MERS mounts up...

In a strange coincidence of numerals, the 4th Middle East respiratory syndrome coronavirus (MERS-CoV) report in a row from the Ministry of Health (MOH) of the Kingdom of Saudi Arabia (KSA) contains very little on 4 cases. 

I use below, the FluTracker's (FT) case numbering scheme because frankly, they produce the only numbering schemes for tracking cases of new or returning infectious disease that are systematic, reliable and worthy of our trust. 

It should form the basis for a worldwide numbering system for infectious disease outbreaks because it is also freely and publicly available such that any potential manuscript author can easily check it before submitting a research paper and then we could all know which case is being discussed. And by "we" I mean fellow researchers, not just interested parties. 

The KSA MOH could consider running their own table of data akin to that of FluTrackers, but augmented and using an adapted version of Crawford Kilian's wishlist to the MOH. Each (deidentified) case entry should include the following headings along the top row, filled out if and as they become relevant:

1. A unique, continuous identifying code specific to this emerging virus
2. Sex
3. Age
4. Occupation
5. Co-morbidities
6. Date of illness onset
7. Town of illness onset
8. Town of acquisition
9. Date of hospitalisation
10. Type of laboratory testing
11. Date of laboratory confirmation
12. Date of death
13. Date of release from hospital
14. Treatments/management
15. Town of treatment
16. Relationships to any other cases

Today's MERS-CoV cases are mostly asymptomatic. These cases are announced amid rumours of larger case numbers being tested, panic in hospitals over potential MERS cases, frustration from within KSA over the MOH's poor performance, and of the KSA cracking down on healthcare workers who pass on rumours as well as prosecuting bloggers.

Today we have:

1. FT#125: 22-year old asymptomatic male, citizen of Madinha (Medina), contact of another confirmed case (we shall call him Mr/Mrs/Ms/Dr X)
2. FT#126: 24-year old asymptomatic male healthcare worker in Madinha
3. FT#127: 60-year old asymptomatic male citizen of Riyadh, contact of another case (also unknown)
4. FT#128: 47-year old male citizen of Riyadh, contact of another unknown case, symptomatic but stable

This brings the tally to 128 with 57 deaths (proportion of fatal cases, PFC, at 45%). Where data for sex exists, males comprise 63% of cases and 74% of deaths in people confirmed as positive for MERS-CoV. 82% of cases come from the KSA and, if counting back to the retrospectively identified cases from Jordan, we take the first week of disease associated with MERS-CoV infection as that beginning 19-Mar-=2013, then we are in 78th week of MER. 

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FluTrackers: Updating the ordinary about the harmful.

FluTrackers are a rock onto which we bloggers hold for dear life while the torrents of poorly-crafted, or well-crafted but just plain overwhelmingly vast, information break over and around us each day.

It sometimes seems like FT posts before the events even happen. Possibly they do since they also track a lot of related detail and background information so they see trends that may precede the particular case or outbreak "offical" announcement  But they have very strong principles and they clearly discriminate between what is confirmed and what is under investigation  They want you to know what's going on when no-one else has yet got the message to you. 

I think the dedication that this driven band of multi-lingual fact-seekers displays is worthy of honorary doctorates. 

Perhaps they could be made founding members of  a Division, Infection Notification: Forum for Organised Real-time Monitoring - now that's a name by someone who really wanted the initials to spell out I.N.F.O.R.M.

Anyway, I wish the example set by FluTrackers was one that more public health entities followed. Information that is quickly and publicly available, all the time, on everything, from everywhere.

Cheers from VDU.

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MERS-CoV fatal cases by week

Click to enlarge. MERS-CoV deaths (red bars) each week against a
backdrop (green) of total cases surviving + fatal, globally.

As requested on Twitter overnight, this shows the confirmed weekly MERS-CoV-positive deaths across time.

Not updated for today's 4 new cases though.

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The case against over-interpreting MERS-CoV detection by month...

Click to enlarge. MERS-CoV cases plotted by month of
detection (global data; combining 2012 and
2013 confirmed detections).

There are a number of reasons why I started my post yesterday (my time) with "I'm the first one to say its way to early to be talking about the seasonal distribution". Let's look at some of those reasons today:

1. Where there are few positives in the chart, there has also been very little testing done. The first validated PCR assay was published in 27th September 2012. So Sept-Dec 2012 cases are few and far between for this reason.
2. We are not yet 12-months beyond the announcement of the discovery of MERS-CoV (then nCoV and subsequently HCoV-EMC/2012). It was announced via ProMED on the 20th of Sept and the first genome and clinical study went online 17th October 2012. So no real screening had been done before that time. Cases shown prior to Sept 2012 that identified were retrospectively and not the result of systematic screening
3. As far as I know, screening is still mostly done on a case by case (and contacts thereof) basis. We don't know whether MERS-CoV is circulating endemically in the KSA or any other peninsula country. This is an important data gap since it may be humans that are acting as the reservoir - for all we know
4.  If we look at my post prior to the seasonality chart last night, we can see that cases are climbing steadily - have been since April, and there is no real sign that there is a change in that climb by month. Some reduction of numbers July & August but September is shaping up to be a big month.
5. The spike in cases starting in April was related to a hospital outbreak (the Al-Hasa cluster). And things have rolled on since then. What triggered that outbreak or how the first case(s) acquired the infection remains unknown

So why draw the chart if it is not an accurate representation of true seasonality? Because it gives us an idea of how all the cases officially announced so far are falling out over time, based on the data we have. 

But it should not be over-interpreted. 

We'd need a much greater number of cases and probably a couple of years of surveillance (including community screening) before we could accurately define whether MERS-CoV appears with any seasonal recurrence. Nonetheless, the seasons, or events that happen with seasonal regularity, may influence the risk of exposure and spillover. Also, most of the other seasonal human CoVs occur at their peak every couple of years, and even then, some occur in very low proportions of specimens from people with acute respiratory tract infections. That may be irrelevant to an emerging CoV, or not, so it may take even longer before we can speculate on any seasonal regularity to MERS-CoV infections; if we don't first stamp out the virus altogether as we did with the human SARS-CoV.

So to conclude, before I have to find something and PCR it, given the small amount of data we have, and hints that it might be only the tip of that well referred to iceberg, the more we can extract from what we have the better our chances of finding some clues to the host and some risks for acquiring infection.

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Can MERS-CoV seasonality tell us anything about acquisition of MERS?

Click to enlarge. Combined MERS-CoV cases for 2012 & 2013.

I'm the first one to say its way to early to be talking about the seasonal distribution of a new or emerging virus when there are only 124 cases worldwide. 

Right. 

Having said that, I thought I'd plot the cases by date of illness onset or (less satisfactorily) date they were first reported (even if that first was the report of a death). 

When combining the 15-months worth of case data for 2012 and 2013, the graph revealed a single "season" or at least larger numbers around summer in the Kingdom of Saudi Arabia (KSA). Because >80% of cases have occurred in the KSA, I have also listed a few festivals (some of which are frequented by camels) as well as the peak temperature variations and dust storm activity.¹ 

While I have no idea whether weather could be kicking up clouds of infectious CoV, it is an interesting co-occurrence, as are the presence of a number of festivals before case numbers spike. The Saudi Gazette commented that the risk of [acquiring?] bacterial and viral infections increases during dust storm season as do complication due to allergen exposure.

Of course we also know that some large clusters of cases have originated form hospital outbreaks and so environmental factors may play very little role at all. Or they might. Its impossible to say. But it is worth considering what could be happening up 2-weeks prior to a sharp rise in cases - if only to identify 1 index case that then ended up triggering a hospital outbreak.

1. Dust Storms in the Middle East: Sources of Origin and Their Temporal Characteristics. http://ibe.sagepub.com/content/12/6/419.short
2. http://www.magazine.noaa.gov/stories/mag86.htm
3. http://www.saudiaramcoworld.com/issue/200803/heads.high.htm

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MERS-CoV cases continue to climb

Click to enlarge. Global MERS-CoV cases by week and
the accumulation of cases.

The latest chart of Middle East coronavirus case spikes by week combined with the accumulating tally of cases.

This paints a picture of unrelenting case growth. The curve took a sharp turn upwards in April and hasn't slowed since. This is in marked contacts to influenza A(H7N9) virus cases which were brought to a screeching halt in south east China earlier in the year.

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