What are the chances of Ebola spreading?
What are the implications for others if virus is diagnosed? asks Dr Muiris Houston
File photograph of a high level isolation apparatus. Photograph: Jonathan Brady/PA Wire
Reports of tests for the Ebola virus being carried out today on the remains of a man who was found dead in Co Donegal last night have understandably raised concerns.
As a recent traveller from one of countries badly affected by the prolonged outbreak of the sometimes fatal infectious disease, health authorities must look at Ebola as a possible cause of death. How likely is this and if Ebola was indeed the cause of the person’s death what are the implications for others?
Despite the obvious link between recent travel to West Africa and exposure to the Ebola virus, the chances of the person having died of the viral infection are low. There are many other potential causes of death in an individual than infection; even where death is due to infection there are a number of common bugs that are statistically more likely to be the reason for a person’s demise.
In the current outbreak, the majority of Ebola virus disease cases are a result of human-to-human transmission and failure to apply appropriate infection prevention and control measures in home care, some clinical settings, and in burial rituals. It is important to emphasise that Ebola, unlike the influenza virus, is not an airborne disease. Individuals may become infected as a result of contact with the bodily fluids (vomit, diarrhoea, sputum, blood) from people confirmed to have the virus. The Health Service Executive (HSE) said the risk of transmission in this case was considered to be “extremely low”.
The World Health Organisation (WHO) has not recommended any travel restrictions except in cases where individuals have been confirmed or are suspected of being infected with Ebola.
A type of haemorrhagic fever, Ebola virus first emerged in 1976 in what is now the Democratic Republic of Congo. There have been several major outbreaks since then with the most severe registering fatality rates in the region of 90 per cent.
The main reservoir for Ebola is thought to be a particular type of bat that lives in the region’s rainforests. There is a mistaken belief that the virus is harboured by monkeys; however all primates contract the virus when they handle the blood and other bodily fluids of infected animals. Human to human transmission occurs when an infected person’s bodily fluids enter the next victims broken skin or mucous membranes.
The symptoms of Ebola are quite similar to having a flu-like illness, with a high temperature, muscle aches and fatigue. Patients look weak and are very ill, but contrary to popular belief they do not die by exsanguination.
Although Ebola has a very high fatality rate, the overall number of deaths from the infection is relatively low compared with the number of deaths from malaria each year. And compared with a virulent influenza outbreak, Ebola is far less contagious.
In a worst case scenario where the deceased is found to have Ebola infection, there is virtually no chance they infected a fellow airline passenger during their journey to Ireland. It is possible that healthcare workers here may contract the virus from directly handling the body. However the chances of Ebola spreading beyond a health professional and from person to person in the community is extremely low.