Fomites are things to fear

Answer: Shunning respectfully and knowledgeably is never a bad idea with objects that can pass along infection from person to person — fomites — such as money, a dirty towel, a doorknob. But "filthy lucre" is no more the villain than many others. Consider that hand you just shook, which likely spent the day going from fomite to fomite: So many in fact it has been said you're more likely to catch something from shaking someone's hand than from kissing the person's lips.

Money's a funny fomite because of its overwhelming positive connotations, yet there the pesky little pathogens are, like warriors in a Trojan horse. One study of coins showed E. coli surviving for 7, 9, 11 days on U.S. pennies, nickels and quarters—shorter for the pennies probably due to copper's toxicity to cells, says microbiologist Timothy Paustian of the University of Wisconsin-Madison. Salmonella tested similarly. Paper currency too has been implicated.

Question: It had a reputation as an aphrodisiac, was used to treat tuberculosis, and as a pesticide in agriculture. Swiss mountain climbers once consumed it believing it gave them strength. For many years its toxicity went unrecognized, but today it is known that as little as a tenth of a gram can be lethal in some forms. Poisoning is cumulative, with tiny amounts from tap water building up until physical symptoms emerge. In some areas of the world, quantities leaching into village wells have caused skin lesions and cancer in hundreds of thousands of inhabitants. Bizarrely, though, there is a group of indigenous villagers in Chile who, for generations, apparently have been drinking water laced with dangerous levels of the substance but show no signs of cancer. Can you name this puzzling element?

Answer: Arsenic, says Stanford chemist James Collman in "Naturally Dangerous." Its famous forensic possibilities, as in the dark comedy "Arsenic and Old Lace," have been largely undercut by modern scientific methods for detecting it in minute amounts, even in a single strand of hair, says John Emsley in "The Elements of Murder: A History of Poison." "Hair grows at a fairly constant rate so that, for example, a high arsenic level at a point 5 mm from the root shows the person was given the poison 14 days previously."

Send STRANGE questions to brothers Bill and Rich at strangetrue@compuserve.com