A few more things worth knowing about influenza | House Calls
June 1, 2009 · 10:45 AM
By DR. MARK FISHAUT
In January 1976, a virus called influenza A H1N1 caused illness at Fort Dix, N.J. This was the influenza that caused the 1917-20 pandemic.
That July, a large number of attendees at the American Legion convention in Philadelphia developed a respiratory illness and many died. It was later identified as Legionnaire’s disease. At that time, the two became linked and the specter of worldwide illness was raised. The mixture of knee-jerk reactions and mixed and inaccurate information resulted in the so-called swine flu fiasco.
In the outbreak of the current novel influenza, the management and dissemination of information both locally and nationally has been much better than it was 33 years ago. But the technical jargon and terminology has made it difficult for many to understand the vast amount of information that has been publicized.
It is inevitable that those “on the inside” of any subject develop their own language about what they do. This becomes so second nature that they forget that others are not familiar with what we are saying. For example, in soccer, we talk about “playing a square ball” — huh?
So, let’s decipher a few terms:
Influenza: Obviously comes from “influence,” but from where? Of what? The word first appeared in the mid-14th century meaning the influence of the stars producing cough and fever. It was specifically applied to an epidemic of what seems to have been typical influenza in the Kingdom of Naples in 1742-3. Recurrences of widespread illness have been identified ever since.
The description of the waves of illness have often been associated with where it was thought to have originated (the Russian flu of the 1880s) or who was irrationally blamed for its spread (the Spanish flu pandemic of 1918-20). The term is also the virus itself.
Virus: It is non-living entity composed of genetic material (either DNA or RNA), proteins, and sometimes membranes borrowed from the host cell. A virus cannot reproduce without help: it must use the structure of living cells to make more of itself.
Influenza is a family of viruses, some of which affect only humans, but others can also infect domestic animals including horses, fowl, and swine. There is even one that causes illness only in salmon!
The most important is influenza A whose subtypes and variants have been the major cause of widespread human illness. How it infects and spreads within the human host is the key to the naming of the strains and to understanding resistance to the virus.
There are two proteins on the surface of the virus: One attaches the virus to cells. It is called the hemagglutinin because in a test tube, it makes red blood (heme) cells agglutinate or clump. This is the H.
The other is an enzyme called neuraminidase, which changes a target cell’s surface and allows the virus to spreads across its surface. This is the N.
These surface proteins are named in the order which they appeared. The 1918 flu was the first one studied and hence the first named: H1N1. This remained the only circulating virus for the next 40 years. Lots of people developed immunity and illness diminished.
By 1957, the influenza A developed mutations of both the H and the N: the world encountered a new major strain called H2N2, or Asian flu. No one was immune to this virus, and worldwide illness associated with many deaths (call a pandemic) occurred.
The next change happened in a shorter time. The hemagglutinin underwent major change but the neuraminidase did not: the H3N2 Hong Kong flu of 1968 spread globally.
Now we have a “new” and truly unique H1N1. Why it’s back is not yet understood. The world has changed, the virus has changed, and the response has changed. So much more is known. There is so much more to say and ask.
Jargon is a barrier to understanding, and barriers produce confusion and fear. The more that we understand in language that we can comprehend; the more we can all listen to and cooperate with those whose mission is to protect us and our communities.
— Dr. Mark Fishaut is a physician at San Juan Healthcare and a periodic columnist for The Journal. E-mail him at firstname.lastname@example.org