TWO decades after young, ultrafit orienteers in Sweden mysteriously started
dropping dead of heart attacks, researchers think they鈥檝e finally discovered
what killed them.
Lars Wessl茅n of Uppsala University has found evidence that the culprit
was a bacterium called Bartonella, which infects some animals as well
as humans and is found all round the world. Nobody knows if the same thing could
happen elsewhere, though.
鈥淚t鈥檚 very surprising,鈥� says Didier Raoult of the University of the
Mediterranean in Marseilles, an expert on Bartonella. He says the
findings need to be confirmed.
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In Sweden, 16 elite orienteers died of heart attacks between 1979 and 1992.
鈥淣ormally you鈥檇 only expect one case or fewer,鈥� says Wessl茅n. Because
orienteers can be exposed to disease carriers such as ticks and fleas as they
race from one spot to another, doctors suspected some kind of infection.
As a precaution, competitions were stopped for six months and some athletes
given antibiotics. This ended the deaths, but no one knew what was to blame. One
suspect was Chlamydia pneumoniae, a bacterium that has been linked to
heart attacks (New 杏吧原创, 31 March, p 18), but no evidence was
found to support this idea.
Another suspect was Bartonella. But at that time, it was very
difficult to test for it. Now Wessl茅n has found two strains of
Bartonella in the hearts of four out of the five sudden death victims he
looked at, and in the lungs of the fifth. The bacterium has already been shown
to damage cats鈥� heart muscle in the same way that 12 of the 16 victims鈥� hearts
were damaged. Wessl茅n鈥檚 results appear in the Scandinavian Journal of
Infectious Diseases.
In Sweden, he also found antibodies to Bartonella in 31 per cent of
orienteers, compared with just 7 per cent of blood donors. Wessl茅n
believes the orienteers may have fallen victim because they were training too
hard. 鈥淲e have been trying to slow them down.鈥� Nobody knows whether
Bartonella is to blame for heart problems in other sections of the
population, he says. 鈥淚 don鈥檛 think anybody has bothered to take a look.鈥�
Until recently, little was known about Bartonella. But Raoult says a
growing number of diseases are being blamed on the bug. 鈥淓very year we are
finding two or three new diseases caused by Bartonella,鈥� he says.