It is, according to the World Health Organisation director general, Margaret Chan, the “most severe acute health emergency in modern times”, one that is “threatening the very survival of societies and governments in already very poor countries”. Almost 4,500 people have been killed by the ebola outbreak in West Africa. Although most of the deaths have occurred in just three countries – Liberia, Sierra Leone and Guinea – where infection rates are still rising exponentially, western governments are preparing themselves for the arrival of the virus on their shores. The US and Spain have confirmed cases, and in the UK Jeremy Hunt, the Health Secretary, expects ebola to be putting the National Health Service to the test by Christmas.

Amid the rising panic, a few calm voices are struggling to be heard. Sarah Wollaston, who chairs the House of Commons health select committee, has said that she expects the UK to get five cases in total, at the rate of roughly one a month. The NHS, she says, is perfectly ready and able to cope. Seth Berkley, chief executive of the Global Alliance for Vaccines and Immunisation, concurs: ebola is not a disease you have to fear when living in a wealthy country. “The likelihood of this causing a major epidemic in Europe or the US is very, very low,” he says.

The rapid transmission in West Africa is largely a result of broken civil structures and health-care systems. Sierra Leone and Liberia are recovering from decades of conflict that also sucked in neighbouring Guinea. The consequences are a dearth of medical resources and a mistrust of government: a perfect storm that leads the population to pay scant attention to advice from the state. Diagnosis of the disease has been slow and in some areas people have insisted on following local traditions, rather than best practice, when caring for – and disposing of – ebola-stricken relatives. This is what has cleared a path for the virus through the population of these countries. In the west, with highly responsive and respected health-care systems and no tradition of physical contact with the sick or dead, there should be little worry. The boring flu virus is more likely to get us, and yet we have let ebola, a somewhat self-defeating virus, become a major concern. It might be said that we are suffering from Ebola Panic Disorder.

Ebola is not an especially dangerous pathogen. It was first identified in 1976 but because it did not seem much of a threat a vaccine was never developed. Periodic outbreaks were fairly easily contained. A few hundred people died in Africa but no money or urgency was given to finding a cure. The US military paid ebola a bit of attention at first, in case it could be weaponised. That interest soon waned, however: bioterrorists would find it almost useless. It coexists happily with certain animal hosts – the current outbreak originated in fruit bats – but is so deadly to us that the virus is normally stopped in its tracks.

“It’s not airborne, and it kills its victims too quickly for them to pass it on efficiently: it just doesn’t spread fast enough,” says Melissa Leach, director of the Institute of Development Studies at the University of Sussex.

The virus is carried in body fluids and enters through cuts in the skin or through mucous membranes. Infection can occur through sexual intercourse, ingestion of breast milk and through physical contact if protective measures are not taken. Once ebola takes hold, it disables its host’s immune system. Survival depends on certain factors. One is simply the strain of the virus (some are deadlier than others). Another is early and copious use of rehydration solution, replacing the fluids that the disease will cause to leak from the body. In some cases, a transfusion of plasma from a recovered victim has also assisted recovery.

The first signs of infection are fever and malaise; a few days later come diarrhoea, nausea, vomiting and abdominal pain. Despite the frenzied reporting, bleeding from the eyes is not that common. However, the ebola virus halts the mechanism that clots blood, and gastrointestinal bleeding is a common symptom. Eventually, the mucous membranes (including those in the eyes) and any cuts or other wounds may ooze blood continuously. If you are going to die of the disease, you will usually know by about day six after the first symptoms show – the point at which most surviving patients’ condition has improved. The last stages of the disease are painful and horrific. The average time to death in West Africa, mostly through septic shock and multiple organ failure, has been just over a week.

It is what happens next that presents the greatest problem. Traditional funerals in the affected countries often require relatives to wash the corpse, in some cases multiple times over a few days. This provides an opportunity for the virus in the dead person’s leaking body fluids to make the leap into a new host. Disposing of the body while following strict protocols – using disinfectant while wearing full-cover protective clothing – cuts the risk of transmission to near zero.

This has been proven time and again in previous ebola outbreaks. The protective protocols are so straightforward, in fact, that rural communities in parts of Africa have been successfully implementing them for decades without outside help. Some of the flare-ups in the Democratic Republic of Congo have been staunched rapidly without ever coming to prominence in the western media. Two other West African countries have had cases in the recent outbreak, but contained them by implementing stringent public health measures. In Nigeria, which has a population of 170 million and where roughly 15 million live in Lagos alone, eight people have died (of 20 confirmed cases) and there are now no residual infections. In Senegal, just one person has died.

So while we should be doing all we can to help West African countries deal with the disease, there is little reason for us to panic in the west – especially as a vaccine is in development. Two vaccine candidates have proved promising in animal trials, and human safety tests run by the University of Oxford began last month. If the vaccines perform as well as expected, and mass-production techniques are developed in time, 2015 might bring a huge effort to eradicate susceptibility to animal-borne ebola.

Seen in this light, both the tragedy playing out in West Africa and the panic besetting the developed world are actually a result of ebola’s lack of virulence. As Berkley points out, a vaccine is finally being developed, not because of the disease ravaging Africa, but because of a sudden realisation that, as a result of poor decision-making early in the current outbreak, the disease is not necessarily going to stay in Africa this time. “It’s more about fear of the disease taking hold in the west than it is about the disease in the south,” he says.

The threat has arisen because no one in charge realised that it would be so tough to implement even straightforward protection protocols in the broken health-care systems of Liberia and Sierra Leone in particular. The index case (that is, the first one) in the present outbreak was reported in December last year and attracted no response. “Then, very late, the international community started to get interested,” Melissa Leach says. “And the focus was on how we contain and control this.”

Leach sits on the Scientific Advisory Group for Emergencies, which informs the government about risks and recommends strategies. The discourse has at last evolved, she says: the decision to scale up aid was well motivated, and the entire discussion about how we help stop the disease killing people in West Africa, rather than how to prevent it coming here. Nonetheless, motivating politicians to do the right thing did require some discourse about the threat to the UK, channelled through the media. And that’s when the silliness started.

There is a stark contrast between the calm, low-profile checks on NHS preparedness for ebola and the pointless but highly visible implementation of screening programmes at UK airports. The latter is only to allay public fears; it is close to impossible to spot ebola-carrying travellers. Yet in some senses the panic is predictably human, according to Wandi Bruine de Bruin, professor of behavioural decision-making at Leeds University Business School. One reason we are failing to assess the risk sensibly, she says, is that we hear stories of things such as people bleeding from their eyes; it is an upsetting mental image, and one that hampers our cognitive processing. “People use the emotions they feel about an event as a ‘mental short cut’ for assessing risk,” she says. “Horrific images of ebola are likely to evoke strong negative emotions, potentially leading to higher perceptions of risk.”

Another issue highlighted by de Bruin’s research is the human need for control. The two biggest threats in the developed world are stroke and heart disease. The problem is, stroke, heart disease – and cancer – are slow and steady killers. These are familiar, comfortable threats; it doesn’t feel as if they’re out of control. Ebola is different.

No matter how few deaths have occurred compared to other diseases, or what the likelihood of coming into contact with an ebola-infected person might be, if many people are being afflicted at once, in an unfamiliar environment, with a disease that evokes horror and has no cure – that is a frightening scenario, and our control-hungry minds are disturbed by it.

It’s easy to see this playing out in the US and Europe but it is also at work in West Africa, says Heidi Larson, an anthropologist who researches interactions with health-care systems at the London School of Hygiene and Tropical Medicine. “They are freaked out,” she says. “Look at the levels of panic and anxiety after one case in a western country: imagine how the people of West Africa feel.” It is almost certainly a desperate desire for control that is keeping people away from health centres, she argues. “Who would want to go to a hospital if you didn’t have to right now?” The same desire compels people to maintain customary burial practices, keeping infection rates high.

One consequence is that it’s not just ebola that is running rampant in West Africa. Now that the hospitals are no longer seen as places where you take control of a disease, malaria, pregnancy complications, pneumonia and dysentery will kill even more people than usual. Not that there would be resources to deal with these afflictions even if people did present themselves at clinics and hospitals. Health-care workers are consumed, sometimes literally, by ebola: there is no slack in the system.

Those who do seek care when ebola symptoms manifest are thrust into an environment that creates even more fear and loss of control. Generally in the west, we have little contact with the sick; we leave them in the care of professionals. In many West African hospitals, doctors and nurses are for diagnosis and treatment; everything else is the family’s responsibility. If your child or your partner is hospitalised, you take them food, give them fluids, wash them and meet all their basic needs. You touch them, hold their hand, reassure them it’s going to be all right. But not with ebola.

“They see a family member getting sick; they’re not supposed to touch them; they’re told that they are to be taken away to a place where they can’t be accessed, and that they may never see them again,” Larson says. The prospect is too much for many to cope with; hence the suspicion that Guinea, Liberia and Sierra Leone are harbouring many unreported cases. “The panicked relatives are the real risk.”

These fears can be allayed. Health-care workers in previous outbreaks in the DRC became so concerned by the disengagement of families that they changed disposal routines. Bodies would be disinfected and bagged in front of relatives, who were given protective clothing. The bagged corpse was physically handed to the family, and family members put it into a grave. These rituals, performed 30 times a day at the peak of one outbreak, seemed at first to be a waste of precious resources. However, in the longer term, increasing relatives’ engagement with the health-care system helped stem the tide of new infections.

Implementing such measures requires trust in the authorities and donor agencies – a rare currency in West Africa now. Many developing countries have lost confidence in western programmes, says Didier Raoult, a disease researcher at Aix-Marseilles University. Several high-profile failures are to blame, he notes. In what he calls the “Haiti mess”, international aid workers imported cholera into the country following the 2010 earthquake and killed more than twice as many people as have died in the present ebola outbreak.

The CIA’s covert use of a vaccination programme in Pakistan to try to identify Osama Bin Laden’s children was, in effect, a subversion of essential aid programmes to protect a few westerners from the possibility of death in terror attacks. “That undermined our credibility,” Raoult says. It led to a long-standing boycott of vaccination drives and attacks on health workers, causing enormous setbacks to the effort to eradicate diseases such as polio.

Mistrust is also a problem in the UK, where the panicked reaction to ebola can be correlated with the public mood. Unpopular political leaders and a loss of confidence in the NHS are potent stimulants to overreaction. “People underestimate the amount that underlying political or social issues affect the public’s reaction to an event,” Larson says. “Think about the MMR [jab] scare. The panic around that was because it came hot on the heels of the poorly managed and frightening BSE saga.” The result was a severely reduced uptake of vaccines and an ensuing series of measles outbreaks. The west’s reaction to ebola, given our current economic and political gloom, will be similarly exaggerated, she suggests.

It is vital that we stem the panic, otherwise our reaction will be short-sighted and short-lived. During an outbreak of plague in India a few years ago, health-care workers went to the world’s premier plague labs for help and found none; the researchers had retired and hadn’t been replaced. “There was no capability almost anywhere to work on this disease,” Berkley says. “Because we don’t see these diseases commonly, we get hysterical, and then when it’s over we tend to move completely away from it.”

Stringent budget cuts at WHO and other agencies and a lack of political attention to global health challenges between outbreaks have exacerbated the crisis in West Africa, and heightened the wider panic, Berkley reckons. Contrast that with our preparedness for nuclear war. “The likelihood of that is pretty low but the UK has nuclear submarines going round the world, always available in case a nuclear attack occurs.

“Everybody accepts it’s OK to spend the money on armed forces and nuclear submarines, but when you say, ‘Let’s keep disease labs up to date, let’s keep a fast response team, let’s do the training necessary to prepare for an outbreak,’ people don’t respond. There’s no perspective.”

Michael Brooks is the New Statesman’s science correspondent. His latest book is “At the Edge of Uncertainty: 11 Discoveries Taking Science By Surprise” (Profile, £12.99)