Glossary: Nasty foreign bugs translate into English: In his new weekly column, the writer considers what we say and what makes us say it

JOHN DONNE'S warning that 'no man is an island' has been hammered into a dull truism by the years, but when he first sounded the words over the heads of his congregation they must surely have had a more combative ring. After all, most of us instinctively think we are part of an archipelago rather than a continent.

That's never more true than when we're threatened by invasion. Listen to the names that people use to describe unspecified illnesses, such as the viral special edition that has just done the rounds, and you detect a bodily xenophobia1 that would do credit to the most die-hard opponent of Maastricht.

It can be quite explicit - the word 'flu' has become so cosily domesticated that it frequently comes with foreign baggage tags to remind you that what you are suffering is an illegal immigrant: Spanish Flu, Beijing Flu, even, as I recall, Mao Flu, with its nice added spin of something conspiratorial cooked up in the laboratories of the People's Republic. There's a certain legitimacy to these tags (they usually identify the geographical origin of an outbreak), but their popular appeal can't be detached from an English paranoia about the microbial battlefield of Abroad. We don't like to say it now, indeed most of us probably don't even think it, but the language preserves a trace of a primitive suspicion: foreigners make us sick.

Flu itself, redolent of candlewick bedspreads and Boots the Chemist, started as an exotic continental import. L'influenza first broke out in Italy in 1743 ('News from Rome of a contagious distemper raging there', wrote the London Magazine), from where it spread throughout Europe. In 1762 Mrs Montagu wrote that her husband 'had been much pulled down by the fashionable cold called l'influenza', which suggests that even then trendiness was almost as contagious as a virus. The word influenza gestured anxiously towards the malign or astral influence (as in 'the 'fluence') which was supposed to have engendered the illness.

It may be that a similar superstition2 lies concealed in our use of 'bug' as a catch-all description of some unspecified malaise. On one level it is clearly popular science, a cartoon3 version of the new theories of disease. The Oxford English Dictionary's first citation in the sense of infection is from 1919, but the word has a much longer history as a generic name for small insects, probably the closest most people could come to the notion of microscopic organisms.

It's intriguing, though, that the sense of 'bug' as a defect in a system had already been around for 30 years (in 1889 the Pall Mall Gazette reported that Edison had been up for two straight nights trying to detect a bug in his phonograph). This may be one of those occasions when different usages come together to speed the dissemination of a word, as two small raindrops on a window will blink together to form a larger, faster drop.

For the most part, however, our vulgar diagnoses are a matter of pointing a finger at our neighbours rather than supernatural forces. The great boost for this was the first experience of mass intercontinental travel - not the package travel boom of the Sixties but the Second World War, which took unprecedented numbers of Britons (and Americans) abroad for the first time.

'Delhi belly', 'the Tokyo Trots', 'the Rangoon Runs' and 'gyppy tummy' all date from the war and all convey a vague squaddie's suspicion of foreign bodies, as though war- time British kitchens weren't breeding their own perfectly respectable crops of bacteria.

As with all theories about language, it is best to proceed cautiously. I was convinced that 'the lurgi', as a term for unspecified disease, must have an Indian connection, even though the OED cites its first appearance in print (as 'the dreaded lurgi') in 1954, in a Radio Times billing4 for The Goon Show.

Surely there was some Hindi in there, hinted at by that suffix - surely this was more evidence of the base nationalism of our gut feelings. Unfortunately, as Spike Milligan remembers it, it was pure invention. 'I actually made it up when I was in the Army,' he recalled last week, before offering a brief symptomology. 'When I was asked what it was I said, 'Little spots of shit on the liver'.'

So at least you know how to use it with scientific accuracy from now.

1: xenophobia - from the Greek xenos, foreign, stranger, guest; and phobos, fearing.

2: superstitious - from the Latin superstare, to stand over or upon.

3: cartoon - from the Italian cartone, an expanded form of carta, paper.

4: billing - from the medieval Latin bulla, a seal, from which any sealed or formal document.