Emerging Food Pathogens

1. Emerging Food Pathogens Irene Gallou Helen Greet Jo McIntyre

2. E.coli Salmonella Campylobacter Listeria Norwalk Virus Data from the Public Health Laboratory Service was used to compile the graphs on the following slides. All the pathogens studied are notifiable infections. The authorities, in the shape of the Communicable Disease Surveillance Centre must be informed of any suspected cases of these infections. The GP or attending medical officer is responsible for notifying the CDSC of any suspected infection. We considered a number of pathogens : -

3. E.coli 0157and Salmonella Infections in England and Wales, 1981/2 – 2001. E.coli infections have increased dramatically over the years and remain high to date. S.enteridis is the most common salmonella infection since 1988, accounting for two thirds of all cases reported.

4. Campylobacter and Listeria Infections in England and Wales, 1980/6 – 2001. Listeria in pregnancy can cause damage or death to the fetus and is a very serious condition. Cases of listeria peaked in 1987 and have decreased since, though a smaller peak occurred mid 1990s. Campylobacter is the most prevalent food pathogen, and cases have increased steadily since data began in 1980.

5. This virus is becoming more widely recognised as a common pathogenic agent in cases of gastroenteritis, particularly in children. The rate of transmission is greater than 50% in outbreaks among children such as in schools and nurseries. It is thought the virus can be transmitted through the air as well as in contaminated food and/or water. Several modes of transmission would account for the high infectivity of this virus. From 1992 – 2000 there were 1877 outbreaks of Norwalk related disease in England and Wales, and three quarters of them were in ‘Health Care Situations’, i.e. nursing homes and hospitals. Negative stain Transmission Electron microscopy of Norwalk Virus: - (From a stool sample of a patient suffering from gastroenteritis) Norwalk is a ‘Small Round Structured Virus’ (SRSV) Norwalk Virus

6. Total Food Poisoning Cases in England and Wales, 1982 – 2000. Note: Formal = Formally Notified. Other = Informally Notified/ Reported. Food poisoning cases rose steadily to peak in the mid-1990s and have declined slightly since then.

7. Food poisoning cases tend to follow a pattern, reported cases increase to a peak, and become ‘News’. Then public awareness of the pathogen in question is raised by media coverage of outbreaks and increasing prevalence. Media campaigns disseminate the necessary information to allow the public to guard against the pathogen. Guidelines are published by the Department of Health or similar organisations, on how to avoid a particular infection, or how to minimise the risk of contracting it. Cases will fall as the public becomes aware of guidelines and procedures to avoid infection. A ‘new’ pathogen will emerge and the cycle begins again with the ‘latest thing’ as the major source of outbreaks. Many food poisoning cases are underreported, particularly if medical attention is not sought. Also people tend to ‘suffer from’ whichever pathogen was last brought to their attention, i.e salmonella in the 1980s and E.coli in the 1990s etc. Particular pathogens in the News at any time become ‘fashionable’ and are blamed for every upset stomach that occurs. Trends in Food Poisoning Cases

8. Public Health Laboratory Service. • The PHLS publish data relating to the numbers of reported cases of various diseases and infections, including food poisonings. • They also publish guidelines on the control of outbreaks, for example in schools and nurseries. • PHLS data is accurate and reported without hysteria or ‘hype’. The PHLS deal with the FACTS of the infections and pathogens they deal with. • The PHLS publish accurate figures for confirmed cases of all the diseases they deal with. www.phls.co.uk

9. References. • Baron RC, Murphy FD, Greenberg HB, Davis CE, Bregman DJ, Gary GW, Hughes JM, Schonberger LB. Norwalk gastrointestinal illness: an outbreak associated with swimming in a recreational lake and secondary person-to-person transmission. Am J Epidemiol 1982; 115: 163-72. • Kaplan JE, Feldman R, Campbell DS, Lookabaugh C, Gary GW. The frequency of a Norwalk-like pattern of illness in outbreaks of acute gastroenteritis. Am J Public Health 1982; 72: 1329-32. • Kaplan JE, Gary GW, Baron RC, Singh N, Schonberger LB, Feldman R, Greenberg HB. Epidemiology of Norwalk gastroenteritis and the role of Norwalk virus in outbreaks of acute nonbacterial gastroenteritis. Ann Intern Med 1982; 96: 756-61. • PHLS. www.phls.co.uk/home • PHLS. Outbreaks of Norwalk-like virus infection. Commun Dis Rep CDR Weekly [serial online] 2002 [cited 10 April 2002]: 12 (4): news. Available at <http://www.phls.org.uk/publications/CDR%20Weekly/archive02/News/news0402.html#Norwalk>. • Sawyer LA, Murphy JJ, Kaplan JE, et al. 25- to 30-nM virus particle associated with a hospital outbreak of acute gastroenteritis with evidence for airborne transmission. Am J Epidemiol 1988; 127: 1261-71.

10. References 2. • Thornhill TS, Kalica AR, Wyatt RG, Kapikian AZ, Chanock RM. Pattern of shedding of the Norwalk particle in stools during experimentally induced gastroenteritis in volunteers as determined by immune electron microscopy. J Infect Dis 1975; 132: 28-34. • URL: http://www.epa.gov/nerlcwww/norwalk.htm • White KE, Osterholm MT, Mariotti JA, Korlath JA, Lawrence DH, Ristinen TL, Greenberg HB. A foodborne outbreak of Norwalk virus gastroenteritis: evidence for post-recovery transmission. Am J Epidemiol 1986; 124: 120- 6.