Solving large scale diseases outbreaks is a job for a Detective

Wed, Feb 20th 2019 at 12:50 pm - 2:00 pm

What role is there for Medics, Vets and Governments?

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Arthur Griffiths related case histories from his career as a government veterinary surgeon.These were veritable detective stories.

In 1964 two Aberdeen students contracted typhoid fever, an exceptional occurrence in Scotland. Over a matter of weeks 540 farther cases arose in the surrounding area.

Investigation traced the outbreak to infected canned meat from a single source - William Lows in Aberdeen. At that time there was no legislation covering food hygiene. Everything was sliced on the same machine which was never cleaned between uses and the staff never wore gloves.

Further enquiries traced the canned meat to corned beef from Argentina - from the same cannery! A UK vet seconded to Buenos Aires studied the canning process. It was discovered that imperfectly sealed cans were cooled with untreated river water. Farther upstream there had been outbreaks of human typhoid.

One consequence of these investigations was greater UK supervision of Argentine canning processes. Another, less well known, was that our government held twelve years worth of canned meat in emergency stocks. This was at the height of the Cold War. No one could tell whether these stocks contained infected meat or not. They were eventually released for use with instructions that the contents be well cooked before consumption!

Three years later, a case of foot and mouth disease was reported to the local veterinary officer in Shropshire. He knew exactly what action to take. It was market day. He ordered closure of the market by noon. F&M is a wind borne virus. The prevailing south-westerlies spread the infection into neighbouring counties, resulting in 2,000 cases. With outbreaks in so many areas what could possibly be the cause?

Detective work found wrappers from sheep meat in farm bins. These all came from the same place - Argentina. Three vets were sent out to Argentina. The virus can survive processing, lying dormant in bone marrow. The import of boned meat was banned. All plants had to be licensed. Infected animals were culled and the outbreak brought under control.

Twelve years later, in 1978, a case of F&M was detected in a bull in Hampshire and also in a batch of sows in Newcastle. Unfortunately, the government interfered, allowing markets three days to close. Over this period infected animals were transported all over the country and even abroad. This prolonged the outbreak leading to thousands of animals being slaughtered before it could be brought under control.

The greatest investigative success came in the 1980’s over handling the BSE epidemic. Some cows were observed with a condition similar to scrapie in sheep. There was no known causal organism. Creutzfeldt-Jacob disease in man is very similar. Only dairy herds were affected, not meat herds which were fed on grass Dairy cattle were given concentrated feeds containing animal protein. Where these were heat treated there were no cases. Chemical treatment did not destroy the prion responsible. Now no animal product is allowed in feed. At the height of the epidemic 40,000 animals were slaughtered every year.

Last year’s case in Moray was shown to be an isolated mutation.

Douglas Jackson proposed thanks, praising Arthur’s detective skills while conceding the masterly presentation had put him off corned beef for life.