During the anthrax episode, the Secretary of Health and Human Services
Tommy Thompson repeatedly provided incorrect information to the news
media on the number of spores required to produce an infection. The
same misinformation was often repeated by public health authorities.
Failure to communicate the fact that the risks from even a small number
of spores could result in infection may have contributed to the deaths
of two postal employees at the Brentwood facility in Washington, DC.
Misinformation
from those who should know better is also occurring in the aftermath of
hurricane Katrina. DHHS Secretary Leavitt, for example, has warned of
the risk of "typhoid and cholera" as a result of contaminated water,
while others have talked generally of mosquito-borne disease and the
hazards caused by dead people and animals. It is time to separate the
real risks from the phantom risks.
Diarrheal disease from
contaminated water is a concern, but not cholera and probably not
typhoid. In order to get these diseases the water has to be
contaminated with the organisms that cause those diseases,
neither of which is endemic in that region. What is more likely is
gastroenteritis or hepatitis A from enteric viruses or bacteria. Most
are spread by the fecal-oral route, which means they are not spread
directly person to person. If they get in a contaminated, piped water
supply they can cause an epidemic, because piped water is an efficient
way to distribute pathogens to a population. But localized
contamination of flood waters is not. Individuals can get serious
diarrheal disease and even die of consequent dehydration, but there is
not likely to be a point source epidemic of cholera or typhoid or even
diarrheal disease, only sporadic cases (which may be relatively
numerous but not epidemic in nature). Lack of clean water and food can
produce a risk of diarrhea and dehydration and must be attended to
quickly, but not to prevent an epidemic.
Similarly the presence
of dead animals and people is not a health hazard. Dead animals
decompose naturally in the environment. Unless they were infected with
a contagious organism before death, they will not themselves become the
source of disease. The persistent concern in mass disasters over
unburied bodies is an urban myth. Mass disasters like floods rarely
cause epidemic disease and to suggest otherwise results in misplaced
concern and potential diversion of resources from more important issues.
Mosquito-borne illness is a potential concern for some, but needs to be
properly understood. Being bitten by mosquitoes is not a health hazard.
The mosquitoes themselves must be vectors for a pathogenic agent like
malaria or West Nile. Almost all malaria cases in the US are in people
exposed and infected elsewhere who travel to this country and become
sick shortly after arriving. We do not have endemic malaria, at least
not at this point (global warming might change that, of course). West
Nile is a possibility, because there are an unknown number of infected
birds and possibly other animals in that region. However the mosquitoes
that multiply in the wake of the flooding have to be the kind that both
bite infected birds and bite humans. We don't know what the disaster
did to the ecological niches of the potentially infected animal
population nor do we know whether any increase in s specific mosquito
population will be in the kind of "bridge vector" capable of biting
both humans and whatever existing infected animals are around. So even
a huge increase in the mosquito population does not necessarily, or
even probably, mean an outbreak of West Nile or other mosquito-borne
illnesses.This is important because the fear of "an epidemic" might
encourage interventions that themselves carry undue risk, such as
broadcast spraying of pesticides to kill adult mosquitoes. Mosquitoes
reproduce exponential quickly and these techniques have not been shown
to interrupt the transmission of human disease. They have the potential
to just add one more biologically active toxin to the environment.
The
biggest health hazards may well be those we would classify under
"injury." Heat-related illness might be at the top of the list here. As
body core temperatures rise above 105 degrees F., mortality increases
quickly. The high heat and humidity of the area, coupled with
dehydration are a significant health hazard that requires intervention
by providing fluids and cooler shelters. The many sources of physical
injury, whether from feral animals (snakes, alligators, etc.), sharp
metal debris, falls and injuries in an environment where the hazards
are numerous and not easily visible can result in substantial
accumulated morbidity and even mortality. The only remedy is removal of
people to a safer environment, which should be the top priority. this
is also true for the many chronically ill and vulnerable people who
require medication, external support from power dependent devices and
supervision.
The situation is complex but the bottom line here is simple: mobilize
resources to remove people from the area as quickly as possible, while
providing fresh food and water to those waiting evacuation. This is
something a well-organized military force, like the National Guard,
should have been equipped to do from the outset. If they can plan how
to put hundreds of thousands of soldiers to invade an area in a twelve
hour period, they can also plan how to remove civilians in a three day
period.
