Anthrax and Crypto: Prime Suspects in Water

Anthrax and Crypto: Prime Suspects in Water
Anthrax and Crypto: Prime Suspects in Water

June 5, 2003

Urbana - In Russia, scientists have found anthrax bacteria that are close to 100 years old still lurking in the soil. In its spore state, anthrax bacteria are tough, resilient creatures. This is why they have also become one of the most feared biological weapons today, said Benito Mariñas, University of Illinois professor of civil and environmental engineering.

As a spore, Bacillus anthracis (the bacterium that causes the anthrax disease) is ideal for stockpiling as a weapon. Anthrax bacteria are like miniature bombs, ready to trigger disease when they are planted in the ideal environment--such as within the human body.

The actual bacteria are not hard to kill, Mariñas said. But when anthrax bacteria wind up in an unfavorable environment, they develop into spores, which are difficult to kill. They form a tough outer coat, like a cocoon. Then the spores go dormant, almost as if they were hibernating, and they wait for the chance to land in a more favorable environment.

"They sit there and don't do anything until they get inside your lungs and inside your stomachs," Mariñas said. "Then they will transform and do the damage."

In water systems, the strong outer coat is what makes anthrax spores a major concern. As spores, these bacteria are highly resistant to chlorine. What's more, they can hide behind "biofilms"--the scum that forms inside pipes.

The anthrax disease is much more common in wild and domestic lower vertebrates, such as cattle, sheep, goats, camels and antelopes. However, it can infect humans by inhalation, by entering the skin through cuts or by being ingested. Spreading anthrax by person-to-person contact, on the other hand, is highly unlikely.

In addition to anthrax, Mariñas said there are other microorganisms of concern when it comes to our water system. Among them is Cryptosporidium, a protozoan parasite found in feces.

In 1993, about 400,000 residents of Milwaukee had gastrointestinal problems due to Cryptosporidium in the water system. In this case, Crypto was traced back to a natural source--animal waste. But in our post-9/11 world, the question becomes: Could such a microorganism be introduced by terrorists?

It's possible, Mariñas said, but Crypto is not as big of a threat as something like the anthrax bacteria. That's because Crypto is an "opportunistic pathogen. It will kill only people who have immune system deficiency. It's not going to kill healthy people. It will give them diarrhea for a week."

Nevertheless, the Milwaukee incident underscores the vulnerability of our water system.

"That's the scare now," Mariñas said. "We know that if certain microorganisms reach the water distribution system, the entire population of a city is at risk of getting sick."