named after Marburg, Germany, the site of one epidemic. This virus induces symptoms similar to that of Ebola, although it may not be quite as lethal. Compared to Ebola, Marburg has generated fewer epidemics. That said, a recent Marburg outbreak (April 2005) caused hundreds of deaths and widespread panic in northern Angola.

There is no treatment for either disease. Mortality ranges up to 85% for Ebola, and 30% for Marburg. These statistics, of course, only hold true under conditions of extremely intensive care; without such care, both diseases are close to 100% lethal.

Interestingly, such lethality isn't uncommon among emerging diseases. There are two reasons for this. First, the new host population simply hasn't had a chance to develop any immunity to the newly emergent pathogen. The new disease constitutes a biological surprise attack. Second, the pathogen itself hasn't fully adapted to its host, and so has an innate tendency to run rampant. Thus, newly emergent diseases tend to be bad news.

Generally speaking (but not always), the level of a pathogen's lethality decreases over time. Over many generations the host species develops resistance while the virus itself evolves into more benign forms. The idea of evolving immunity probably makes sense to you, but why would the virus itself become friendlier? Although it might seem counter-intuitive, this in fact makes evolutionary sense. The pathogen, after all, really doesn't care if you live or die - but it does have a vested interest in its own life. Once it kills you, the party is over. No more happy reproduction, no more spreading of the genes. Once you're dead, the virus needs to find a new host pronto or die itself. Failing to spread, the virus will share your own fate. (Faint consolation, perhaps, as you witness your liver drain out of your anus).

Conversely, the longer the pathogen allows you to live, the more time it has to spread to other hosts. Therefore, over time, diseases such as this tend to be selected for relative gentleness. This increases their spread and survival prospects and, by happy coincidence, decreases overall suffering.

Unfortunately, Ebola hasn't been around people long enough to evolve into something more akin to the common cold. Unless the doctor is unusually hurried, it will never be mistaken for a case of the sniffles.

Given its ferocity Ebola is of special interest for biological weapons. Seeing the opportunity, a number of nations and cults have made shopping-expeditions to Ebola zones in attempts to acquire the virus. If successful, presumably they've been very careful with the resulting product. Handling ebola is about as safe as handling plutonium, and requires a similar attention to strict standards of protection.

Research efforts have been made to "tune" Ebola down, so that it has a chance to spread before killing its victim. It is also reported that Ebola has been genetically combined with other microorganisms, such as smallpox, to create chimeric weapons of tremendous spread and lethality. Therefore, even if natural Ebola itself isn't a great threat to most of the world, the Ebola genotype could be a different matter.

Link: Ebola Symptoms, Other Haemorrhagic Fevers
Link: Reemergence Of Ebola Virus In Africa
Link: Ebola Fact Sheet
Link: Viral Hemorrhagic Fever - Ebola And Marburg
Link: BBC: Thousands Flee Ebola Scare