A 2010 Austrian Salmonella enteritidis PT4 outbreak associated with a laying hen holding previously involved in an S. enteritidis PT4 cluster: pitfalls of regulatory responses in risk management.

We report on an outbreak caused by Salmonella enteritidis phage type 4 (PT4) among 143 participants at a soccer camp in Austria in August 2010. The outbreak affected 34 persons, including 24 epidemiologically related cases and 10 laboratory-confirmed cases. Food-specific cohort analyses revealed spaetzle (homemade noodles) (relative risks (RR): 2.68; 95% CI: 1.13-6.45), hamburger (RR: 2.70; 95% CI: 1.13-6.45) and potato salad (RR: 2.91; 95% CI: 1.69-5.02) as the most biologically plausible infection sources. Eggs used as ingredients were considered to be the vehicle of infection for the outbreak strain. The sole egg producer supplying the hotel that housed the soccer camp participants with table eggs operated two flocks. One flock had been epidemiologically and microbiologically related to a previous S. enteritidis PT4 outbreak affecting the same Austrian province in the four months preceding the August outbreak. We hypothesize that eggs from this flock, already condemned for industrial use only, were falsely declared table eggs and sold among eggs from the non-banned flock causing the subsequent outbreak. In Austria, the illegal distribution of eggs designated for industrial use (i.e., false declaration of these eggs as table eggs) has been previously documented. Our findings underscore the potential of proper epidemiological outbreak investigation to identify the pitfalls of regulatory responses in risk management.

Rubella in Austria 2008-2009: no longer a typical childhood disease.

BACKGROUND: In February 2009, a cluster of rubella cases was recognized in Austria occurring between calendar weeks 3 and 7, 2009 after a long period of low rubella virus activity. A nationwide 2-dose measles, mumps, and rubella vaccination program had been introduced in 1994 to prevent this childhood illness. METHODS: An epidemiologic investigation was conducted to describe the cluster by time, place, and person. A confirmed outbreak case was defined as a febrile person (1) with generalized rash, which was laboratory confirmed or epidemiologically linked to a laboratory confirmed case and (2) who became ill after October 1, 2008 in the 2 affected provinces. A probable outbreak case was defined as any person meeting the clinical criteria of rubella and meeting the criterion 2 of a confirmed outbreak case. All cases were telephone interviewed on demographics and vaccination status. RESULTS: A total of 355 outbreak cases (including 247 confirmed cases) occurred in 2 neighboring Austrian provinces from mid-October 2008 until the end of June 2009, peaking in mid-March. The 2 most-affected age groups were 15 to 19 (44.4%) and 20 to 24 year olds (32.4%). The vaccination status was available for 230 cases; 10% of cases had received 1 measles, mumps, and rubella vaccine dose. No case had received 2 doses. Of the 146 female cases, one laboratory-confirmed rubella infection in a pregnant 18-year-old native Austrian resulted in elective abortion. CONCLUSIONS: These findings underline the waning epidemiologic role of children in maintaining the circulation of rubella virus and indicate that additional vaccination activities targeting >15 year olds are needed to achieve the 2010 WHO target for rubella elimination in the European Region.

Foodborne outbreaks, Austria 2007.

In 2007 Austria reported a total of 438 foodborne outbreaks affecting 1715 people, including 286 hospitalized patients and one death. Salmonella spp. and Campylobacter spp. accounted for 95% of all reported outbreaks. Forty-eight (11%) of the 438 Austrian outbreaks were acquired abroad. Of the 390 domestically acquired foodborne outbreaks, bacterial infection caused 376, viruses (norovirus and 1-time hepatitis A virus) caused 11, and intoxications (Staphylococcus aureus enterotoxins, alkaloid toxins) caused two. In one outbreak the causative agent was unknown. Salmonella spp. caused 264 (70%) of the bacterial outbreaks, Campylobacter spp. caused 104 (28%), enterohemorrhagic Escherichia coli (EHEC O145:H-, O157:H-, O157:H7, O182: H49, O91:H7, ONT:H4) caused six, Shigella flexneri and Shigella sonnei each caused two. The hospitalization rates were 22% for domestically acquired infections with Salmonella spp. and 14% for Campylobacter spp. Among outbreaks where the source was known, eggs were implicated in 49%, meat products (especially poultry) in 44% and fish in 2%. The ratio of household outbreaks to general outbreaks was 82.3% to 17.7%. In 54 of the 62 general domestic outbreaks the following locations of exposure were documented: commercial food suppliers (e.g. restaurants, cafeterias) 24 times, family celebrations, nursery schools, take-aways and barbecues 22 times, nursing homes and hospitals eight times. It is likely that the relatively high number of household outbreaks reflects an insufficient level of epidemiological investigation of outbreaks in Austria. More resources may be needed for identification of individual clusters that belong to larger foodborne outbreaks exceeding district or provincial borders.

Epidemiology of listeriosis in Austria.

A total of 150 human cases of listeriosis (case definition based on isolation of Listeria monocytogenes from normally sterile material) were reported in Austria between 1997 and 2007. Of these, 14 cases (9.3%) were pregnancy-associated (mother/child illness considered as a single case) with a mean age of 29.3 years (median: 26.5; range 24-36). Among the non-pregnancy-associated cases (n = 136), 75 were male (55.2%) and 61 female (44.9%); patients in this group had a mean age of 64.3 years (median: 66.2; range 1-93). The average incidence of listeriosis in Austria in the period studied was 0.168 cases per 100,000 population. The majority of cases (90.7%) were caused by systemic infection, only 9.3% of cases were local infections. Among non-pregnancy-associated cases the fatality rate was 28.7% (39/136) and among the pregnancy-associated cases 35.7% (5/14: miscarriage x3, stillbirth x1, and one death in a newborn within 15 days of birth). Serotyping results for the 150 isolates revealed serovar (SV) 4b: 54%, SV 1/2a: 31.3%, SV 1/2b: 10%, SV 1/2c: 2.7%, 4d: 1.3% and SV 3a: 0.7%. Predisposing risk factors were determined for 131 of the 150 cases: age > or = 65 years (n = 73), pregnancy (n = 14) and 44 cases of carcinoma, blood malignancies, autoimmune diseases and status post solid organ transplants (7 patients had more than one underlying illness). During the period studied, the incidence of listeriosis doubled, despite a drastic reduction in the frequency of pregnancy-associated cases.

A foodborne outbreak of Salmonella Enteritidis phage type 6 in Austria, 2008.

In April 2008, a general foodborne outbreak of Salmonella Enteritidis phage type 6 affected nine persons (two households in Salzburg and one household in Tyrol; eight microbiologically confirmed cases and one possible case). Epidemiological investigation revealed that all cases had eaten lunch together at a farm. Homemade bread dumpling loaf, prepared with eggs from the farm, was the most likely vehicle for the pathogen. Six eggs were bacteriologically tested and yielded the outbreak strain on the egg shells. The farm's egg laying flock consisted of 12 hens, which were identified as the source of infection by isolating the outbreak strain from samples of hen fecal material and dust. Molecular subtyping using multiple loci variable number of tandem repeats analysis (MLVA) revealed a pattern unique to isolates from the outbreak, different from nine epidemiologically unrelated isolates tested for comparison. The laying hens were culled and no further cases of salmonellosis were associated with the farm. This example demonstrates the considerable potential of outbreak investigation to elucidate the transmission of infection along the food chain and to provide information essential for implementation of targeted measures for prevention of foodborne illness.

Imported Salmonella Enteritidis cases: a multiphage outbreak among Austrian vacationers in Turkey, 2008.

An outbreak of Salmonella Enteritidis infection among high school graduates was associated with the 2008 three-week Summer Splash event in Turkey. A similar outbreak, caused by Salmonella Enteritidis PT6, affected 70 of 2879 graduates attending the 2007 Summer Splash event. A total of 103 cases of Salmonella Enteritidis were identified by passive and active case finding among the 8914 participants of the 2008 event. A case series investigation was performed. The cases originated from eight of the nine Austrian provinces. Among 59 laboratory-confirmed S. Enteritidis cases, the most commonly identified phage type was PT21 (72.9%), followed by PT6 (18.6%), PT7 and PT3 (3.4% each). To our knowledge, none of the published outbreaks of salmonellosis in the past 10 years has involved multiple phage types. Among the three hotels within the resort complex, the highest number of outbreak cases was identified among the students who stayed at Hotel A (n = 37), followed by Hotel B (n = 33) and Hotel C (n = 32). Eggs and egg-containing products frequently offered at meals in all three hotels were hypothesized as the source of infection. Reliable findings from investigation of imported outbreaks enable the appropriate response measures in the country of origin. As a consequence of the effective programs for reducing salmonella in domestic animals intended for human consumption in Austria, the number of imported cases will gain importance in the coming years, and salmonellosis will increasingly appear as traveler's diarrhoea.

A food-borne outbreak of Shigella sonnei gastroenteritis, Austria, 2008.

We report on the first foodborne outbreak of Shigella sonnei described in Austria. On July 14 2008, AGES was informed of a cluster of 22 laboratory-confirmed cases of infection with S. sonnei restricted to public health district X in the province of Salzburg. All cases had attended a youth-group trip to a small village in the province of Tyrol from July 7 to July 9. An outbreak case among the trip participants was a person who (1) attended the trip and (2) fell ill with diarrhea in the period between July 8 and July 12. Among the 61 trip participants, 42 fitted the outbreak case definition, including 31 culture-confirmed cases. A household outbreak case was a person who (1) did not participate in the trip, (2) fell ill with diarrhea not before July 10 and (3) had household contact with an outbreak case between one and three days before onset of illness. Of the 11 household outbreak cases, 10 were tested by stool culture and four of these had a laboratory-confirmed S. sonnei infection. In addition, one of the two hostel staff tested positive for S. sonnei. All 36 isolates were biotype gl, lysotype 12, and were indistinguishable from each other by PFGE. A cohort study among the trip participants revealed a risk ratio of 2.71 for consumption of salad (on at least 1 of the 3 days of the trip) (95% CI: 1.38-5.32, P = 0.004). Among the 42cases, 34 could be explained by consumption of salad. The landlady of the hostel, who prepared the salad with bare hands, was a carrier and was assumed to be the source of contamination of the salad. Without proper epidemiological analytical investigation of this shigellosis outbreak, its association with food consumption would not have been identified.

An outbreak of febrile gastroenteritis associated with jellied pork contaminated with Listeria monocytogenes.

In September 2008, the Austrian Agency for Health and Food Safety (AGES) learned of an outbreak of diarrheal illness that included a 71-year-old patient hospitalized for gastroenteritis with a blood culture positive for Listeria monocytogenes. Three stool specimens provided by seven of 19 persons attending a day trip to a foreign city, including a final break at an Austrian tavern, yielded L. monocytogenes. All isolates were of serovar 4b and had fingerprints indistinguishable from each other. A cohort study revealed that the outbreak of gastroenteritis occurred among 16 persons who had eaten dinner at the wine tavern on September 6. Of the 15 persons who ate from platters of mixed cold-cuts, 12 (80%) developed symptoms of febrile gastroenteritis within 24-48 h. The median age of those who became ill was 62 years. A 72-year-old patient recovered from gastroenteritis but was hospitalized with bacterial meningitis on day 19 after the dinner. The epidemiological investigation identified the consumption of mixed cold-cuts (including jellied pork) at the wine tavern as the most likely vehicle of the foodborne outbreak (P = 0.0015). This hypothesis was confirmed by microbiological investigation of jellied pork produced by the tavern owner on September 3. L. monocytogenes was isolated from leftover food in numbers of 3 x 10(3)-3 x 10(4) colony forming units/g and was indistinguishable from the clinical outbreak isolates. Symptoms reported by the 12 patients included unspecified fever (12x), diarrhea (9x), headache (5x), vomiting (4x), body aches (2x) and sore throat (1x). Active case finding identified one case of rhombencephalitis (female, age 48) among another group of four guests, among whom only the patient and her asymptomatic husband had eaten jellied pork on September 6. This is the first outbreak of L. monocytogenes-associated gastroenteritis reported in Austria. The occurrence of a secondary case of meningitis (diagnosed on day 19 after consumption of jellied pork) indicates a significant risk of systemic listeriosis among elderly patients with febrile gastroenteritis caused by L. monocytogenes; antibiotic therapy should therefore be considered in such cases of documented listerial gastroenteritis.