MANILA, Philippines?With just a few days left before the Beijing Olympics come to an end, only a handful of athletes attending have tested positive for performance enhancing substances. A cyclist from Spain, a hurdler from Greece and a gymnast from Vietnam are among those who have either been sent home for not living up to the Olympic motto of ?faster, higher, stronger? on their merits.

Perhaps the small number of violations is due to increased scrutiny and regulation over drug doping?over 4,500 blood and urine samples from Olympic athletes are being collected and tested at these Games.

Competitive animals must abide by anti-doping regulations of their own, and are subject to urine tests as well that check for the presence of banned substances such as steroids and caffeine. Because the latter is a stimulant, it can reduce the horse?s feelings of fatigue and make it more alert, giving it an edge in competition even if the animal?s not having a particularly good day.

Horse doping case

In the July 3 issue of the Journal of Forensic Science, researchers from Argentina?s National University of La Plata reported on a horse-racing case of drug doping they were asked to investigate.

The case was fairly straightforward: A racehorse had tested positive for caffeine doping, but the owner insisted the animal was clean. The owner suspected that the urine sample for his horse had been switched or tampered with, and asked the researchers to confirm that the sample had come from the animal in the first place.

Lead author Silvina Diaz and her colleagues collected blood and hair samples from the horse themselves, and then matched them against the then 3-month-old positive urine sample through DNA tests. The tests proved the horse?s owner was right: as he?d suspected, the genetic information in the blood and hair samples taken from his horse matched each other. However, neither of the samples matched the DNA in the urine sample.

Manipulation of samples

Diaz and her colleagues wondered if there just wasn?t enough DNA in the urine sample to make a match; after all, only a third of urine samples collected provide enough useful DNA for testing. But they also wondered if the positive urine sample had come from a horse in the first place.

Testing the latter theory, the scientists conducted another series of tests to determine the species that had provided the urine sample compared to horse and human controls. The result of their analysis: the caffeinated sample in the doping case was actually from a human.

?In conclusion,? Diaz and her colleagues wrote in their paper, ?we demonstrated that the alleged horse urine was of a human origin, indicating the manipulation of samples. This evidence supports the innocence of the breeder suspected of horse doping.?

So the horse is proven innocent and his owner is vindicated. Diaz and her colleagues don?t mention what happened then, but presumably the police would have gotten involved in the search for the person or persons involved in switching the racehorse?s original urine sample with that of a human. Still, one has to wonder how easy it would be to make a list of potential suspects based on the description of a caffeinated human hanging around the racetrack.

E-mail the author at massie@massie.com.