Guinea pigs in history

Image of Professor Marshall Edwards

In late 2010, the Campbelltown Macarthur Advertiser carried a story celebrating remarkable Sydney alumnus, Marshall Edwards (BVetSc ’49 PhD ’70 DVetSc ’79). Professor Edwards had just delivered the inaugural Sarah Smith Paediatric Oration at the University of Western Sydney’s school of medicine.

Professor Edwards spoke to students about what happened when a group of guinea pigs delivered unusual numbers of deformed and stillborn babies and his realisation that there might be a cause-and-effect in play because they occurred immediately after a heatwave.

‘‘We had a guinea pig colony which was housed temporarily in an uninsulated iron shed,’’ he said. ‘‘Suddenly, out of the blue, came two very hot days, between 41C to 43C, and it really did stress the guinea pigs. They started to abort and miscarry.”

A few days later, the situation deteriorated further when guinea pigs were born with joint problems and other flaws – absence of eyes and teeth; heart defects, cataracts, clubfeet.

‘‘I couldn’t believe it,” recalled Professor Edwards. ‘‘I thought it was time to do some experiments.’’ And it was on a cold winter’s night in the University’s Vet Science lab at Camden when Professor Edwards made the breakthrough link between heat and birth defects. He found that outside temperatures had to be just two degrees above the animals’ normal body temperature to have a devastating effect on their pregnancies and unborn young. Professor Edwards’ findings then sparked further research in the United States and Europe that led to greater knowledge of the dangers of maternal fevers and other hitherto unknown environmental concerns.

UWS professor of paediatrics John Whitehall said the students benefited from hearing of the discovery and research.

‘‘As a veterinary scientist, Professor Edwards may be an unexpected selection to give a lecture on pediatric medicine, but his work has helped to identify the risks of maternal fever, and it is inspiring that the work was done locally,’’ he said.