Salmonellas and eggs.

Salmonella food poisoning is a common cause of human illness in the United Kingdom, and in the last two years the incidence has increased appreciably. Much of the increase can be attributed to a particular subtype of one of the many serotypes, Salmonella enteritidis phage type 4 (PT4). This is predominantly a poultry serotype, but the current epidemic has been attributed not only to poultry meat but also to a more unusual source, hens' eggs. Furthermore S enteritidis PT4 is not the only strain that has recently been responsible for egg associated outbreaks. Other phage types of S enteritidis have caused egg associated outbreaks in hotels in 1988 (Communicable Disease Surveillance Centre (CDSC), unpublished observations), and S typhimurium PT49 was responsible for a widely publicised incident associated with eggs used to make mayonnaise at the House of Lords.2 The number of cases of human salmonellosis reported to the Public Health Laboratory Service (PHLS) CDSC in 1978 was 9042, and only 661 (7.3%) of these were S enteritidis. In 1987, 16 991 cases of salmonella were reported and 5653 (33.3%) of these were S enteritidis (CDSC, unpublished observations) and for 1988, the provisional estimates are that 12 500 of 23 000 salmonella infections (54.3%) were S enteritidis. At present, about 35% of the S enteritidis isolates reported are in those under 15 years of age. Although children and infants are more likely than older people to have stool samples cultured, there is undoubtedly considerable underascertainment of salmonella infection in all age groups.1 Salmonella infection can lead to serious complications especially in children. In the 10 years to 1987, 1655 salmonella bacteraemias were reported to the PHLS CDSC, and of these 312 (19%) were in patients under 15 years old, and 124 (7%) in those under 1 year (CDSC, unpublished observations). The corresponding figures for salmonella meningitis were 40 in total, 31 (78%) in patients under 15 years old and 27 (68%) in those under 1 year old. Although the proportion of salmonella infections progressing to bacteraemia does not appear to be increasing, the total annual number of salmonella bacteraemia has risen from 131 to 226 during this 10 year period.