Department of Epidemiological Surveillance and Intervention

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1 Department of Epidemiological Surveillance and Intervention EPIDEMIOLOGICAL DATA FOR SHIGELLOSIS IN GREECE MANDATORY NOTIFICATION SYSTEM NATIONAL REFERENCE CENTRE FOR SALMONELLA AND SHIGELLA Key Points The notification rate of shigellosis has been rising in Greece the last four years. The mean annual number of reported cases is small (57 cases, SD=32) A seasonal pattern was apparent: the mean monthly notification rate increased during summer months, reaching a peak in August. The disease was more frequent among children, especially in the age group of 0-4 years. Only 7.5% were travel-related. 53.5% of the notified cases were Roma. Shigellosis, also called bacillary dysentery, is a foodborne disease caused by the bacteria of the genus Shigella. Shigella comprises of 4 species or serogroups: S. dysenteriae (Group Α), S. flexneri (Group Β), S. boydii (Group C) and S. sonnei (Group D) [1]. The incubation period of the disease is usually 1-3 days, and may range from 12 to 96 hours; for S. dysenteriae it can be up to one week [1]. In developed countries, the disease often occurs among young children and adults after traveling to endemic areas. The pathogen can cause both sporadic cases and outbreaks [2,3]. In Greece, shigellosis is a mandatory notifiable disease *. Additionaly, the National Reference Centre for Salmonella and Shigella is responsible for the laboratory surveillance of Shigella. * The presented data refer to the period , as Mandatory Notification System was reorganized in

2 Time trend The number of reported cases per year, for the period , is shown in Table 1. The temporal distribution of shigellosis notification rate for the same years is depicted in Graph 1. The annual notification rate ranged from 1.7 cases in 2008 to 10.8 cases per 1,000,000 population in The mean annual notification rate for the period was 5.1 cases per 1,000,000 population and the mean annual number of reported cases was 57 (standard deviation: 32). Age and gender distribution Shigellosis is more common among children. In particular, for the period, the disease had a higher mean annual notification rate in the age group 0-4 years (57.9 cases per 1,000,000 population), followed by the age group of 5-14 years (13.5 cases per 1,000,000 population) (Graph 2). During the same period, the mean annual notification rate did not significantly differ between males (5.2 cases/1,000,000 population) and females (4.9 cases/1,000,000 population). Seasonality The mean monthly notification rate for the same 12-year period, increased during summer, reaching a peak in August, and remained high during autumn (Graph 3). Geographical distribution The geographical region of Western Greece had the highest mean annual notification rate (10.2 cases per 1,000,000 population), while the lowest rate was noted in the area of Southern Aegean (0.3 cases per 1,000,000 population). The highest increase in 2015 was noted in the region of Attica (from 9.3 cases in 2014 to 14.1 cases per 1,000,000 population in 2015). It should be noted that in 2015, in Attica, Shigella cases were reported in the population of refugees/immigrants [3]. Laboratory data During , S. flexneri and S. sonnei were the most frequently notified species of Shigella. Only six cases of S. dysenteriae were identified during this period. A high 2

3 percentage of strains were not further classified. Frequency distribution of Shigella species, for the years , is presented in Table 2. Risk factors For the period , 363 (53.5%) of the notified cases were Roma. One hundred and twenty three of the 603 notified cases (20.4%), for which the respective information was available, reported the presence of another person with similar symptoms among their contacts, whereas 42 (7.5%) cases had recently travelled abroad (during incubation period). Discussion The notification rate of shigellosis has been rising in the last years. The high incidence among Roma indicates the need for public health measures targeting at this specific population. The mean notification rate of shigellosis in the EU and the EEA/EFTA countries was 13.6 cases per 1,000,000 population for the year 2014 [4]. When interpreting these data, the surveillance systems probable under-reporting should be taken into account. The seasonal and age distribution agrees with that reported by other European countries [4]. References 1. Heymann DL. Control of Communicable Diseases Manual. Washington DC: American Public Health Association; The Community Summary Report on Trends and Sources of Zoonoses and Zoonotic Agents and Food-borne Outbreaks in the European Union in The EFSA journal 2010; Available from: 3. Georgakopoulou T, Mandilara G, Mellou K et al. Resistant Shigella strains in refugees, August-October 2015, Greece. Epidemiol Infect. 2016, 16: European Centre for Disease Prevention and Control. Surveillance Atlas of Infectious Diseases. Shigellosis Data by Country and Year. Current time period: Available from: 3

4 Table 1. Annual number of notified cases of shigellosis, Mandatory Notification System & National Reference Centre for Salmonella and Shigella, Greece, Year Number of cases Total 679 Graph 1. Time trend of shigellosis notification rate (cases/1,000,000 population), Mandatory Notification System & National Reference Centre for Salmonella and Shigella, Greece,

5 Graph 2. Mean annual notification rate (cases/1,000,000 population) of shigellosis by age group, Mandatory Notification System & National Reference Centre for Salmonella and Shigella, Greece, Graph 3. Mean monthly notification rate (cases/1,000,000 population) of shigellosis, Mandatory Notification System & National Reference Centre for Salmonella and Shigella,, Greece,

6 Table 2. Frequency distribution of Shigella species, Mandatory Notification System & National Reference Centre for Salmonella and Shigella, Greece, S. flexneri S. sonnei S. boydii S. dysenteriae Unknown Total n (%) n (%) n (%) n (%) n (%) n (%) (30.6) 13(21.0) 1 (1.6) 0 (0.0) 29 (46.8) 62 (100.0) (30.8) 11 (42.3) 1 (3.8) 0 (0.0) 6 (23.1) 26 (100.0) (14.8) 2 (7.4) 1 (3.7) 0 (0.0) 20 (74.1) 27 (100.0) (8.5) 23 (48.9) 0 (0.0) 0 (0.0) 20 (42.6) 47 (100.0) (50.0) 1(7.1) 0 (0.0) 0 (0.0) 6 (42.9) 14 (100.0) (50.0) 1(2.9) 1 (2.9) 0 (0.0) 15 (44.1) 34 (100.0) (63.0) 2 (7.4) 0 (0.0) 2 (7.4) 6 (22.2) 27 (100.0) (36.4) 1(2.3) 1(2.3) 0 (0.0) 26 (59.1) 44 (100.0) (29.7) 1 (1.1) 0 (0.0) 0 (0.0) 63 (69.2) 91 (100.0) (43.7) 28 (23.5) 0 (0.0) 1 (0.8) 38 (32.0) 119 (100.0) (41.1) 19 (21.1) 1 (1.1) 0 (0.0) 33 (36.7) 90 (100.0) (52.6) 15 (19.2) 4 (5.1) 3 (3.8) 15 (19.2) 78 (100.0) Foodborne and Waterborne Diseases Section K. Mellou. T. Sideroglou Tel: National Reference Centre for Salmonella and Shigella G. Mandilara, A. Vatopoulos 6