February 17, 2015

expert reaction to UK health worker being flown back to the UK for monitoring for Ebola after potential exposure to the virus

A British healthcare worker has been flown back to the UK for assessment and monitoring following potential exposure to the Ebola virus, though they have not yet developed any symptoms.

Prof. Mark Fielder, Professor of Medical Microbiology, Kingston University, said:

“Contact with the Ebolavirus either from a breach of the skin or at a mucosal membrane may possibly lead to infection. This is also the case when contact is made with contaminated material and the eye.  Having said that there are a number of factors that also need to be considered in terms of the potential for developing infection. These include the actual number of virus particles contained in the contaminating material, the time of exposure and method of cleaning.

“Having a rapid robust response to the potential contamination of a person is very important, not only for monitoring and possible infection control if required but also to administer supportive therapies at the earliest possible juncture should that be required.

“It is important to remember that it is not certain that an infection has taken place in this case at this point so an ongoing monitoring of the situation is called for.  As a patient only becomes infectious once they are showing symptoms it is important to keep in mind that the risk to the wider UK public is extremely small.”

Prof. Jonathan Ball, Professor of Molecular Virology, University of Nottingham, said:

“We think that Ebolavirus enters the body either directly, for example through a needlestick injury, or if it comes into contact with what are known as mucosal membranes, which line a number of places in your body, including the eyes.

“Clearly, anyone suffering direct exposure to body fluids contaminated with Ebolavirus, especially if that exposure occurs at one of these relatively unprotected mucous membranes, is at risk of becoming infected. The degree of risk depends on a variety of factors, not least the amount of virus is present in the contaminating body fluid and the time period that the fluid is in contact with the eyes before being washed off.

“Because there is a risk, even small, it is important that the person is monitored so that if, and it’s a big if, they become infected they can get the care that’s needed to protect the patients and the wider public.

“It is important to reiterate that people only become infectious to others when they start to show symptoms, so the risk to the wider public in returning this person to the UK is incredibly small indeed.”

Dr Peter Walsh, University Lecturer in Primate Quantitative Ecology and researcher in emergent disease dynamics, Division of Biological Anthropology, University of Cambridge, said:

“All mucous membranes, including those in the eye, are potential sites of Ebola virus entry.

“In laboratory experiments on pigs, introduction of Ebola virus onto the surface of the eyes has been shown to produce viral infections as strong or stronger than oral challenge.

“While the eye has less surface area for infection than the oral cavity it also lacks the high concentration of virus destroying enzymes that are found in saliva.”

Declared interests

None declared