14 July 1995

Moredun unearths clue in cryptosporidium fight

By Allan Wright

EDINBURGH scientists have made a breakthrough in understanding the spread of an organism which is a major cause of scour in cattle and can also infect humans.

Dr Bob Coop at the Moredun Research Institute has discovered that adult cattle which have built up their own immunity to cryptosporidium remain infected and continue to shed eggs from the organism.

"The other thing we have discovered is that a single egg is enough to cause scour in calves and also that the adults can survive for a long time, especially if they get into water courses," said Dr Coop, speaking on the Moredun stand at the show.

He explained that cryptosporidium was a small protozoan parasite similar to the one causing coccidiosis in poultry.

"A lot of calves suffer from scour and the farmer usually follows a routine which clears the infection without really understanding the cause," said Dr Coop. "We now know that cryptosporidium is a major cause and we are beginning a joint study with Cornell University to learn more about the organism and how it can be controlled."

He explained that the American interest stemmed from the famous Milwaukie incident when 400,000 people suffered diarrhoea caused by cryptosporidium getting into water supplies.

"We have had about seven incidents in this country as well and we are concerned that one source could be waste water from dairy farms," said Dr Coop.

Cryptosporidium attacked animals or humans with a weak immune system, he said, which was why young calves were particularly at risk from it. "People on suppressive drugs are at risk and the organism is a major killer among Aids patients," added Dr Coop. &#42