Comments on: Seasonality of influenza revisited

By: 2006 TN State Fair: Crested Guinea Pig | What are allergies

2006 TN State Fair: Crested Guinea Pig | What are allergies — Tue, 06 Dec 2011 10:22:45 +0000

[...] Or Here, on a blog about viruses http://www.virology.ws/2009/01/08/seasonality-of-influenza/ and then for a second time http://www.virology.ws/2009/02/19/seasonality-of-influenza-revis…; [...]

By: Guest

Guest — Thu, 07 Oct 2010 01:36:16 +0000

There are more than one identified each year.

By: profvrr

profvrr — Wed, 19 May 2010 02:59:10 +0000

A high mutation rate means the viral RNA changes, but that does not
always translate into a different protein. There are more evolutionary
constraints on protein than on RNA. Many changes occur in influenza
viral RNA, but few make it into viral protein. Among the viruses
circulating each year there are certainly many variants, especially at
the RNA level, but these do not all lead to antigenic changes.

By: fbedoya

fbedoya — Tue, 18 May 2010 23:25:13 +0000

How come if the influenza virus has a high mutagenic rate and a high infectious capacity, there is only one virus strain identified every year? Wouldn't there be more than one strains of influenza virus detected per year?
Thank you.

By: Influenza in the US, week 23

Influenza in the US, week 23 — Wed, 24 Jun 2009 18:40:39 +0000

[...] number of infections in the northern hemisphere in June. We’ve previously discussed how temperature and humidity are believed to be important factors in determining the seasonal patterns of influenza in temperate [...]

By: New swine influenza viruses in humans « SWINE INFLUENZA - H1N1 FLU - PIG FLU

Thu, 30 Apr 2009 20:11:17 +0000

[...] not been very severe. Another mitigating factor is that the influenza season is nearly over – viral transmission wanes when the weather becomes warmer and more [...]

By: Hot News » Influenza B

Hot News » Influenza B — Mon, 23 Mar 2009 12:43:24 +0000

[...] al. (2005-07-21). "Influenza A (H3N2) Outbreak, Nepal. Emerg Infect Dis. Usefull Posts Seasonality of influenza revisited…What is Influenza (Flu) and treatment for Influenza ? – Medical…ASKDOCTORANCA » Flu vaccine [...]

By: profvrr

profvrr — Mon, 02 Mar 2009 09:36:22 +0000

Good question. We actually didn't explain it very well on TWiV.

Humidity measurements are all about determining how much water is in
the air. The measurements are made with instruments designed for that
purpose.

Absolute humidity is the amount of water in a volume of air. It is
usually expressed as grams of water per liter of air. Another way to
look at it: the mass of water vapor divided by the mass of dry air in
a volume of air at a given temperature. The hotter the air is, the
more water it can contain.

Relative humidity is the ratio of the current absolute humidity to the
highest possible absolute humidity. The latter depends on the current
air temperature.

So they are just different ways of expressing how much water is in the
air. One is absolute, (mass of water per volume of air), the other is
relative - how much water is in the air compared to the maximum water
the air can hold.

By: profvrr

profvrr — Mon, 02 Mar 2009 09:18:14 +0000

How was your daughter tested for influenza? Does she have symptoms? It
is likely that it's too late for Tamiflu to be effective; it has to be
given early in infection. I can't advise you what to do, but remember
that influenza B is usually (but not always) milder than influenza A.

By: profvrr

profvrr — Mon, 02 Mar 2009 01:36:22 +0000

By: profvrr

profvrr — Mon, 02 Mar 2009 01:18:14 +0000

By: Scott

Scott — Sun, 01 Mar 2009 15:01:15 +0000

Also, my daughter just tested positive for Influenza B. Our doctor has offered us some Tamiflu to avoid getting the flu, but we are very concerned about the side effects and are likely going to trust our quarantine system versus the antiviral. What is your advice on this? Thanks.

By: Scott

Scott — Sun, 01 Mar 2009 14:33:23 +0000

Your articles are wonderful. If you don't mind, could you explain the relative humidity a bit further. I used to think I was intelligent, but I cannot seem to wrap my brain around your relative humidity explanation to Kelly!

By: Kelly

Kelly — Fri, 20 Feb 2009 13:04:06 +0000

Prof,
Thank you so much for the clarification!

By: profvrr

profvrr — Thu, 19 Feb 2009 12:42:17 +0000

Great question! We are talking about that on TWiV today (my virology
podcast, twiv.tv) but since it won't be out for a few days, here is
the answer: relative humidity is the ratio of the partial pressure of
water vapor in a gaseous mixture of air and water vapor to the
saturated vapor pressure of water at a given temperature. It is
expressed as a percentage; the weatherman (and woman) uses this term.
Absolute humidity - is the actual amount of water vapor in a liter of
gas. This is not used by the weatherperson.

By: Kelly

Kelly — Thu, 19 Feb 2009 11:51:59 +0000

I'm finding your blog quite facinating! Can you clarify for me, what is the difference between relative humidity and absolute humidity? Which is being referred to in weather reports?
Thanks!