Ebola virus disease

Ebola is a rare, severe infection whose outbreaks arise in particular districts of central and western Africa. Outside those areas it has been seen only a handful of times: in people returning from an outbreak, and in health workers who had been working there. It is not something you catch on an aeroplane or at a hotel poolside. Even so it is worth knowing about if you are heading for that region, for two reasons. The first is that the rules for avoiding Ebola are simple and genuinely work. The second is more practical: a fever after travelling in Africa nearly always means something else, and that something else kills far more people than Ebola does, precisely because nobody suspected it in time.

Where the virus comes from and how it spreads

The virus lives in wildlife; fruit bats, which do not fall ill themselves, are considered its most likely natural host. It reaches people through butchering or eating the meat of wild animals — bats, monkeys, forest antelope — or through handling a carcass found in the forest. After that, person-to-person spread begins, and it is that which turns a single case into an outbreak.

Three facts remove half the fear and explain the other half:

• the virus passes only through body fluids — blood, vomit, faeces, urine, sweat, saliva, breast milk, semen — and through objects those fluids have soaked into: bedding, clothing, needles. It does not travel through the air the way flu or measles do;
• a person becomes infectious only once symptoms have appeared. During the incubation period they pass it to nobody;
• the body of someone who has died is infectious and remains so after death. Traditional funerals, with washing of the body and farewells that involve touching it, have historically been one of the main engines of outbreaks, which is why burials in an outbreak zone are carried out by specialist teams.

The people most at risk are not tourists but those caring for the sick: relatives and health workers without protection. Before travelling to the region, check the current situation — outbreaks flare and die down, and information a year old is worthless.

How the illness runs

Between infection and the first signs there are anything from two days to three weeks, most often about a week. The onset resembles flu and gives nothing away: the temperature shoots up, muscles and joints ache, the head and throat hurt, and a weakness settles in so heavy that the person cannot get up.

A few days later the crucial part arrives, which is fluid loss: heavy vomiting, watery diarrhoea, abdominal pain, sometimes a rash. That is the phase in which the outcome is decided, because litres of fluid and electrolytes are lost each day, and death comes more often from dehydration and kidney failure than from bleeding.

Bleeding, which gave the illness its old name of haemorrhagic fever, occurs in nowhere near everyone and appears late: blood from the gums and from injection sites, bruising, blood in the stool or vomit, yellowing of skin and eyes. Severity differs between virus species, and the proportion of people who died has varied several-fold between outbreaks; treatment started early changes that proportion very substantially.

A fever after travelling: Ebola is not the first thought

This is the most practically useful part of the page. If you have come back from Africa with a temperature, the commonest and also the most dangerous cause is not Ebola but malaria. Falciparum malaria kills within days, is treated well and only if treated in time, and starts in exactly the same way: fever, chills, aching, headache, sometimes diarrhoea. Telling them apart without a blood test is impossible.

Hence a simple rule: any fever within a year of returning from the tropics calls for a malaria test, and calls for it urgently if less than three months have passed. Tell the doctor exactly where you were and when you came back — it changes the whole order of investigation. Alongside malaria the same list holds typhoid fever, dengue, hepatitis A and ordinary gut infections; every one of them is thousands of times commoner than Ebola.

What to do if the risk was real

Ebola is seriously considered when, within the past three weeks, a person has been in an area with an active outbreak and has also nursed a sick person, worked in a health facility, taken part in a funeral, or had contact with wild animals.

In that situation the order of events is not the usual one:

• do not go to a clinic and sit in a waiting room. Ring first — the emergency service (across Europe, 112) or the infectious diseases service — and say where you have been and what is wrong. You will be told where to go and how;
• until help arrives, stay at home in a separate room, away from the household, and use a separate toilet if that is possible;
• nobody should clear up your vomit or faeces without gloves; crockery, bedding and towels are kept apart from everyone else's;
• the people who have been in contact with you are not isolated, but they are monitored and have their temperature taken for three weeks; that period is enough.

Ebola is a disease doctors are obliged to notify to the public health authorities. That is not bureaucracy: rapid detection and the tracing of contacts are exactly what puts an outbreak out.

What treatment can do now

Ten years ago care amounted to keeping the patient alive. That is no longer the case, and the difference is large.

The foundation is still intensive supportive treatment: replacing fluid and electrolytes intravenously, supporting blood pressure and breathing, treating concurrent malaria and bacterial infection. Careful replacement of losses alone cuts mortality several-fold, so the sooner someone reaches hospital, the better their chances.

To that have been added specific medicines — monoclonal antibodies directed against the Ebola virus. In a large trial during an outbreak in the Congo they noticeably reduced deaths, particularly in those who came forward early and had little virus in the blood. Vaccination exists as well: licensed vaccines are used to immunise health workers and the contacts around each case, so-called ring vaccination, which is what closes a focus down.

An important caveat: both the antibodies and the vaccines were developed against a single species, the Zaire virus, responsible for most of the large outbreaks. Against the Sudan virus, which also causes outbreaks, there are no licensed medicines or vaccines, and treatment there remains supportive. The ordinary traveller is not vaccinated: the vaccine is used within a focus and on specific grounds.

In people who recover, the virus can persist for a long time in certain sanctuaries — in semen, inside the eye, in the linings of the brain. Hence the advice to survivors: use a condom until semen tests are negative, and do not delay seeing a doctor about eye pain, failing vision or severe headache. Many live for months with joint pain, fatigue and reduced hearing; that is not unusual and needs following up.

Reducing the risk while travelling

If you are going to a country where outbreaks occur, book a travel health appointment in advance, ideally four to six weeks ahead: they will work out which vaccines you genuinely need, and malaria prevention, which you will almost certainly need. Going at the last minute is still better than not going at all.

• Wash your hands with soap often, especially before eating; where there is no water, use an alcohol hand rub.
• Do not buy or eat the meat of wild animals, and do not handle bats, monkeys or animals found dead.
• Eat food that has been thoroughly cooked; wash and peel fruit and vegetables yourself.
• Do not nurse strangers who have a high fever, vomiting and diarrhoea, and do not take part in funeral rites.
• Avoid contact with other people's blood and body fluids; do not share razors or toothbrushes.
• Do not neglect mosquito protection: against malaria it does more than any tablet taken too late.
• After returning, keep an eye on how you feel for three weeks, and mention the trip to a doctor at the first sign of a fever.

Online consultation

Remotely, the sensible things to settle are the before and the after of a trip: what the risk currently is in the specific country you are visiting, which vaccines and which malaria prevention suit you, what to pack in a medical kit and what to do about diarrhoea or a fever on the road. On your return, a doctor will help work out what a temperature means, which tests come first and how urgent it all is. If what you have is genuine contact with an Ebola patient, or a fever straight after working in an outbreak, the consultation does not happen through a screen: then you ring the emergency service and warn them about the travel in advance.

This material is for information only and does not replace medical advice.