When employees in 52 car dealerships across 27 US states simultaneously develop food poisoning, who are you going to call? The Centres for Disease Control, in Atlanta, of course. The CDC are the Ghost Busters of bad bug tracing.
Telling the story of the boxed banquet that went sadly awry for the car salespersons, Dr Maureen Lynch, of the CDC's viral gastroenteritis section, said more than 800 car dealership employees were interviewed.
The boxed banquets, a reward for meeting sales targets, were made up of components supplied by four catering companies and then sent to the dealerships.
Eventually the illness was traced back to the salads supplied by one of the catering companies. A Norwalk-like virus was the culprit. Two of the food handlers had IgA antibodies to the virus, indicating recent infection.
Pictures showing a cracked tray full of pasta, sitting beside a bin in a catering establishment of dubious quality, were put on the screen at the Foodborne Viruses seminar, held recently in Dublin under the auspices of the Food Safety Authority of Ireland. The bare arm of a food handler (who was IgA positive) was the mixing utensil for the pasta salad, Dr Lynch said. The company was indicted on 72 violations and closed.
Dr Lynch, a graduate of UCC's medical faculty, worked on rota viruses in medical microbiology in Cork University Hospital before joining the CDC in January 2000. As a researcher in the epidemiology of food-borne viruses in the US, she concentrates mainly on Norwalk-like viruses, while continuing her work on rotavirurses.
Norwalk-like viruses are the predominant agent in outbreaks of acute gastro-enteritis and are spread by food, water and person-to-person contact. Many of the car dealership employees' families also became ill, although they hadn't actually eaten the salads.
The dangers of how food-borne viruses can spread illness were also illustrated at the American football game where more passed between the players than tough tackles. The North Carolina team struggled through the match, occasionally visiting the sidelines to vomit.
Their opponents, a Florida team, won easily but became ill the next day, although the only contact they had with the North Carolina team was on the pitch. The culprit: turkey sandwiches consumed in North Carolina, which contained the Norwalk-like virus.
It is estimated that in a single year in the US, there are 267,000,000 episodes of food poisoning with 612,000 hospitalisations and 3,000 deaths.
Here, new figures released by the FSAI for the past 18 months show 44 outbreaks of gastro-enteritis with 1,920 people sick and 109 hospitalised. Of those, 1,476 had viral infections with 36 of the hospitalisations were attributed to viruses.
The reported figures for viral gastro-enteritis were a gross under-representation according to the chief executive of the FSAI, Dr Patrick Wall. "When it comes to reporting, you must jump over more hurdles than Istabraq," he said. "Viral diseases are self-limiting so patients may not go to doctors and, even if they do, samples may not be sent to labs."
Preliminary results from an ongoing study to determine the real incidence of gastro-enteritis in Ireland indicate that eight per cent of householders had suffered from vomiting or diarrhoea in the month previous to the interview, Dr Wall said. In all, 10,000 people will be interviewed by telephone by the end of the year as part of the study.
A similar telephone survey is underway in the US, Dr Lynch said. Viral outbreaks are significant because of the low infective dose and prolonged shedding of the virus after the illness, she said. The current recommendation that food handlers do not work for 48 hours after an episode of gastro-enteritis may have to be re-adjusted upwards, she believes.
Clearly enthusiastic about her post, Dr Lynch said the CDC is one of the most fascinating places in the world, with an international as well as an US dimension. As a reference lab, it has huge resources, she said. "It's a great learning experience for someone from a small country like Ireland. My ultimate aim is to bring that experience back home."