MERS-CoV snapdate on canaries...

MERS-CoV detections among healthcare workers (HCWs)

HCWs are akin to the canary in the coal mine - when HCWs get sick with a particular bug, this can signal that the bug may well be more active in the the wider community. 

This graph looks at the canaries and suggest that there has been a relatively long period in which they have been getting infected.

Healthcare workers positive for MERS-CoV over time.
Some reported or hypothesized clusters and outbreaks are flagged.
Click on image to enlarge.

A quick look at my database shows that most of the MERS-CoV-positive HCWs reported since October have been from Riyadh in Ar Riyadh region and Taif in Makkah region. 

Just before that, in early September, there were 2 HCWs from Jubail in the Ash Sharqiyah (eastern) region. 

If we look at the new time-based occurrence heatmap I have on my MERS-CoV static page here, the recent group of HCWs come from the areas with most cases. No big surprise there. Perhaps more surprising is why these HCWs are, presumably, still acquiring there infection in hospital settings given eh attention that infection prevention and control practices had, especially (before?) during and after the Jeddah outbreak last year.

A recent paper from Profs Drosten and Memish speaks to this topic of infection control and hospital spread of MERS-CoV a little.[1] 

It reports finding a 40-year old female (40F) nurse who, despite MERS-CoV being such a wimpy transmitter between humans, became infected after attending an infected patient. 40F did not perform any aerosol-generating procedures  but also wore only a surgical mask and gloves - it reads as though she was not fully protected against droplet, and certainly not against airborne, exposure. 

The 40F HCW then went on to shed virus for a 42-day period as determined by MERS-CoV specific RT-PCR. She was not ill during this time. Hard to contain much?

So with all that in mind, it's no longer hard to imagine how spread of MERS-CoV virus occurs within, around and between hospital settings. Also helps to explain how some of the new cases might seem strange - if not testing for subclinical or asymptomatic cases as a routine. I recall that in Saudi Arabia routine testing of milder cases is not occurring, but I cannot find a source for that recollection just now so I stand to be corrected (please send if you know if a reference that alludes to that).

A couple of quick questions spring to mind:

1. Just how widespread is this lengthy shedding period?
2. What does this say about how mild a virus MERS-CoV is when comorbidities are not a factor?
3. What role do genetics play in the host's containment and clearance of MERS-CoV infection?

Heatmap of MERS-CoV detection by date and region
within the Kingdom of Saudi Arabia
Click on image to enlarge.

Reference..

1. A Case of Long-term Excretion and Subclinical Infection With Middle East Respiratory Syndrome Coronavirus in a Healthcare Worker. Manal Al-Gethamy, Victor M. Corman, Raheela Hussain, Jaffar A. Al-Tawfiq, Christian Drosten and Ziad A. Memish.
   http://cid.oxfordjournals.org/content/early/2015/01/01/cid.ciu1135.long

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MERS-CoV snapdate...

MERS-CoV detections by month and year

As can be seen from the graph below, the peaks of MERS-CoV detection have been driven by humans and their infection prevention and control issues - but what maintains the virus in between those lapses? 

It seems clear that MERS-CoV is entrenched among camels in the Middle East and Africa but how is it getting to humans, and how is it dong that in such small numbers over such a wide area? These have been questions for 148 weeks. 

It's a good thing this infection transmits so poorly between humans.

Click on image to enlarge.

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Case->outbreak->epidemic->publication->learn a lesson...repeat

The global cumulative curve of suspect+probable+confirmed
cases EVD cases (orange) , suspect+probable+confirmed
EVD deaths (red) and the confirmed cases (yellow dots)
Updated from last WHO data posted 10JAN2015 AEST.
Click on image to enlarge.

When looking at the PubMed database search results for 'ebola', one can have no doubt that something big must have happened lately to drive such a massive number of science doers and writers to their keyboards. 

And of course something did - the world's largest, most widespread, multinational and longest running epidemic of Ebola virus disease (EVD) which roared through Guinea, Sierra Leone and Liberia. At the end of 2014 there were 20,000 cases and 8,000 fatalities - and those were just the cases we have seen added to official lists and made public.

A tally downloaded from the PubMed search engine
based on numbers returned using the search term 'ebola'.
Click on graph to enlarge.

The adjacent image shows what the US National Library of Medicine's search engine generates when one searches for 'ebola'. The search engine, called PubMed because it makes the MEDLINE database public (MEDLINE being the Medical Literature Analysis and Retrieval System Online, or MEDLARS Online), lists many of the world's life science and biomedical publications that meet the PubMed standards; currently >24,000,000 citations. In 2014, a lot was written about EVD.

While a lot of the 'ebola' publications in 2014 were commentaries and a lot of reviews that mostly presented the same information, these were necessary to feed many different groups of readers and specialities hungering for background on EVD and the ebolaviruses and how these related to them and their roles, patients and lives. 

I had cause to scan the literature on a daily basis for a few weeks and was particularly impressed with the New England Journal of Medicine's clinical papers and the BMJ's summaries and updates. Of course Science/Sciencexpress and Nature had some beautifully informative articles as well - delving into the humanity behind the numbers and seeking answers to questions we were all asking. I thought PLOS Current Outbreaks (although I'll never enjoy reading that layout), Lancet, Lancet Infectious Diseases and Morbidity and Mortality Weekly Report also stood out in 2014. 

Some of these articles came out very quickly and many were available without the need to breach a paywall. But some of the research...I can't help but wonder how many lives could have been saved if studies detailing and reinforcing the apparent benefits to survival from the aggressive use of intravenous fluids and electrolytes could have come out sooner-through whatever venue. What if we'd talked about, researched or actually published better personal protective gear designs earlier? Imagine if the world had registered that Ebola virus seemed to be in the region years ago, when research papers suggested it. Would any of this knowledge have saved more lives? Who knows? Would the focus on what needed to be delivered to West Africa have changed because of earlier dissemination of need? Would more point of care chemistry instruments have been prioritised? Would the urgency about the need for more healthcare workers have been stepped up if more specific examples of why they were needed were out there for our leaders to be briefed on? Probably unanswerable questions.

Why can't humans ever seem to learn enough to prevent the event sneaking up and whacking us senseless? Why is it always after the event that the light dawns and processes are created for 'next time'?

There will be many more publications to come in 2015, spinning out of this epidemic and the events yet to unravel. Hopefully they will create enough memory for the world to be better prepared for next time. Prepared for a little...uooh - goober fish...

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