A Couple Of Curious Flu Reports From India

Flu Virus binding to Receptor Cells – Credit CDC

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It has happened so often over the past decade as to have become a bit of a cliche (see here, here, and here), but there are rumbles coming once again out of India of unusual symptoms reported with seasonal flu, and suggestions that the H1N1 (or some other) virus has `mutated' into a more virulent form.

Despite having been designated a seasonal flu 8 years ago, H1N1 is still treated as if it were a pandemic strain by many in the Indian press - often still referring to as `swine flu' - and confirmed cases (and deaths) are treated like breaking news.

Even local health department officials seem to classify H1N1 as something other than seasonal flu, with the following quote appearing yesterday in a Times of India report:

"Since the symptoms of the H1N1 virus are similar to that of influenza and common cold, unless its severe, the disease can easily go unreported," said a senior health department official.

A couple of sample headlines from the past 24 hours include:

Five more H1N1 deaths in TN over two days

Two succumb to swine flu at govt hospital in Coimbatore

With a population of over 1 billion people, India could easily expect in excess of 100,000 flu deaths - even during a mild year - making anecdotal reports of flu cases like these nearly impossible to assess.

Overnight, however, reports have been published (see Mumbai: Doctors suspect new H1N1 variants) citing `unusual' symptoms - particularly among pregnant women - of hypertension, vomiting and diarrhea associated with a `flu-like' illness.

The article goes on to state:

While 15 samples sent from Mumbai to the National Institute of Virology (NIV) tested negative for H3N2 viral infection, doctors suspect the variant may be present in patches across Mumbai.

No other lab results are mentioned, and the article presents no evidence (beyond citing unusual symptomology) to support their theory.

Another article, published overnight in the Times of India (Influenza 2.0), takes a different tack, and instead suggests it is H3N2 - not an H1N1 variant - causing these unusual symptoms, while acknowledging that none of the samples sent to NIV have come back positive for the H3N2 virus.

While H3N2 tends to produce more serious illness than H1N1 - particularly in the elderly -  the symptoms of infection are quite similar.  Trying to deduce the subtype of an influenza infection by clinical presentation seems a bit of a reach.

The reported lack of lab confirmation of H3N2 (and apparently, H1N1) for these patients could indicate another non-influenza (Adenovirus, Enterovirus, Parainfluenza virus,  etc.) is at work, or even a co-infection (see Double-Whammied By Influenza).

Less likely, but still possible, would be a novel virus. Hopefully, someone is forwarding samples to a WHO reference lab.

Meanwhile, the Deccan Herald is reporting:

Thiruvananthapuram: The District Medical Office (DMO) has put all hospitals including private hospitals on high alert following a spike in H1N1 cases in the state capital. The death of a 16-year-old at Chammaruthy this week has set alarm bells ringing for health authorities across the district. On Tuesday, two more suspected H1N1 cases were reported in the district. Around 20 H1N1 cases have been reported in the state so far this month.

While it would be easy to dismiss these reports as hyperbolic reporting, influenza viruses do have an unfortunate history of mutating over time, and that includes the 2009 H1N1 virus (see Nature Sci Rpts: Continued Evolution Of The 2009 H1N1 Virus).

In 2015, we saw some evidence of mutations in the 2009 H1N1 virus in India (see MIT: Genetic Changes In A 2014 Indian H1N1pdm09 Virus), which was followed in 2016 by Eurosurveillance: Emergence of A(H1N1)pdm09 Genogroup 6B In India, 2015.

All of which means, that while what is being reported in India is likely nothing  more than seasonal flu, we need to take note of these reports, and keep one eye on them.