[Study on the dynamic prevalence of serum antibody against severe acute respiratory syndrome coronavirus in employees from wild animal market in Guangzhou].

OBJECTIVE: To investigate the dynamic trend of specific antibody against severe acute respiratory syndrome (SARS)-CoV in serum collected at various periods among employees in Guangzhou Xinyuan animal market. METHODS: Volunteers from employees of the animal market were recruited and their serum specific antibody against SARS-CoV were determined by enzyme linked immunesorbent assay (ELISA) method. RESULTS: Positive SARS-CoV specific IgG antibody was found 25.61% (n = 328), 13.03% (n = 238), 12.59% (n = 135), 5.04% (n = 139) and 9.43% (n = 53) among volunteers, which were sampled in May 2003, Dec. 2003, Jan. 2004, July 2004 and June 2005 respectively. No specific IgM antibody was found in all of those samples. Among 129 samples which were tested twice or more, 97 were all negative, 18 all positive, 13 changed from positive to negative but only one sample from negative to positive. When the volunteers were divided by the duration of their working experiences as short-term or long-term, those who had worked at animal market for less than or more then 6 months when being tested, the positive rate for long-term employees were relatively constant, however, all of the persons employed after January 2004, when the palm civets and raccoon dogs were culled from the market, were tested negative. CONCLUSION: The prevalence of specific antibody against SARS-CoV in employees of the animal market were somehow related with the presence or absence of palm civet. No serum was tested positive for persons who were employed after palm civets and raccoon dogs were culled from market. This data indicated that the SARS-CoV might have been from the palm civets and raccoon dog, and the animal market seemed to serve as one of the sources of infection.

Cross-host evolution of severe acute respiratory syndrome coronavirus in palm civet and human.

The genomic sequences of severe acute respiratory syndrome coronaviruses from human and palm civet of the 2003/2004 outbreak in the city of Guangzhou, China, were nearly identical. Phylogenetic analysis suggested an independent viral invasion from animal to human in this new episode. Combining all existing data but excluding singletons, we identified 202 single-nucleotide variations. Among them, 17 are polymorphic in palm civets only. The ratio of nonsynonymous/synonymous nucleotide substitution in palm civets collected 1 yr apart from different geographic locations is very high, suggesting a rapid evolving process of viral proteins in civet as well, much like their adaptation in the human host in the early 2002-2003 epidemic. Major genetic variations in some critical genes, particularly the Spike gene, seemed essential for the transition from animal-to-human transmission to human-to-human transmission, which eventually caused the first severe acute respiratory syndrome outbreak of 2002/2003.

[Evaluation of a pilot study on needle and syringe exchange program among injecting drug users in a community in Guangdong, China].

OBJECTIVE: To evaluate the feasibility and effectiveness of needle and syringe exchange program among a community of injecting drug users (IDUs) on AIDS prevention. METHODS: A quasi-experiment design was used in a controlled community intervention study. Needle and syringe exchange program was implemented for 10 months in IDUs of an intervention community, including peer education and health education, provision of free needles and syringes, and collecting back of used needles and syringes by trained peer educators and local health workers, whereas no intervention measure in a control community was instituted. Interviews with IDUs were conducted before and after intervention with a snowballing strategy to evaluate its effectiveness. RESULTS: A total of 428 and 429 IDUs were interviewed with structured questionnaire before and after intervention in intervention and control communities, respectively. Results revealed that awareness of HIV-related knowledge increased from 29.4% to 58.7% in the intervention community. Multivariate logistic regression analysis showed that awareness of HIV-related knowledge was higher in those who had read health education materials (OR = 2.93, 95% CI 2.12 - 4.04). As compared with the baseline data, frequency of sharing needles and syringes in past 30 days in the intervention community decreased from 48.9% to 20.4% in before intervention community (chi(2) = 41.02, P = 0.001), whereas there was no significant change in the control community. The causes of sharing needles and syringes in the intervention community included 'disable to get needle and syringe during the night', 'lack of needle and syringe when injecting at friend's home', 'not daring to buy needle and syringe for fear of being arrested' and 'no money to buy needle and syringe', declined markedly. CONCLUSIONS: Needle and syringe exchange program was feasible and effective in reducing their risky drug injecting behavior among IDUs in communities. Such strategy should be adopted in the country to reduce rapid spread of HIV.

Epidemiologic clues to SARS origin in China.

An epidemic of severe acute respiratory syndrome (SARS) began in Foshan municipality, Guangdong Province, China, in November 2002. We studied SARS case reports through April 30, 2003, including data from case investigations and a case series analysis of index cases. A total of 1,454 clinically confirmed cases (and 55 deaths) occurred; the epidemic peak was in the first week of February 2003. Healthcare workers accounted for 24% of cases. Clinical signs and symptoms differed between children (<18 years) and older persons (> or =65 years). Several observations support the hypothesis of a wild animal origin for SARS. Cases apparently occurred independently in at least five different municipalities; early case-patients were more likely than later patients to report living near a produce market (odds ratio undefined; lower 95% confidence interval 2.39) but not near a farm; and 9 (39%) of 23 early patients, including 6 who lived or worked in Foshan, were food handlers with probable animal contact.

[Severe acute respiratory syndrome in Guangdong Province of China: epidemiology and control measures].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

[Epidemiological study on severe acute respiratory syndrome in Guangdong province].

OBJECTIVES: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

SARS: epidemiology.

Severe acute respiratory syndrome (SARS) originated in Southern China in November 2002, and was brought to Hong Kong in February 2003. From Hong Kong, the disease spread rapidly worldwide but mostly to Asian countries. At the end of the epidemic in June, the global cumulative total was 8422 cases with 916 deaths (case fatality rate of 11%). People of all ages were affected, but predominantly females. Health care workers were at high risk and accounted for one-fifth of all cases. Risk factors for death included old age and comorbid illnesses, especially diabetes. The disease is caused by a novel coronavirus and is transmitted by droplets or direct inoculation from contact with infected surfaces. Contaminated sewage was found to be responsible for the outbreak in a housing estate in Hong Kong affecting over 300 residents. The mean incubation period was 6.4 days (range 2-10). The duration between onset of symptoms and hospitalisation was from 3 to 5 days. The relatively prolonged incubation period allowed asymptomatic air travellers to spread the disease globally. The number of individuals infected by each case has been estimated to be 2.7. Effective control of nosocomial transmission included early detection of disease, strict isolation of patients, practice of droplet and contact precautions and compliance with the use of personal protective equipment. Effective control of disease spread in the community included tracing and quarantine of contacts. Development of a validated diagnostic test and an effective vaccine as well as elimination of possible animal reservoirs are measures needed to prevent another epidemic.