Effect Measure

Some end-of-the day (but not end-of-the-world) bits and pieces in the emerging swine flu story.

From Helen Branswell (Canadian Press):

In Mexico, Secretary of Health Jose Angel Cordova Villalobos said in a television interview that there have been 45 deaths, but only 16 of those were directly related to the flu in question.

An estimated 943 people are ill, the television report said.

The majority of the cases are occurring in young, previously healthy adults in their mid 20s to mid 40s, reports suggest. Experts aren?t certain if all of those people are sick with this virus or if other flu or respiratory viruses are also circulating and muddling the picture.

Schools were closed Friday in Mexico City, one of three areas of the country where cases have been reported.

Hartl said the WHO is sending staff to Mexico to help authorities there get a better handle on the scope of the problem.

“We?re extremely concerned because we?re looking at five different influenza events which may or may not be connected,” he said, referring to California, Texas and three possibly linked outbreaks in Mexico.

“But they are unusual events, either because of the time of the year that they happened and or because of the people that have been affected. This is a great concern to us and we have activated our strategic health operation centre which is a 24-hour around-the-clock command and control centre.” (Helen Branswell via Calgary Sun)

The number of people who are actual cases of swine flu in Mexico is yet to be determined. It is almost certain that many of the reported 943 cases are not swine flu, and of the specimens sent to laboratories in Canada and the US, half or less were determined to be that virus. On the other hand, there are definitely many swine flu cases in Mexico, some of the severely ill, and the unusual age distribution of young adults is a sign of infection with a new flu virus. There is ample room for serious worry. WHO is convening its expert panel under the International Health Regulations to determine if the pandemic threat level should be increased from phase 3 to phase 4. In our view, this isn’t even a close call. We are in phase 4 and if WHO doesn’t call it they risk being considered irrelevant and without credibility.

CDC, through an MMWR Dispatch (just issued), provides some additional details about the six additional US cases:

San Diego County, California. On April 9, an adolescent girl aged 16 years and her father aged 54 years went to a San Diego County clinic with acute respiratory illness. The youth had onset of illness on April 5. Her symptoms included fever, cough, headache, and rhinorrhea. The father had onset of illness on April 6 with symptoms that included fever, cough, and rhinorrhea. Both had self-limited illnesses and have recovered. The father had received seasonal influenza vaccine in October 2008; the daughter was unvaccinated. Respiratory specimens were obtained from both, tested in the San Diego County Health Department Laboratory, and found to be positive for influenza A using reverse transcription–polymerase chain reaction (RT-PCR), but could not be further subtyped. Two household contacts of the patients have reported recent mild acute respiratory illnesses; specimens have been collected from these household members for testing. One additional case, in a child residing in San Diego County, was identified on April 24; epidemiologic details regarding this case are pending.

Imperial County, California. A woman aged 41 years with an autoimmune illness who resided in Imperial County developed fever, headache, sore throat, diarrhea, vomiting, and myalgias on April 12. She was hospitalized on April 15. She recovered and was discharged on April 22. A respiratory specimen obtained April 16 was found to be influenza A positive by RT-PCR at the San Diego Country Health Department Laboratory, but could not be further subtyped. The woman had not been vaccinated against seasonal influenza viruses during the 2008–09 season. Three household contacts of the woman reported no recent respiratory illness.

Guadalupe County, Texas. Two adolescent boys aged 16 years who resided in Guadalupe County near San Antonio were tested for influenza and found to be positive for influenza A on April 15. The youths had become ill with acute respiratory symptoms on April 10 and April 14, respectively, and both had gone to an outpatient clinic for evaluation on April 15. Identification and tracking of the youths’ contacts is under way.

Five of the new cases were identified through diagnostic specimens collected by the health-care facility in which the patients were examined, based on clinical suspicion of influenza; information regarding the sixth case is pending. The positive specimens were sent to public health laboratories for further evaluation as part of routine influenza surveillance in the three counties. (CDC, MMWR Dispatch)

These case reports emphasize once again the relatively mild nature of the US cases. The only one hospitalized was immunosuppressed with an autoimmune disease (said elsewhere to be an autoimmune hepatitis). Only one of the eight had received a flu vaccination this year (the 54 year old father of the father – daughter household cases). It’s not possible to say whether the lack of vaccination has any bearing on risk. There is not enough data.

We will keep following this. We are not the only ones, of course. There is an army of flu bloggers on the net. If you go to one of the best, Crof’s H5N1 blog, you will also find an extensive international blog roll. Many of you are also in a position to hear or see things, so pass on any information you think has been missed.

Comments

  1. #1 tendrel
    April 24, 2009

    I will be watching this one closely, as I live in San Diego, north county. Not cool at all. =(

  2. #2 Achak
    April 24, 2009

    Suspension of the plan of general vaccination for Mexico

    On the suspension of the plan of general vaccination, the secretary of Health of the city, said that now the alternative to take care of the patients will be the application of antiviral who have given excellent results to fight the epidemic. It informed that the Osetamivir medicine is the one that is applied to the patients with high degree of success, because in the first three days a recovery of the physical state is observed.

    http://www.eluniversal.com.mx/notas/593502.html

  3. #3 Joanna
    April 24, 2009

    I just saw a story about possible flu in NYC – 75 students ill in one school and that they are testing them now…any info on this?

    http://wcbstv.com/topstories/swine.flu.nyc.2.994071.html

  4. #4 Phila
    April 24, 2009

    This may be completely off the wall, but given the serious air quality problems in Mexico City, is it possible this accounts for (or contributes to) the higher mortality?

  5. #5 Cheetos
    April 24, 2009

    I haven’t posted here in a long time. Is it at all possible that a vaccine could be developed, produced and distributed for mass innoculation in time to divert a global catastrophe?

  6. #6 revere
    April 24, 2009

    Phila: They indeed have some serious photochemical oxidant pollution there. But the unusual thing about the reports is that it affects previously healthy young adults, which isn’t the picture of air pollution co-morbidity.

    Joanna: Saw the NYC rept., This sounds more like periodic psychogenic outbreaks of acute illness in this age group. Fairly common. But it is important to rule out flu, which is what the NYC officials are doing, so we’ll hear soon.

    CNN reported that Mexican authorities discovered the outbreak when the expected end of the flu season didn’t happen but kept into April. If true, this suggests that the situation isn’t so overwhelming as reports suggest. Again, we’ll have to wait further info.

  7. #7 D. C. Sessions
    April 24, 2009

    This may be completely off the wall, but given the serious air quality problems in Mexico City, is it possible this accounts for (or contributes to) the higher mortality?

    That would in part explain a higher case mortality rate in the very young and the very old. Unfortunately, that’s not what we’re seeing — we’re seeing an increased case mortality in young healthy adults.

  8. #8 revere
    April 24, 2009

    cheetos: A vaccine is 6 months away. But global catastrophe may not occur, even if this is a pandemic. It depends on the virulence of this virus and its transmissibility, neither of which we know at the moment. But we should know more soon. Lots of hands and heads working on this one.

  9. #9 Phila
    April 24, 2009

    But the unusual thing about the reports is that it affects previously healthy young adults, which isn’t the picture of air pollution co-morbidity.

    Understood, thanks.

  10. #10 Cheetos
    April 24, 2009

    I’m no scientist (obviously), but over the past few years I have followed news about Bird Flu…and I recall reading reports about flu death statistics in Southeast Asia and China where a preponderance of victims were ‘young and previously healthy’.
    Could this outbreak be ‘Bird Flu’ related?

  11. #11 Carl
    April 24, 2009

    Not to be dumb but has there been description of cause of death in the fatal cases (e.g., respiratory failure or whatever)?

  12. #12 tcoreyb
    April 25, 2009

    Cheetos: It’s probably not avian flu. The first analyses are showing that this virus seems to combine genes from bird, swine and human flu. However, the consensus so far seems to be that it is a form of A/H1N1, which is a type of swine flu.
    This doesn’t mean they know whether this particular strain originated in pigs, but it is the most probable scenario so far…
    it’s an emerging situation but I am sure the genome crunchers are working on it as fast as we can blog on it :)

    http://www.cidrap.umn.edu/cidrap/content/influenza/panflu/news/apr2409swine.html

  13. #13 pft
    April 25, 2009

    From Rebuilding Americas Defenses, a publication of the now defunct PNAC headed by Rumsfeld, Cheney & Co.

    “…advanced forms of biological warfare
    that can “target” specific genotypes may
    transform biological warfare from the realm
    of terror to a politically useful tool.”

    It seems this flu is affecting Mexicans more severely.
    SARS targeted primarily those of Asian descent. HIV has a preference for those of African descent. Not saying there is anything to this, but you can see where the health minister from Indonesia gets her paranoia.

    It is interesting to note that last time there was a significant outbreak of a new form of swine flu in the U.S. it originated at the army base at Fort Dix, New Jersey.

    I mean, a politically useful tool? Come on.

  14. #14 Pork Flu
    April 25, 2009

    Does this swine flu prefer warmer weather? It is 80 in Mexico City now and quite warm in TX and CA. So does this mean this summer would be the best environment for it to thrive?

  15. #15 Bob
    April 25, 2009

    I hear that on some places it is a mild illness and on others a severe one. An Candian returned from Mexico has been on a ventilator in Canada. So air pollution may not be a key point.
    May it be that there are already different strains ( clades ) of this flu with wildly different case fatality rates?
    Revere, you had very recently an excellent post, just about this kind of things.

  16. #16 anon
    April 25, 2009

    if most of the other cases are not swine-flu,
    then what else ?

    wouldn’t that be a strange coincidence ?

  17. #17 K
    April 25, 2009

    PFT, while the PNAC lusted after a targeted bio-warfare virus or bacteria, it is unlikely that any form of flu would be so used. The rate at which flu viruses recombine and share gene sequences would make it an insane choice for bio-warfare. They would need something much more stable.

  18. #18 Lisa Unander
    April 25, 2009

    The fact that we have not closed the boarder to Mexico and are letting people come and go freely by air, land, and sea, has left me in a state of undeniable disbelief! If one single Cow (bovine) was found to contain a “potential positive” for any virus (mad cow disease) there would have been an instantaneous lock down on any further importing of the animal in to the United States. And a full army of news reporters would have made sure that the public was protected and informed instantly. My thought is WHY is travel being allowed?? How is this not a State of Emergency?? How is Human Contamination less important than COW infection? I am in a state of awe!! Am I alone? Am I the only one who is frightened by the lack of concern for a major pandemic that could potentially wipe out our self, our families and our friends?

  19. #19 Rose
    April 26, 2009

    Because *cows* don’t have human rights to freely move…we have to deal with semi-serious rights infringements if the govt is going to start closing borders or quarantining people. Unless it’s deemed very, very serious & deadly, they don’t want to go there.

  20. #20 PB
    April 26, 2009

    Work by Andrew Noymer (now at UC Irvine) suggests that a significant share of those killed in the 1918 Spanish Flu pandemic were infected with TB. This flu has a similarly unusual age structure in its mortality. One possible reason for the high mortality in Mexico is higher TB prevalence. However, at this point there are really too few identified cases in the US to be sure the mortality level is lower here.

  21. #21 Rick
    September 23, 2009

    ThaNKS