Risk factors for severe hand foot and mouth disease.

BACKGROUND: Hand foot and mouth disease (HFMD) and herpangina are enteroviral infectious diseases caused mainly by Coxsackie virus A (CA) or enterovirus 71 (EV71). From 2000 to 2002, many complicated cases were reported in Japan, therefore a nationwide questionnaire survey was carried out to assess the situation. The subjects were patients with HFMD or herpangina, or other enterovirus infection from 2000 to 2002, who were either hospitalized over 24 h or who died. The response rates were 41.3% in 2000 and 2001 and 31.6% in 2002. The survey period included the year 2000, when HFMD epidemics due to EV71 occurred. To examine risk factors causing complications of enterovirus infection, severe cases of HFMD were focused on. METHODS: HFMD cases in 2000 were divided into two groups according to severity: 'more severe' and 'less severe'. 'More severe' was defined as 'fatal, involving sequelae, or involving hospitalization for 7 days or longer'. Statistical analyses were conducted with Epi info version 3.3 and the association between risk factors and severity was estimated. RESULTS: The number of patients with more severe and less severe cases was 96 and 103, respectively. There was no difference in sex, age, having siblings and family history between the two groups. There was a significant association between attending child care center and severe HFMD. CONCLUSIONS: It is not clear why attending child care centers was associated with HFMD severity. Further study is needed.

Surveillance, recognition, and reporting of Tsutsugamushi disease (scrub typhus) and Japanese spotted fever by general practice clinics in Miyazaki Prefecture, determined by questionnaire survey in 2007.

In June 2007, a questionnaire survey related to the surveillance, recognition, and reporting of Tsutsugamushi disease (TD) and Japanese spotted fever (JSF)--diseases considered endemic in Miyazaki Prefecture--was distributed to general practice clinics in the prefecture. The response rate was 40.9% (232/567). While 75.5% of the responding clinics knew TD to be a notifiable disease, only 41.8% knew JSF was notifiable. The recognition level of JSF surveillance was lower in the low-incidence areas of JSF within Miyazaki Prefecture. In 2006, 25 cases were clinically suspected as TD by the responding clinics; of the 25 cases, 9 were confirmed and 8 of these were reported to the National Epidemiological Surveillance of Infectious Diseases (NESID). Only 1 of 6 clinically suspected JSF cases from the responding clinics was confirmed in 2006, and it was not reported to NESID. The clinics located in the high-incidence areas for TD tended not to perform laboratory confirmation of the clinically suspected cases of either of the diseases. Considering that NESID requires laboratory confirmation of the reported cases of these diseases, their extent may be underestimated, especially in the high-incidence areas. For clinics in Miyazaki Prefecture, we need to publicize the existence of JSF surveillance and inform clinics about the laboratories available for confirmation of JSF and TD in the prefecture.

Seasonal influenza surveillance using prescription data for anti-influenza medications.

Surveillance is critical for both early detection and a timely public health response to infectious diseases. Electronic information systems have been widely adopted by pharmacies in Japan. The aim of this study is to evaluate the feasibility of using prescription data for influenza surveillance in Japan to facilitate the development of a daily reporting system. This is a retrospective study using questionnaires mailed to pharmacies in Sakai City, Osaka, Japan in October 2007. The total number of prescriptions for oseltamivir and zanamivir and the number of influenza cases reported by sentinel surveillance in Sakai during the investigation period showed excellent correlation, with a correlation coefficient of 0.954. Further analysis showed that the data from as few as eight pharmacies result in a correlation coefficient of 0.9. These results demonstrate the feasibility of such a system and that pharmacy prescription data are a very useful indicator of sentinel surveillance for influenza.

Time-tradeoff utilities for identifying and evaluating a minimum data set for time-critical biosurveillance.

BACKGROUND: Researchers and policy makers are interested in identifying, implementing, and evaluating a national minimum data set for biosurveillance. However, work remains to be done to establish methods for measuring the value of such data. PURPOSE: The purpose of this article is to establish and evaluate a method for measuring the utility of biosurveillance data. METHOD: The authors derive an expected utility model in which the value of data may be determined by trading data relevance for time delay in receiving data. In a sample of 23 disease surveillance practitioners, the authors test if such tradeoffs are sensitive to the types of data elements involved (chief complaint v. emergency department [ED] log of visit) and proportional changes to the time horizon needed for receiving data (24 v. 48 h). In addition, they evaluate the logical error rate: the proportion of responses that scored less relevant data as having higher utility. RESULTS: Utilities of chief complaints were significantly higher than ED log of visit, F(1, 21)= 5.60, P < 0.05, suggesting the method is sensitive. Further utilities did not depend on time horizon used in the exercise, F(1, 21) = 0.00, P = ns. Of 92 time tradeoffs elicited, there were 5 logical errors (i.e., 5% logical error rate). CONCLUSIONS: In this article, the authors establish a time-tradeoff exercise for valuing biosurveillance data. Empirically, the method shows initial promise for evaluating a minimum data set for biosurveillance. Future applications of this approach may prove useful in disease surveillance planning and evaluation.

Estimation of measles vaccine coverage needed to prevent transmission in schools.

BACKGROUND: The aim of the present study was to produce the first estimation in Japan of the basic reproduction number (R(0)) and the minimum level of vaccine coverage needed to prevent measles outbreaks (P(c)). METHODS: A questionnaire survey was conducted during two measles outbreaks among 12-15-year-old middle school students in one prefecture in spring, from the end of February to the beginning of May 2002, and a stochastic mathematical model was constructed to calculate vaccine effectiveness (VE) and the basic reproduction number (R(0)). P(c) was calculated from R(0) and VE. RESULTS: In outbreak 1 (school A), 62 (94%) of 66 patients responded to the questionnaire. Of a total of 601 students, 534 (88.9%) responded. Of these, 82.6% (441/534) had previously received measles vaccine. In outbreak 2 (school B), 20 (99%) of 21 patients responded. Of a total of 375 students, 373 (99.5%) responded. Of these, 317 (85.0%) received measles immunization. Mathematical analysis was as follows: in outbreak 1 R(0) was 7.40 (95% confidence interval [CI]: 7.36-7.44) and VE was 76.55% (95%CI: 53.24-87.54). In outbreak 2, R(0) was 18.89 (95%CI: 18.88-18.90) and VE was 98.54% (95%CI: 94.89-99.73). Consequently, P(c) was 112.97% (95%CI: 92.29-145.52) in outbreak 1 and 96.11% (95%CI: 93.81-98.53) in outbreak 2. CONCLUSION: Because of the lower VE in outbreak 1, measles virus transmission could not have been stopped even if all students received a single dose of vaccine. In outbreak 2, with higher VE, the outbreak could have been prevented by increasing the proportion of students who had been vaccinated.

A nosocomial outbreak of febrile bloodstream infection caused by heparinized-saline contaminated with Serratia marcescens, Tokyo, 2002.

In January 2002, 12 patients with Serratia marcescens bloodstream infection (BSI) were identified in a hospital in Tokyo, Japan. We conducted an epidemiological investigation of this outbreak. We undertook a medical-records review and employee interviews, and performed a case-control study to determine risk factors for S. marcescens BSI. An observational study of the hospital's procedures and an environmental microbiologic sampling were performed. We identified 12 suspected and 12 confirmed patients with S. marcescens BSI, including 7 who died. A case-control study showed that vascular access devices (odds ratio [OR] = 30.46; 95% confidence interval [CI] = 3.5-685.6) and the use of heparin-locks, between December 26 and January 15 (OR = 25.7; 95% CI = 2.3-680.4) were significant risk factors for S. marcescens BSI. The observational study revealed multiple lapses in infection control, including use of multi-dose vials of heparin. The outbreak strain was isolated from a hand-towel in the nurse station. The use of multi-dose vials of heparinized-saline during a particularly busy period was associated with BSI risk. The results underscore the risks inherent in infection-control lapses and the use of multi-dose vials.

[Present status of Tsutsugamushi disease detection at regional public health laboratories--a comparison between the results from a questionnaire survey and the National Notifiable Diseases Surveillance System].

Tsutsugamushi disease has been a notifiable disease in Japan since the implementation of the Infectious Diseases Control Law in April 1999. In order to assess the role of public health laboratories in detecting Tsutsugamushi disease, a questionnaire regarding routine testing of suspected cases of Tsutsugamushi disease was sent to 73 regional public health laboratories (47 prefectural laboratories and 26 municipal laboratories) in July 2001. The response rate was 92% (67/73 laboratories). It was found that most prefectural laboratories are well prepared to routinely receive and test specimens of suspected Tsutsugamushi disease cases. Additionally, we found that some regional public health laboratories are using two or more detection methods to improve the accuracy of their routine tests. In southern Japan. Kawasaki and Kuroki strains, strains endemic to the region, are widely used in addition to Kato, Karp, and Gilliam strains, the standard strains used for serum antibody tests in Japan. For the years 2000 and 2001, we found that for some prefectures, the annual number of cases confirmed by regional public health laboratories was nearly equal to the annual number of cases the prefecture reported to the National Notifiable Diseases Surveillance System. In these prefectures, it appears that an effective communication network has been established between physicians, public health laboratories, and local health centers, ensuring laboratory confirmation and proper notification.

Lake-associated outbreak of Escherichia coli O157:H7 in Clark County, Washington, August 1999.

CONTEXT: Escherichia coli O157:H7, one of hundreds of strains of the gram-negative bacterium E coli, has been implicated in numerous lake-borne outbreaks of infection during the past decade. In August 1999, several children who later became ill with E coli O157:H7 infection reported swimming in a lake in Clark County, Washington. The lake was closed and an investigation begun. OBJECTIVES: To identify the source of the outbreak and determine risk factors for infection with E coli O157:H7.Design, Setting, and Patients Two case-control studies were performed among residents of and visitors to Clark County in August 1999 by using community and campground-registrant control subjects. Main Outcome Measure Risk factors for infection with E coli O157:H7 among Clark County residents or visitors. RESULTS: We identified 37 case patients (including 29 primary-case patients) with a median age of 5 years (age range, 1-14 years for primary-case patients). Eight children were hospitalized, 3 with hemolytic uremic syndrome; none died. With analysis restricted to primary-case patients, illness was strongly associated with swimming in the lake (18 of 18 case patients vs 1 of 18 neighborhood-matched and age-matched control subjects; matched odds ratio undefined; P<.001). All primary-case patients were children younger than 15 years who swam in the lake. Illness was associated with placing the head underwater, getting lake water in the mouth, or swallowing lake water (26 of 27 case patients vs 43 of 62 control subjects; matched odds ratio = 11.5; P =.005). Cultures of lake water yielded E coli O157:H7 that matched the outbreak strain according to results of pulsed-field gel electrophoresis. CONCLUSIONS: To date, this is one of the largest documented outbreaks of E coli O157:H7 infection associated with unchlorinated recreational water and represents the first outbreak in which the strain was isolated from lake water. Guidelines are needed to decrease the risk of enteric illness associated with swimming in recreational lakes.