Our French food safety friend, Albert Amgar, sends along the abstract of this unique outbreak:
An epidemic of streptococcal tonsillitis (SGA) in camps in children and adolescents was investigated in a camp in Corsica in July 2012. The majority of cases were registered in 48 hours making suspect a collective foodborne outbreak although this mode of transmission is rare.
The retrospective cohort investigation aimed to confirm this hypothesis and find the source of the contamination. A clinical case was defined as any person who, from July 18 to 31, had at least a sore throat or tonsillitis or pharyngitis, associated with a rapid diagnostic test (RDT) positive or one of the following signs: fever, headache, dysphagia. Cases classified as primary related to dietary exposure were those that occurred before July 25, the later cases being considered secondary cases related to human transmission.
The epidemiological survey in the camps has identified 156 cases of streptococcal tonsillitis which 46 cases confirmed by TDR and/or throat swab. The attack rate was 30.3% for primary cases and 2.4% for secondary cases. It was higher for people living with full board (38.5%) than for those who were half board (13%). The most risky meals were served on 20 and 21 July at noon, but it was not possible to determine with certainty or foods causing contamination.
The investigation service and kitchen staff showed that the first cases of angina had appeared on 18 and 19 July in servers, which were probably the source of the contamination. She also found two asymptomatic carriers of group A streptococcus (GAS) and 8 patients.
The SGA strain involved, rare emm4.4 type was identical among cooks, children and facilitators, emphasizing a common origin to this epidemic.
Health Watch Institute
Saint-Maurice: Institute for Public Health
Pascal L, M Ruello Marchand E, Neveu A, Korhonen T, J. Mattei