An epidemiological study on the norovirus detected in the field environment after an outbreak of norovirus gastroenteritis / 中华流行病学杂志

Objective To study the status of norovirus in environment of the patient's residence and water samples after a norovirus gastroenteritis outbreak, to provide evidences for the development of strategies for prevention and control of the disease. Methods After a norovirus gastroenteritis outbreak, anus swabs from the patient, swabs from the household environment and the water samples were collected to detect the norovirus by RT-PCR methods. Sequencing analysis was conducted on those positive specimens. Results Three specimens of the anus swabs from 9 patients and 2 samples of the 46 house environment swabs were positive to the virus. The latter were from the surface of water-closets of two families that the illness were asymptomatic. Among 5 water samples, only one was positive, which was the rivulet water that the feces of the villagers evacuated directly. Results showed that the sequences of the virus detected from the anus swabs of the patients, the swabs from the household environment and the samples of the rivulet water belonged to the same species. Conclusion It is necessary to strengthen activities as supervision and disinfection to the feces of the patients, especially on monitoring the feces that might have contaminated the water during the noroviru gastroenteritis outbreak.

Pathogens of high incidence of other infectious diarrhea in Guangdong Province, from November 2008 to January 2009 / 病毒学报

From November 2008 to January 2009, a sharp increase of diarrhea in children in Guangdong province appeared, we randomly collected 53 stool specimens from out-patient children with dirrhea in 3 major hospitals (Guangzhou City Children's Hospital, Shenzhen Baoan District Maternal and Child Health Hospital, First Affiliated Hospital of Shantou University). Rotavirus and calicivirus were screened by ELISA and RT-PCR. We found 29 cases of rotavirus infection with diverse serotypes. Only four cases were identified as calicivirus infection. The result indicated that rotavirus was a major pathogen of this high incidence of diarrhea from November 2008 to January 2009 in Guangdong Province.

Molecular epidemiological characteristics of norovirus gastroenteritis outbreaks in Guangdong from 2005 to 2008 / 病毒学报

To study the molecular epidemiological characteristics of norovirus gastroenteritis outbreaks in Guangdong, we collected fecal and anal swabs specimens from 24 outbreaks of acute gastroenteritis from 2005 to 2008 to detect norovirus. Specimens were detected by RT-PCR and then sequenced. The descriptive data were also collected. According to our research, 19 of 24 outbreaks of gastroenteritis were positive for norovirus. The occurrence time was from October to next February mainly. The strains in 2005 belonged to G II-3 genotype and all outbreaks occurred in kindergarten and school. But from autumn of 2006, the outbreaks were all caused by G II-4/2006b variant and occurred in universities and community. The number of outbreaks in 2007 increased greatly and covered all over province. The nucleotide sequences of Guangdong strains in some sites showed high regional identity. Our results showed that with the shift of genotype from G II-3 to G II-4, occurrence of norovirus outbreaks increased greatly. The outbreaks of norovirus caused by G II-4/2006b variant spreaded widely and the involved population covered children and adult, indicating the strong invasiveness of this variant.

Investigation of a norovirus outbreak through contaminated centralized water supply system / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the etiology and source of an infectious diarrhea outbreak and control the epidemic.</p><p><b>METHODS</b>Through the retrospective cohort study, we had surveyed all the residents who complained symptoms of diarrhea or vomiting since Nov. 20th,2007 from the five villages in the north of town Y, and collected hygiene information on the water supply system of the five villages, the environment information of three villages and hygiene information of some case-indexed families, and tested the etiological biomarker, including nucleoside acid of norovirus through Real-time PCR and nested PCR technologies.</p><p><b>RESULTS</b>From Nov. 24th to Dec. 3th in 2007, 435 diarrhea or vomiting cases were found in the north of Y town, where tap water A was supplied for daily use. The attack rate was 12.93%. The diarrhea cases were distributed among all country groups who has used tap water A and the attack rate was ranged from 5.21% (20/384) to 21.23% (100/471). Drinking the tap water A was significantly associated with an increased risk of infection (RR = 9.246, 95% CI: 6.25 -13.68). About 85.9% (262/ 305) of the cases were from Nov. 25th to 27th. An investigation of a country of S2 group showed that the incidence of different age groups was distributed as the following: 0 - year-old 20.0% (3/15); 10 - year-old 17.3% (9/52); 20 - year-old 15.2% (16/105); older than 60 year-old 23.3% (7/30). No statistical significance was identified between age and infection(chi2 = 1.15, P >0.05). Most of the patients were not serious and well prognostic, and no hospitalized or dead cases were reported. On site investigation and daily water quality monitoring showed that disinfection procedures were not strictly followed. The monitoring data also indicated the bacteriology index of tap water A was disqualified. The test of Salmonella, Shigella and Staphylococcus aureus were negative in two vomit and one stool samples from patients. Three specimens by Real-time PCR, and six by nested PCR were positive for norovirus among the three feces and three anal swabs samples. With the drinking water sterilization and health education, the epidemic had been controlled rapidly and effectively.</p><p><b>CONCLUSION</b>The epidemic was a diarrhea outbreak that might be caused by norovirus through drinking the contaminated tap water A.</p>

An epidemiological study on the index cases of severe acute respiratory syndrome occurred in different cities among Guangdong province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To analyze the epidemiological features of the index cases of severe acute respiratory syndrome (SARS) occurred in different cities in Guangdong province and to trace for the source of infection.</p><p><b>METHODS</b>Standardized individual case inventory was adopted to conduct investigation on index cases and on persons who had close contact with index cases in Guangdong province. Data on the epidemiological characteristics, secondary cases and the links among index cases were analyzed.</p><p><b>RESULTS</b>Between November 16, 2002 and April 16, 2003, there had been 13 index cases of SARS including 3 cadres, 3 farmers, 2 retirees, 2 workers and 1 shop attendant, reported from 13 cities in Guangdong province. Between November 2002 and January 2003, there had been 7 cities reported to have identified index cases of SARS with 6 of them being infected in their own cities and 1 imported from Guangzhou city. All of the cases had no close contacts to similar patients but 6 of them later caused 2nd or even 3rd generation cases of SARS. Most cases hit young people (7/13) with a sex ratio of 1:0.6. The fatality rate of index cases was high (4/13).</p><p><b>CONCLUSION</b>No evidence showed that there was direct transmission among the index cases. Data regarding the geographical origin of those index cases led to the assumption that the infection had started in six cities of Pearl river delta region and the Hong Kong Special Administrative Region.</p>

Epidemiological study on severe acute respiratory syndrome in Guangdong province / 中华流行病学杂志

<p><b>OBJECTIVES</b>To understand the epidemiological characteristics of severe acute respiratory syndrome (SARS) outbreaks in some areas of Guangdong province and to provide scientific basis for prevention and control measures against it.</p><p><b>METHODS</b>Standardized questionnaire was used on individual cases. Data on the epidemiological characteristics as time, place, persons and aggregation status of SARS cases, development of the epidemics, were analyzed with software EPI 6.0.</p><p><b>RESULTS</b>The incidence of SARS in Guangdong province was 1.72/100,000 with case fatality rate as 3.64%. Most cases of SARS occurred between the last ten days of January and the first ten days of February with the peak (61.88% of the patients) occurred in the first ten days of February. As to the distribution of place, Pearl river delta region-economically developed with great number of mobile population-was heavily affected areas (account for 96.66% of the total patients). The majority of patients were young adults and medical staff seemed to be the most affected subgroup (account for 24.9% of the patients in total). Family and hospital aggregation of patients comprised the another two important characteristics of SARS (account for 37.1% of the total patients).</p><p><b>CONCLUSION</b>Current knowledge on SARS suggested that it was an air-borne infectious disease with human beings served as the source of infection. The incubation period of the disease was from 1 to 12 days with a median of 4 days. Respiratory secretions and close contact contributed to person-to-person transmission. Most cases were distributed in Pearl river delta region, an area famous for its economic development and heavy flow of mobile population.</p>

Severe acute respiratory syndrome in Guangdong Province of China: epidemiology and control measures / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore epidemiological features and risk factors of severe acute respiratory syndrome (SARS) in Guangdong Province of China, so as to work out effective strategies for its better control.</p><p><b>METHODS</b>A total of 1 511 clinically confirmed SARS cases in Guangdong Province of China from November 16, 2002 to Jun 15, 2003 were retrospectively analyzed.</p><p><b>RESULTS</b>The first SARS case was identified in Foshan municipality on November 16, 2002, followed by 1 511 clinically confirmed cases (including 58 deaths) up to May 15, 2003. Of all cases, health care workers and community family cluster cases accounted for 19.38% and 12.04%. 65.86% SARS patients aged 20 - 49 years, and increased incidence was positively related to their ages. 95.97% cases lived in the following five cities around Pearl Delta Area: Foshan, Guangzhou, Shenzhen, Zhongshan, and Jiangmen. Eleven early reported cases in the communities took animal-related positions. Face-to-face contacts with infected droplets were the main transmission route. An epidemic peak occurred during January 28 to February 26, and those cases accounted for 50.69% of total. Incidence, mortality, and case fatality of SARS were 1.77/100,000, 0.07/100,000, and 3.84% respectively. The mean incubation period was 4.5 days.</p><p><b>CONCLUSION</b>The most effective way to control SARS is to break the chain of transmission from infected to healthy persons-early identification, prompt and effective isolation, and vigorous close contact tracing. Hospital infections among health care workers is critical. Several observations support the hypothesis of an animal origin for the disease.</p>