
Our handling of public health issues indeed seems schizophrenic and inconsistent. The government treated a young lawyer with unusual drug-resistant tuberculosis (which turned out not to be quite so unusual) almost as a criminal, isolating him in Denver, and invading his body to take out infected lung (I guess the patient consented). We did that for a disease that in practice is extremely hard to transmit and that often causes no symptoms for life.
Since about 2003 or so, we have seen an escalation in public panic over the possibility of an avian influenza epidemic, a recurrence of the 1918 Spanish Flu. In fact, yesterday I received a printed flier from the local health department on it. Back then, theaters and public gathering places had “health rules” about coughing in public; some of the public posters have been printed in history anthologies like “The Century.” The 2006 ABC TV film “Fatal Contact: Bird Flu in America” demonstrated the public panic that could ensue were H5N1 to mutate into a readily contagious form. An unusual feature of Spanish flu was that it hit young and healthy adults harder because of more robust immune response (generally most infectious diseases hit the frail or very young harder). Extreme economic disruptions would occur, people could be quarantined, entire industries could be destroyed, and health experts warn that waves of such disease could hit an area several times and last several weeks or months each time, and will not be winter-season dependent. While clusters of bird flu appear in southeast Asia and appear to possibly have short chains of person-person transmission, the chains seem to die out. A similar possibility existed with SARS in 2003, and public health officials claim that their diligence prevented a major outbreak in the West.
In fact, over the past several decades, we have become accustomed to the idea that the rapid circulation of people in an urban environment, particularly when they are young, probably builds up resistance so that many adults can tolerate most common respiratory or digestive infections without much disruption; they can go to work and cause the problem of “presenteeism.” We hear about outbreaks of Nora virus on campuses and nursing homes, and sometimes cruise ships; we hear about meningitis on campuses (one form can cause catastrophic circulatory damage because of bacterial endotoxins, leading to amputations). Generally, these occur with people who are younger and have less lifetime exposure to develop immunity, or to the very elderly or sick . (Colleges should, however, insist on vaccinations for bacterial meningitis, because of the possible catastrophic outcomes.) Some families are sensitive to the possibility that socially active adults can bring new or common infections home as carriers because they, having built lifelong resistance, have fewer symptoms.
The bird flu scenario even can question our modern assumptions about individual sovereignty. Like other disasters, it leads to discussions of families and communities planning to survive together while external public services and utilities, necessary for normal personal autonomy, are suspended or compromised. Persons who survive a pandemic might even be expected to care for those still infected.
Indeed, some worldwide patterns now becoming apparent with globalization, such as the tendency in SE Asia and some of China for people to live close to farm animals and poultry, may increase the likelihood that novel infections spread person-person could upset the normal pattern where active adults develop resistance to common infections through normal social circulation, as in crowds, subways, airports, bars, etc. The ability of the pharmaceutical industry to respond with vaccine manufacture depends partly on limiting their liability, and Congress needs to address vaccination health policy. It has not done so satisfactorily, as there have been spectacular failures with ordinary flu vaccine manufacturing in the past few years. It is possible to make a vaccine for H5N1 (Indonesia is already using it, against WHO recommendations) and our own public health community needs to get its act together. It has done so in the past, with other pandemic flus. But this one at least has the potential to be much worse.
Not to be lost in all of this is the grim possibility of bioterror, particularly smallpox, the subject of at least one major TV film in 2002 (by Dan Percival: "Silent Weapon", from the UK). That's why it's important to rebuild smallpox vaccination supplies and might be wise to start revaccinating people. Anthrax is not transmissible person-to-person, but could (as in 2001 by mail, or as demonstrated in a 1999 fictitious ABC Nightline series) be introduced deliberately into the air if possessed illegally.
One issue of particular importance is the speculation over viral mutation. Estimating its possibility seems to be like estimating the likelihood of extraterrestrial life; we have no Drake Equation. The presence of a large population of people with active ordinary influenza might increase the likelihood of mutation through gene exchange.
One comparison that interests me is that with HIV, AIDS, which is strictly bloodborne. (That is true of a number of other diseases like Hepatitis B and C; it is less clear with some catastrophic infections like Ebola or Marburg). In the 1980s, responsible public health officials repeatedly reassured the public that HIV (or HTLV-III as it was first known) could not be spread through casual contact. (There was a notorious medical column in 1983 from Anthony Fauci where such a speculation was actually made.) Members of the religious right (Gene Antonio, Paul Cameron) would jump on the “there is always a first time” paradigm are argue that HIV could mutate into a contagious form, and if so, it would be the “fault” of tolerating male homosexual behavior. How is this different from current speculations about H5N1? There is no room for “failure of imagination” here, so people go around speculating, “What if ….?”
There are, in principle, major differences. For HIV to mutate into something spread like flu, it would have to change the cell types that it infects. It would have to change into a different disease. In the course of doing so, it is likely that it would become milder and adapt to its host. Viruses do not thrive by killing their hosts. What was so unusual about HIV was the very long incubation period before symptoms, as well as the apparent irreversibility of disease (until modern anti-retroviral drugs were available). HIV did become pandemic in Africa, but in third-world conditions where there were rampant sexually transmitted diseases that made bi-directional heterosexual transmission more likely. In the West, it thrived in relatively closed communities (gay men, and then IV drug users) where certain practices could sustain a chain of transmission.
There is still another public health twist, that takes us back to the TB case. Immunocompromised people are more susceptible to both unusual TB’s and the more common tuberculosis. TB, “the white plague” or “consumption” has been greatly feared, and teachers have to take TB tests. Theoretically, it would sound as though an immunocompromised population (HIV positive) could incubate TB and then infect (through “casual contact”) “innocent” others (especially those whose immune systems are compromised by chemotherapy, genetics or aging). In practice, that has not really happened to any significant extent (after 25 years of experience with HIV). Why? Because TB really is, in practice, very hard to catch. That’s what was so baffling about the way the government treated Andrew Speaker (and about his exposure to civil lawsuits). It should be added that Mr. Speaker probably was “infected” with drug-resistant TB by travel to remote primitive areas of the world as media reports indicate (that is, not by HIV or other immune system compromise). The practical risk to others around him probably was negligible to non-existent. If I had sat next to him on a flight, I would not be concerned.
See also Sept. 12 2007 posting on this blog on MRSA staph.
Update: Oct 18, 2007
The Washington Times, p A1. has a story by Sara Carter and Audrey Hudson, "Man criscrossed border with TB" (Mexican border) and the story reports that health officials insist that people with drug resistant TB should not fly in commercial airliners, although it probably takes a while to have any risk of airborne transmission. Link.
Congressman James Moran's letter on avian influeza, here.





