Clostridium perfringens outbreak associated with minestrone soup.

Clostridium perfringens food poisoning usually occurs after animal protein foods such as meat or poultry are consumed. In November 1990, an outbreak of gastrointestinal illness occurred among attendees at a conference of cake decorators held in Michigan. All 42 conference attendees were surveyed. Thirty-two of 42 (76%) attendees reported gastrointestinal symptoms. The median incubation period was 6.5 hours (range, 1.5-15 hours). Ill persons were almost five times more likely to have consumed minestrone soup than were those who were not ill (relative risk = 4.92, 95% confidence interval 1.23-infinity). Bacteriologic analysis identified C. perfringens in the soup and in 11 of 12 stool specimens from ill persons. The soup was cooked 2 days prior to serving and was slowly cooled before refrigeration; it was briefly reheated on the day served. Failure to monitor time and temperature controls during the cooling and reheating of the soup probably allowed for C. perfringens proliferation in the minestrone soup. This investigation demonstrated that nonanimal protein sources, such as legumes, can support substantial C. perfringens growth and should be regarded as potential vehicles in C. perfringens outbreaks.     

An outbreak of a food-related illness resembling boric acid poisoning

An outbreak of an illness suggestive of boric acid poisoning occurred among 51 persons who had eaten lunch at the cafeteria of the United States Agency for International Development in Islamabad, Pakistan, on February 11, 1990. Affected patients had headache and severe myalgias 2 to 4 hours after eating lunch. Fever, nausea and vomiting, red eyes, and photophobia were also reported. Among 25 patients (49%), a sunburn-like inflammation of the skin of the face developed, which subsequently desquamated. One patient required hospitalization for 1 day because of dehydration. Among all patients, the only symptoms remaining 72 hours after the meal were mild headache, fatigue, and peeling skin. Those persons who became ill were more likely to have eaten one particular food item (minestrone soup) for lunch than were those who did not become ill. A similar illness has been described following ingestion of boric acid. However, the results of an analysis of serum samples collected 3 days after the lunch from 24 patients did not show boron above normal background levels. Because of boron's short half-life, however, these data do not rule out the possibility that patients may have had higher boron levels at the onset of the illness.     

An outbreak of Bacillus cereus food-poisoning in Finland associated with boiled rice.

A food-poisoning outbreak caused by Bacillus cereus occurred in a Finnish industrial plant in January 1975. Eighteen of the 36 persons who ate a lunch including boiled rice, meat and vegetables became ill. The disease pattern was similar to previously reported short incubation time B. cereus food-poisonings associated with cooked rice. The median incubation time was two hours, the main symptoms being nausea, abdominal pain and vomiting. Rice and certain seasonings were the contaminated raw materials. Gas chromatographic fatty acid analysis of a bacterial cell was used as a diagnostic method as well as to identify a certain strain of B. cereus.     

A large outbreak of gastroenteritis associated with a small round structured virus among schoolchildren and teachers in Japan

In March 1989 a large outbreak of acute gastroenteritis occurred simultaneously among schoolchildren and teachers at nine elementary schools in Toyota City, Japan. Illness was observed in 3236 (41.5%) of 7801 schoolchildren and 117 (39.4%) of 297 teachers. The main clinical symptoms were diarrhoea, vomiting, nausea and abdominal pain. Gastroenteritis was significantly associated with the consumption of school lunch served by one particular lunch preparation centre. One food handler at the centre suffered from gastroenteritis during the outbreak. Small round structured virus (SRSV) was detected in 4 of 8 stool specimens from sick persons. The school lunch contaminated by the infected food handler is the most probable source of this outbreak due to SRSV.     

A large outbreak of scombroid fish poisoning associated with eating yellowfin tuna (Thunnus albacares) at a military mass catering in Dakar, Senegal

On 26 November 2010, an outbreak of scombroid fish poisoning occurred in the French Armed Forces in Dakar, Senegal. This chemical intoxication, due to high histamine concentration in fish, is often mistaken for an allergic reaction. A case-control study was undertaken including the 71 cases and 78 randomly selected controls among lunch attendees. The usual symptoms for scombroid fish poisoning were observed in cases, i.e. flushing (85.9%), headache (83.1%), rapid/weak pulse (59.1%) and diarrhoea (47.9%). Symptoms occurred from within a few minutes to up to 3 h following the meal. Most patients quickly recovered with antihistamine and/or symptomatic treatment. Tuna was the only food item positively associated with illness (odds ratio 36.3, 95% confidence interval 6.3-210.0), with the risk of illness increasing with the quantity of fish consumed. No bacterial contamination was found in leftover food, but histamine concentration in tuna was found to be 4900 mg/kg, almost 50-fold higher than the concentration allowed by European regulations. This report is unique because of the large size of the case series - to our knowledge, the largest event of scombroid fish poisoning ever reported - and the chemical and bacteriological analyses results obtained on leftover food.     

Outbreak of SRSV gastroenteritis at an international conference traced to food handled by a post-symptomatic caterer.

In an outbreak of small round structured virus (SRSV) gastroenteritis at an international AIDS conference 67 people were ill with diarrhoea or vomiting, one requiring admission to hospital. Epidemiological investigations demonstrated that the vehicle of infection was food prepared by a foodhandler who was recovering from a mild gastrointestinal illness. The food most strongly associated with illness, coronation chicken, was prepared by the food handler on the second day after symptoms ceased. The investigation confirms the view that foodhandlers may contaminate food with SRSVs after cessation of symptoms and should remain off work until at least 48 h after recovery.     

An outbreak of xylene intoxication in a hospital

On January 3, 1980 an outbreak of illness occurred in 15 employees of a small community hospital. Symptoms included headache, nausea, vomiting, and dizziness or vertigo; the duration of illness ranged from 2 to 48 hours. The employees who became ill all worked in areas of the hospital served by one central ventilation system. None of the 180 persons working in other parts of the hospital developed symptoms requiring medical care. Less than 1 hour before the outbreak occurred, 1 liter of liquid xylene had been discarded down a sink drain in the pathology laboratory. Simulation experiments confirmed that xylene vapor could have been drawn into the room that contained the fan unit of the ventilation system. This outbreak illustrates an unusual route of exposure to a widely used laboratory chemical.     

Clostridium perfringens food-borne outbreak: an epidemiological investigation

Abstract: On 3 April 1994, the Western Sector Public Health Unit was notified of an outbreak of gastroenteritis at a Christian youth camp. Attending the camp were 820 people; 241 (42 per cent) of 574 camp participants who completed a questionnaire reported illness. Of these, 230 met the case definition. Main symptoms reported were stomach cramps (78 per cent), diarrhoea (67 per cent) and nausea (46 per cent). Bacterial analysis of leftover chicken grew 2.3times10⁷ and 3.3times10⁷ colonies/g of Clostridium perfringens, and we identified Type A enterotoxin of C. perfringens in four of seven stool samples collected from ill people. Camp participants who consumed chicken at lunch on the second day of the camp were nearly four times as likely to be ill than those who did not (relative risk 3.81, 95 per cent confidence interval 3.07 to 4.72). There were deficiencies in hygiene and food preparation. We highlight the importance of time and temperature controls in food preparation and storage to prevent contamination and subsequent poisoning by C. perfringens or other food pathogens. This investigation demonstrates the importance of a multidisciplinary team when investigating disease outbreaks.     

Norovirus outbreak in an elementary school--District of Columbia, February 2007

On February 8, 2007, the District of Columbia Department of Health (DCDOH) was notified of an outbreak of acute gastroenteritis in an elementary school (prekindergarten through sixth grade). The school nurse reported that 27 students and two staff members had become ill during February 4--8 with nausea, vomiting, and diarrhea; because symptoms lasted <48 hours, a viral etiology was suspected. DCDOH recommended two preinvestigation interventions, which were implemented the same evening (February 8): 1) more thorough handwashing and 2) bleach cleaning of all shared environmental surfaces with a diluted (1:50 concentration) household bleach solution. This report summarizes the subsequent investigation of the outbreak, which suggested that noncleaned computer equipment (i.e., keyboards and mice) and person-to-person contact resulted in illness. To decrease disease transmission during gastroenteritis outbreaks, public health officials should emphasize good handwashing practices, exclusion of ill persons, and thorough environmental disinfection, including fomites that are shared but not commonly cleaned.     

An outbreak of Norwalk-like gastroenteritis associated with contaminated drinking water at a caravan park

Abstract: During the 1989 Christmas holiday period, a large outbreak of gastroenteritis occurred among persons staying at a caravan park in southern New South Wales. Review of local hospital records found that 77 per cent of patients presenting with infective diarrhoea between 29 December and 3 January had stayed at the caravan park. In a retrospective cohort study we compared rates of illness among caravan park patrons exposed to different water sources. Stools were tested for pathogens and convalescent sera for viral antibodies. Rain and reticulated river water sampled from the caravan park were tested for bacteria and viruses. Of 351 persons interviewed at the caravan park, 305 (87 per cent) reported an illness characterised by diarrhoea, vomiting and abdominal pain. Of 196 persons who used reticulated river water for drinking or ablutions, 175 (89 per cent) became ill compared with 47 of 72 persons (65 per cent) who did not use this water (relative risk 1.4, 95 per cent confidence interval 1.2 to 1.6). The outbreak was probably caused by a 27–28 nm small round structured virus found in the stool from one ill person. High levels of faecal coliforms in the reticulated river water and enterovirus in sediment samples suggest that the outbreak was caused by sewage contaminating the reticulated river water through a break in the pipe directly over the underground water tanks. To prevent such outbreaks, poor water and sewerage system layouts should be avoided and nonpotable water should be clearly labelled. Where feasible, all camping-ground water should stem from town supplies.     

Snow Mountain agent gastroenteritis from clams

A 1983 investigation of two clambake-related gastroenteritis outbreaks in Rochester, New York, showed that 84 (43%) of 196 persons interviewed had an acute illness characterized by watery diarrhea, vomiting, and abdominal cramps. None of the ill persons were hospitalized or had complications. Illness was associated with eating raw (p = 0.002) or baked (p less than 0.01) hard-shell clams, with the risk of illness increasing with the total number of clams consumed (p less than 0.01). The median incubation period and duration of illness were 36 and 44 hours, respectively. Stool samples obtained 2-4 days after onset of illness were negative for commonly recognized bacterial and viral pathogens. However, of 31 persons whose stools were tested, the stool of only one ill person was positive by enzyme-linked immunosorbent assay for the Snow Mountain agent, one of the Norwalk-like viruses. Paired serum specimens from six (67%) of nine ill and two (29%) of seven well persons showed a fourfold or greater rise in antibody titer to Snow Mountain agent. Persons who ate clams were more likely to seroconvert to Snow Mountain agent (eight of 12) than were those who did not eat clams (zero of four) (p = 0.04). The clams were harvested off the coast of southern Massachusetts in late October, when harvest waters were documented to be contaminated by untreated municipal sewage. This report describes the first documented outbreak of shellfish-associated gastroenteritis attributed to Snow Mountain agent of which we are aware.     

某杂技班食堂1起食物中毒流行病学分析

目的查明中毒事件发生原因和环节,提出针对性防控措施和建议。方法采用回顾性队列研究、进行食品卫生学调查和实验室检测分析危险食物。结果本次事件共有18例病例,罹患率为82%。主要临床症状为呕吐（100%）,恶心（94%）,腹痛（44%）和腹泻（17%）。流行曲线形态表现为快速上升,快速下降,高峰持续时间短,提示为点源暴露。未发现有统计学意义的暴露食物。蛋炒饭为所有调查对象的共同食物,比较不同的蛋炒饭进食量（按体重调整）引起的呕吐次数,发现≥2碗/100 kg.bw组平均呕吐次数3.7次明显高于1碗/100 kg.bw组（平均呕吐次数1.0次）,差异有统计学意义（t=2.3,P〈0.05）。同时对蛋炒饭进食量（按体重调整）与引起的呕吐次数作spearman相关分析,相关系数r s=0.472（P〈0.05）,提示进食炒饭的量与呕吐次数存在剂量反应关系。蛋炒饭所使用的米饭有1/3来自上一餐次的剩饭（该剩饭在22℃下放置了4 h）。剩余蛋炒饭和患者呕吐物的蜡样芽孢杆菌和金黄色葡萄球菌检测为阴性。结论这起事件很可能由剩余米饭不当存放所致,其致病因子可能是腊样芽孢杆菌呕吐毒素。     

Notes from the field: norovirus infections associated with frozen raw oysters - Washington, 2011

On October 19, 2011, Public Health - Seattle & King County was contacted regarding a woman who had experienced acute gastroenteritis after dining at a local restaurant with friends. Staff members interviewed the diners and confirmed that three of the seven in the party had consumed a raw oyster dish. Within 18-36 hours after consumption, the three had onsets of aches, nausea, and nonbloody diarrhea lasting 24-48 hours. One ill diner also reported vomiting. The four diners who had not eaten the raw oysters did not become ill.     

Scombroid poisoning after eating tuna fish]

On two separate occasions, a total of eight subjects ate tuna fish. Three out of four persons in the first case (a father aged 54, a mother aged 51 and a daughter aged 24 years) and one out of four persons in the second case (a 28-year-old woman) experienced erythema, respiratory distress and diarrhoea shortly after eating the fish. These symptoms are indicative of scombrotoxic fish poisoning. Histamine is produced in the muscle tissue of scombroid fish, such as tuna or mackerel, if it is kept at a temperature which is too high. Since the concentration of histamine is not evenly distributed through the fish's flesh, not everyone who eats the same fish will become ill to the same extent, and some may not even become ill at all. Furthermore, since the complaints are often mild and of short duration, most patients do not seek medical help, and probably few cases are officially reported. Despite the fact that sometimes only one person from a group of people eating the same fish becomes ill, and that the clinical complaints resemble an IgE-mediated allergic reaction, the illness is a food-borne intoxication with exogenous histamine. Therefore, patients can safely eat the same type of fish again.     

四川省2009年一起因甲鱼被污染导致的霍乱暴发

目的 查明某镇卫生院报告发现1例疑似霍乱病例疫情规模、调查传染来源、控制疫情蔓延.方法 制定统一的病例定义,开展病例主动搜索,对就餐人员食用菜品情况开展回顾性队列研究.结果 共24人感染,其中10人发病,均参加了2009年7月14日一次午餐聚会,未参加者未发病.对参加14日午餐的265名就餐者开展回顾性队列调查,结果显示食用蒸甲鱼和花生米为危险因素,RR=3.6(95%CI:1.1～12)和RR=3.1(95%CI:1.2～8.0).在食品加工过程中,甲鱼宰杀与花生米共用盛装器具,甲鱼蒸煮时间45 min,花生米室温下存放超过16 h,甲鱼未熟及交叉污染花生米的可能性极大.结论 该起疫情为聚餐中食品受O139霍乱弧菌污染所致,传染源为体内带菌的甲鱼,传播途径为甲鱼蒸煮未熟透,且制作过程中污染了花生米,经食用后引起发病.     

A common-source outbreak of trichinosis from consumption of bear meat

This paper discusses an outbreak of trichinosis that occurred in 1998 in Montgomery County, Ohio, and the investigation that followed. The outbreak was associated with consumption of bear meat from a hunt in Ontario, Canada. The person who had the index case had eaten two bear burgers that were cooked rare in a microwave oven. Bear meat from the same hunt later was consumed by 15 other people at a church supper and an additional 13 people who did not attend the supper. Of the 15 attendees at the church supper who ate the bear meat, seven developed illness consistent with Trichinella infection (attack rate about 47 percent). An additional seven people attended the supper but did not eat the bear meat and did not become ill. Having eaten bear meat at the church supper was associated with an increased risk of illness (p = .05). Inadequate cooking of the bear meat resulted in the transmission of live trichinae. The 13 other people who ate the bear meat but did not attend the supper reported no illness. A total of eight people, including the person with the index case, met the case definition for trichinosis. Adequate cooking of the bear meat or consumption of uninfected portions of the meat was probably the protective factor for those who did not become ill after consuming the bear meat.     

Outbreak of cryptosporidiosis at a California waterpark: employee and patron roles and the long road towards prevention

In August-September 2004, a cryptosporidiosis outbreak affected >250 persons who visited a California waterpark. Employees and patrons of the waterpark were affected, and three employees and 16 patrons admitted to going into recreational water while ill with diarrhoea. The median illness onset date for waterpark employees was 8 days earlier than that for patrons. A case-control study determined that getting water in one's mouth on the waterpark's waterslides was associated with illness (adjusted odds ratio 7.4, 95% confidence interval 1.7-32.2). Laboratory studies identified Cryptosporidium oocysts in sand and backwash from the waterslides' filter, and environmental investigations uncovered inadequate water-quality record keeping and a design flaw in one of the filtration systems. Occurring more than a decade after the first reported outbreaks of cryptosporidiosis in swimming pools, this outbreak demonstrates that messages about healthy swimming practices have not been adopted by pool operators and the public.     

A foodborne outbreak of gastroenteritis involving two different pathogens.

On the evening of October 10, 1990, many of the 474 inmates of a state prison in Florida began to experience symptoms of gastroenteritis. An investigation included interviews with inmates, evaluation of the kitchen and food-handling practices, cultures of leftover food, stool cultures, and cultures from the nares and skin lesions of food handlers. Of the 331 inmates interviewed, 215 (65%) had diarrhea, vomiting, or both. The median incubation period was 5 hours (range, 1-41 hours). Cases with onset of illness 8 or more hours after the evening meal were more likely than those with earlier onset to have had only diarrhea without vomiting (p < 0.001). Eating turkey at the evening meal on October 10 was associated with risk of illness (relative risk = 4.8, 95% confidence interval 1.7-13.7). Cases who became ill within 8 hours of the evening meal and those who became ill later were both more likely to have eaten turkey than those who did not become ill (p < 0.001 and p < 0.007, respectively). Salmonella infantis and enterotoxin-producing Staphylococcus aureus were both isolated from samples of leftover turkey, and S. infantis was isolated from 18 of 20 stool specimens. Cultures of the anterior nares and skin lesions of food handlers grew S. aureus, but phage typing failed to link these strains to the outbreak. Improper food-handling practices contributed to the development of this outbreak. This report highlights the importance of recognizing multiple-organism outbreaks, since the authors' recommendations for prevention of more cases depended upon knowing the risks associated with the distinct organisms and the possible sources of contamination.     

Norwalk virus gastroenteritis following raw oyster consumption

In January, 1980, six out of 13 persons (46%) attending a party in a small northwest Florida town near the Gulf of Mexico became ill with Norwalk virus gastroenteritis after eating raw oysters. Symptoms experienced by the ill persons were principally nausea (100%), vomiting (83%) and diarrhea (50%) and were of brief duration. The symptom complex and epidemiology of Norwalk virus infection closely resemble the gastrointestinal illness commonly referred to as the 24-hour intestinal flu or "stomach flu." Norwalk virus infection was identified in this outbreak by application of a recently developed sensitive and specific serologic radioimmunoassay. Oysters from the incriminated batch had fecal coliform levels above recommended standards; however, recent studies of oyster-harvesting waters have shown only a weak correlation between fecal coliforms and the presence of enteric viruses. Further studies are needed to determine whether modifications of monitoring modalities for oyster-harvesting waters are needed.     

Waterborne Gastroenteritis due to the Norwalk Agent: Clinical and Epidemiologic Investigation

An outbreak of gastroenteritis occurred at a Pennsylvania summer camp in July 1978. Symptoms included abdominal pain (81 per cent), nausea (72 per cent), and vomiting (53 per cent); upper respiratory infection symptoms occurred in 35 per cent of the campers. Illness was associated with consumption of five or more glasses of water or water-containing beverages. Stool cultures from affected persons were negative for bacterial pathogens; however, a fourfold or greater rise to the Norwalk agent was demonstrated in serum samples of three of three ill persons tested and in none of eight controls (p < .02). Campers ill during the first session who were also present during the second session did not become ill during the second session (p < .001). (Am J Public Health 1982; 72:72-74.)