When did the 1918 pandemic "officially" end?

[marcovth]

When were the last cases of the 1918 pandemic registered?

Do I understand it well that years after 1918 there were still cases?

 

[Snicklefritz]

Re: When did the 1918 pandemic "officially" end?

Interesting question. When does a pandemic end? The 1918 H1N1 continued to circulate world wide and cause excess deaths unitl it was replaced by H2N2 in 1957 (?) At that point H1N1 disappeared for the time being. H2N2 shifted and became H3N2 causing the 1968 pandemic. In the late 1970's H1N1 re-emerged (lab accident?) and has been co-circulating with H3N2 since then.

That's a rough sketch. But, I've never actually heard of an 'official' date the 1918 pandemic ended. I guess at some point a pandemic strain becomes endemic causing epidemics, but I don't know when that might be.

Hope that helps. If anyone has other information, please feel to correct my chronology or terminology.

 

[marcovth]

Re: When did the 1918 pandemic "officially" end?

Is it likely (but no prove?) it became a seasonal flu, and that's why elderly people seem to have partial immunity against the current H1N1 ?

 

[LMonty]

Re: When did the 1918 pandemic "officially" end?

its known it stuck around. my guess is that the population also developed enough immunity that it was no longer novel. I would also guess it attentuated virulence at some point. IIRC it was into the early 20s that serious cases were still found, but were scattered. Lost my copy of The Great Influenza, lent it out and never got it back, but IIRC thats where I got that info from.

 

[marcovth]

Re: When did the 1918 pandemic "officially" end?

Another thought, but difficult to explain ...

Aren't there many more people still alive in 2009, because of medical advances,
who would have died from "ordinary" diseases if they were living before 1918,
before 1957, or even before 1968?

In other words, aren't there many more people with weak immune systems alive
now than would have been during past pandemics? Could this mean that even
the current/coming "mild" pandemic can have a potential higher death rate
with people who would otherwise have died before from other diseases?

 

[AlaskaDenise]

Re: When did the 1918 pandemic "officially" end?

Interesting question. When does a pandemic end? The 1918 H1N1 continued to circulate world wide and cause excess deaths unitl it was replaced by H2N2 in 1957 (?) At that point H1N1 disappeared for the time being. H2N2 shifted and became H3N2 causing the 1968 pandemic. In the late 1970's H1N1 re-emerged (lab accident?) and has been co-circulating with H3N2 since then.

That's a rough sketch. But, I've never actually heard of an 'official' date the 1918 pandemic ended. I guess at some point a pandemic strain becomes endemic causing epidemics, but I don't know when that might be.

Hope that helps. If anyone has other information, please feel to correct my chronology or terminology.

I would ask when did 1918 loose the NS1/92 mutation? (it allows the virus to not be impacted by the humane innate immune system) That would account for a considerable virulence decline.

Regarding the 1970s re-emergence of H1N1 - Dr. Niman posted information showing that it never really disappeared, but rather was circulating in domestic swine and poultry, then re-emergeded when applicable.

Marcovth: Your comments about more low-immune functioning people is interesting. Following that thought, we'd need to consider other things that impact immune functioning - nutrition, toxins, influenza immunity acquired via illness/immunization, etc.

Here's a paper with comments about 1918 H1N1 re-emergence:

(snipped)

The most debated evolutionary question relating to this virus is how, and from where, A/H1N1 emerged in such a virulent form in 1918 to kill 20–50 million humans in the global influenza pandemic at the time of World War I, arguably the most severe single disease event in history [1],[2]. Perhaps as perplexing, however, is the evolutionary pattern of A/H1N1 influenza viruses following the 1918 pandemic, which is marked by a series of highly unusual occurrences, including the ‘pseudo-pandemic’ of 1947 [3] and several other severe epidemics in the 1920's through the 1950's, a twenty-year disappearance and sudden reappearance in 1977, and cycles of alternating dominance with the H3N2 influenza A virus subtype ever since.

Following the 1918 pandemic, the A/H1N1 influenza virus continued to circulate in humans, causing seasonal epidemics of varying severity [4] and also in swine, as ‘classical’ swine influenza [5]. In the post-pandemic period, epidemiologically severe outbreaks occurred in 1928–1929, 1932–1933, 1936–1937, and 1943–1944 in the United Kingdom [4] and the United States [6]. In 1947, the A/H1N1 virus underwent a major antigenic change that caused a total vaccine failure [7]. The virus was globally distributed much like a pandemic virus, but mortality was relatively low [8]. The virus was renamed ‘A-prime’ based on its antigenic divergence [9] from the previously characterized human A/H1N1 viruses of the early 1940's, although subsequent sequence analysis showed that these 1947 viruses were still of the A/H1N1 subtype, yet with numerous nucleotide and amino acid differences in antigenic regions of the hemagglutinin (HA) [10]. However, the evolutionary and epidemiological processes that precipitated such extensive divergence are currently unclear.

Another unusually severe A/H1N1 epidemic occurred in 1950–1951 [11], in which mortality levels in the United Kingdom and Canada exceeded those of both the 1957 and 1968 pandemics, again without a change in antigenic subtype [12]. In 1957, the A/H1N1 virus disappeared and was replaced by a novel H2N2 reassortant virus [13]. The A/H1N1 virus then resurfaced in 1977 after a twenty-year disappearance, causing an epidemic in children who lacked antibodies from prior exposure [14]–[17]. However, this emergent A/H1N1 did not replace the dominant H3N2 subtype [18], so that A/H1N1 and H3N2 have co-circulated to the present day.

 

[AlaskaDenise]

Re: When did the 1918 pandemic "officially" end?

Regarding the 1970s re-emergence of H1N1 - Dr. Niman posted information showing that it never really disappeared, but rather was circulating in domestic swine and poultry, then re-emergeded when applicable.

Read the travelog here. Note:

CY022349 A/swine/Kentucky/1/1976 HA (4) 1744 1976 H1N1
CY026419 A/swine/Tennessee/23/1976 HA (4) 1745 1976 H1N1
CY026139 A/Wisconsin/301/1976 HA (4) 1746 1976 H1N1

From here:

CY022069 A/swine/Iowa/1/1976 HA (4) 1744 1976 H1N1
CY026459 A/swine/Tennessee/10/1976 HA (4) 1740 1976 H1N1
CY022029 A/swine/Tennessee/3/1976 HA (4) 1744 1976 H1N1
CY022037 A/swine/Tennessee/7/1976 HA (4) 1744 1976 H1N1


.

 

[AlaskaDenise]

Re: When did the 1918 pandemic "officially" end?

Doing my own search for swine A/H1N1 HA between 1958 and 1976 I found 27 samples:

AAD25302 566 Swine HA H1N1 USA 1961 Influenza A virus (A/swine/Wisconsin/1/1961(H1N1))
ABQ45414 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Tennessee/3/1976(H1N1))
ABQ45425 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Tennessee/7/1976(H1N1))
ABQ45436 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Tennessee/15/1976(H1N1))
ABQ45447 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Tennessee/17/1976(H1N1))
ABQ45533 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Tennessee/19/1976(H1N1))
ABQ45458 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Iowa/1/1976(H1N1))
ABR15819 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Iowa/4/1976(H1N1))
ABR28603 566 Swine HA H1N1 USA 1975 Influenza A virus (A/swine/Illinois/1/1975(H1N1))
ABR28614 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Kentucky/1/1976(H1N1))
ABR28625 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Minnesota/27/1976(H1N1))
ABR28680 566 Swine HA H1N1 USA 1975 Influenza A virus (A/swine/Tennessee/1/1975(H1N1))
ABR28702 566 Swine HA H1N1 USA 1971 Influenza A virus (A/swine/Wisconsin/1/1971(H1N1))
ABR28724 566 Swine HA H1N1 USA 1970 Influenza A virus (A/swine/Wisconsin/2/1970(H1N1))
ABU80188 566 Swine HA H1N1 USA 1975 Influenza A virus (A/swine/Minnesota/24/1975(H1N1))
ABV82584 566 Swine HA H1N1 USA 1967 Influenza A virus (A/swine/Wisconsin/1/1967(H1N1))
ABV82595 566 Swine HA H1N1 USA 1966 Influenza A virus (A/swine/Wisconsin/2/1966(H1N1))
ABW36322 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Tennessee/23/1976(H1N1))
ABW36366 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Tennessee/10/1976(H1N1))
ABX58668 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Wisconsin/30747/1976(H1N1))
ACD85154 566 Swine HA H1N1 USA 1961 Influenza A virus (A/swine/Wisconsin/1/1961(H1N1))
ACK99410 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/Wisconsin/30954/1976(H1N1))
ABV25636 566 Swine HA H1N1 USA 1968 Influenza A virus (A/swine/Wisconsin/1/1968(H1N1))
ABV25637 566 Swine HA H1N1 USA 1973 Influenza A virus (A/swine/Iowa/1973(H1N1))
AAB39851 566 Swine HA H1N1 USA 1976 Influenza A virus (A/swine/New Jersey/11/1976(H1N1))
CAA40728 358 Swine HA H1N1 Hong Kong 1974 Influenza A virus (A/swine/Hong Kong/1/1974(H1N1))
CAA40730 357 Swine HA H1N1 USA 1963 Influenza A virus (A/swine/Illinois/1963(H1N1))

.

 

[AlaskaDenise]

Re: When did the 1918 pandemic "officially" end?

Here are samples of it "hiding" in poultry. Search was for A/H1N1 HA 1958 to 1976:

AAD25304 566 Avian HA H1N1 Canada 1976 Influenza A virus (A/mallard/Alberta/35/1976(H1N1))
BAA01280 566 Avian HA H1N1 Canada 1976 Influenza A virus (A/mallard/Alberta/35/1976(H1N1))
ABS18465 553 Avian HA H1N1 Hong Kong 1976 Influenza A virus (A/chicken/Hong Kong/14/1976(H1N1))
AAB50961 360 Avian HA H1N1 Hong Kong 1976 Influenza A virus (A/goose/Hong Kong/8/1976(H1N1))
AAB50962 385 Avian HA H1N1 Hong Kong 1976 Influenza A virus (A/chicken/Hong Kong/14/1976(H1N1))
AAB52910 327 Avian HA H1N1 Canada 1976 Influenza A virus (A/mallard/Alberta/35/1976(H1N1))

.

 

[AlaskaDenise]

Re: When did the 1918 pandemic "officially" end?

The re-emergence must have actually started in 1976, as I found some human cases:

ABQ44394 566 Human HA H1N1 USA 1976 Influenza A virus (A/New Jersey/1976(H1N1))
ABV45838 566 Human HA H1N1 USA 1976 Influenza A virus (A/Wisconsin/301/1976(H1N1))
ACQ99821 566 Human HA H1N1 USA 1976 Influenza A virus (A/New Jersey/8/1976(H1N1))

.

 

[Skatman]

Re: When did the 1918 pandemic "officially" end?

The re-emergence must have actually started in 1976, as I found some human cases:

ABQ44394 566 Human HA H1N1 USA 1976 Influenza A virus (A/New Jersey/1976(H1N1))
ABV45838 566 Human HA H1N1 USA 1976 Influenza A virus (A/Wisconsin/301/1976(H1N1))
ACQ99821 566 Human HA H1N1 USA 1976 Influenza A virus (A/New Jersey/8/1976(H1N1))

.

1976 was the outbreak at Fort Dix, New Jersey that lead to the rushed vaccination in the U.S. as it was feared a repeat of 1918 but the virus failed to spread.

 

[AlaskaDenise]

Re: When did the 1918 pandemic "officially" end?

I thought the Ft. Dix outbreak was confined to Ft. Dix. So where did the Wisconsin case fit in? I guess it's back to the reports, however, my foggy memory tells me that the Ft. Dix problem started from a pig farmer (from Wisconsin???)

yep, looking at the swine list above, there are two 1976 cases from Wisconsin. AND there's a 1976 swine case in New Jersey.....looks like the little piggy from Wisconsin went to town in New jersey.

There are a total of 13 samples from 1976, spanning 7 states.

.

 

[AlaskaDenise]

Re: When did the 1918 pandemic "officially" end?

http://www.pandemicflu.gov/general/historicaloverview.html

1976: Swine Flu Threat
When a novel virus was first identified at Fort Dix, it was labeled the "killer flu." Experts were extremely concerned because the virus was thought to be related to the Spanish flu virus of 1918. The concern that a major pandemic could sweep across the world led to a mass vaccination campaign in the United States. In fact, the virus--later named "swine flu"--never moved outside the Fort Dix area. Research on the virus later showed that if it had spread, it would probably have been much less deadly than the Spanish flu.

Interesting that they don't consider the Wisconsin case.

.

 

[Amish Country]

Re: When did the 1918 pandemic "officially" end?

Since the current swine flu is H1N1 is it possible that it never actually ended just continued to mutate and adapt to the present day and form?

In my family an infant died, an uncle of mine. He had problems with his lungs, pneumonia, tb? Whatever happened to him my grandmother was adamant that it was not influenza. I believe there was a powerful stigma to any influenza death during and in the years immediately following the 1918 pandemic. As a child elders would routinely and strongly correct children regarding covering there noses during a sneeze, discouraging spitting in public and blessing them when they did sneeze. These behaviors may have become strongly ingrained in that generation as a result of the 1918 pandemic. While there seemed to be an unwritten taboo against discussing the pandemic, my Grandmother was not very forth coming on the topic, these habits may be an attempt to instill preventative measures in the next generations. I wonder if this social stigma inhibited further testing for the disease in later years? Many insurance companies suffered significant losses due to flu deaths. If flu deaths became an exclusion to the recite of benefits from a policy would there be a possibility some doctors issuing death certificates might be more inclined to list causes other than flu? In tight knit communities a doctor known to be issuing death certificates that would keep families from collecting on insurance policies may have found himself with less income as the reslut of lossing return and potential new patients?

 

[Laidback Al]

Re: When did the 1918 pandemic "officially" end?

Given the discussions in this thread, would anyone care to speculate on why Wisconsin has the highest number of confirmed cases of A(H1N1) in the United States?

 

[AlaskaDenise]

Re: When did the 1918 pandemic "officially" end?

I cannot find current production stats, but for 1996 Wisconsin was #15 in swine production. Iowa was #1, NC was #2. See: http://cal.vet.upenn.edu/projects/swine/prod/states.html

.

 

[AlaskaDenise]

Re: When did the 1918 pandemic "officially" end?

I found the 2007 stats:

Wisconsin only has 410,000 head of swine, while Iowa has 18,200,000 and NC has 9,700,000 head.

So why does Wisconsin have highest 2009 A/H1N1 confirmed cases?

.

 

[Amish Country]

Re: When did the 1918 pandemic "officially" end?

I found the 2007 stats:

Wisconsin only has 410,000 head of swine, while Iowa has 18,200,000 and NC has 9,700,000 head.

So why does Wisconsin have highest 2009 A/H1N1 confirmed cases?

.

The numbers may reflect state animal care laws and the degree of regulatory enforcement of those laws. In those states where high pork production represent a significant source of the state's gross income there may be political pressure not to fund the regulatory staff to enforce the reporting laws and regulations. Corporate farms have historically made significant lobbying efforts to gain regulations and funding that would favor their industries over smaller sustainable and or organic farming practices. Anecdotal reports seem to indicate that regulatory agencies seem more intent on enforcing regulations on smaller sustainable and or organic farming operations that lack the funding, lawyers and political lobbyists to fight back as the larger better organized corporate interests.

Mother Earth News
Oct. 1, 2008 Megan Phelps Interview with Joel Salatin
"Everything He Wants to Do is Illegal"
What should you know about food, farming and the meat you eat? Farmer and writer Joel Salatin sounds off on government regulations, pasture-based farming and more.

http://www.motherearthnews.com/Sustainable-Farming/Joel-Salatin-Interview.aspx

 

[marcovth]

Re: When did the 1918 pandemic "officially" end?

So why does Wisconsin have highest 2009 A/H1N1 confirmed cases?

I can not give an answer about Wisconsin, but if you compare the U.S. vs Canada ... Canada has a public health-"care" system.

(The care is ok ... if you want to wait for 18 hours in emergency)

You don't have to pay for tests here, where in the States, I assume, most people (if they don't have insurance) will be asked to pay for it ???

I can imagine, if that's the case, per number of patients, more tests are done in Canada than in the U.S.? Perhaps if the State of Wisconsin pays for the tests, while other states don't, this could result in more confirmed cases there ???

 

[Mamabird]

Re: When did the 1918 pandemic "officially" end?

I would ask when did 1918 loose the NS1/92 mutation? (it allows the virus to not be impacted by the humane innate immune system) That would account for a considerable virulence decline.

(snipped)

The H1N1 1918 virus never had the D92E mutation in NS1. Only a few early H5N1 viruses have had this unique marker, and fortunately, it has not reappeared as far as I can tell.