Infectivity of severe acute respiratory syndrome during its incubation period.

OBJECTIVE: To evaluate the infectivity of severe acute respiratory syndrome (SARS) during its incubation period by investigating chains of transmission and individuals isolated for medical observation with a view to providing scientific evidence for updating protocols of medical isolation. METHODS: Individuals related with the two SARS chains of transmission in Beijing in 2003 and a group of individuals isolated for medical observation in Haidian district of Beijing during the SARS outbreak were selected as subjects of study. Contactors with SARS patients and those with symptom development following the contacts were investigated via questionnaire. Serum samples were collected from super transmitters and tested for SARS-CoV antibody by neutralization test and enzyme linked immunosorbent assay (ELISA). RESULTS: A total of 1112 contactors were investigated in three surveys. Of them, 669 had a history of close contact with symptomatic SARS patients, 101 developed symptoms with a rate of 15.1%, 363 had a history of close contact with patients in their incubation period, none of whom developed symptoms (0%). Serum samples were collected from 32 highly-exposed individuals, of whom 13 developing SARS symptoms after contact had serum samples positive for SARS-CoV antibody. Samples collected from the asymptomatic contactors were all negative for SARS-CoV antibody. CONCLUSION: SARS cases are infectious only during their symptomatic period and are non-infectious during the incubation period. Isolation for medical observation should be placed for individuals who are in close contact with symptomatic SARS patients. The results of our study are of decisive significance for the Ministry of Health to the definition of SARS close contactor.

[Study on the public health emergent events in Fujian province in 2004--2007].

OBJECTIVE: To study the public health emergent events (PHEE) in Fujian province, from 2004 to 2007. METHODS: Descriptive and analytic methods were used to analyze the PHEE in Fujian province according to the internet-based surveillance reports. RESULTS: From 2004 to 2007, there were 304 emergency events being surveyed. Of all the events, there were 7 (2.30%) belonged to serious-degree of grade II, 57(18.75%) to grade III and 240 (78.95%) to grade IV, but with no grade I. Results showed that the attack rate in affected population was 25.82 per thousand, the mortality rate was 0.08 per thousand and the fatality rate was 0.32%. The numbers of emergency events decreased 2.82% on average, each year. A total number of 169 (55.60%) events occurred in schools with 71 (23.36%) in the countryside. Numbers due to infectious disease-born was 233 (76.64%) including avian flu, cholera and dengue fever were predominant pathogens of the grade II and grade III emergency events. 57 (18.75%) of the events was due to food poisoning. The epi-garph showed that there were two peaks. i.e. in Mar-Apr and Sep, contributed 43.1% to the total number of events. CONCLUSION: Emergency events showed a stable decrease in Fujian province with communicable disease and food poisoning the two major sources and more commonly seen in schools and countryside. We suggest that the government and community pay more attention to the emergency events of avian flu, cholera and dengue fever.

[Study on the timeliness of the notifiable communicable diseases surveillance system in Fujian province, China, 2004].

OBJECTIVE: To understand the timeliness of the notifiable communicable diseases surveillance system in Fujian province. METHODS: Database from the internet based communicable diseases reporting system was used. RESULTS: The 50th percentile of time between the disease diagnosed and report recorded in medical faculties was 1 day in 2004 which was 6 days less than that in 2001 - 2003. The timeliness rate of 0 day was 46.46%, a 2.7 times over that in 2001 - 2003. The timeliness of notifiable communicable diseases surveillance system in different administrative areas, reporting units and on different diseases was significantly different. Time between the disease diagnosed and report recorded was the shortest in those cases reported by hospitals and traditional Chinese medicine(TCM) hospitals at the county level and above, with 50th percentile as 0 day, but the timeliness rate of 0 day was 50.76% with 70.04% of the cases were reported from hospitals and TCM hospitals of county level and above. Length between the disease diagnosed and reported was the longest in those cases recorded by Centers for Disease Control and Prevention(CDCs) with the 50th percentile as 3 days. The source of cases recorded by CDCs came from hospitals at the township level, where there was no connection to internet but the reporting cards had to be sent to local CDCs. Time between the disease being diagnosed and reported was 2 days in those cases reported by hospitals at the township level. 21.21% of cases were recorded by hospitals of township level and CDCs. The 50th percentile of time shown between the reported records and confirmed by CDCs was 4 hours The 24 hour timeliness rate was 63.65%. CONCLUSION: The timeliness of the notifiable communicable diseases surveillance system had been improved significantly after the medical personnel recording the cases directly through internet. Timeliness could be further improved through access to internet at the hospitals of township level, training of staff and better hospital management systems.

[Epidemiological study of the transmission chain of a severe acute respiratory syndrome outbreak].

OBJECTIVE: To investigate the process of SARS transmission and to evaluate infectivity of SARS patients in different periods of disease development. METHODS: A case of SARS outbreak beginning from a male, 74-year-old patient in Beijing. Two hundred and seventy five primary, secondary and tertiary contacts, including family members relatives, colleagues, and others exposed to him, were traced by field investigation and telephone interview using a standardized questionnaire. The transmission process and infectivity of disease were analyzed with transmission chain diagram and contact history diagram. RESULTS: Among the 275 contacts of the index case, 41 fell ill of SARS with an attack rate of 14.9% and 5 deaths with a fatality rate of 12.2%. The transmission chain of this outbreak could be clearly delineated, and all the 41 cases had close contacts with their infectors, SARS cases of the previous generation within the symptomatic period thereof. All of the 114 contacts that contacted their infectors, SARS cases of the previous generation during the incubation period thereof remained healthy. The incubation period of 27 cases that had contacted their infectors only once was 1 - 10 days with a median of 3 days. The highest risk of being infected was caring the patients unprotectedly, followed by living together with patient, visiting patient, and handling patient without protection. CONCLUSION: All the secondary cases have the history of close contact with their symptomatic infectors of previous generation. It cannot be proved at all that SARS is infective during the incubation period. The infectivity of SARS is related to the degree of closeness of contact with the patient.

[Rapid assessment of safety injection in one county, north rural area in China].

OBJECTIVE: To estimate the frequency of injections and proportion of unsafe injections and to analyses the critical determinants of poor injection practices in general population in China. Also, to study knowledge, attitudes, practice research in providers and general population. METHODS: A random sample consisting residents and health care providers in a rural county was elected and interview about the frequency of received injection, as well as knowledge, attitudes and practices regarding injections were studied. RESULTS: Overall, 1 004 village residents, and 94 providers were interviewed. Among residents, 145 persons (14.4%), with 457 times (0.46 times per person) had received at least one injection during the previous 3 months. The frequency of injection was 1.84 per year. The proportion of received injections on treatment and immunizations was significantly different among > 12 years age group and < or = 12 years age group. Ninety-four point four percent of disposable syringes/needles were used for injections. Knowledge among the population and providers regarding injection safety was limited. CONCLUSION: Injections were moderately frequent in this rural area and the proportions of disposable syringes/needles used for injections was very high. Knowledge of safe injection and reasonable injection as well as consciousness of self-protection in the providers and residents need to be improved.

[A cross-sectional survey on injection safety in health facilities in Wulong county, Chongqing city].

OBJECTIVE: To provide evidence for intervention measures on safe injection through a survey on the safety of injection in the health facilities in Wulong county, Chongqing city, China. METHODS: An investigation on injection safety was conducted among health care providers with a uniform questionnaire. RESULTS: Glass syringes which were not appropriately sterilized was found in 52.2% (12/23) of the health facilities. Injection practices were not correct in 31.4% (11/35) of the health facilities. Used disposable syringes were discarded directly without any disposal in 63.6% (21/33) of the health facilities. At least one of the unsafe injection practices mentioned above existed in 77.1% (27/35) of the health facilities. CONCLUSIONS: The main unsafe factors in the practice of injection are included: the practice to change needle but not syringe in penicillin allergic test and the injuries caused by used disposable syringes in medical staff. The important measures to improve injection safety were to train the medical staff on the knowledge about safe injection and the risks caused by unsafe injection, and to equip the health facilities with safe tools to destroy the used disposable syringes.

[Efficiency of the quarantine system during the epidemic of severe acute respiratory syndrome in Beijing, 2003].

OBJECTIVE: An epidemic of severe acute respiratory syndrome (SARS) hit Beijing, China, between March and July 2003 with an attack rate of 1.9 per 10 thousand. (2,521 cases). To control the epidemic of SARS, a total of 30,173 residents were quarantined either in their residence or in quarantine sites. In order to understand the personal need of being quarantined and to estimate the risk of developing SARS during the quarantine period, a survey on the quarantined residents of Haidian District, Beijing, China was carried out. METHODS: 33 precincts in Haidian District divided into five groups (7 in north, 6 in south, 7 in west, 6 in east and 7 in central of Haidian District) according to the location of the precincts were involved. The director of Center of Disease Control and Prevention of Haidian District was asked to select 1 precinct from each group according to the workload of the precinct quarantine officers. From those 5 precincts we obtained lists of all quarantined persons from the precinct quarantine officers. All quarantinees were asked to complete a self-administered questionnaire. The SARS patients were diagnosed and verified according to the diagnosis criteria released by Chinese Ministry of Health which was equivalent to the SARS 'probable case' definition of WHO. All SARS cases had been reported to the relative authorities. RESULTS: By May 23, 2003, 5,186 persons had been quarantined in Haidian district, accounting for 0.23% of all residents. 1,028 of sampled quarantined residents completed the questionnaire. Of those who completed the questionnaire, 2.3% (95% CI: 1.5% - 3.5%) developed SARS while under quarantine. The median quarantine period was 14 days (range 1 day to 28 days). 61% of the quarantinees had a direct contact history with SARS patients, and all secondary SARS patients developed through contact to these quarantinees. The remaining 39% quarantinees who did not have a direct contact history with SARS patients had not developed SARS during the period under quarantine. 37% of the quarantees had direct contact during original patients' symptomatic period with an AR of 6.3%. Persons who looked after the illed SARS patient(s) during their symptomatic period, had an highest attack rate of 31% (95% CI: 20% - 44%). 63% (95% CI: 60% - 66%) of the total quarantined persons did not have direct contact with a SARS patient during his/her symptomatic period, with an attack rate of 0% (95% CI: 0% - 0.73%). CONCLUSION: Only those persons having direct contact with ill SARS patients need to be under quarantine. The overall cost for quarantine on SARS prevention could be reduced by as much as 63% if the quarantine program was limited to this group. No evidence was found that SARS patient was infective during the incubation period.