In Japan it is a rite of spring as familiar as the flowering of the cherry blossoms and the melting of the snow on Mount Fuji – every year in March millions of Japanese are reduced to sneezing, weeping helplessness by powerful hay fever that sweeps across the country in an invisible cloud.

Now the problem has become so serious that it is afflicting some of the country’s most famous non-human inhabitants – the Japanese snow monkeys, the world’s most northerly apes.

Naturalists across the country have noticed that the symptoms that so inconvenience humans in the pollen season – running eyes, sniffing and paroxysms of uncontrollable sneezing – are afflicting troops of the Japanese macaque.

“More monkeys seem to be suffering than in previous years,” says Toshikazu Nobuhara, head of the Awaji Island Monkey centre, a wild monkey reserve in western Japan. “When they suffer badly, they have difficulty eating. We can’t do anything but watch over them.”

Cast from your mind images of delicate sniffling on freshly mown lawns – Japanese hay fever is industrial in its scale and ferocity.

Pharmaceutical companies reckon that one in four – that is 32 million – Japanese are affected by it, and that it costs the economy £1.42 billion a year in lost productivity. Japanese MPs even founded a parliamentary group dedicated to the problem – the Hakushon Giin Renmei, which translates as the Atishoo! MPs' League.

The problem is caused by one of the most beautiful and magnificent of Japanese trees, the cryptomeria or Japanese cedar. In the boom years of Japan's post-war growth, millions were planted for use in construction, until it became cheaper to import foreign timber. Every year pollen billows invisibly from the unharvested trees and is borne across the country on the spring breezes.

Traffic pollution seems to make the situation worse in cities – and dry summers are said to have increased the pollen yield. More and more people – and now apes – are affected every year and the prescription drugs available are unreliable, working for some people and not for others.

“The first time we spotted a monkey suffering from the pollen allergy was around 1988,” Mr Nobuhara’s wife told The Times last night. “First we spotted one monkey suffering, and then three more, then three more. At first, only adult monkeys, but now the young one get it too.” As she spoke over the telephone, stentorian monkey sneezes were audible in the background.

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