Published on 03rd September 2018
The most recent outbreak of the Ebola virus is located in the war-torn East of the Democratic Republic of Congo. This is the tenth Ebola epidemic that this country has suffered, the ninth having finished only a few weeks ago in the West of the DRC. Although figures for the current outbreak vary, more than 120 people have been infected so far, which has resulted in almost 80 deaths. The health measures that have been effective in controlling the transmission of the virus during previous epidemics have now all been implemented in the month since the first case was reported.
Surveillance for the disease has been heightened, as has the ability for local facilities to test for the disease. A 50-bed Ebola treatment centre is being constructed that will be used not only to quarantine but also to provide a space for experimental treatments to be given, treatments only recently sanctioned by the Congolese Government. Furthermore, 100 community engagement experts have been selected to prepare local villages to accept health education messages and also the new Ebola vaccine VSV-ZEBOV – 4,130 individuals have so far been immunised; another 5,000 doses of the vaccine are stored locally for future use.
As with previous outbreaks, contact tracing is crucial to the containment of the virus. At present, there are still cases of Ebola occurring in patients who are outside of any known contact groups, meaning that the WHO have some work still to do to map the disease transmission in order to isolate and then treat those affected. This is not unexpected, however, as not only is it early on in the epidemic but critically, the region is heavily affected by conflict making any healthcare intervention problematic. In fact, even on the day that the outbreak was announced, the feared ADF militia was said to have kidnapped and murdered a group of villagers near the Ebola-affected city of Mangina. Such oft-occurring terrorism has fuelled the internal displacement of one million or so Congolese, provoking escape over the casual border into next-door Uganda, and created no-go areas for the WHO and partners – all effects that will hamper efforts to control the virus. More cases of Ebola are expected in the coming weeks.
The fruit bat is thought to be the natural host of the Ebola virus, but the virus has also been found in animals that the bat has infected. These include monkeys, apes, pigs, forest antelopes and porcupines. Humans have been affected by being involved with the slaughter of any of these animals, the ingestion of their blood or milk, or by eating raw or undercooked meat. Human to human transmission can then occur by people coming into contact with the blood, secretions or bodily fluids of infected individuals.
Which settings are particularly risky?
Evidence from previous outbreaks has shown that transmission commonly occurs in three settings: at local funerals, when infected patients are cared for by family members, and in hospital when a failure of the personnel protective equipment occurs.
Local funeral practices can involve the ceremonial washing of the Ebola-infected corpses, making transmission to uninfected individuals likely. In fact at some stages of the 2014 epidemic, most patients were infected in this way. It is worth noting that as there is often considerable, yet understandable, resistance to changing cultural practices. Some have cited the re-emergence of these rituals as a major cause for the subsequent outbreaks of Ebola, seen in most of the affected countries.
As transmission within a family setting is common, during outbreaks the early identification of feverish patients is important so that diagnosis and rapid isolation of Ebola-infected individuals can occur – stopping the spread of the virus to those caring for the patient.
As there is no specific treatment for this serious illness and outbreaks have often occurred in remote locations where medical provision is very poor, the fatality rate can be up to 90%.
What are the symptoms?
Like many viral illnesses, the initial symptoms are those of fever, lethargy and muscle ache. These symptoms usually occur from 2 to 21 days after being infected. The virus spreads by infecting certain white blood cells that carry it in the blood to more distant parts of the body, causing further symptoms. For example, in the gut diarrhoea and abdominal pain can occur; shortness of breath can follow when the respiratory system is affected; whereas in the brain confusion or even coma results.
The severe illness which occurs from this multi-system involvement often results in death in only 6 to 16 days.
Diagnosis is possible but difficult as it depends upon specialised blood tests that may not be available at the site of the outbreak. The most useful test during epidemics is the Ebola PCR (polymerase chain reaction) which is able to demonstrate the presence of the tiny viral particles themselves. Using this procedure, patients can be diagnosed early on in the disease process, allowing for rapid isolation and decreasing subsequent spread to other people. Even taking the blood specimen and performing the appropriate tests is hazardous, however, as healthcare workers and laboratory staff are at risk of infection from the blood.
There is as yet no specific treatment for Ebola Virus Disease. The only possible therapeutic approach is to support the patient whilst their own immune system combats the infection. This is best done in an intensive care unit setting, where machines can aid lung and kidney function for example. Such a unit must be equipped with specialised devices to protect the medical staff from the infection themselves – there are few such facilities in Africa, however.
As the outlook for an infected individual is bleak, healthcare professionals have utilised isolation practices to limit further infections whilst offering what support they can to the patients in the field.
By far, the best approach is to avoid infection in the first place but consideration should also be taken to prevent diseases that might be mistaken for Ebola, especially as the symptoms in the early stage of the disease are common to several infections. Malaria prevention is particularly important as are good hand-washing practices and ensuring food and water safety.
Travellers who develop viral symptoms within 21 days of returning from an affected country should seek medical attention, detailing their travel history.
What precautions should I take?
- Avoid contact with:
- symptomatic patients and corpses – post-mortem infection has been described
- close contact with live or dead wild animals.
- Avoid consumption of bush meat.
- Wash and peel fruit and vegetables.
- Prepare and cook meat thoroughly.
- Practise hand-washing.
- Practise safer sex – Ebola virus is found in all bodily fluids.
- Take precautions to avoid illnesses which may be confused with Ebola:
- take anti-malarials and use mosquito bite prevention strategies.
Vaccines against the Ebola virus have developed significantly in the last few years. The VSV-ZEBOV vaccine was trialled towards the end of the West African Ebola outbreak in Guinea; those vaccinated did not develop Ebola, whereas there were 23 infections in the unvaccinated group. Although the numbers involved are modest, it is hoped that in future outbreaks, further evidence will be amassed that will secure the place of this immunisation in the fight against Ebola.
Ebola Haemorrhagic Fever. H Feldmann and TW Geisbert. Lancet. (2011), 377 (9768): 849-862.
WHO News Release
Written by Dr. Simon Worrell, Head of Medical Communications.