Rats! We can’t f lea the plague

Coffee break 1

QUESTION Were the rats that carried the Black Death immune to the disease?

Most school children know that the Black Death claimed an estimated 25 million lives, more than a third of Europe’s population, between 1347 and 1351. But it is less well-known that the plague is not a thing of the past.

Although it disappeared from Europe in the early 20th century, it still persists in many pockets around the world, as witnessed by an outbreak in Madagascar last year, which killed 200 people.

In the central highlands of Madagascar, its main reservoir is the black rat, Rattus rattus. this species is highly susceptible to the plague bacteria Yersinia

pestis, dying soon after. Its resident fleas, also infected, then jump ship to find another suitable host — for example, a human.

this is considered the most common form of plague dispersal, though contact with contaminated material or inhalation of respiratory droplets can also cause infection. Plague is still endemic in some countries of Asia, Africa and the Americas.

Adrian Jevons, Oxford.

QUESTION What was the first electronic musical instrument?

though post- dating the Musical telegraph and the telharmonium, the theremin — invented in 1920 by the Russian Leon theremin — could be considered the first successful electronic instrument.

Pre-war radio sets would often howl when being tuned, with the pitch varying as one moved one’s hand towards and away from the tuning variable capacitor.

the theremin works on this principle. there are two ‘antennae’, one to control pitch and the other volume, the two being controlled by the proximity of the musician’s hands.

An eerie sound is produced, even though the player is not actually touching the instrument.

A familiar example is the theme tune of tV’s Midsomer Murders.

Phil Alexander, Farnborough, Hants.