At last month's Whanganui Science Forum talk Massey University's Professor David Hayman spoke about the Ebola virus. FRANK GIBSON got the lowdown.
Before I began to write this account of David Hayman's talk about Ebola, I wanted to see what the disease looked like.
A YouTube video from Monrovia, Liberia, showed a young man lying on rough ground surrounded by rubbish. He was groaning in agony and pleading for help.
He writhed in a mess of his own vomit and excrement — the reporter tells us these are the classic symptoms of Ebola in its final stages. As they pour water into his mouth from a plastic bottle, the boy's parents avoid contact with their son.
The mother and father know that getting their son's sweat or saliva or mucus or vomit on their skin could be their death sentence. They cannot touch their dying son.
The background to the video was a corrugated ramshackle iron building — a hospital locked from the inside.
The father was pleading for help through a slot next to the gate. Eventually the gate opened and a man emerged, dressed in overalls covering every square inch of his body, a thick apron and gloves, breathing mask, thick goggles and heavy rubber boots.
Speaking through his mask, he said the hospital was full and could not admit the boy. He returned to the hospital and bolted the gate having hardly looked at the young man dying on the filthy ground.
Some hours later the boy was admitted. Space in the hospital had been found when someone died. We are not told what happened to the young man.
So, what is Ebola and where did it come from?
Ebola is a type of filovirus, meaning string-like. It is essentially very simple. Even bacteria have nucleotides (DNA building blocks) in the millions, but in viruses this is reduced to a few thousand.
The disease is pretty horrific and, typically, from infection to death takes about three weeks.
The initial symptoms are muscular weakness and fever. This progresses through liver failure, diarrhoea, kidney damage and meningitis-like symptoms, leading to respiratory and heart problems.
In many cases there is bleeding from body openings and internally. The 30 per cent who survive the disease are often left with permanently damaged heart functions and vision problems.
Although we tend to think of Ebola as an African problem, Ebola type viruses are found in many areas of the world and this is part of the problem. The way that infection is spread is poorly understood.
It is known that Ebola can spread from human to human by contact with bodily fluids. It is known that Ebola can spread between bats. It is highly probable that Ebola can move from bats into humans.
What is not understood are possible infection pathways linking bats to animals such as rats, pigs, deer and insects such as mosquitoes and from these to humans.
Many gorillas have died from Ebola and it can spread from apes to humans. What is not understood is any link between bats and apes.
Zaire ebolavirus viruses are found across India and South East Asia but have not been isolated from bats in these areas. It is possible that there have been cases of Ebola in these areas that have been undiagnosed or incorrectly diagnosed or simply that the conditions in these areas do not lead to the disease happening in humans. To complicate matters further, there is a European version of ebolavirus known as Lloviu virus which is found across southern Europe and into Turkey and parts of North Africa.
In his talk a couple of months ago about DNA testing Dr Richard Winkworth spoke about how a disease (in the case of this talk it was mainly plant diseases) could be present in an environment but not be a problem unless the conditions were suitable. We saw two examples of this in Dr Hayman's Ebola talk.
We saw data concerning an outbreak that had peaked and then seemed to be dying out. The outbreak then went into another peak with the loss of several thousand lives. Dr Hayman attributed this to a few chance events that caused a new sequence of infections.
If things had been done slightly differently with the original outbreak the secondary peak would not have happened. Unfortunately, because of the lack of trained doctors and medical workers the lessons learned from the outbreak may not to be put into practice in later outbreaks.
The second example of the possible effects of environment was illustrated by analysis of data. A computer model was set up to look at where and when outbreaks had occurred with a view to predicting the most likely place for new outbreaks.
This showed an interesting environmental correlation. People living in areas of undisturbed forest were at very low risk. People living in areas where the forest had been totally cleared were at very low risk. Hotspots for outbreaks were areas of what Dr Hayman called "habitat fragmentation".
These were mainly areas undergoing logging operations. This disruption of the ecosystem seemed to greatly increase the likelihood of an outbreak of Ebola.
Dr Hayman presented some very complex data and ideas. However, to me, a layman in this area of science there were some glaringly obvious factors at work. Firstly, was the connection to extreme poverty in terms of living standards and access to medical services. Secondly, was the link to uncontrolled exploitation of natural resources. These two factors are themselves also probably linked.
Frank Gibson is a semi-retired teacher of mathematics and physics who has lived in the Whanganui region since 1989.