Anthrax and Beyond: Potential Bioterror Agents
How prepared is America's public health system to identify and contain the threat of bioterrorism?
By C.J. Peters
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If a terrorist wanted to move to the next level of bioterrorism, what agent might he or she choose? How easy would it be to find and distribute? How prepared is America's public health system to identify and contain that threat? WebMD posed those questions and more to C.J. Peters, MD, former chief of special pathogens at the Centers for Disease Control and Prevention (CDC), and former chief of the disease assessment division at the U.S. Army Medical Research Institute of Infectious Diseases. He's also the co-author of Virus Hunter.
Q: While the nation is focused on anthrax, terrorists could be preparing other biological or chemical attacks. Walk us through some that are not familiar to the general public, such as tularemia, plague, botulinum toxin, Ebola and other viral hemorrhagic fevers and, of course, smallpox.
Peters: Bioterrorism is a very complicated issue that could be carried out in a lot of different ways. We think that there are only a few bugs that are really bad and would really let a terrorist be able to do a lot of damage to many people. That's why you hear the same words come up again and again. Words like tularemia, plague, smallpox, anthrax, and the viral hemorrhagic fevers.
Tularemia is better known as "rabbit fever," and there are a few cases every year in the U.S. It was discovered in Tulare, Calif., and it's naturally acquired from infected rodents such as rabbits or through the bite of contaminated flies. It starts out with fever. It can be treated with antibiotics.
Plague is the bacterium that caused the Black Death in Europe, but remember that they had no medical care and no curative antibiotics like we have. It spread there mainly through rats and fleas and not from person to person.
Smallpox is a viral disease and there's no specific treatment, but we can protect people who are in contact by vaccination.
Those bugs can all be grown in large quantities at a special state-sponsored factory or some other factory such as the Japanese terrorist cult in Tokyo. They could be spread around in an airborne fashion so as to infect many people. Fortunately, the only one of these that can spread from person to person is smallpox. The others only have limited ability to spread from one person to another.
We think that smallpox is probably only found in two places where it is kept safe, one in Atlanta and one in Russia. But we are worried that other people might have smallpox and would use it to start a smallpox epidemic. That is why the government has 7 1/2 million doses of smallpox vaccine stored away and why they are contracting to make 300 million more doses. The other bugs can make you very sick and have a mortality rate of up to 100% if not treated, but they won't spread and cause an epidemic.
The government is stockpiling antibiotics. There are already eight stockpiles around the country that could be dispatched in the case of one of these massive bioterrorist attacks. Right now we've seen no evidence that anyone has large quantities of any of these agents that could be used to cause a massive attack.
Q: Government leaders say we have a plan in place to deal with a smallpox bioterrorism attack. What is this plan? In your opinion, is it sufficient? What use should be made of these new doses of smallpox vaccine?
Peters: The government has had much experience with smallpox in the past. Cases were introduced in the 1960s and 1970s from overseas. And it was possible to stop smallpox transmission by vaccinating all the people in contact with the cases, including medical staff and family, of course. Vaccination during the incubation period, particularly the first four days, is very protective against smallpox. This ring of vaccinated people prevented further spread of smallpox.
We use this same approach to rid the world of smallpox including even difficult places like India and Africa. It has a very good chance of controlling smallpox if there are only a few cases. If there are many cases then it will be difficult to deal with this, particularly because we only have 7 1/2 million doses of vaccine.
However, there is a fallback plan. The 7 1/2 million doses can be diluted to give perhaps 50 or 75 million doses -- these studies are under way. The government is also making an additional 40 million doses in the short-term and 300 million doses in the long-term. I think this will give us protection -- you have already seen that it's not perfect, but it's also unlikely that smallpox will happen.
Q: Besides the smallpox vaccine, are there any other vaccines available?
Peters: There are several vaccines available for the other threat agents in addition to smallpox. The anthrax vaccine is not an ideal vaccine but could be used in special risk populations. Among the hemorrhagic fevers, there are vaccines that protect against Bolivian and Argentinean hemorrhagic fever as well as Rift Valley Fever. Unfortunately, these vaccines have not been pursued, so they could be used widely after initial development by the Department of Defense.
Q: Which bioterror agents are the most likely to be used and why?
Peters: I think it's a fool's game to try to outguess terrorists. They all have different motives, different abilities, and different capabilities. We must be ready to respond to anything by strengthening our public health infrastructure.
There are some things that we must guard against more specifically, and those are anthrax, smallpox, plague, tularemia, and the viral hemorrhagic fevers. These are capable of causing so many deaths and such disruption that we are obliged to make specific plans for them. That's why the U.S. is purchasing additional smallpox vaccine and has been stockpiling antibiotics. Parenthetically, strengthening the public health system, although it sounds boring, will makes us better able to deal with everyday diseases from food poisoning to AIDS and will help us respond to emerging diseases like epidemics of influenza and new diseases that may appear.