Effect Measure

TB joins the Mile High Club

It was only last week we posted about XDR-TB. Yesterday CDC warned passengers on two international flights — Air France 385, Atlanta to Paris on May 12 and Czech Air 104, Prague to Canada on May 24 — they may have been infected by another passenger who had Extensively Drug Resistant TB (XDR-TB). Reportedly authorities could not reveal which row the male passenger sat in as this would violate medical confidentiality laws (HIPAA). So anyone on the plane could think themselves at risk, although it was probably only those in the same row and several rows front and aft of the passenger who were really at risk. And the cabin crew, of course.

It’s natural to think of an airplane as the ideal place to contract an infectious disease. After all, you are strapped in a seat in a narrow cylinder for hours at a time, next to people from diverse geographic origins, breathing recirculated air. If this isn’t the perfect recipe for spreading an infectious disease, it is hard to think of what might be better. But in fact there is precious little evidence that airplane rides are a lottery ticket for a respiratory infection, as noted in a 2005 Commentary that accompanied Mangili and Gendreau’s review of the subject (Commentary: Lancet. 2005 Mar 12-18;365(9463):917-9).

It turns out that while an airplane provides the smallest volume of air per person of any public space, the movement of air is transverse, i.e., from side to side, not along the length of the airplane. The air descends from the top of the cabin to the middle, sweeping in two circles on either side. Thus the people in the middle section of a wide body jet get the freshest air, with passengers seated to either side getting the air sweeping past the more medial seat mates. The poor soul on the window gets the air from everyone else in the row on their side of the plane (see figure 1 in Mangili and Gendreau). So the seat of the index case is probably critical, although this pattern is “on average.” There is enough turbulence in cabin air to allow currents to go several rows front and aft. While it is true about 50% of the cabin air is recirculated, in all but the smallest regional jets it is passed through HEPA filters first. This was certainly true for the transatlantic planes in the current case.

There are a number of reports in the literature of infectious diseases contracted via airplane travel, including measles, influenza, TB and SARS. But not many. In general secondary cases were within a few rows of the index case, but in one notable instance, Air China flight 112 in 2003, SARS cases occurred in passengers seven rows in front and five rows behind the index case.

The paucity of cases in the literature might mean passenger to passenger transmission happens rarely, or it might merely be a reflection of the difficulty of detecting a disease cluster when all the contacts disperse widely upon reaching their destination. Since TB is largely a large droplet transmission, the belief that transmission is limited to those two rows in front and behind is probably justified.

Probably. But meanwhile the passengers have to be found, evaluated for infection and their contacts, likewise. Welcome to My World. Or should I say, Welcome to Our World. Because we are surely in it together.

Update: Later posts here.

Comments

  1. #1 SaddleTramp
    May 30, 2007

    Dear Revere(s):

    Am I being paranoid about this? Flights on May 12 and May 24. And the story broke yesterday, May 29. Did it really take the CDC this long to get the facts together? Or were they just not in such a big hurry because of the “minimal risk” involved?

    Just wondering – If the bug had been influenza, how many people would have died by the time the CDC got around to notifying the public? With testing protocols, etc., how soon do you think the MSM would have the story if the first case of panflu had broken out in the US?

    Thanks.

  2. #2 crfullmoon
    May 30, 2007

    So, Mr.”ButI’mSuccessful-IHavePrivileges”, who defies medical advice
    (only “advice” no one locked him up – and, no one flagged his passport) went to Europe anyway, CDC phones him in Rome and says, turn yourself in; don’t fly -CDC doesn’t have Rome pick him up- he flies anyway, then sneaks in, over the border from Canada
    (aren’t there any instant international warnings for infectious travellers yet this long after SARS and H5N1?)
    faces “no criminal charges” as Gerberding keeps saying –
    while Mr.Unsuccessful (who is name is in the press- despite “the stigma” the Mr.Honeymoon guy Gerberding flew home -on the expensive CDC jet? instead of keeping in the NY hospital he was already at is being shielded from)
    Mr.Unsuccessful has been sitting in solitary in jail the past ten months, cut off from his wife and child, with no release in sight?
    http://www.democracynow.org/article.pl?sid=07/04/06/142246
    http://www.azcentral.com/arizonarepublic/local/articles/0410B1-update.html
    Both men have XDR-TB and went out without a mask when they weren’t supposed to; why such unequal treatment?

  3. #3 crfullmoon
    May 30, 2007

    Oh and SaddleTramp; get this – another article said,
    this fly-guy was given 4 antibiotics in late March.
    Who all did he expose all of April
    and, before his really stupid and thoughtless (I’d say criminal) adventure? When would she have become contagious, if she’s been exposed since March?

    Why does it take doctors about 60 days to know if anyone has XDR-TB?
    Where do we plan to put the TB asylums, if panflu holds off another year?

    How are people going to be kept from fleeing?
    What if this person had just been told he’d been exposed to a h-h-h H5N1,
    and to stay put? People won’t obey; officials have to be ready for that.

  4. #4 revere
    May 30, 2007

    ST: I think the facts are still emerging here, but my impression is that while they knew he had TB they were still testing the bug from him for antibiotic sensitivity. The TB organism grows very, very slowly and XDR TB is very uncommon in the US, so I think they didn’t know it was XDR-TB until very late in the game.

  5. #5 crfullmoon
    May 30, 2007

    Call the Hallmark Channel; they won’t have to invent a thing.

    http://www.ajc.com/health/content/h…0530meshtb.html
    He has TB since (at least) January.

    Given the cost of treatment; is anyone fast-tracking faster diagnosis?
    And, better actions ready than Gerberding’s little “covenant of trust” that people won’t selfishly gad about and expose others?
    What’s different about AZ law enforcement officials and all the jurisdictions Mr.Honeymoon just caused the cost of tracking, testing, and possibly treatment to?

    What a fiasco; he claims they didn’t tell him to take precautions, (he also claims to be “intelligent”; I disagree).
    Why doesn’t local law enforcement lock he and his wife up? Obviously they will just do whatever they want, otherwise.

    Who were the health officials working with this guy prior?
    …”But it turned out his TB was resistant to the first-line drugs — and the second-line drugs. So county officials stopped treatment. The man said he and his private doctor — with the agreement of government health officials — made plans for him to undergo cutting-edge treatment with specialists at National Jewish Medical and Research Center in Denver after his honeymoon.

    The treatment will involve surgical removal of the mass coupled with drugs to kill the infections. The man said he’s been told the course of treatment could take 18 months — and that the only place that can do it is the Denver hospital.

    “The county health department knew I was going over to have a honeymoon. We had a meeting before I left,” the man said. He acknowledges that the health department told him they “preferred” that he not to travel. But reluctant to cancel his long-planned wedding, the man said he asked what does “prefer” mean? Does it mean I can’t, the man asked.

    But even when health officials were quizzed, the TB patient said they never told him he couldn’t travel. He told officials he’d be going ahead with his wedding and noted that they didn’t tell him to take any precautions, even around close family and friends.”…

    Should have kept him in the office right there, while he cancelled his travel plans… and book him his hospital room, and a jail cell, if he didn’t stay put.
    Maybe his private doctor and the county health offical would like to pay for all the additional testing and treatment letting him give them the slip caused?
    Why couldn’t they say, NO you can’t travel and I’ll go write the legal paperwork up right now, (and flag your passport in such a way all nations’ airports actually hold you)?

  6. #6 stu
    May 30, 2007

    So who is this guy? I see that he is from Georgia, but no other info. Am I right that he lives in hotel, and that others in the hotel have TB? Maybe I misread something…

    I guess this tells us a lot about what people will be doing in a pandemic.

  7. #7 M. Randolph Kruger
    May 30, 2007

    Those HEPA filters are 98% effective which aint bad. They were installed in most aircraft after the SARS gig from a few years ago. I NEVER though aim that air flow into my face, in fact I keep them off when I am traveling. About that same time of SARS a test was done on the surfaces of three airliners from two different airlines. They found TB, all sorts of bacteria, fecal matter. As a result of that test a recommendation was made to the Clinton Administration via that all airliners be cleaned daily as a part of their daily inspections. It was declined to be entered to the requirements and they were citing costs.

    Let an airline or two get sued because someone got onto a plane with TB and infect someone and see if that changes.

    Revere…A question. Does a Mantoux / PPD Tuberculosis Skin Test cover all types of TB. E.g. XDR/MDR TB ?

    Here is the latest on this guy. Its serious and he is in forced confinement.
    .
    http://www.iht.com/articles/2007/05/30/america/health.php

  8. #8 revere
    May 30, 2007

    Randy: HEPA filters are not just from the SARS era. By then most (85%) passenger airplanes already had them. Whether they remove viruses is a matter of some question, but certainly TB and most bacteria wouldn’t make it through a HEPA filter and probably most viruses, either. Small planes often don’t have these filters, however (e.g., small regional jets or turboprops), although some do.

    stu: All we know is the guy is a Georgia resident (Fulton country). I think his identity is protected by federal law (HIPAA).

    crfullmoon: You want to forcibly restrain all TB cases? Remember 90 – 95% of people infected with TB don’t have clinical disease. This is a lot harder problem than you give it credit for. Diagnosing XDR-TB is not a snap and it isn’t done instantly. It can take many weeks. The bug grows very slowly and is often difficult to culture, period. There is a reason this nasty disease is still with us. It is very tough to fight. Doctors nd nurses and health department people give it tremendous respect and don’t treat it lightly. They know what they are dealing with and know the consequences to themselves of being infected. Even if they don’t get clinical illness they will spend a year or two taking INH daily.

  9. #9 M. Randolph Kruger
    May 30, 2007

    Revere-most aircraft at the turn of 2000 had low grade filters that were not HEPA type. Most of the older ones didnt have them at all such as the B727, DC-9, L1011.

    A few links:
    http://www.pall.com/Aerospace_36271.asp#36275
    http://www.volpe.dot.gov/ctug/docs/abt-120805.doc
    http://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/ame/media/Section%20II.7.1%20Transportation%20of%20Patients%20by%20Airline.doc

    Boeing didnt have them on planes until 98 and it was an optional retrofit. How do you know you didnt have them and still dont? The burning smell coming in thru the bleed air system on the startup. When the engine turns over the bleed air system is off as the turbocompressor air is diverted to turn the engine over. Until its sucking fresh air the TC is loaded with unburned fumes. Ever seen the cabin get a little smokey? Thats the reason.

    Remember that folks when you get onto a plane now, stinky air means the bleed air valve is sticking a bit from carbon buildup and maybe moving bugged up air. To answer the obvious there is still no FAR requirement for them to use them. Prudent though to do so.

    Revere check out that last one especially as its really good as to who should be on a plane when they are sick. I dont plan to lose you from an airborne bug, only at the end of a Puritan witch hunt rope. You need to read it from the aspect of the constant traveler-its FYI

  10. #11 revere
    May 30, 2007

    Randy: Thanks for the links. They are printing out now. I know Clark Abt but hadn’t seen this piece from him. Your first set of links worked for me, BTW.

  11. #12 caia
    May 30, 2007

    My question is, why are they focusing soley on the flights he took? He was gadding about in Europe for weeks. Is it because the CDC has no jurisdiction in Europe?

    The IHT article says people typically get TB when they’re in crowded, poorly ventilated areas, but if this guy took any buses or trains in his travels, he could well have exposed people there.

    Nearly impossible to track, I suppose. It’s not like he’s going to remember the route number and time of every bus and train he took, or even the days he took them. But that doesn’t mean someone(s) didn’t catch it from him

    He “can’t believe” all this is happening to him when all he did was defy one teensy weensy instruction not to fly on a public flight? I can’t believe he’s not facing criminal charges. Reckless endangerment springs to mind.

  12. #13 caia
    May 30, 2007

    Sorry, he said it was “insane” that he had an armed guard, not that he couldn’t believe it. Well, guy, if you’d proved amenable to recommendations or even instructions about not travelling, maybe they wouldn’t consider you a flight risk.

    Flight risk. I kill me.

  13. #14 Ann
    May 30, 2007

    caia – talk about trains and buses, think about all the places he ate or visited … the list of who he might have infected could be never-ending.

  14. #15 C
    May 30, 2007

    If a health official tells you you probably shouldn’t fly, and you’re not sure what that means, then ASK. How selfish was this person that he KNEW he had TB and “probably shouldn’t fly” and that he did it anyway. To make matters worse, he snuck back over the border? Remind me again why we’re not prosecuting this person?

    I certainly hope everyone who was on that flight was personally notified and given information on seeking treatment. Revere, I am comforted by your remarks on the air circulation systems, but I’m also a little concerned by the fact that they’re only tracking down people sitting in his immediate vicinity. Surely he got up to use the restroom at some point, right? Who is going to pay to monitor the care of these people who probably aren’t infected, but could be? Is anyone keeping up with them? Do they know about warning signs?

    I hope this little incident has let CDC know that “good faith” doesn’t keep sick people from potentially starting pandemics…

  15. #16 revere
    May 30, 2007

    C: I’m a little more forgiving. First he may not be very infectious. He also didn’t know he had drug resistant TB. We also don’t know exactly what he was told (e.g., “Here are the options . . . “) and the story was he was going on his honeymoon and without a clear message he may have cognitively overridden it. It sounds like there was not good communication and probably some wishful thinking. Remember, he’s not ill. He felt fine. If it hadn’t been XDR we wouldn’t be reading about it. We’ll find out more as time goes on if some serious blunders were made, but right now I don’t see it.

  16. #17 marquer
    May 30, 2007

    Ah, yes, the inherent fatal weakness of most modern “public health” systems. They rely upon the general public to be smart and cooperative.

    Then when the public is, invariably, shown to instead be stupid and insolent, the system flounders helplessly.

    Witness the preposterous Gerberding repeating for the media that the individual in question “faces no criminal charges”. File that under pour encourager les autres.

    If I were an immunosuppressed person, I would be up in arms over CDC’s feckless, flaccid response to this. It is clinically well understood what happens when XDR-TB gets into, say, HIV patients. It slaughters them like a cougar in a chicken coop.

    However, this self-described “successful” gentleman is about to be challenged by something more dangerous than XDR, HIV, Ebola, H5N1 and hantavirus combined. To wit, the American plaintiffs’ bar. If this guy was in fact advised of his status and told not to fly, and then did so in defiance of advice, and infected someone else as a result, there you have the textbook tort. “But for the negligence and arrogance of Mr. X, my client would not today be ill with this dreadful disease.”

    Note as well that airliner HVAC systems are perfectly capable of providing 100% fresh, nonrecycled air at all times, should the operator choose to do so, and this mode of operation was very much the norm up until the first petroleum price crises in the 1970s. The flight deck continues to get 100% fresh air today, at the (reasonable) insistence of the pilots’ unions.

  17. #18 marquer
    May 30, 2007


    C: I’m a little more forgiving. First he may not be very infectious. He also didn’t know he had drug resistant TB. We also don’t know exactly what he was told (e.g., “Here are the options . . . “) and the story was he was going on his honeymoon and without a clear message he may have cognitively overridden it. It sounds like there was not good communication and probably some wishful thinking

    Wait a minute. There were two fundamentally different situations with which this person was presented. Let us not conflate them.

    He also didn’t know he had drug resistant TB.

    Before the guy left for Europe, he did know that he had drug resistant TB. He did not know that he had XDR TB. And he had not been stringently warned not to fly. It does seem that what he was told at this point was vague, more of a guideline than a rule.

    Then, while the guy was in Europe, he was contacted by US officials, and he was told directly and clearly that he had dangerous XDR TB, was told directly and clearly that he was a potential hazard to others, was told directly and clearly NOT TO FLY HOME, and was told directly and clearly that he must report to the Italian authorities. He chose to ignore all of these specific warnings and directives. That is very different from before.

    I can see that being understanding and forgiving might be appropriate in the first of these circumstances. In the second? Completely inappropriate. This fellow behaved like a selfish, reckless ass.

  18. #19 crfullmoon
    May 30, 2007

    He knew he had first and second line drug-resistant TB; he said so in an interview, and that they had “stopped treatment”! Nothing left to try but lung surgery and 18 months of treatment, and they wanted him to not travel.

    XDR-TB; yes, forceably detain; better than having the expense and worry of tracing all his contacts, testing, and possibly treating people ($100,00 – $500,000?) that may not recover?

    If they were only allowed to say, “we don’t recommend you travel until after your treatment” because they didn’t have a signed legal order from the president in hand when they said it, then something needs a lot of work!
    The CDC couldn’t even get his passport internationally flagged?
    Doesn’t the EU care about XDR-TB?
    Airlines are going to let bioterrorists
    (or tourists fleeing pandemic “bird flu”) right on in, and never find them in time.

    How long until people become infectious?
    If he’d been exposing his finacee and whoever since Jan. when are those people a risk to others?

  19. #20 Lea
    May 30, 2007

    This all sounds like a test from the CDC to see how a pandemic will be handled, or not.
    How’s this thought?: “let’s get them warmed up to the idea of a health alert, that way when the pandemic hits the public will be _______”.
    I had primed in the blank but it didn’t sound right.

  20. #21 Debbie
    May 30, 2007

    Oh,crap! I’m flying Air France to Paris in a few days…. Wonder if I’ll get the same cabin crew….

    If it’s true that he was notified in Rome of his condition and told not to fly, then I agree with marquer.

  21. #22 Paul Todd
    May 31, 2007

    Not sure I have the story straight but my understanding is the guy has TB, but is not sick, meaning it is not active, and thus not infectious. If I am wrong disregard what follows.

    Any treatment after his diagnosis would have been preventive, to help prevent the TB from going active. The type of treatment would depend on the level of drug resistance his TB was at. After drug resistant testing showed he had XDR TB, any treatment he was on would have been terminated.

    Assuming I am not wrong on his not having an active infection, this all seems to be a bit of overkill to my way of thinking given the prevalence of TB worldwide.

    Couple of facts. 1/3 of the worlds population has TB.
    Ninety (90%) of those with TB will never have an active infection, including those with XDR-TB.

    Now if he does have an active case of TB, it seems strange he is not sick, but I am not a Doctor. Having an active XDR-TB is the only excuse for him being being Quarantined. He was also denied the right to fly home directly from Europe (hence his European travel route where he ended up in Canada so he could drive home), even though it seems unlikely he would be infectious if the infection was not active.

    My guess is that if there is no evidence that he has an active case of XDR-TB infection, the possibility that he would was enough for this government to put him on the no-fly list and thus leave him stranded in a foreign country and have to cough up the cost of chartering an aircraft or reimbursing the CDC to fly him home, which supposedly was not available until he checked into a NY hospital and the CDC chose to fly him home to Atlanta.

    Seems that if this country was really concerned about the risk of TB, they would have a National Health Insurance program, as only such a program can ensure that enough people get tested for TB, and continue treatment once treatment is started. Many Americans with TB may start preventive treatment that is then discontinued due to financial reasons if they are without health care insurance, which facilitates the evolution of XDR-TB and other forms of drug resistance TB.

  22. #23 revere
    May 31, 2007

    Paul: Your comments point up a number of inconsistencies about the facts and I think we will need to know more to get an accurate picture. He is reported to be without symptoms, his case discovered by a routine chest x-ray. One news report said his sputum was negative for organisms, although it isn’t clear if this was just microscopically (no visible AFB). On the other hand, it seems clear they cultured some bugs from somewhere. Maybe they grew yout of a sputum sample or TB aspirate. That takes a lot of time, since it grows so slowly. Then they would have to do drug sensitivity. I’d like to know ore about how hi XDDR status was discovered, because, as you say, he seems to be a latent TB case, not an active one. But then they got the bugs, somehwere . . .

  23. #24 caia
    May 31, 2007

    Ann True, but I was going by what the IHT article said about confined spaces being the best (worst) for TB spread, and guessing that trains and buses are less well ventilated than restaurants and museums. And not all trips on them might have been short. After all, he flew to one country, and back from another, so chances are he took trains from one to the other.

  24. #25 M. Randolph Kruger
    May 31, 2007

    Ahnnnnd… The US gets the bill for treating him. Sounds like a real jerk to begin with and it was a preconceived plan to get into the US. He knew he was doing wrong. That same CDC plane that transported him could take him back to his country for a lot less than what we are going to get stuck with.

    Sheesh!

  25. #26 revere
    May 31, 2007

    Randy: The CDC refused his request to take him back to “his” country. He is an American. But that’s the problem. Americans infecting Europeans with their diseases. The EU should stop Americans from coming there, I guess. BTW, this guy doesn’t seem to be infectious.

  26. #27 Stan
    May 31, 2007

    Another twist to the story. The father-in-law of the patient works for the CDC on TB….

    http://www.fox21.com/Global/story.asp?S=6593091&nav=2KPp

  27. #28 Galen McBride
    May 31, 2007

    Dear Revere(s) et al –

    In that really awful panflu movie, the CDC screwed around for about two weeks before it (a) recognized that the people had a highly communicable pandemic bird flu and (b) that there were multiple/simultaneous cases across the country.

    SO – I’m still wondering if you have a guesstimate (based on who and what you know, of course) re this: If the bug had been influenza, … how soon do you think the MSM would have the story if the first case of panflu had broken out in the US? (or more specifically, how long do you think the CDC would be able to keep it under wraps)?

    Thanks.
    SaddleTramp

  28. #29 revere
    May 31, 2007

    Galen: We’ll know about it weeks ahead of time because it will start elsewhere. If it starts here we’ll also know about it because it can’t be covered up. What we are more likely to see is multiple false positives.

    Stan: Wow. My guess is the father-in-law told him it was OK, and that’s why he went.