Monday 26 December 2016

Snapdate: influenza H7N9 cases in humans, by the numbers...

An updated chart.
[SNAPDATE'S are snap updates that don't have lots of detail and chat...although they almost always end up having lots of chat!]

A summary of the monthly, weekly and daily data graphing human avian influenza A(H7N9) virus infections in humans reported from the hotzone, China.

Daily weekly and monthly H7N9 numbers, taken from the
FluTrackers curated line list [1] and the World Health
Organization disease outbreak news reports
Click on image to enlarge.


Friday 23 December 2016

H7N9:2016 has been the most quiet year to date...

Influenza A(H7N9) virus, or 'H7N9', has had a quiet year when compared to past outbreaks.

All human cases to date have been linked to China. The majority of human cases have had some link with poultry - chickens or ducks - although we do hear of human-to-human transmission, this seems to be limited. H7N9 has been found in poultry from backyard farms and in live poultry markets (LPMs) in China - sometimes in the company of other influenza viruses, like H9N2.[1]

Cases and deaths each month over the 4 years we have known
about human cases of H7N9 infection.
Click on image to enlarge.

Despite the slow year,the 2016 graph above shows the usual December uptick in human cases. It will be what happens next that matters. Will be see a big January surge as in 2014, or a later Feb-April surge as in 2013 and 2015? Will live LPMs be quickly closed, disinfected, the animals destroyed and any outbreaks in 2017 squashed or will they remain open allowing more human cases as the virus spreads among market animals?

Time, and testing data - which China generates lots of but does not seem to enjoy publicly reporting - will tell.

In 2016 - 2 new regions were added for the first time - Tianjin municipality and Liaoning province - both in the north-eastern coastal region of China. 

In 2013, no sustained human-to-human transmission had been reported [2] - this remains true up until today.



Sunday 18 December 2016

Happy Festive Season to all who read this....

This post has been moved to the new Virology Down Under platform on Wordpress.

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Apologies for any inconvenience.

Sunday 4 December 2016

Zika virus-positive microcephaly in Colombia...

The latest epidemiological report (epidemiological week 47) from Colombia, which includes data on Zika virus (ZIKV) disease (ZVD; 20NOV2016-26NOV2016), has been produced by the Colombian National Institute for Health team.[1]
NOTE: While these data were reported the past epidemiological week (EW), they may not be from that week. See earlier post about possible reporting lag.

As of this report, 60 (+0 from last EW) live births have been diagnosed with congenital ZIKV syndrome (CZVS; microcephaly/central nervous system disorder), confirmed as being ZIKV positive. That represents 1.0% of all confirmed ZIKV positive mothers-a slowly but steadily rising proportion.

The change in confirmed ZIKV infection numbers when detected in
association with a microcephaly diagnosis, Colombia, compared to the
preceding week's total (yellow bars, right-hand axis). Those diagnoses still in question and under investigation are shown as yellow dots (left-hand axis).
Data are from [1]. 
Click on graph to enlarge.
It has now been 415 days, or 1 year, 1 month and 18 days, since ZIKV was first confirmed in Colombia on 16th October 2015.[5] Keep in mind that when talking about microcephaly - we have to think back in time to what insult or infection might have occurred during pregnancy. The counts of ZIKV occurring this week will have zero impact on what happened back then. Also keep in mind that Colombia may be reporting things differently from Brazil.[3]

The cumulative curve of confirmed ZVD cases
(green circles, left-hand axis) and the change in confirmed ZVD case
numbers when compared to the preceding week's total
(green bars, right-hand axis). Data from [1].
Click on graph to enlarge.

No new laboratory confirmed ZIKV detections have been reported in Colombia for eh 20th week (green graph, above).

Brazil first reported positive (but unconfirmed) laboratory tests for ZIKV disease on 29th April 2015. Brazil then started to report a rise in foetal anomalies (an initial 141), in the form of microcephaly on 30th October 2015. This was 184 days - or about 6 months later.[4] However, the genetic analyses suggest ZIKV was in Brazil from around 2013. It had a lot longer to get established. Perhaps this is the difference between Brazil and Colombia, given reports a growing 2,180 ZIKV congenital syndrome diagnoses [2] compared to Colombia's 60.