The current Ebola outbreak began in Guinea, West Africa, in December 2013. It rapidly became the largest Ebola epidemic in history, with confirmed cases reported in Guinea, Liberia, Sierra Leone, Nigeria, Senegal, Spain, Mali, United Kingdom, and the United States.
According to the CDC, as of January 29, 2015, the total (reported) case count is 22,101, with 8,818 deaths.
Scientists have been tracking mutations in the Ebola virus, and are investigating whether it has become more contagious – and if it has the possibility to become truly airborne (if it hasn’t already).
Researchers at the Institut Pasteur have started to analyze hundreds of blood samples from Ebola patients in Guinea in an effort to determine if the new variation poses a higher risk of transmission, according to the BBC:
“We know the virus is changing quite a lot,” said human geneticist Dr Anavaj Sakuntabhai.
“That’s important for diagnosing (new cases) and for treatment. We need to know how the virus (is changing) to keep up with our enemy.”
It’s not unusual for viruses to change over a period time. Ebola is an RNA virus – like HIV and influenza – which have a high rate of mutation. That makes the virus more able to adapt and raises the potential for it to become more contagious.
“We’ve now seen several cases that don’t have any symptoms at all, asymptomatic cases,” said Anavaj Sakuntabhai.
“These people may be the people who can spread the virus better, but we still don’t know that yet. A virus can change itself to less deadly, but more contagious and that’s something we are afraid of.”
Yesterday, in an update on the outbreak in Guinea, International SOS reported the following:
Only about 30% of the nation’s new cases occurred in “registered” contacts of known cases. This shows that there are undetected chains of transmission. Of the 16 confirmed deaths, almost 20% occurred in the community, rather than in Ebola treatment units.
That statistic is for the week prior to January 25. Before that, 53% of new confirmed cases in Guinea arose among registered contacts, reports the WHO.
In the last week, Guinea has suffered a resurgence – with reported cases increasing by a third.
Reasons for the increase have not been provided, but may be attributable to the mutations making the virus more contagious, and the possible increase in asymptomatic people unknowingly spreading the disease.
More mutations can make it harder to diagnose – and treat – Ebola.
So far, there is no solid evidence that the current strain is (or could become) airborne, but some scientists are not ruling out the possibility:
Institut Pasteur virologist Noel Tordo said: “At the moment, not enough has been done in terms of the evolution of the virus both geographically and in the human body, so we have to learn more. But something has shown that there are mutations.
“For the moment the way of transmission is still the same. You just have to avoid contact [with an Ebola sufferer]”
“But as a scientist you can’t predict it won’t change. Maybe it will,” he admitted.
Health officials continue to assure us that no virus transmitted by bodily fluids (like HIV and Hepatitis B) has ever mutated to airborne transmission, and say that it is highly unlikely that Ebola will ever mutate to that point.
But some experts believe Ebola is already airborne.
In a commentary piece titled Health workers need optimal respiratory protection for Ebola published on The Center for Infectious Disease Research and Policy (CIDRAP) website, the authors (who are reported to be “national experts on respiratory protection and infectious disease transmission”) point out the need for respiratory protection when dealing with Ebola:
The precautionary principle—that any action designed to reduce risk should not await scientific certainty—compels the use of respiratory protection for a pathogen like Ebola virus that has:
- No proven pre- or post-exposure treatment modalities
- A high case-fatality rate
- Unclear modes of transmission
We believe there is scientific and epidemiologic evidence that Ebola virus has the potential to be transmitted via infectious aerosol particles both near and at a distance from infected patients, which means that healthcare workers should be wearing respirators, not facemasks.
We recommend using “aerosol transmissible” rather than the outmoded terms “droplet” or “airborne” to describe pathogens that can transmit disease via infectious particles suspended in air.
Being at first skeptical that Ebola virus could be an aerosol-transmissible disease, we are now persuaded by a review of experimental and epidemiologic data that this might be an important feature of disease transmission, particularly in healthcare settings.
The authors go on to say…
…other routes of entry may be more important and probable, but, given the right conditions, it is possible that transmission could also occur via aerosols.
By the way…the CDC classifies Ebola as a Category A bioterrorism agent/disease (emphasis mine):
The U.S. public health system and primary healthcare providers must be prepared to address various biological agents, including pathogens that are rarely seen in the United States. High-priority agents include organisms that pose a risk to national security because they
- can be easily disseminated or transmitted from person to person;
- result in high mortality rates and have the potential for major public health impact;
- might cause public panic and social disruption; and
- require special action for public health preparedness.
- Anthrax (Bacillus anthracis)
- Botulism (Clostridium botulinum toxin)
- Plague (Yersinia pestis)
- Smallpox (variola major)
- Tularemia (Francisella tularensis)
- Viral hemorrhagic fevers (filoviruses [e.g., Ebola, Marburg] and arenaviruses [e.g., Lassa, Machupo])
Oh, and there are currently 35 designated Ebola centers in the United States (for which $6 billion has been allocated).
Should we be concerned?
It is probably too soon to tell.
Hope for the best, but prepare for the worst, as they say.
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