Small
pox
Smallpox is caused by the variola
virus. The most common form of the disease has a 30 percent mortality
rate [source: CDC].
Signs of smallpox include high fevers, body aches, and a rash that develops
from fluid-filled bumps and scabs to permanent, pitted scars. The disease
predominantly spreads through direct contact with an infected person's skin or
bodily fluids, but also can be spread though the air in close, confined
environments.
In
1967, the World Health Organization (WHO) spearheaded an effort to eradicate
smallpox through mass vaccinations. As a result, 1977 marked the last naturally
occurring case of smallpox. The disease was effectively eliminated from the
natural world, but laboratory copies of smallpox still exist. Both Russia and the United
States possess
WHO-approved stores, but as smallpox played a role in several nations'
bioweapons programs, it's unknown how many secret stockpiles still exist.
The
CDC classifies smallpox as a Category A biological weapon due to its high
mortality rate and the fact that it can be transmitted through the air. While a
smallpox vaccine exists, typically only medical and military personnel undergo
vaccination -- meaning the rest of the population is very much at risk if
smallpox were unleashed as a weapon. How might the virus be released? Probably
in aerosol form or even in the old-fashioned way: by
sending an infected individual directly into the target area.
The method for unleashing a biological
weapon doesn't have to be flashy, however.
Anthrax
Most
cases of anthrax are cutaneous, transmitted
through skin contact with the spores. The most deadly form is inhalation
anthrax, when the spores travel to the lungs and then the immune
cells carry them to the lymph nodes. Here, the spores multiply and release
toxins that result in such symptoms as fever, respiratory problems, fatigue, muscle aches, enlarged lymph nodes, nausea,
vomiting, diarrhea and black ulcers. Inhalation anthrax carries the highest
mortality rate of the three (100 percent, 75 percent with medical treatment),
and unfortunately, that was the form contracted by all five casualties from the
2001 anthrax letters [source: NPR].
The
disease isn't easy to catch under normal situations, and it can't be
transmitted from person to person. Still, health workers, veterinarians and
military personnel normally undergo vaccinations. The rest of us, however,
remain at risk if someone were bent on another anthrax attack.
Along
with the lack of widespread vaccination -- a common theme among our scary
bioweapon nominees -- longevity is another point in anthrax's favor. Many
harmful biological agents can only survive a short while under certain
conditions. But hardy B. anthracis can sit on the shelf for 40 years or
more and still pose a lethal threat.