Swine Flu - Mexico Travelers vs. Person-to-Person Spread...

[JeffreyWilliamson]

I've been following updates in cases on Veratect's Twitter feed for a couple of days now, and one thing that's puzzling me is that it seems more often than not that cases of swine flu seem to be primarily turning up in people who have recently traveled to Mexico. That's not surprising of course, but if this is leading to something much larger, shouldn't we be seeing a growing number of person-to-person cases, where the infected have no links to Mexican travel at all, or can this be explained by a lag in the time between infection and the first sign of symptoms?

[TechBear_Seattle]

1. Most viruses go through a latent phase of one to three weeks

Basically, it takes time for a virus to replicate into sufficient numbers to provoke the immune system, and that is when the symptoms begin. Typically, there is a one to two week lag between exposure and the onset of symptoms, but that can sometimes take longer. Except towards the end of this latent phase, a person is generally not contageous, as there are not enough viruses to pose a significant risk.

[Name removed]

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[luvspeas]

5. Most panic go through a latent phase of one to three weeks

Basically, it takes time for a panic to replicate into sufficient numbers to provoke the panic system, and that is when the panic begin. Typically, there is a one to two week lag between exposure and the onset of panic, but that can sometimes take longer. Except towards the end of this panic phase, a person is generally not panicing, as there are not enough panic to pose a significant panic.

[SidDithers]

11. Whereas, teh stupid apparently sets in immediately...nt

Sid

[Sigh Sister]

7. I didn't know that it was that long

I thought it was 24-48 hours!

[TechBear_Seattle]

10. It depends on the virus and how much you are exposed to

Mono, hepatitis, measles, chicken pox, HIV, all have latency periods averaging around 10 days. Influenza can be much quicker if your exposure is by breathing in a cloud of virus particles, because you suddenly have millions of viri in your system, all working to reproduce. If your exposure is from touching a door knob or a pen at the bank and then touching your face, yeah, it will take a week or two for the virus to grow to sufficient numbers.

[kestrel91316]

29. It is. Flu and colds spread very quickly. There is NO long latency.

[Avalux]

14. Not correct. 24-48 hours with this.

From exposure to onset of symptoms; contagious phase estimated to be 8 days.

[JeffreyWilliamson]

17. If this is the case...

Then why aren't we seeing more person-to-person cases now as opposed to cases involving links to Mexico?

Here's what I guess I'm really wondering:

The WHO has confirmed that the flu is spreading person-to-person. The scenario appears to be that an individual travels to Mexico, is exposed to the flu, returns home, and spreads it to a very few people over the following days/weeks, and a few people come down with mild flu symptoms.

But in Mexico, it's raging and people are panicked and dying.

So what gives? Is there another, yet uncovered mode of transmission, or a slightly different strain floating around down there? We've all read about the pig farms and waste problems and flies. Could something like flies be helping it spread more quickly in Mexico?

[nadinbrzezinski]

21. Yesterday Besser corrected it up to a week

as is this is so fluid they are just getting info, and it moves

[kestrel91316]

30. I think basic health education and sanitation are less than adequate in Mexico.

I wouldn't discount flies spreading the virus around a bit. And water for handwashing is less available.

[TechBear_Seattle]

19. I sit corrected. Sorry for the incorrect information. n/t

[kestrel91316]

28. Influenza doesn't have a long latency at all. Medical authorities in

this outbreak have stated that, if you aren't starting to get sick within 2-3 days of exposure, you are home free. We all have personal experience with how fast flu and colds will spread through a school or office or home.

At the other end of the spectrum would be rabies, which can lurk undetected for 6 months before it causes illness (and inevitable death).

[TechBear_Seattle]

36. As I said, most viruses

I wasn't aware that influenza could activate so quickly.

[kestrel91316]

37. That's why it spreads so fast. The contagious period runs about 8 days,

from when you first feel that little tickle in the throat or something "off", through the next 7-8 days. In fact, that contagiousness before you're sure you are actually sick is a trick that works very well for the little devil.

[nadinbrzezinski]

2. We are, see New York CIry

where it seems to be firmly establishing itself

The first kids where from St Francis, but if we are to believe Bllomberg, now it has spread to hundreds of kids

That is what worries health authorities

[nadinbrzezinski]

3. We are, see New York CIry

where it seems to be firmly establishing itself

The first kids where from St Francis, but if we are to believe Bllomberg, now it has spread to hundreds of kids

That is what worries health authorities

[Sigh Sister]

6. Over the next week or two, we'll have a better picture

There is a lag time and I suspect that some people who get sick may not seek treatment if it's mild so we'll never know about them. Then there's the potential second wave that won't come until the fall.

[JeffreyWilliamson]

12. I guess that's kind of what I'm wondering, though...

There are reports of illness breaking out in areas of Mexico as far back as February. I've also read that the incubation period is around 48 hours up to 9 or so days. If a traveler went to Mexico a few weeks ago, say during Spring Break, was exposed, and then returned to home only to find themselves sick a week later, then why aren't we seeing a larger spread at this point, several weeks after that? I suppose one answer would be that the cases here are much milder, and so fewer people are reporting them.

But that just makes me wonder why the cases are so much milder everywhere outside of Mexico. Upthread the New York prep school students are mentioned. I've read that a few students at that school traveled to Mexico, came back, got sick, and now more students are sick. But these students would be confined in close proximity to one another day after day, and there are still only a couple dozen confirmed cases among them.

Could it be that this is spreading between people, but not very efficiently? And if this is so, why is it spreading so efficiently in Mexico--is there another factor, or am I just imagining this? The CDC says it isn't airborn, but can be spread by droplets, (sneezing, coughing). Is there something else at play here aiding in the spread and severity there, or is it merely that it has been active in Mexico longer, and had more time to manifest itself?

[Sigh Sister]

18. I think it's been there longer

so more cases. But I have a suspicion that it's more widespread here. There have been several people at work who have been sick with symptoms consistent with this flu. They were out of work for up to a week, but didn't go to the doctor. This started about a month ago. As for the severity there vs. here, I don't know. Listening to CDC and WHO, they expect more severe cases here as it spreads.

[nadinbrzezinski]

22. And in Mexico they saw the same pattern

I read papers while visiting as they were puzzled that there was an uptick of influenza infection at a time when it should be crashing

I told my BIL that is odd.

One thing I do in Mexico City I never do here, is read the paper. It is a shadow of what it used to be, but far better than my local fish wrap

[JeffreyWilliamson]

27. So then the factor in travel vs. personal is time...

Meaning that what we are seeing out of Mexico is really just the beginning. We are seeing in the US what they were seeing in Mexico a month ago. That's what I would expect, but it seemed odd to only be reading that the majority of cases were still from people who had traveled there recently. But we can chalk that up to this still being so early in the game.

So why is it so much more deadly there? The cases here sound so much milder in comparison?

[nadinbrzezinski]

31. Yes, I fear we are at the beginning

as to why it SEEMS to be more deadly down there... will know once the picture is far clearer

For the moment they went from 20 confirmed cases to 7

Second test at CDC... and that COULD BE very good news

Not to the people who died, but to the lethality level

It would mean that it is less lethal and that people are dying from other stuff too

Now best course is to wash hands, wash them some more, stay home if sick... et al

And be aware what is going on in your community and if things get really bad, we may see measures like we saw in mexico city

They essentially closed the city down and had voluntary home bound quarantines.

Their rate of infection seems to be stabilizing, SEEMS, is the trend, and if that is the case, props, because that was the actions they took, including closing churches and temples for health reasons

[FarCenter]

34. I think that it has been here too

On 4/10 may grandson was at a children's museum. 4/17 he came down with severe nausea, diahhrea, etc. He was very sick for several days with fever up to 102+. It could have been Norovirus or similar gastrointestinal flu, but the museum would have been a place where tourists from Mexico would take their kids. It has lots of "inteactive" exhibits, covered with kid snot and slobber.

[nadinbrzezinski]

20. I'll take a stab

first there are factors that we really do not know about why it is more deadly in mexico... something an egg head or two with a PhD behind name will try to figure out.

Second, the virus may not be fully adapted, and when it comes back, like even Doc. Bessser mentioned today, i a second wave it will be that far more virulent and deadly (you can bet this year's vaccine will have it)

Now as to the kids in NYC... we are not just talking St Francis now, but hundreds of kids in the Queens area in other neighboring schools were nobody has a history of recent travel to Mexico. That means they got it from those kids, that is your point of origin for NYC

Also some patients in other countries that are now coming down with this, are coming down with this after travel to the US..

[Sigh Sister]

23. A second wave

A second wave being more deadly is only one of the possibilities, right? Couldn't it mutate to a less virulent and deadly virus?

[nadinbrzezinski]

25. Yes, and here's to it mutates to a far less deadly strain

the virus will do what the virus will do

The best to do is keep eye on news, wash hands, and go on with your life

And of course stay away from the sick et al

[FarCenter]

8. Here is an example of transmission person-to-person on an airplane

The excerpt below is from The New Zealand Herald. New Zealand's progress will be interesting to watch because it is a small and well developed country. Most of their cases are a group of students, but one appears to have just been on the same LA to Auckland flight.

Ignore the "death toll still at seven" bit in the headline. That is just the official WHO number.

---

"Swine flu: Tamiflu more accessible, death toll still at seven"

http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10569397

"We've got 14 confirmed in Auckland and five suspected," she said. "The numbers are going to change – it's an evolving situation."

Dr Peters said the latest case was a person who had been travelling in North America.

The fourteenth person was on the same Air New Zealand flight from Los Angeles as the Rangitoto group.

[FedUpWithIt All]

9. There have already been suspected second generation US cases.

WHO "confirmation" takes a couple of days. Combining the incubation period with the testing period should bring us more confirmed second generation infections by Friday or so possibly.

This thing did not start last week but the agencies are trying to play a serious game of catch up with the testing of all the cases. Takes time.

[FourScore]

16. Meanwhile, it's spreading rapidly.

I find WHO's response to be overly cautious.

[Mojorabbit]

26. They have a history of being overly cautious.

There are political ramifications too. I think it they raise the phase to the next level from what I am reading we stop making a vaccine for next years flu and start making one for this. If it ends up being mild we won't have a vaccine for seasonal flu next year. I think a lot of countries also have plans they have to roll into place for each level. With the economic situation as it is it could be a mess. I think they will be even more cautious than normal.

[nadinbrzezinski]

32. Also they raise it to five

some countries, counties et al will knee jerk react

Oh wait, Egypt already did.

But we will see borders closed... as useless as that is... but hey don't ever let policy get in the way of politics

[Avalux]

13. We are. There is a lag in reporting cases.

And, if the infections are somewhat mild, people may not be seeking medical care. We are now a week into this; a lot more will be known a week from now.

[JeffreyWilliamson]

15. Well, we're a week into serious investigations of this...

It's been out and about down there for a couple of months. I understand that there will be a lag in reporting cases, but what I'm wondering is, why are all the current cases mostly still revolving around people who have traveled to Mexico recently?

There would have been people traveling to Mexico last month as well. Some of them have been home for a while now, and I haven't heard of very many reports of family members or co-workers turning up with cases. Shouldn't we be at least seeing an equal number of travel vs. personal links by now? And moving forward, shouldn't at some point shouldn't we be seeing the number of person-to-person cases begin to increasingly outnumber cases involving a link to Mexico?

[nadinbrzezinski]

24. I think they are, why the WHO is consider raising to 5

[bluedawg12]

33. The CDC reported 11 lab confirmed cases Sat. today it's 91.

If anyone has specifics about transmission data here is a great place to post it, this thread has some good info. and it's a good idea to try and keep it in one thread.

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=389&topic_id=5545680&mesg_id=5545680

Also, at the link above an update on the WHO meeting later today.

[FourScore]

35. This will give you a clearer picture of what's going on

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=389&topic_id=5557659&mesg_id=5557659