Because of recent events and the fact that there
is so much misinformation being provided to the public from all
sources, ASA suggested to Prof. Meselson that we reprint this
article with an update from him to precede the reprint. The original
ASA article received outstanding comments from scientists all
over the world.
Note Regarding Source Strength
by Professor Matthew Meselson
The "Note Regarding Source Strength" reproduced
below is the same as that published in the ASA Newsletter of June
8, 1995, except for the correction of a typographical error (the
omission of "pi") in the equation for dose in Table 1.
that source strength is defined as "the number of viable spores
released at the source that travel in the atmosphere as particles
small enough to initiate inhalation anthrax". Using this definition,
the source strength estimates in Table IV are given in milligrams,
taking the number of spores per milligram, as stated, as 109.
The question of whether the aerosol released at Sverdlovsk consisted
only of viable spores or also contained inviable spores and other
material is obviously not addressed in the present estimates.
These estimates should be regarded only as what they are: estimates
of source strength, as defined in the note, that follow from the
stated assumptions regarding atmospheric dispersion and regarding
dose-response relations for the infectious aerosol and the human
population exposed to it.
the present estimates follow from the assumptions made, the most
relevant dose-response data available are for non-human primates,
not for any human population, and none of it is for the low attack
rates observed in the Sverdlovsk outbreak. Neither do we know
if the virulence of anthrax spores in the aerosol released at
Sverdlovsk was like that in aerosols employed in published experiments
with monkeys. And even the well done experiments at Fort Detrick
and Porton with monkeys gave ID50 values covering a
more than twenty-fold range -- from 2,000 to 45,000 respirable
spores. These uncertainties are only imperfectly addressed by
considering a number of different dose-response relations, as
is done in Table IV.
An ASA Book Review by: Professor John Ellis van Courtland
Germs: Biological Weapons and America's Secret
by Judith Miller, Stephen Englelberg and William
New York: Simon and Schuster, 2001.
Bibliography. Index. Pp. 381. $27.00.
a fascinating account and analysis of the bioterrorist threat,
was written and released before the horrific events of 11 September
2001 and the subsequent anthrax incidents. The accidental timing
of its publication has contributed to placing it on the New York
Times best seller list. The narrative is largely chronological,
stretching from the end of World War II to the present. While
the authors convey a sense of simultaneous developments, each
chapter is skillfully focused. Chapter 1 describes a little publicized
event: the 1984 poisoning with salmonella (of salad bars in Wasco
County, Oregon, by the Rajhneeshees, a religious cult, an attack
which made 751 people ill. Although the attack was non lethal,
the cult fanatic, Ma Anand Puja, had ordered far more dangerous
agents. The subsequent investigation did not uncover the causes
of the subsequent illnesses until a year later. This incident
provided a frightening forecast of the dangers posed by bioterrorism
and of the difficulties in detecting and countering it in a timely