The microbe of the moment, Bacillus anthracis , is an effective killer and a born survivor. Its toxin is notoriously swift and usually deadly. Symptoms appear within days and, if breathed in, it is almost always fatal. What is more, when conditions get difficult for it, the bacterium produces spores capable of surviving decades until things improve.
That pernicious combination has been used to devilish effect in the current terror campaign in the United States, thrusting Bacillus anthracis under the spotlight as never before.
It is a giant among bacteria - each rod-like organism is five thousandths of a millimetre long - and just 10,000 of its spores constitute a lethal dose.
However, anthrax does not often infect humankind - animals such as sheep and cattle are its preferred hosts. Meanwhile, diseases such as Aids, tuberculosis and influenza claim many more lives.
It seems that anthrax becomes a significant threat only when given a helping hand by humans.
Yet Bacillus anthracis has a special place in science. It was the first bacterium shown to cause disease. German doctor Robert Koch conducted his pioneering experiments in the flat he shared with his wife and daughter in the 1870s.
It was also among the first to have a vaccine formulated against it by the French microbiologist Louis Pasteur.
Humankind's war against the bug got a double-measure fillip this week when two separate US studies revealed the three-dimensional structure of its lethal toxin and how it gets inside living cells.
The bacterium secretes a substance that opens a particular kind of protein door in the cell membrane. Once the cell's defences are breached, the toxin prevents the immune response from being triggered and wreaks havoc within.
Either discovery could prove to be the bug's Achilles' heel, possibly leading to new, more powerful drugs for anthrax, though given the disease's low incidence, the demand may prove insufficient.
In the meantime, production of the antibiotic ciprofloxacin is being jacked up as it is an effective treatment if given soon enough. A vaccine is also available.