And some of the theories out there at the moment really take some believing. Here are five:

1. The Ebola virus is an escaped bioweapon

Some believe the Ebola outbreak started with sinister armed men poisoning wells, a successful attempt at mass murder that led to arrests in Liberia. Louis Farrakhan, leader of the Nation of Islam, reckons the virus has been designed to affect only black people. If you are black or brown, you are being selected for destruction.

Others believe its an escaped military bioweapon. This theorys chief proponent is Prof Francis Boyle, a noted scholar of biowarfare and international law at the University of Illinois. In the US Prof Boyle literally wrote the rules of biowarfare. He was a member of the governments Committee of Military Use of Biotechnology and principal author of the Biological Weapons Anti Terrorism Act of 1989 which was signed into law by George Bush Snr. This isnt normal Ebola at all, he says. I believe its been genetically modified.

Boyle points to the existence of US government laboratories in Africa that are creating bioweapons under the guise of innocently working on cures. What they tell you is, We can imagine some exotic disease out there that could be used as a biological weapon, so therefore we have to look into it. The first step is to weaponise the disease so we can develop a vaccine for it. What diseases are they working on? Every type of biowarfare agent you can possibly imagine, including dengue fever and Ebola.

One of these laboratories, says Boyle, is in Kenema, Sierra Leone. Kenema is the absolute epicentre of the outbreak. Something happened there. It could have been an accident in the lab or they might have been testing an experimental vaccine [on the population] using live genetically modified Ebola and calling it something else. The proof, for Boyle, that this is a modified form of Ebola is in both the speed of its spread and the number it is killing. In the other outbreaks its a 50 per cent fatality rate and it was contained. Right here, were dealing with a 70 per cent and its not contained. All the evidence Ive been able to locate leads me to believe it came out of the Kenema lab. How high does the cover-up go? I think the people at the top know. Probably Obama too.

Critics of the theory observe that if this was an altered version of the disease, the changes to its structure would be observable to scientists. However, DNA analysis of samples sourced from 78 individuals affected by the current outbreak was recently published in the journal Science. It found this subtly different variant likely diverged from central African lineages around 10 years ago before spreading into west Africa in May. It is, in other words, perfectly natural.

2. Aeroplanes are killing us

We are being sprayed by sinister aeroplanes. We are being poisoned, en masse, from the heavens. You can tell by looking up. Why is it that some condensation trails, or contrails, left by commercial craft dissipate after a short amount of time, whereas others remain for hours and expand? And why is it that these suspected chemical trails, or chemtrails, tend to be laid out in rows of the same direction, as if theyre part of a meticulously planned pattern?

The Chemtrails Project UK is one of hundreds of websites devoted to the popular chemtrails theory. It confidently asserts the streaks are highly toxic trails left by jet planes that contain high levels of heavy metals. Their purpose? Its a geo-engineering project, perhaps an attempt to control global warming. Others say theyre brain-numbing chemical agents used to control the population.

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'Ebola is man-made', and other crazy conspiracy theories