Update: 17th May 2018
The Ebola outbreak in the Democratic Republic of Congo (DRC) is causing increased concern as the numbers affected increase, and it moves from a rural to an urban setting.
The latest updates from the region state that 44 people are now known to have become infected, which has resulted in the death of 23 patients so far. First starting around the remote town of Bikoro, one case of Ebola has recently been identified from the city of Mbandaka – which has a population of over one million people. Fears abound that even though Ebola requires close contact to be transmitted, in such a populated city many further cases may occur. In fact, the WHO will meet tomorrow to determine whether a ‘Public Health Emergency of International Concern’ should be announced. Such a declaration during the large West African Epidemic of Ebola, allowed for increased global support, without doubt foreshortening the outbreak.
Lists of contacts of each Ebola patient, and contacts of the contacts, are now being established. These individuals will not only be tested for the virus but may well receive the recently developed Ebola vaccine VSV-ZEBOV, otherwise known a V920. First pioneered by Canada’s National Microbiology Laboratory, the immunisation is now licensed by the pharmaceutical company Merck. Four thousand doses of V920 have already arrived in the DRC, and another 4,000 are en route. As more than 4,000 individuals are believed to be contacts, vaccinations in these numbers are essential. A ring- vaccination programme has previously been effective during the trials of V920, whereby the general population is not vaccinated, but only individuals who have been contacts of Ebola patients. This method not only targets resources more effectively, but by ‘surrounding’ known patients with immunised individuals, limitation of the spread of the virus is achieved: such a method was used successfully in small pox trials previously. There are significant logistical difficulties, however, as the vaccine must be stored at -80°C prior to its use; a difficult feat when transporting V920 in rural DRC.
Although, the chances of acquiring Ebola in the DRC are very low, as the epidemic is in the early stages of its development and much is unknown, avoiding affected regions if travelling to the DRC, is certainly wise.
First published: 10th May 2018
Described after the Ebola River in the Democratic Republic of Congo, which was the site of an early outbreak, the Ebola virus is able to cause disease by its ability to disorganise and deplete our immune response, leading to the failure of many systems in the body. It is back to the DRC that the latest Ebola outbreak has returned, with 17 deaths occurring around the village of Ikoko Impenge, near Bikoro.
Two of the cases have now been laboratory-confirmed as being caused by the Ebola virus. The WHO and MSF have sent teams into the area but it is unknown at present how many contacts of the deceased are involved and whether any local practices, such as customary burial rites, have occurred with the dead before they were identified as Ebola victims. Furthermore, as yet there are no reports of healthcare workers being affected; this has been a prominent feature of many Ebola outbreaks, where those treating the patients become infected following the necessarily close contact involved.
Although following on the heels of the large West African outbreak of Ebola, the DRC epidemic is unlikely to involve so many cases. Firstly, this is the ninth outbreak in the region: Ebola is known in the DRC, and successive cycles of education of how to avoid infection will likely prevent its widespread transmission. Secondly, the WHO and partners have acted very quickly in sending teams in to the field, and lastly, there is now a vaccine (VSV-ZEBOV) that has been used previously with limited, but very promising results.
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.