An outbreak of gastroenteritis caused by both rotavirus and Shigella sonnei in a private school in Rio de Janeiro

In May 1980 an extensive outbreak of gastroenteritis occurred in a private school in the city of Rio de Janeiro. Examination of faeces and paired sera showed that this outbreak was caused by both rotavirus and a virulent strain of Shigella sonnei. In the first 19 stool samples collected seven (37%) had rotavirus only, six (32%) had Sh. sonnei only, while four (21%) had both agents. Examination of the second and third stool collections revealed only the presence of Sh. sonnei. The 18 paired sera showed seroconversion for rotavirus in four cases (22%) and in seven cases (39%) for Sh. sonnei. The overall attack rate of the disease was approximately 75%, the nursery and kindergarten having higher attack rates. Students in all grades became sick at the same time, and the unimodal curve of the onset dates of symptoms indicates a common source outbreak. Evidence suggested a contaminated water supply.     

Shigellosis in the south-western Cape of Good Hope 1968-85

During the period 1968-85 shigella organisms were isolated from stool specimens of 1562 patients attending Tygerberg Hospital, situated in the south-western province of the Cape of Good Hope of the Republic of South Africa. Shigella flexneri (72% of patients) was the commonest subgroup identified. Sh. sonnei was the second-commonest isolate (20%), with smaller numbers of Sh. boydii (5%) and Sh. dysenteriae (3%). Sh. dysenteriae has not been isolated since 1979. In 1985 30% of isolates were resistant to ampicillin and 52% to trimethoprim-sulphamethoxazole. During this period 12 cases of shigellaemia were seen, 11 in young infants less than 13 months of age who were malnourished in 6 cases. The single adult had had a previous gastrectomy and splenectomy.     

Evaluation of an intervention program in the control of an urban outbreak of shigellosis.

Community-wide outbreaks of shigellosis are a persistent public health problem. We evaluated the effect of a household-based intervention program on the control of an urban outbreak of S. sonnei gastroenteritis. During the intervention we attempted to contact all households with culture-confirmed S. sonnei and provide education in methods to prevent spread of Shigella. Subsequently we conducted a survey of intervention (n = 43) and nonintervention (n = 33) households. We also conducted a serosurvey of children three to five years of age. The number of new cases of S. sonnei infection declined steadily over several months after the intervention began. Members of the intervention households were more knowledgeable about handwashing (rate ratio [RR] 4.7, 95% confidence interval [CI] = 2.1-10.8) and others methods of S. sonnei transmission and control than members of nonintervention households. However, intervention households had higher attack rates of Shigella-associated diarrhea in susceptible household members (RR 1.4, 95% CI = 1.0-2.0). During the intervention we were able to contact only 25% of households by the eighth day after onset of diarrhea in the index case, when 90% of intrahousehold transmission of Shigella had already occurred. Two months after the outbreak ended, 42% of children in the outbreak community had elevated antibody titers against S. sonnei; an additional 19% had borderline elevated titers. The intervention program improved knowledge but may have occurred too late to prevent intrahousehold transmission of Shigella. Exhaustion of susceptible hosts, rather than the education program, likely accounted for the decline in shigellosis cases.(ABSTRACT TRUNCATED AT 250 WORDS)     

一起细菌性痢疾暴发疫情的流行病学调查

目的:调查衢州市衢江区某乡两学校菌痢疫情暴发的原因和特点,为制定突发疫情防制对策提供科学依据。方法:采用现场流行病学调查资料进行统计分析。结果:两所学校共发病133例,罹患率为9.49%;男女发病比1.09∶1,初中男女罹患率差别有统计学意义;133例病例中3,3例从粪便中检测出福氏志贺氏菌(4a型)。结论:这是一起由福式志贺菌引起的细菌性痢疾暴发疫情。     

一起学校细菌性痢疾暴发疫情的病原追溯 和流行病学特征分析

摘要:目的　对学校发生的一起细菌性痢疾暴发疫情进行调查,并采用脉冲凝胶电泳（PFGE）方法对菌株进行同源性分析,为查找传染源、切断传播途径,提供参考依据。方法　开展现场流行病学调查,采用描述流行病学的方法对暴发原因进行分析,同时采集患者粪便、水样进行细菌学培养,运用PFGE对分离的菌株进行同源性分析。结果　此次暴发疫情的调查共发现病例60例,罹患率为10.12%,发病人群均为小学学生;从53例患者的粪便中共检出30例痢疾阳性病例,且菌群均为宋内志贺菌;水样检测发现2号水井及其旁边的水塘存在宋内志贺菌;对4份病例的粪便、2份水样进行PFGE分析,其结果显示,6份样本所检出菌株的电泳带型完全相同。结论　该事件是一起因饮用宋内志贺菌污染的水源而导致的细菌性痢疾暴发疫情。     

Changes in the trend of shigellosis in Dhaka: family study on secondary infection, clinical manifestation and sensitivity pattern: 1980

The incidence of shigellosis and the death rate have increased and the resistance of shigellae to antibiotics has changed in Dhaka during our experiences. In 1980, we investigated the secondary infection and case rates, infection to case ratio, duration of illness, excretion of shigellae and antibiotic sensitivity pattern in 100 families with cases of shigellosis, culturing rectal swabs obtained by home visits for a 10-day period. Standard methods were used for culture and sensitivity tests. The over-all secondary infection rate in contacts was 27.3% and the case rate 10.7%. The rates were higher for Shigella flexneri than for Sh. dysenteriae. When the index cases were nought to four years old the secondary infection and case rates were higher than when index cases were older. Contacts aged nought to four years had highest attack rates. The average duration of excretion of Sh. flexneri was 4.5 and Sh. dysenteriae 2.6 days. Illness was one day longer for Sh. dysenteriae than for Sh. flexneri. Cases of shigellosis in hospital had higher rates of fever and blood in stool than those who were not in-patients. 40% of Sh. dysenteriae and 14% of Sh. flexneri were sensitive to tetracycline, 0 to 5% to streptomycin and 100% to sulphamethoxazole, trimethoprim and gentamicin. Incidence of Sh. flexneri had increased in 1980 but that of Sh. dysenteriae remained the same as in 1973 although Sh. dysenteriae type 1 appeared to be less infective in 1980 than in 1973.     

Notes from the field: outbreaks of rotavirus gastroenteritis among elderly adults in two retirement communities--Illinois, 2011

In February 2011, three residents of a retirement community in Illinois were hospitalized for acute gastroenteritis. The admitting physicians ordered testing of stool specimens for several pathogens, including rotavirus. The hospital laboratory detected rotavirus antigen in specimens from each patient, and the hospital infection control practitioner reported that information to the Cook County Department of Public Health. Two additional residents were hospitalized for rotavirus gastroenteritis shortly thereafter. The health department sent stool specimens from the five patients to CDC for testing for rotavirus and norovirus. Rotavirus was detected in each specimen; norovirus was not detected. During a subsequent investigation, all available residents were queried regarding recent diarrheal symptoms. Preliminary data indicated that 22% of residents had confirmed or probable rotavirus disease and 10 residents were hospitalized. In May 2011, another outbreak of rotavirus gastroenteritis was detected at a second retirement community in the county. On preliminary analysis, the overall attack rate in the second retirement community was 11%, and 20 residents were hospitalized. No deaths were identified in either outbreak. Based on preliminary results of the investigations and general knowledge of rotavirus transmission, within each community, rotavirus likely was transmitted from person to person via contaminated hands or fomites (e.g., environmental surfaces). The outbreaks lasted ≥4 weeks.     

Shifting serotypes,plasmid profile analysis and antimicrobial resistance pattern of shigellae strains isolated from Kolkata,India during 1995-2000

One hundred and sixty-six shigellae strains, isolated from stool samples of paediatric patients (< 5 years old) at a Childrens' Hospital in Kolkata, India during the period of 1995-2000 were examined for serotyping, drug resistance pattern and plasmid profiles. Sh. flexneri (58 %) was found to be commonest isolate of total shigellae, followed by Sh. sonnei (28 %), Sh. boydii (9%) and Sh. dysenteriae (5%). This profile of species was in sharp contrast to the picture obtained before 1995, when Sh. dysenteriae 1 predominated over Sh. flexneri. In Sh. flexneri strains, Sh. flexneri 2a (35%) was the most prevalent serotype, following Sh. flexneri 3a (31%), Sh. flexneri 6 (14%), Sh. flexneri 2b (11%) and Sh. flexneri 4 (9%). Resistance patterns of the strains to 12 commonly used antimicrobial agents and minimum inhibitory concentrations (MICs) of the antibiotics were also tested. All strains were found uniformly susceptible to norfloxacin, but more than 90% strains were resistant to tetracycline, co-trimoxazole and 67% strains were resistant to ampicillin. Resistance to amoxicillin, chloramphenicol and nalidixic acid was found in 55% (range 45-74%), 46% (range 40-60%) and 29% (range 15-40%) strains respectively. Overall, shigellae strains showed statistically significant increase in resistance against tetracycline, nalidixic acid and furazolidone (P < 0.05) over the years of this study. This indicates decreased efficacy of furazolidone, cotrimoxazole and nalidixic acid for the empirical treatment of shigellosis in Kolkata. Although a few strains showed intermediate susceptibility to ciprofloxacin (4%) and cefotaxime (10%) by disk diffusion test, but the MICs of those antibiotics were within the normal limits. Almost 57% of the strains were resistant to four or more drugs with high MICs of the antibiotics. Plasmid profile analysis revealed presence of large plasmid of 220 kb in majority of the strains except in Sh. sonnei and a correlation between presence of smaller plasmids and shigellae serotypes. Hence this study reports epidemiological change of shigellae species in Kolkata, India with regard to serotypes and antibiotic resistance patterns.     

Giardia transmission in a swimming pool.

In the fall of 1985, an outbreak of giardiasis occurred among several swimming groups at an indoor pool in northeast New Jersey. Nine clinical cases were identified, eight of whom had Giardia positive stool specimens. All were female; seven were adults (greater than 18 years) and two were children. The attack rate was highest (39 per cent, 5/13) for the ladies lap group who had exposure on one day. These cases had no direct contact with children or other risk factors for acquiring Giardia. Infection most likely occurred following the ingestion of swimming pool water contaminated with Giardia cysts. The source of Giardia contamination was a handicapped child who had a fecal accident in the pool. He was a member of a group that swam at the same time as the ladies lap group. A stool survey of the handicapped group showed that of the 20 persons tested, nine were positive for Giardia, including the specimen from this child. Examination of the pool records showed that no chlorine levels had been taken on the day of the fecal accident and that on the following day the chlorine level was zero. This is the second report of Giardia transmission among swimming pool attendees. It emphasizes the need to maintain appropriate chlorine levels in swimming pools and to institute measures to clear pools after a fecal accident.     

长阳县一起水源性细菌性痢疾爆发疫情的调查分析

目的通过对一起水源性细菌性痢疾爆发疫情的流行病学调查分析,探讨疫情发生的原因。方法采用现场流行病学调查方法,对患者逐一进行调查,采集患者、水源水和末梢水进行肠道致病菌培养。结果共发病69例,2006年9月6日出现首发病例,9月12日流行结束,整个流行期为7天,罹患率为6!98%,患者以发热、头痛、恶心、呕吐、腹痛、腹泻为主,外环境病原检索与患者病原检索一致,均为宋内志贺氏菌。病例分析提示,发病学生均饮用过生水。结论证实本起疫情是由饮用水受到污染而引起的细菌性痢疾爆发。     

Dysentery in 1998

Since the year 1992 a dramatic decrease of dysentery cases notified every year has been observed in Poland. In 1994 the microbiological examination of diarrhoea stool specimens stopped to be free of charge. Dysentery started to be recognised only in the cases suspected as foodborne disease outbreak investigated for epidemiological reason. This practise influenced the change in the epidemiological feature of dysentery in 1998: increase of cases due to S. flexneri infection (all together 36% of cases) mostly serological type 4a, and decrease of cases due to S. sonnei infection (from 90% to 60%). There were no more summer-autumn seasonal increase in number of monthly registered dysentery cases in July-September but spring increase March-May was observed that is rather unusual in Poland. We suggest that free of charge microbiological examination of diarrhoea stool specimens should be reintroduced due to epidemiological interest--surveillance of infectious diseases.     

Waterborne epidemic outbreak of Shigella sonnei gastroenteritis in Santa Maria de Palautordera, Catalonia, Spain

In August 2002 an outbreak of Shigella sonnei infection occurred in a Spanish town of 6343 inhabitants. In total, 756 people developed acute gastroenteritis and 181 cases were shigella-confirmed. The peak incidence was during 5-6 August 2002. The estimated primary attack rate was 9.97%; the attack rate for secondary cases was 38%. The <15 years ago group was most affected (16.49%). The town and its surroundings were served by two water systems, A and B. The cases had consumed water provided by system A (attack rate 164 cases/1000 population). Microbiological analysis of water from system A did not show the presence of coliform bacteria or shigella. This shigellosis outbreak was the largest reported in Spain. The impact of the epidemic was probably greater than the incidence detected.     

2007年攀枝花市某农村中学1起细菌性痢疾暴发调查

[目的]了解和掌握2007年9月8～14日发生在攀枝花市仁和区某农村中学(初中)1起细菌性痢疾暴发疫情的特点,搞清暴发原因,为采取有效控制措施提供依据。[方法]2007年9月15日,到该中学进行调查。[结果]这起暴发共发病58例,均为学生,554名学生的罹患率为10.47%;从10份病人大便(肛拭)检出3株宋内氏志贺菌。细菌性痢疾罹患率,住校生高于走读生,男生高于女生,9月5～8日饮生水者高于不饮生水者,饮自备水生水者高于饮生活用水生水者,饮生水次数多者高于次数少者,喝豆浆次数多者高于次数少者,喝冷豆浆者高于喝热豆浆者,洗碗用自备水者高于用生活用水者(P<0.01或<0.05)。[结论]这是使用被污染的自备水源引起的1起细菌性痢疾暴发疫情。     

Rotavirus,astrovirus and adenovirus associated with an outbreak of gastroenteritis in a South African child care centre.

An outbreak of gastroenteritis in the infant-toddler unit of a child care centre (CCC) in Pretoria, South Africa, was investigated for possible viral enteropathogens. Rotavirus was found in association with seven (70%) diarrhoeal episodes. Co-infection with rotavirus and human astrovirus (HAstV) was demonstrated in two of these episodes, and rotavirus, HAstV and enteric adenovirus (EAd) co-infection in another. Rotavirus occurred alone in four of the diarrhoeal episodes, while HAstV and EAd were each detected alone in one episode. Two HAstV and one rotavirus asymptomatic infection episodes also occurred. Overall, 8 of 10 children had rotavirus infections, of which 7 were symptomatic, 6 of 10 children had HAstV infections (4 symptomatic), and 2 of 10 children had EAd infection, both symptomatic. These results highlight the diversity of viral enteropathogens that may be associated with a diarrhoeal outbreak in a CCC and emphasize the need to investigate the possibility that multiple enteropathogens may simultaneously cause a single outbreak of diarrhoea.     

Outbreaks of astrovirus type 1 and rotavirus gastroenteritis in a geriatric in-patient population

Two outbreaks of viral gastroenteritis occurred in seven psychogeriatric wards of a 469-bed psychiatric hospital. The outbreaks occurred over an eight-week period; the first affected 30 people and rotavirus was detected in 12 of 14 persons from whom faecal specimens were available. The second affected 32 people (15 of whom were affected in the previous outbreak) and astrovirus was detected in 5 of the 24 people from whom specimens were available. Specific IgM to astrovirus was demonstrated in 3 patients. The rotavirus outbreak was characterised by a longer duration of illness (mean 4 days), and more severe symptoms; two elderly female patients had severe symptoms over a 14-15 day period but recovered. In the astrovirus outbreak the duration of illness was shorter and symptoms were milder although the attack rate was higher than that observed for rotavirus.     

International foodborne outbreak of Shigella sonnei infection in airline passengers

During 22-24 August 2004, an outbreak of Shigella sonnei infection affected air travellers who departed from Hawaii. Forty-seven passengers with culture-confirmed shigellosis and 116 probable cases who travelled on 12 flights dispersed to Japan, Australia, 22 US states, and American Samoa. All flights were served by one caterer. Pulsed-field gel electrophoresis of all 29 S. sonnei isolates yielded patterns that matched within one band. Food histories and menu reviews identified raw carrot served onboard as the likely vehicle of infection. Attack rates for diarrhoea on three surveyed flights with confirmed cases were 54% (110/204), 32% (20/63), and 12% (8/67). A total of 2700 meals were served on flights with confirmed cases; using attack rates observed on surveyed flights, we estimated that 300-1500 passengers were infected. This outbreak illustrates the risk of rapid, global spread of illness from a point-source at a major airline hub.     

Outbreak of Shigella sonnei dysentery on a long stay psychogeriatric ward

A ward outbreak of diarrhoea associated with Shigella sonnei on a long stay psychogeriatric ward is described. Nine patients and three staff had positive stool cultures for S. sonnei. The source of infection of the index case was not discovered. Environmental factors at ward level which predispose long stay hospitals to such outbreaks are discussed.     

High and low level tetracycline resistance in Shigella sonnei.

The results presented in this paper confirm the existence of two types of tetracycline resistance in Shigella sonnei. One group of strains had a high level of resistance to tetracycline and oxytetracyline, with a variable level of minocycline resistance. The second group had a lower level of tetracycline resistance and were sensitive to minocycline. After conjugation with E. coli K12 the selected E. coli transconjugants had the same levels of resistance as the parent Sh. sonnei strain, with one exception. Sh. sonnei 87 was resistant to a high level of tetracycline, but was able to transfer only low level resistance. It is suggested that Sh. sonnei 87 carriers two plasmids: pSU1, a conjugative plasmid conferring a low level of tetracycline resistance, and pSU2, a non-conjugative plasmid which confers a high level of resistance to tetracycline.     

一起医院住院病人诺如病毒急性胃肠炎暴发疫情的 调查

摘要:目的　调查某医院住院病人腹泻暴发疫情的致病因子,找出传染源和危险因素,提出针对性的预防控制建议,有效控制疫情。方法　采用统一的调查表对病例进行流行病学调查;开展现场卫生学调查并采集便标本,采用RT-PCR对便标本进行诺如病毒核酸检测。结果　调查该病区暴露的住院患者和医务人员135名,发现22名病例,罹患率为16.30%;患者临床表现以腹泻、恶心、呕吐为主,部分患者出现发热症状;不同楼层住院老人罹患率差异无统计学意义（χ2＝0.82,P＞0.05）;住院老人罹患率高于护工（χ2＝5.35,P＜0.05）,不同性别住院老人发病风险相同（χ2＝0.18,P＞0.05）;采集的14份便标本中,8份检测结果为诺如病毒核酸阳性。结论　该次急性胃肠炎暴发疫情是由诺如病毒引起,传染源可能为隐形感染者或病原携带者,病毒通过某种共用媒介传播后再以人-人传播模式进一步扩散,高危人群为住院老人;采取针对性措施后,疫情得以有效控制。