Medical News Blog Information

MERS-CoV update: Case accumulation over time and by region of suspected acquisition...

Click on chart to enlarge.
It's been about a month since I last updated this chart. While the situation is perhaps not yet worthy of the Jeff Golblum quote from Jurassic Park..."I'm fairly alarmed here"...it's heading that way for me.

There is quite an uptick in the slope of the Kingdom of Saudi Arabia's case numbers and also that of the United Arab Emirates.

This chart will bear watching and I'll endeavour to keep it updated on at least a weekly basis if the cases keep coming out at the rate they have been of late.

One thing to note though; because the KSA Ministry of Health data are patchy, inconsistent and slow. It may be that some/many of the dates for cases between the final 2 data points would spread into previous weeks. Unfortunately these dates have not yet been passed along to the WHO yet (or from the WHO to the public) and so the dates sometimes have to reflect date reported (which may lag behind onset of signs and symptoms by weeks) or date of hospitalisation rather than the more reliable date of illness onset. So take the chart as a trend...but one which may highlight a change in the speed of new case announcements.

Professor Ali Mohamed Zaki on MERS-CoV: camels a secondary concern to person-to-person spread

There have been a seemingly continual and growing stream of Middle East respiratory syndrome coronavirus (MERS-CoV) cases of late, with a particular emphasis on what seem to be increasing numbers of healthcare worker infections, a possibly younger age group and less severe disease.

Professor Ali Mohamed Zaki, Faculty of Medicine, Ain Shams University, Cairo Egypt recently spoke to this in an MBC 2 TV interview. 

I asked Prof. Zaki by email on Friday if he could cover what he said in that interview. He kindly replied with the following.....
"..more cases in humans appeared in hospitals in Jeddah, which may indicate increased virus transmission from man to man due to mutation in the genome leading to virus adaptation. This event may be associated with loss of some virulence elements in the virus."
This could be a possibility but not one we can check very easily right now because there are very few MERS-CoV sequences, complete or partial, on the public sequence databases from cases in 2014.

Prof. Zaki went on to talk about camels in the context of MERS-CoV clusters of person-to-person transmission seemingly on the rise among this flurry of cases in recent months. Prof Zaki noted that...

"..since the virus now is transmitted easily between humans, the role of camels may become less important."
Still, there was a heartening sign indicating some real intent to prevent the citizens and workers of the Kingdom Saudi Arabia (KSA) from acquiring MERS-CoV infections this week. The Governor of Jeddah, Prince Mishal Bin Majed, ordered a clamp down on camel breeding in the city, removal of camels from the streets and direction on the selling of camel milk.[1] Also something about vegetables, but perhaps best we move on from that one.[1] 

A very hard look at infection control and prevention education and its practices in hospitals and ambulance settings is overdue in the KSA. Also needed are some more detailed molecular investigations into the virus itself. It is essential to monitor this slowly growing epidemic to ensure that the viral culprit hasn't undergone any significant changes. Such change may convey upon it the ability to spread more efficiently among people, perhaps, as Prof. Zaki notes, resulting in less severe pathology. Of more concern though is that enhanced spread, without any change in clicnial outcome will put at much greater risk the sizable proportion of older males with comorbidities that reside in the KSA. 

Or course its possible that the rash of cases we are seeing are just due to:

  • Increased exposure to the source
  • Change(s) in seasons
  • Changes in camel, bat or other animal's breeding habits
  • Changes to tests or testing
  • Changes to the way reporting is conducted. 
One thing is certain though, the quality and depth of information accompanying the KSA Ministry of Health MERS-CoV press releases is as poor as ever, if not worse than usual.

I sincerely thank Prof. Zaki for taking the time to reply to my email. Prof Zaki was instrumental in discovering the MERS-CoV during his time working in the Kingdom of Saudi Arabia. I have previously reviewed his role in this and related issues. [2,3,4]

I also thank Mike Coston for picking up on the TV interview that led me to contact Prof. Zaki.

Further reading...
  1. Camels to be off streets as precaution against MERS
    http://www.saudigazette.com.sa/index.cfm?method=home.regcon&contentid=20140408201249
  2. Happy 1st birthday Middle East respiratory syndrome coronavirus (MERS-CoV)
    http://newsmedicalnet.blogspot.com.au/2013/09/happy-1st-birthday-middle-east.html
  3. Questions about MERS, MTAs and mistakes.
    http://newsmedicalnet.blogspot.com.au/2013/08/questions-about-mers-mtas-and-mistakes.html
  4. Dr Ziad Memish discusses MERS in the Kingdom of Saudi Arabia (KSA)
    http://newsmedicalnet.blogspot.com.au/2013/08/dr-ziad-memish-discusses-mers-in.html

Animal contacts among Middle East respiratory syndrome coronavirus (MERS-CoV) cases: UPDATE

Click on image to enlarge.
An update of the total number of cases where animal contact or exposure has been noted. 

Such mentions seem to have been on the rise since October 2013, but the Kingdom of Saudi Arabia (KSA) still has the lowest proportion of mentions among the list, despite the greatest number of MERS-CoV cases overall. 

Perhaps this disparity reflects a greater number of healthcare-associated (infected workers and hospital-acquired infections) transmission chains compared to other countries.

My last post on this back in 21-Mar-2014, was focussed on camels alone but this one differs in that it includes all animal mentions. Camels are most often identified though; 71% (15 of 21) of al cases noting animal exposure of any sort. 

Total cases with "animal" mentioned, according to my database, includes 21 distinct cases.


When 2 - 2 = 2: Ebola case numbers in Sierra Leone

I've been having a little trouble following some aspects of the World Health Organization's (WHO) updates on the Zaire ebolavirus outbreak. There have been a few things - tiny little things - that have made it more confusing for a simple chap like me to track. One of them follows.

Don't get me wrong; this is not a criticism of the fantastic job the social comms team (@HaertlG, @setiogi and @MonikaGehner and no doubt many others I am completely ignorant of) have been doing. I've openly congratulated these guys before, and do so again here; they get so much information out on so many topics to so many endpoints...staggering. The 2014 #ebola communication has been an stunning process/event/big-word-full-of-respect-awe-and-bigness to behold from the outside looking in. It should be a shining example of a multifaceted social media education, updating and mobilisation campaign.

Tonight however, I write about the case numbers from Sierra Leone...and I'm essentially "typing out loud" to work through my confusion here so I forgive you for reading no further.

Lets go back (wavy hands)...


Ebola virus disease, West Africa � update

WHO, 01-Apr-14
The Ministry of Health of Sierra Leone is maintaining a high level of vigilance following the deaths of 2 probable cases of EVD in one family who died in Guinea and their bodies repatriated to Sierra Leone. To date, active surveillance activities have identified no new suspected cases and all contacts of the deceased have remained well.
http://www.who.int/csr/don/2014_04_01_ebola/en/


Ebola virus disease, West Africa � update
WHO, 02-Apr-14
There has been no change in the situation in Sierra Leone following the deaths of 2 probable cases of EVD in one family who died in Guinea and their bodies repatriated to Sierra Leone. As this is a rapidly changing situation, the number of reported cases and deaths, contacts under medical observation and the number of laboratory results are subject to change due to enhanced surveillance and contact tracing activities, ongoing laboratory investigations and consolidation of case, contact and laboratory data.
http://www.who.int/csr/don/2014_04_02_ebola/en/


Ebola virus disease, West Africa � update

WHO, 05-Apr-14
There has been no change in the situation in Sierra Leone following the deaths of 2 probable cases of EVD in one family who died in Guinea and their bodies repatriated to Sierra Leone. The office of the Chief Medical Officer (CMO) is coordinating all operations involving suspected cases of Ebola as well as the follow-up investigations. Enhanced surveillance and public education activities are continuing.
http://www.who.int/csr/don/2014_04_05_ebola/en/


Ebola virus disease, West Africa � update

WHO, 07-Apr-14
There has been no change in the epidemiological situation of EVD in Sierra Leone. The Ministry of Health and Sanitation of Sierra Leone has confirmed that 2 suspected cases of viral haemorrhagic fever are laboratory confirmed as Lassa fever which is endemic in Sierra Leone.
http://www.who.int/csr/don/2014_04_07_ebola/en/

Ebola virus disease, West Africa � update
WHO, 10-Apr-14
Although the epidemiological situation in Sierra Leone remains unchanged, the Ministry of Health and Sanitation (MOHS) continues to lead intensive EVD preparedness activities.
http://www.who.int/csr/don/2014_04_07_ebola/en/


Okay. Cool. So what was all that for?

WHO's super-human Tweeter and communicator, Gregory H�rtl (also called Head of Public Relations/Social Media for the WHO) posted a Tweet today...

What I didn't understand was where these 2 cases from Sierra Leone had come from? See-toldya I was a simple chap.

So by listing them out, it seems they must be the 2 suspected cases - highlighted in yellow in the 07-Apr update above. 

They were 2 cases distinct from the the 2 fatal EVD cases in Sierra Leone. As it turns out those 2 fatal cases will forever remain "probable EVD cases" because they died and were not sampled. As Gregory Hartl Tweeted...
If you'd like to read more of a timeline about these two - have a look at a very detailed analysis prepared by Cedric Moro (@Moro_Cedric).

This case study also confirms that at least some of the EVD cases will not ever be getting a laboratory confirmation as I wondered about in my Ebola virus sampling issues post 09-Apr. Not only do EVD case numbers change, occasionally in slippery ways, but there are also occasions when they won't ever change despite us wanting them too. If I was a pedant this could drive me to insane.

Update on Ebola virus disease (EVD) case accumulation chart with new WHO African Regional Office data...[UPDATED].

UPDATED with 2 Sierra Leone probable deaths.
Click on image to enlarge
Not much of a change to be seen with the data from WHO following that from UNICEF yesterday.

No Species Zaire ebolavirus cases have been confirmed in Sierra Leone nor any in Mali (6 suspected cases however; 2 other samples tested negative) or elsewhere. 


Click on image to enlarge.
Maps purchased from maptorian and adapted by VDU
EVD cases are still restricted to Guinea and Liberia and all cases remain linked to infections in Guinea. 

As I understood the recent WHO virtual press conference, because the index case was known, the transmission chain of contacts is mostly already under observation. While Ebola virus disease (EVD) has a grisly progression, once experts are in place to help track, test and educate, with the help of local and international governments, the spread of EVD can be contained. 

But it will still take time to be sure the outbreak has been contained; 2 full incubation periods worth of time.[3] As the maximum incubation period is 21-days (2-21 days being the full range), you start to see why the WHO speaks in terms of "months" [2,3] before the outbreak can be considered over. And that clock starts sometime around the end of the last case's disease onset I'd guess.
�We fully expect to be engaged in this outbreak for another two, three, four months�
Dr Kenji Fukuda, WHO[3]

So as the outbreak comes under control, as seems to be the case, we should pay attention to when new cases stop appearing. Then it becomes about waiting until everyone can safely say there are no new cases.


The most recent case had an onset of illness on 08-April-2014.

Sources...
  1. WHO-AFRO Ebola virus disease, West Africa (Situation as of 10 April 2014)http://www.afro.who.int/en/clusters-a-programmes/dpc/epidemic-a-pandemic-alert-and-response/outbreak-news/4093-ebola-virus-disease-west-africa-10-april-2014.html
  2. Ebola expected to terrorise West Africa for �months��WHO - Euronewshttp://www.euronews.com/2014/04/09/ebola-expected-to-terrorise-west-africa-for-months-who/
  3. Officials Say Ebola Outbreak Could Last Months - Timehttp://time.com/54299/officials-say-ebola-outbreak-could-last-months/

Update on Ebola virus disease (EVD) case accumulation chart with new UNICEF data...

Click on chart to enlarge.
Thanks to a UNICEF Australia's update I've added a few cases to the produce a new chart; I expect we'll see some WHO numbers soon, and I'll update if there are any differences.

Check the version number in the bottom left hand corner - it defines whether it is the only chart of the day from VDU, or one of several.

The new version shows the proportion of fatal cases holding fairly steady at ~60% of all cases. This calculation includes those cases that also that look like EVD but have not been laboratory confirmed as EVD, as well as those that have been confirmed.

As I went into yesterday, these are very volatile numbers, so regard this chart for its trends only.

Sources...

  1. UNICEF Australia's PDF of numbers from ~3-hours ago
    http://ow.ly/d/24bM

Recorded Ebola virus disease (EVD) outbreaks throughout time...

A guide of case total confirmed cases and those who died from 
Ebola virus over time.
Sourced from Public Health England website [1]:
Click on chart to enlarge.
A quick chart to highlight the larger and smaller outbreaks and importations of EVD and Ebola viruses, respectively, that have been recorded worldwide since 1976.

I've added in the current tally of 167 suspected/probable/confirmed cases for the 2014 Guinea outbreak but this number is inflated compared to the other entries on the chart because those are reportedly based on confirmed cases; only around a third (59) of Ebola cases in the current outbreak have been confirmed to date.

Thanks to @Pawixx for steering me to the PHE page.

Please note that these numbers differ a little from the World Health Organization's Table [2]. Solving that discrepancy is a problem for another day.

Source...

  1. http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/Ebola/GeneralInformation/
  2. http://www.who.int/mediacentre/factsheets/fs103/en/

Ebola virus disease and lab testing...

Virology Down Under's latest Ebola virus case case chart.
Click on chart to enlarge.
Maia Majumder has posted a nice concise comment on her blog. In her latest post [1] she notes that we shouldn't be too surprised that the number of Ebola virus disease (EVD) cases with a lab confirmation (conf) represent a relatively low proportion of the total cases we hear about. 

Currently (see the chart above), 35.3% are lab confirmed. That's 59 confirmed among 167 cases; the remainder are suspected [susp] or probable [prob] cases.[3]

What might contribute to the speed of laboratory confirmation in this and other EVD outbreaks? 

Some thoughts below:
  • Obtaining a specimen. If a body has already been hidden, buried or otherwise disposed off before a sample can be collected. Sampling may have been refused by next of kin-although I am not at all sure if that is a "thing"  during an EVD outbreak
  • The need to work under enhanced safety conditions to prevent laboratory-acquired infections. BSL4/PC4 not strictly available to the field labs (although they are setup to work with those pathogens; see Tweet below), but increased care and awareness still slows down the diagnostic process compared to testing for a much less fatal virus
  • The generally tough conditions for doing precise and careful lab work in a mobile laboratory; work that is often resource-, temperature- and power-sensitive not to mention fiddly and in need of well-controlled experimental conditions
  • Distance from the site of collection to qualified lab and the quality of sample once it reaches that lab. A sample that sat around in the sun or was accidentally frozen, lost, broken, sent to the wrong place, may be falsely or weakly negative requiring further testing
  • The case is positive for a different virus but one that causes similar signs and symptoms. This may also require additional testing to identify. Other virus testing may be run in parallel..or may not
  • You could argue that previous outbreaks used older and often much slower diagnostic methods. That's true, if you compare them side-by-side in a results race. In practice, PCR-based testing comes with lots of extra "bits" that can slow down the production of a final result. The process is still faster than things used to be, quite possible more  sensitive too, but still not as fast as we'd all like. Apples and oranges though.

What defines a suspected case requiring testing anyway? 

Pretty much the same things that define this for any outbreak; a suspected case is a person with the appropriate signs and symptoms of disease, who was in the right place at the right time to have come into contact with a known infected human or animal in such a way that they may have exposed themselves to virus, but they have not yet received a lab confirmation that they have that virus. It may be that a case never receives that confirmation because of a lack of positive specimens (don't have specimen or cannot get a positive result) in which case the person becomes a probable case if they meet the clinical criteria but cannot be confirmed. 

Why would a sample not be collected? 

As noted above, perhaps the next of kin did not allow samples to be collected, perhaps the body was disposed of before sampling could be achieved or perhaps the lab testing failed. To safeguard against the latter, PCR-based testing (not the only method) usually involves multiple assays, running replicates of each sample, and using several assays, each preferably targeted to a spatially different region of the viral genome to overcome the negative impact of any genetic changes in relying on a single site. Such viral genetic change may be an issue during a new outbreak. We haven't seen much by way of sequence analysis from any viral detections to date, but very early on in this outbreak the species was confirmed using genetic sequence determination, to be a strain of the species Zaire ebolavirus.

The numbers are constantly changing.

After all that, even a probable case may still get be discarded after lab test results are in; it may have been a suitably relevant disease, but caused by infection with a completely different virus.

While I think many of us understand that the numbers do change, I also think some of the interest we have in wanting to see them is to understand which way the trends are changing; up, down, steep, flat etc. There has been a fair bit of cautioning about the numbers. In my own defence, these numbers are real. They are collected by people on the ground. They are a much better metric to watch, changeable or not, than the many headlines and blogs and Tweets that may be more aimed at attracting readers and followers, or just be ill- or uninformed.

So the numbers change. What does that mean? As it stands, the Sierra Leone cases have now been taken off the Ebola tally because they were confirmed as haemorrhagic fevers due to a completely different virus; Lassa virus. A suspected EVD case in a child tested negative in Ghana. 2/6 suspected cases from Mali have also tested negative for the Zaire ebolavirus. The Liberian hunter thought to be an isolated EVD acquisition [8,9,10] not linked to Guinea, has now tested negative for the virus. So the numbers change quickly. That's your proof and it confirms what WHO's Gregory Haertl has been saying since Day 1 of this outbreak. These changes have effects too.

The fatal case percentage may rise despite more cases testing negative.

Not as strange as it sounds.

If the number of susp/prob cases drops as some are discarded because the lab confirms they are not EVD, the proportion of cases that are confirmed and died due to EVD will "look" larger-it will be a bigger percentage. The proportion of fatal cases currently sits around 63% of all susp/prob/conf cases now (up from a lowest point of 59%, down from a high of 72%). If the denominator (total susp/prob) cases should shrink while the numerator (fatal EVD cases) remains steady, or grows, the ratio will grow. Be prepared for that and the accompanying headlines or poorly informed Tweets and comments that will scream "the virus is mutating" blah blah blah. It probably isn't. It probably won't. But you may not get that message from using Google alone (try the links below and work your way up).

This EVD outbreak is proving especially challenging.

The term "challenging" seems to have become an agreeable descriptive for both the WHO and MSF, at last, as of yesterday's WHO virtual press conference[5]

The challenges that differentiate this Ebola outbreak from previous mostly seem to be about the wide spread of cases around the countries of both Guinea and Liberia, complicated by the presence of other pathogens that cause clinically similar diseases. More usual problems for tracking, identifying and confirming EVD cases are listed above including working under the requirements of enhanced safety and the need to bring in many essential resources. Careful and accurate confirmation of cases by the lab is a time-consuming process but one that must be given that time in order to ensure it gets the right result. False-negative results or lab-acquired infections would be a very bad outcome at any time but especially if resulting from an unnecessarily rushed testing process. False-positive results have an arguably larger negative impact on the entire situation. Timeliness is a very subjective thing. But lab confirmation is most definitely not like making a cup of coffee.

Can we see the forest for the trees yet?

The most recent EVD susp/prob/conf cases became symptomatic on 06-April-14, but no new healthcare workers were among them and some cases are now being discharged .[4] Some good news there.

We're obviously not out of the woods yet (pardon the pun) in terms of transmission chains. The WHO suggests it will be "some months" before we stop seeing cases. But the recent WHO virtual media conference stressed that while EVD is a serious disease it is one that can be controlled and the risk of infection is low, when the right precautions are in place.[5]

See the latest WHO-AFRO Ebola in Western Africa Situation Update also. It's got totals and charts!! Bloomberg quicktake webpage [6] and the US CDC webpages [7] have lots of digestible information too.

References...
  1. #Ebola2014: On the Topic of Lab-Confirmation
    http://maimunamajumder.wordpress.com/2014/04/08/ebola2014-on-the-topic-of-lab-confirmation/
  2. WHO-AFRO Ebola virus disease (EVD), West Africa Situation Report 07-Apr-14.
    http://www.afro.who.int/en/clusters-a-programmes/dpc/epidemic-a-pandemic-alert-and-response/outbreak-news/4089-dashboard-ebola-virus-disease-in-west-africa-07-april-2014.html
  3. WHO GAR DON Ebola virus disease (EVD), West Africa Update 07-Apr-14
    http://www.who.int/csr/don/2014_04_07_ebola/en/
  4. SUCCESSES AND CHALLENGES IN RESPONSE TO GUINEA EBOLA EPIDEMIC
    M�decins Sans Fronti�res Press Release 08-Apr-2014
    http://www.msf.org.au/media-room/press-releases/press-release/article/successes-and-challenges-in-response-to-guinea-ebola-epidemic.html
  5. Audio file for WHO virtual press Conference
    http://terrance.who.int/mediacentre/presser/WHO-RUSH_Ebola_outbreak_Guinea_presser_08APR2014.mp3
  6. Bloomberg's QuickTake on Ebola
    http://www.bloomberg.com/quicktake/ebola/
  7. The US Centers for Disease Control and Prevention on Ebola in West Africa, 2014
    http://www.cdc.gov/vhf/ebola/outbreaks/guinea/
  8. Liberia reports suspected Ebola outbreak unconnected to Guinea
    http://news.yahoo.com/liberia-reports-suspected-ebola-outbreak-unconnected-guinea-130714958.html
  9. LIBERIA: Ebola Deaths Rise In Liberia, Health Minister Confirms
    http://www.gnnliberia.com/articles/2014/04/05/liberia-ebola-deaths-rise-liberia-health-minister-confirms
  10. Liberia: An isolated Ebola case
    http://crofsblogs.typepad.com/h5n1/2014/04/liberia-an-isolated-ebola-case.html

Editor's Note #17: 500th post

Just noticed that there are 500 posts listed on this blog (501 now). I still have a few to port across from the old site but its kinda weird to think I've posted on stuff that many times. I only have ~60 actual scientific papers...although a lot more citations for VDU's blog than for those papers. Hmm. What does that say about my impact or chosen profession?

Anyhoo - Cool bananas!

I wasn't planning on blogging again for a while but Ebola has drawn me back for a little bit. 

Ebola virus disease (EVD) outbreak in West Africa: chart of cases to 04-Apr

Data are based on WHO DONs, French Embassy Conakry
 figures and WHO Tweeted information.
Click on image to enlarge.
The Ebola virus disease (EVD) case chart adjacent is based on the latest Disease Outbreak News (DON) from the World Health Organization (WHO) posted at the Global Alert and Response (GAR) site [1] and at the African Regional Office (WHO-AFRO) [2].

There are roughly 163 suspected, probable and laboratory-confirmed cases including 95 deaths (58.3% proportion of fatal cases) for which only 56 (34.4%) have been confirmed by laboratory tetsing.

I'm also maintaining a curated Storify timeline here which lists some key Tweets and links on this outbreak. 

A few things to note about the chart and the outbreak:

  1. The susp/prob/conf (shorthand I use on Twitter) numbers change - the 1st 2 numbers can go down as well as up as cases that cannot be laboratory confirmed as due to EVD are discarded from the tally. Other diseases with similar presenting signs and symptoms occur in the West African region so this is not at all unexpected. We see the same thing for other viral outbreaks, like influenzavirus, all the time.
  2. The WHO does not posted "grand totals". The DONs present totals for each region (currently Guinea, Sierra Leone and Liberia), which I've tallied up above.
  3. Its worth remembering that this outbreak was happening back in early Feb, so there was a passage of time during which people were exposed and did not know precisely what was causing illness. This creates a lag between the time of the first announcement and when the situation can come under some semblance of control. Control requires that the various teams arrive, are coordinated and set up in the area to test, trace, educate and reduce virus spread. Each time a new region has a case, the same flurry of activity may well ensue, so case numbers will seem suddenly spike - but as we can see, they do not continue to rise exponentially, or even at all in some regions. This is thanks to the expert teams including those from the WHO, jurisdictional Ministries of Health, UNICEF, the Red Cross and M�decins Sans Fronti�res (apologies to all those I've missed - you are all doing a fantastic job under extreme conditions and you are extremely  appreciated)
  4. Posts on this outbreak do not occur daily - I presume, as for avian influenza virus outbreaks etc, posting of numbers is based on when those data are collated, summarized and provided to the WHO.
  5. There are reports of 4 haemorrhagic fever cases from Mali (some of whom had traveled to Guinea; a suspect case is also reported in Ghana coming from Mali although there are questions about where from precisely) that are not, at writing, laboratory confirmed.[5] Samples are being sent to the United States for confirmation. Why not to the Institute Pasteur in Dakar, or Guinea field labs I do not know; presumably because of pre-existing arrangements?
  6. Liberia has 1 suspected EVD case in a hunter who seems to have acquired his infection locally (no contact with know EVD cases or with Guinea). This suggests to me that the vector is actively infected in the region. Perhaps this is a migratory season (seasonal change, following food sources, breeding) for this Ebola virus's animal hosts, previously found to be fruit bats, chimpanzees, gorillas, monkeys, forest antelope and porcupines in particular, eaten as "bushmeat". I admit to knowing nothing about animal movement in the region however.
  7. While EVD is "highly contagious", close contact with an infected animal host or an infected human cases' bodily fluids (blood, organs, mucous, urine, vomit, faeces and semen for up to 7-weeks post-infection) is required to acquire an infection. Generally the virus doesn't spread across distance as well or quickly as for example, influenzavirus does. This is largely because the virus is not spread the same way:
    • Sneezing and coughing is not considered a method of EVD transmission
    • Once the patient is symptomatic, they do not move around as much; from that point, spread of the virus to new people requires those people to come to the ill person. This is why healthcare workers, especially early on in an uncharacterized outbreak, and close family members caring for an ill or deceased relative number highly in new cases of EVD. 
    • Basic levels of infection prevention and control can interrupt transmission. These include good hand hygiene, use of personal protective equipment and prevention of needle stick injuries.
  8. Airborne transmission is not considered a risk factor for acquiring EVD; this is not the movie Outbreak where the fictional "Motaba" virus mutates into an airborne ebolavirus-like pathogen. Also unlike the movies, bleeding from orifices and the skin can occur, but much more rarely than the movies lead us to believe
  9. EVD signs and symptoms start suddenly 2-21-days (8-10 more common[3]) after virus acquisition and usually include fever, headache, joint and muscle aches, weakness, diarrhoea, vomiting, stomach pain, loss of appetite and may also include rash, sore throat, red eyes, hiccups, cough, chest pain, breathing and swallowing difficulties and sometimes internal and external bleeding. Not everyone dies from infection however the higher end of the mortality spectrum for the species Zaire ebolavirus can reach 90% in outbreaks with >1 case identified.[4]
  10. A person with no signs or symptoms of disease is not considered contagious.
  11. While a border closure (Senegal) and some flight restrictions have come into play, these may only serve to disadvantage the outbreak region rather than provide any true risk mitigation. Closing a border may hinder the flow of food, medical supplies and daily goods as well as interrupting the normal commerce of the country, impacting both economically and directly on the lives of the overwhelming majority of people who are not infected. I'm not aware of any evidence that shows closing a border has any reducing effect on an Ebola outbreak. Closures are a knee-jerk reaction caused by the fear of a scary disease.
And that last point is an important one. Ebola evokes some scary images outside of Africa. And so it's important for us not to run around like a decapitated Gallus gallus domesticus. We need to rein in the excessive over-reaction. As Maryn McKenna aptly noted recently over on Superbug, many things are killing more people, more regularly every day both in and outside of Africa. Having said that, I can totally understand the reactions of those living inside of West Africa just now. Among them, those who both have or have never looked this pathogen in its filovirusy-eye and stared down the barrel of its disease before. 

Viruses can be pretty scary things indeed.

References..
  1. WHO Global Alert and Response (GAR) Disease Outbreak News (DONs) Articles
    http://www.who.int/csr/don/en/
  2. WHO African Regional Office (WHO-AFRO)
    http://www.afro.who.int/en/media-centre/pressreleases.html
  3. Signs and symptoms of EVD or Ebola haemorrhagic fever (HF) from US Centers for Disease Control and Prevention
    http://www.cdc.gov/vhf/ebola/symptoms/index.html
  4. WHO EVD fact sheet
    http://www.who.int/mediacentre/factsheets/fs103/en/
  5. WHO AFRO EVD West Africa SitRep for 4-April-2014
    http://www.afro.who.int/en/clusters-a-programmes/dpc/epidemic-a-pandemic-alert-and-response/outbreak-news/4079-ebola-virus-disease-west-africa-5-april-2014.html
  6. A Patient in Minnesota Has Lassa Haemorrhagic Fever. (Don�t Panic.)
    http://www.wired.com/2014/04/minnesota-lassa/

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