一宗起源于列车的甲型H1N1流行性感冒暴发传播链的调查研究

目的 探讨一起甲型H1N1流行性感冒(流感)传播模式及其影响因素.方法 运用病例访谈、应急监测和回顾性队列研究方法,搜索发现和追踪续发病例以及分析感染因素.结果 本起暴发流行事件由1例乘坐列车的学生引发,在后续追踪调查中发现,共有19例与该学生有关的患者,平均二代续发率为4.8%.研究显示网吧密切接触是危险因素(RR=10.42,95%CI:1.18～91.76);医护过程中、无防护地清理患者污染的房间和与患者同宿舍的罹患率较高,分别为50%、25%和14.3%;不支持社区其他传播方式.结论 密切接触如共同居住、防护不当的医护过程,或共处较密闭空间如交通工具、网吧等比较适合甲型H1N1流感病毒传播;可能存在污染的环境或物品间接传播病毒的现象;需加强学校校医等基层医疗人员的院内感染控制工作.     

H1N1 virus infection associated with acute myocardial infarction in a young patient without coronary artery disease--first reported case

Swine-origin influenza A (H1N1) virus was identified in March of 2009 in Mexico and the United States. The virus spread rapidly, becoming pandemic by June. Previous studies examined the role of influenza infection in cardiovascular disease, however, we present the first case of an acute myocardial infarction in a healthy patient specifically associated with the novel viral infection. This case underscores the importance of prompt diagnosis and treatment as well as vigilance on behalf of health care workers in treating patients affected with influenza A (H1N1). Consideration of this previously undescribed pathology may play a significant role in the coming debates over vaccines and access.     

Hepatitis C virus and B-cell non-Hodgkin lymphomas: an Italian multicenter case-control study

The existence of an association between infection with hepatitis C virus (HCV) and B-cell non-Hodgkin lymphoma (B-NHL) remains controversial, largely because previous studies were based on prevalent case series or comparisons with less than optimal control groups. This hospital-based case-control study was conducted from January 1998 through February 2001 to evaluate the association between HCV infection and B-NHL of different types. Cases were consecutive patients with a new diagnosis of B-NHL; controls were patients from other departments of the same hospitals. Both groups were interviewed using a standardized questionnaire. The prevalence of HCV infection was calculated by histologic type of B-NHL and clinical behavior (indolent or aggressive). Adjusted odds ratio (OR) and HCV-attributable risk (AR) were estimated. HCV prevalence was 17.5% among the 400 lymphoma patients and 5.6% among the 396 controls. The OR of B-NHL (patients vs controls), adjusted by age, sex, level of education, and place of birth, was 3.1 (95% confidence interval [CI], 1.8-5.2); an OR indicative of positive association was found for indolent and aggressive B-NHL. The estimated AR was 4.6%. This study confirms an association between HCV and B-NHL. In Italy, 1 of 20 instances of B-NHL may be attributable to HCV infection and may, thus, benefit from antiviral treatment.     

Carriage of penicillin-susceptible and non-susceptible pneumococci in healthy young children in Göteborg, Sweden

OBJECTIVES: To study carriage of Streptococcus pneumoniae among healthy young children, determine the proportion of strains with decreased susceptibility to penicillin, and study possible risk factors for the carriage of penicillin-resistant strains. METHODS: Between February 1996 and February 1997, 620 healthy, 18-month-old children in Goteborg, Sweden were screened for carriage of S. pneumoniae with decreased susceptibility to penicillin. Nasopharyngeal samples were obtained from children visiting child health centres for routine health control. RESULTS: Streptococus pneumoniae was found in 322 samples and 18 strains (5.6%, CI95 3.4; 8.8) of all pneumococci showed decreased susceptibility to penicillin G with minimum inhibitory concentrations (MICs) ranging from 0.125 to 1.0 mg/l. The proportion of strains with decreased susceptibility was similar to that found in a laboratory-based material (6%), from the same geographical area and time period. A majority of the children with strains with decreased susceptibility to penicillin (n = 11) were not attending day-care centres. CONCLUSIONS: The prevalence of S. pneumoniae with reduced susceptibility to penicillin is still low in unselected healthy Swedish children.     

A critical evaluation of the Mefar dosimeter.

Multicentre studies of airway responsiveness (AR) are increasingly important tools in asthma epidemiology. Because comparisons of AR are made between centres it is essential that measurement techniques are accurate and standard. This study investigated the Mefar dosimeter which is currently used in the 35 centre European Community Respiratory Health Survey (ECRHS) with the next phase currently being planned. Significant differences were found in driving pressures and aerosol outputs between the three Mefar dosimeters in the laboratory. A linear relationship was also found between driving pressure and aerosol output (R2=0.96). These differences are important as they may lead to variations between centres of < or =35% in the drug dose delivered in AR measurement, which could potentially diminish the power of individual study centres to accurately detect national differences in AR. Dosimeter driving pressure and nebulizer output should be standardized in future studies of airway responsiveness. With relatively simple quality control measures in place it is believed that the Mefar dosimeter can produce reliable between-centre longitudinal data with an increase in the accuracy of these important studies.     

Food-borne outbreak of gastroenteritis caused by small round structured virus. 2. An outbreak associated with bakery product consumption]

In December 1989, an outbreak of gastroenteritis associated with cake consumption occurred in a day-care center with 60 children and 12 staff in Saitama prefecture. Children were served cakes at the Christmas party held in the day-care center and ate them with their families. Thirty-three of the 59 children (56%), 16 of the 74 families (22%) and 1 of the 10 staff (10%) eating the cakes became ill. Illness consisted primarily of nausea, vomiting, diarrhea and fever; the median incubation period was 31 hours. Bacteriological analysis of stool specimens did not reveal a causative agent. Small round structured viruses (SRSV) were detected in fecal specimens from 10 of the 17 ill children (59%) and 2 of the 6 ill families (33%) by electron microscopy. Cakes were purchased from a bakery where an employee who prepared the cake denied symptoms, and SRSV was not detected in the fecal specimen from the employee. Thus, it was not determined that the cake was contaminated by a food handler.     

The impact of active intervention on the spread of penicillin-resistant Streptococcus pneumoniae in Swedish day-care centres

Policies for handling cases of penicillin-non-susceptible Streptococcus pneumoniae (PNSP) in day-care groups vary between different counties in Sweden. The aim of this study was to evaluate the epidemiological effect of excluding PNSP-carriers from children's day-care centres (DCC). We followed the incidence in 14 DCC groups with ongoing PNSP-spread, by repeated group screens until no further cases could be identified. All identified carriers were excluded from DCC attendance in study area A (Sk?ne region) while they remained in the group in study area B (G?teborg and ?rebro), according to local policies. The intervention effect was evaluated by comparing the number of additional cases after the baseline screen (start of the intervention period) between the 2 study areas. All PNSP-isolates were characterized by resistance pattern, serotype and pulse-field gel electrophoresis. The relative risk for children in DCCs without active intervention was 6.4 (95% CI: 2.0-20.7). Each prevented case in area A can be estimated to have demanded the exclusion of 2 other children from day care for approximately 4 weeks each. The total cost-benefit outcome of this action has to be seen in the light of the local situation with regard to the population prevalence and the distribution of other risk factors.     

Infectious diseases and day-care centre environment.

During the period from September 1986 to May 1987 all 25 day-care centre departments in the residential district of Teleborg in V?xj? were studied to discover the frequency of absence due to infection. Mean absence/department was 6.6% (SD 2.2), with a range from 3.9% to 10.2%. During the period from September 1989 to May 1990 a follow-up study used the same methods to investigate 7 departments, which in the first study had shown the highest and lowest rates of absence due to infection. In addition, the carbon dioxide content in indoor air was measured in all departments in the district. The new measurements showed that the average absence due to infection in the 7 departments had fallen from 7.5% (SD 2.9) to 5.6% (SD 1.4). It was not possible to reproduce the division seen in the first study into departments with high and low absence rates. The variations in infectious morbidity observed could not be explained by differences between the departments as regards physical environment or working routines. By contrast, a considerable difference as regards carbon dioxide content in indoor air was seen between the 3 departments housed in converted dwellings and the 4 departments in purpose-built day-care centres; the mean values were 822 ppm and 458 ppm, respectively (Mann-Whitney U-test; p = 0.028).     

Epidemiology of echinococcosis/hydatidosis in Anambra State, Nigeria

The prevalence of hydatidosis in cattle, goats and pigs slaughtered in Anambra State, eastern Nigeria during 1973 to 1979, as determined from official meat inspection records, was 7/373,242 (0.002%), 249/476,249 (0.05%) and 1/31,005 (0.003%), respectively. Special point surveys conducted from September 1979 to February 1980 and from March 1985 to September 1987 in two of the slaughterhouses that officially recorded zero infection rates also found no infection in the 551 cattle, 3830 goats and 2126 pigs examined. Similarly, none of the 80 dogs obtained from some of the rural communities in the localities served by these slaughterhouses harboured tapeworms (Echinococcus) at necropsy. Information obtained from rural health centres and some rural and urban-located hospitals, including records of hospital admissions, revealed insufficient awareness of the nature and importance of the disease in man and no evidence even of suspected cases. The apparent absence of infection in humans was confirmed by records at the main specialist hospital in the area, which showed that only one case of human hydatid disease had ever been diagnosed by that hospital. The most important factors that might have been responsible for the virtual absence of canine and human infections include the extremely low infection rates in food animals, limited access by dogs to offal, limited contact between dogs and potential domestic intermediate hosts of hydatid, and absence of a wild-life cycle.     

Cytomegalovirus infection in children with Down syndrome in a day-care center in Brazil

This study evaluates the transmission of CMV infection in 120 children aged 1 to 15 years with Down syndrome who attended a day-care center for handicapped children in S?o Paulo, Brazil. A blood sample was obtained from each children at the beginning of the study for detection of IgG and IgM cytomegalovirus (CMV) antibodies by an immunofluorescence assay. Samples of saliva and urine were obtained every 3 months from the children with CMV antibodies to detect shedding of the virus by culture in human foreskin fibroblasts, by detection of pp65 CMV-antigen and by a nested PCR assay. The prevalence of anti CMV-IgG antibodies was 76.6% (92/120), and IgM anti-CMV antibodies were detected in 13% (12/92) of the seropositive children. During the first viral evaluation, CMV was detected in the urine and/or saliva in 39/90 (43.3%) of the seropositive children. In the second and third evaluations, CMV was detected in 41/89 (46%) and in 35/89 (39.3%) children, respectively. Detection of CMV was shown both in urine and saliva in 28/39 (71.8%), 19/41(46.3%) and 20/35 (57.1%) of the children excreting the virus, respectively. Additionally, in 3(3/4)9 (67.4%) of the excreters CMV could be demonstrated in urine or saliva in at least two out of the three virological evaluations carried out sequentially in a six month period. Of the 28 initially seronegative children, 26 were re-examined for anti-CMV IgG antibodies about 18 months after the negative sample; seroconversion was found in 10/26 (38.5%). Taking all 536 samples of urine or saliva examined by virus culture and pp65 antigen detection during the study into account, 159 (29.6%) were positive by virus culture and 59 (11%) gave a positive result with the pp65 assay. These data demonstrate the high prevalence of CMV shedding and the high risk of CMV infection in children with Down syndrome attending a day-care center for mentally handicapped patients. The virus culture was more sensitive than the pp65 CMV antigen assay for CMV detection in both urine and saliva samples.     

Dynamics of pneumococcal carriage among healthy Icelandic children attending day-care centres

Invasive pneumococcal disease and antimicrobial (AM) resistance in pneumococci are important public health concerns. With the advent of new pneumococcal vaccines, information on serotype prevalence and their temporal fluctuations is important. Information on AM use and consent for participation was obtained by a questionnaire to parents of children at 5 day-care centres in Reykjavik from 1992 to 1999, and nasopharyngeal swabs were cultured selectively for pneumococci. The pneumococci were serotyped and pulsed field gel electrophoresis used to determine clonality. Of 1228 nasopharyngeal swabs, 640 (52.1%) yielded pneumococci of which 89 (13.9%) had decreased susceptibility to penicillin and 1 was resistant. Children receiving AMs during the month preceding nasopharyngeal sampling and children attending a day-care centre where AM use was high were significantly more likely to carry penicillin non-susceptible isolates. Serotypes 6A, 6B and 23F were most common (48%), and 74% of serotyped isolates belonged to 1 of the 7 most common serotypes. Almost all penicillin non-susceptible isolates were of serotype 6B or 19A. Serotype prevalence fluctuated markedly between y. In conclusion, there was significant variation in serotype prevalence between y, and only 51% of the pneumococci belonged to serotypes covered by the current 7-valent conjugated vaccine.     

Hospitalization for HIV infection in public hospitals in Paris. Recent evolution (1988-1990) and short-term projections (1991-2)]

Acute-care hospitalization of subjects infected with HIV in Parisian public hospitals (Assistance Publique-H?pitaux de Paris) increased by 10% between 1988 and 1990, while outpatient day-care rose by 73%. During this time, the percentage of patients coming from the Paris suburbs rose from 30 to 35%. The average length of stay increased from 14.2 to 14.9 days during the same period, and hospital stays lasting longer than 30 days (9.2%) accounted for 39.2% of all hospitalizations. Forecasts for 1991 and 1992 show acute-care hospitalization rising from 25 to 30% and outpatient care increasing from 45 to 94%, depending upon the hypothesis considered.     

Videodensitometric quantitation of aortic regurgitation by digital subtraction aortography using a computer-based method analyzing time-density curves

To assess the clinical role of computer analysis of time-density curves in the evaluation of aortic regurgitation (AR), digital subtraction aortography (DSA) and cineaortography were performed sequentially in 17 patients with varying degrees of AR (1+ to 4+) and in 4 control patients. DSA was performed at a rate of 30 frames/s on a 512 X 512 X 8 bit pixel matrix using the same total volume and injection rate, but with half the amount of contrast agent as standard cineaortography. A 30 X 30 pixel area of interest was identified in the aorta above the valve plane and in the left ventricle where the AR stream was seen. The density of both areas of interest and the ratio of left ventricular/aortic area of interest density was calculated in each frame and then plotted vs time. The ratio at the end of injection (LVd/Aod) had an excellent correlation with cineaortography (chi 2 = 19, p less than 0.001), ranging from 0 to 0.2 in patients with no AR, 0.2 to 0.5 in those with 1+ AR, 0.5 to 0.7 in those with 2+ AR, 0.7 to 0.9 in those with 3+ AR and more than 0.9 in those with 4+ AR. Thus, quantitative assessment of AR by computer analysis of time-density curves derived from DSA is a new and objective technique with significant clinical potential.     

Androgen insensitivity syndrome: somatic mosaicism of the androgen receptor in seven families and consequences for sex assignment and genetic counseling

Androgen insensitivity syndrome (AIS) is caused by numerous mutations of the androgen receptor (AR) gene. The phenotype may range from partial AIS (PAIS) with ambiguous genitalia to complete AIS (CAIS) with female genitalia. In 70% of the cases, AR mutations are transmitted in an X-linked recessive manner through the carrier mothers, but in 30%, the mutations arise de novo. When de novo mutations occur after the zygotic stage, they result in somatic mosaicisms, which are an important consideration for both virilization in later life-because both mutant and wild-type receptors are expressed-and genetic counseling. We report here six patients with AIS due to somatic mutations of the AR and one mother with somatic mosaicism who transmitted the mutation twice. Of the four patients with PAIS, three presented spontaneous or induced virilization at birth or puberty. These cases underline the crucial role of the remnant wild-type AR for virilization because the same mutations, when they are inherited, lead to CAIS. We also report two novel mutations of the AR, with somatic mosaicism, detected in patients with CAIS. Thus, the remnant wild-type receptor does not always lead to virilization. In one of these patients, a high ratio of wild-type to mutant AR expression was found in the gonads and genital skin fibroblasts. Although no prenatal virilization occurred, the possibility of virilization at puberty could not be excluded, and early gonadectomy was performed. A seventh patient had a CAIS with a novel germline AR mutation. The mutation was inherited from the mother, in whom mosaicism was detected in blood and who transmitted the mutation to a second, XX, offspring. The detection of somatic AR mutations is particularly important for the clinical management and genetic counseling of patients with AIS. Before definite sex assignment, a testosterone treatment trial should be performed in all patients with PAIS, but it becomes crucial when an AR mosaicism has been detected. In patients with CAIS or severe PAIS raised as female, there is no consensus about when (early childhood or puberty) gonadectomy should be performed. When somatic AR mutations are detected, however, gonadectomy should be performed earlier because of the risk of virilization during puberty. When a germline de novo mutation is identified in the index case, the risk of transmission to a second child due to a possible germ cell mosaicism in the mother cannot be excluded. However, given the high number of AR de novo mutations and the rarity of such reports, this risk appears to be very low.     

COVID-19 outbreak investigation and response in a penitentiary setting: the experience of a prison in Italy,February to April 2020

Prisons are high-risk settings for COVID-19 and present specific challenges for prevention and control. We describe a COVID-19 outbreak in a large prison in Milan between 20 February and 30 April 2020. We performed a retrospective analysis of routine data collected during the COVID-19 emergency in prison. We analysed the spatial distribution of cases and calculated global and specific attack rates (AR). We assessed prevention and control measures. By 30 April 2020, 57 confirmed COVID-19 cases and 66 clinically probable cases were recorded among a population of 1,480. Global AR was 8.3%. The index case was a custodial officer. Two clusters were detected among custodial staff and healthcare workers. On 31 March, a confirmed case was identified among detained individuals. COVID-19 spread by physical proximity or among subgroups with cultural affinity, resulting in a cluster of 22 confirmed cases. Following index case identification, specific measures were taken including creation of a multidisciplinary task-force, increasing diagnostic capacity, contact tracing and dedicated isolation areas. Expanded use of personal protective equipment, environmental disinfection and health promotion activities were also implemented. Outbreaks of COVID-19 in prison require heightened attention and stringent comprehensive measures.     

HIV seroprevalence among healthy blood donors in northeastern Zaire

Human immunodeficiency virus (HIV)-antibody screening of blood donors in northeastern Zaire was reviewed to determine overall seroprevalence in the population and to identify particular subgroups of the population who are at relatively high risk. Six hundred and seventy-five healthy blood donors were tested from March 1989 to May 1990 using either the HIV-CHEK or Karpas cell tests. A total of 25 donors (3.7%) were seropositive, and seropositivity was more common in female donors (5.4%) than in male donors (2.5%, P less than 0.05). Donors who came from major population centres had a higher rate of seropositivity than did individuals coming from rural villages (10.5% vs 2.0%, P less than 0.001). There was a tendency toward increasing seroprevalence during the 13 months of the study with 2.8% of donors positive in 1989 and 5.8% positive in 1990 (P less than 0.1). It is concluded that in healthy blood donors in northeastern Zaire: (1) HIV seropositivity is more frequent in women and in individuals coming from major population centres, and, (2) HIV seropositivity seems to be increasing rapidly.     

Shigella dysenteriae serotype 1 in west Africa: intervention strategy for an outbreak in Sierra Leone

In November 1999, a Médecins Sans Frontières team based in the southeastern part of Sierra Leone reported an increased number of cases of bloody diarrhoea. Shigella dysenteriae serotype 1 (Sd1) was isolated in the early cases. A total of 4218 cases of dysentery were reported in Kenema district from December, 1999, to March, 2000. The overall attack rate was 7.5%. The attack rate was higher among children younger than 5 years than in the rest of the population (11.2% vs 6.8%; relative risk=1.6; 95% CI 1.5-1.8). The case fatality was 3.1%, also higher for children younger than 5 years (6.1% vs 2.1%; relative risk=2.9; 95% CI 2.1-4.1]). Among 583 patients regarded at increased risk of death who were treated with ciprofloxacin in isolation centres, case fatality was 0.9%. A 5-day ciprofloxacin regimen, targeted to the most severe cases of bloody diarrhoea, was highly effective. This is the first time a large outbreak caused by Sd1 has been reported in west Africa.     

Early chains of transmission of COVID-19 in France,January to March 2020

IntroductionSARS-CoV-2, the virus that causes COVID-19, has spread rapidly worldwide. In January 2020, a surveillance system was implemented in France for early detection of cases and their contacts to help limit secondary transmissions.AimTo use contact-tracing data collected during the initial phase of the COVID-19 pandemic to better characterise SARS-CoV-2 transmission.MethodsWe analysed data collected during contact tracing and retrospective epidemiological investigations in France from 24 January to 30 March 2020. We assessed the secondary clinical attack rate and characterised the risk of a contact becoming a case. We described chains of transmission and estimated key parameters of spread.ResultsDuring the study period, 6,082 contacts of 735 confirmed cases were traced. The overall secondary clinical attack rate was 4.1% (95% confidence interval (CI): 3.6–4.6), increasing with age of index case and contact. Compared with co-workers/friends, family contacts were at higher risk of becoming cases (adjusted odds ratio (AOR): 2.1, 95% CI: 1.4–3.0) and nosocomial contacts were at lower risk (AOR: 0.3, 95% CI: 0.1–0.7). Of 328 infector/infectee pairs, 49% were family members. The distribution of secondary cases was highly over-dispersed: 80% of secondary cases were caused by 10% of cases. The mean serial interval was 5.1 days (interquartile range (IQR): 2–8 days) in contact tracing pairs, where late transmission events may be censored, and 6.8 (3–8) days in pairs investigated retrospectively.ConclusionThis study increases knowledge of SARS-CoV-2 transmission, including the importance of superspreading events during the onset of the pandemic.