The annual conference of the Royal Pharmaceutical Society's Agricultural and Veterinary Pharmacists Group was held in Milton Keynes on November 6 and 7. Steven Kayne reports
Mr Martin Shakespeare (community pharmacist, York) spoke on the highly topical subject of food-borne zoonoses - diseases that could be contracted from eating foods of animal origin. He began by defining the term "zoonosis", using the World Health Organisation definition, as "those diseases and infections which are naturally transmitted between vertebrate animals and man".
Mr Shakespeare continued by outlining the importance of food-borne zoonoses to the agricultural industry, public health authorities and consumers.
In general, people most at risk were those individuals who came into daily contact with animals, either alive or dead (animal handlers, food industry workers), were less resistant to infection (children, the elderly, the infirm, theimmunocompromised, pregnant women), or who had less regard than normal for hygiene routines.
Mr Shakespeare emphasised the economic impact of food-borne zoonoses to producers through loss of product, poor quality and contamination of animal carcasses. From a consumer perspective there could be extreme anxiety, long-term effects, morbidity and mortality.
He described a number of different zoonotic conditions in detail.
Shellfish poisoning Planktonic algae called dinoflagellates produced toxins which accumulated in shellfish and certain other fish and could cause acute symptoms of poisoning. These included perioral numbness and tingling, nausea and vomiting, diarrhoea, elevated temperatures and neurological symptoms.
E coli Escherischia coli was found in meat, and produced a toxin that damages the gut lining. The bacterium was first isolated in the 1980s and it had been estimated that 15 per cent of cattle were carriers. Fortunately, only 30 per cent of humans who were infected showed symptoms. The most susceptible groups were children, the immunocompromised and the elderly. In 1991, the incidence had been 361 cases, rising to over 1,000 in 1997.
CJD Creutzfeld-Jakob disease had first been described in 1920-21. It was now known to be a human disease closely related to bovine spongiform encephalopathy, a fatal neurological disease of cattle first formally identified in Britain in November, 1986. Mr Shakespeare detailed the various forms of the disease and outlined the measures taken by the Government to contain it.
Listeriosis Listeriosis was caused by Listeria monocytogenes. Approximately 5 per cent of the population carried the organism in the gut asymptomatically. After consumption of contaminated food, infection commenced with symptoms resembling a mild chill. It could cause premature birth or miscarriage in pregnant women and meningitis in neonates. Septicaemia and meningitis could occur in adults who were immunologically impaired. Treatment involved using antibiotics. There were no vaccines and one third of cases were fatal. Usual incidence was one to three cases per million per year. The foods implicated included raw meat and fish, poultry, shellfish, dairy products (ripened soft cheeses, inadequately pasteurised milk), vegetables, cook-chill meals, and raw eggs.
Salmonella Salmonella enteritidis (fish and poultry) and Salmonella typhimurium dt104 were responsible for 30,000 cases of food poisoning per year. Salmonella was primarily associated with cattle but it had also spread to pigs, sheep and poultry. Symptoms included sickness, diarrhoea, abdominal pain, and fever. Susceptible groups were the elderly, the very young and the infirm.
Brucellosis Brucellosis brucella abortus (cattle), Brucella melitensis (sheep and goats) were transmitted by milk and caused malaise, chills, fever, sweating, weakness, myalgia, headache and psychoneurosis.
Q-fever Q-fever (Coxiella burnetti) could be spread by milk. Most cases resolved in two weeks but the symptoms could be serious in at-risk groups
There were several ways to minimise the risk of zoonotic infection from food, said Mr Shakespeare. Appropriate animal management, disinfection, hygiene and keeping raw and cooked meats apart in the retail environment were vital. Refrigeration and complete cooking in the household were also important.
Surprisingly, up to 50 per cent of the general public did not follow cooking instructions.
Completing his comprehensive review, Mr Shakespeare considered briefly antimicrobial bacterial resistance. He finally concluded with the assurance that food was safer now than ever, leaving the last word to J. Edgar Hoover: "The price of safety is vigilance."