Estimation of Incubation Period and Serial Interval for SARS-CoV-2 in Jiangxi, China, and an Updated Meta-Analysis.

INTRODUCTION: This paper aims to estimate the incubation period and serial intervals for SARS-CoV-2 based on confirmed cases in Jiangxi Province of China and meta-analysis method. METHODOLOGY: Distributions of incubation period and serial interval of Jiangxi epidemic data were fitted by "fitdistrplus" package of R software, and the meta-analysis was conducted by "meta" package of R software. RESULTS: Based on the epidemic data of Jiangxi, we found the median days of incubation period and serial interval were 5.9 days [IQR: 3.8 - 8.6] and 5.7 days [IQR: 3.6 - 8.3], respectively. The median days of the infectivity period at pre-symptomatic was 1.7 days [IQR: 1.1 - 2.4]. The meta-analysis based on 64 papers showed the pooled means of the incubation period and serial interval were 6.25 days (95% CrI: 5.75 - 6.75) and 5.15 days (95% CrI: 4.73 - 5.57), respectively. CONCLUSIONS: Our results contribute to a better understanding of COVID-19 and provide useful parameters for modelling the dynamics of disease transmission. The serial interval is shorter than the incubation period, which indicates that the patients are infectious at pre-symptomatic period, and isolation of detected cases alone is likely to be difficult to halt the spread of SARS-CoV-2.

An Outbreak of Dengue Virus Type 1 - Jiangxi Province, China, 2019.

What is known about this topic? Dengue fever is an acute febrile illness caused by four types of dengue virus (DENV 1-4), and is a mosquito-borne infectious disease. The incidence of dengue has increased dramatically around the world in recent decades. An estimated of 3.9 billion people in 128 countries are at risk of infection with dengue viruses, 70% of whom are in Asia. In 2017, the first local infections of dengue virus (DENV-2) in Jiangxi Province was reported in Zhanggong District, Ganzhou City. What is added by this report? From August to September 2019, the first dengue outbreak happened in Xin'gan County, where 81 local dengue fever cases were reported, 35 were laboratory-confirmed cases, and 46 were clinically-diagnosed cases; all cases were dengue virus type 1. The DENV-virus strains isolated from the cases of Xin'gan County were close to the strains isolated in Singapore (MF033254|25657|Singapore|2016) and Henan (MK905537|Henan201903|China: Henan Province|2019). What are the implications for public health practice? The outbreak might have been caused by imported cases or covert infections. The outbreak in Xin'gan County indicated that more proactive countermeasures should be taken during the dengue epidemic period such as intensifying surveillance for dengue cases, virus serotype, and Aedes vector density and strengthening cooperation with customs and tourism departments. Moreover, the outbreak should prompt training in medical institutions and improved ability for doctor's to diagnose dengue fever, which is very important for early detection of dengue cases and taking preventive measures.

Utilization pattern of Haemophilus influenza type b vaccine in eight provinces of China.

OBJECTIVE: In China, Hib vaccine is a private-sector vaccine that is an option for parents to select to give to their children; it must be paid for out-of-pocket because it is not included in the government's Expanded Program on Immunization (EPI). We evaluated utilization patterns of Hib vaccine to provide evidence in support of development of a national Hib vaccination strategy. METHODS: We obtained lists of children from immunization information systems (IIS) of counties or districts in 8 provinces of China. Using these lists, we selected 10 children at random from each birth cohort from 2008 through 2012. We obtained Hib vaccination dates from official vaccination certificates. The target sample size was 1,000 children. RESULTS: We were able to obtain records for 978 subjects of the selected subjects; of these, 44.79% had received at least 1 dose of Hib vaccine, and 15.54%, 5.83%, 12.27%, and 11.15% had received one, two, three, and four doses, respectively. Per capita GDP was positively correlated with receipt of at least one dose of Hib vaccine. Among the 438 subjects who received Hib vaccine, 27% received 1 dose after 12 months of age; 15%, 7%, and 23% received one of three other patterns of Hib vaccination recommended by the World Health Organization (WHO) [a 3-dose primary series; 2 primary series doses and 1 booster; or 3 primary series doses and 1 booster]. The other 28% of subjects received patterns of Hib vaccination not recommended by WHO. Considering protection from Hib disease as receipt of a WHO-recommended Hib vaccine schedule, 29% of subjects could be considered protected after 12 months of age, 52% could be considered protected during infancy and beyond, and 19% could be considered to not have been protected adequately, despite being vaccinated. CONCLUSIONS: Coverage with Hib vaccine was low. There were significant differences between WHO recommendations and actual patterns of use of Hib vaccine, with half of vaccine recipients receiving no protection during infancy and one fifth receiving non-protective Hib vaccination patterns. Inclusion of Hib vaccine into China's EPI system, which provides vaccine at no charge to parents and makes specific vaccination schedule standards, has potential to make more effective use of Hib vaccine.

An outbreak of acute gastroenteritis associated with contaminated bottled water in a university - Jiangxi, China, 2012.

BACKGROUND: On 23 May 2012, a university in Jiangxi, China reported a gastroenteritis outbreak. We investigated the outbreak to identify the agent, source and mode of transmission and to recommend control measures. METHODS: A case was defined as any person from the university with onset of diarrhoea (≥ 3 times/24h) from 1 to 31 May 2012. Active case finding was conducted by reviewing university hospital and drug-store records and interviewing students, workers and teachers. We then conducted a case-control study in which we compared food, water and environmental exposure history. Water samples were collected and tested. RESULTS: We identified 417 cases - an attack rate (AR) of 4.7% (417/8781) for the university. There were 416 student cases (AR = 5.7%) distributed across all 11 colleges, five of which were more heavily affected (AR range = 5.9-14%). In the case-control study, cases had higher odds of having drunk bottled water (odds ratio [OR] = 4.1; 95% confidence interval [CI] = 1.7-9.9), and there was a dose-response relationship (χ(2)trend = 4.6, P < 0.05). Drinking boiled bottled water was inversely associated with being a case (OR = 0.22, 95% CI = 0.07-0.71). Eating in any of the three university canteens or drinking-water from the city water supply was not associated with being a case. Pathogenic Escherichia coli was isolated from two unopened bottled water specimens and from four student cases. CONCLUSION: This gastroenteritis outbreak was most likely caused by contaminated bottled water. The company in question has been shut down and no further cases have been reported. Increased regulation of bottled water plants and better coordination between different investigators for future outbreaks is recommended.

[A hepatitis A outbreak caused by contaminated well water in a primary school of Jiangxi province, China, 2009].

OBJECTIVE: A hepatitis A outbreak in a primary school was reported by Gan County Center for Disease Control and Province (CDC) and an investigation was conducted to identify the possible source of infection and risk factors for transmission. METHODS: A probable case was defined as having onset of jaundice (yellow urine, sclera or skin) or a 2-fold increase in Alanine aminotransferase with 2 or more, of the followings symptoms: anorexia, disgust of oil, abdominal pain, nausea, fatigue, vomiting, in students and staff of the primary school between 1 November 2008 and 14 February 2009. A confirmed case was IgM positive for hepatitis A, added on a probable case. We searched for cases through reviewing medical records in the township hospital and village clinics and conducting symptom screening among students or teachers. We also conducted a case-control study to compare the exposure histories of 19 cases and 53 anti-HAV-IgM negative controls randomly selected from those asymptomatic students in the same grade. RESULTS: 21 cases from all the students was identified, with the attack rate as 3.5%. The epidemic curve showed the two peaks of the outbreak were 28 days apart, both indicating that they were related to the exposure of the source of origin. 74% of the case-students drank the unboiled Well B water, compared to 42% of control-students (OR = 4.0, 95%CI: 1.1 - 15). The total bacterial count was 600 cfu/ml and the total coliform was 23 MPN/100 ml in one sample collected from the well water. CONCLUSION: This hepatitis A outbreak was caused by drinking contaminated water in Well B. We recommended that all the schools should use chlorinated municipal pipe water. Public health authorities should strengthen the supervision of quality of water in schools.

[Study on the application of pulsed-field gel electrophoresis regarding infection sources identification during an outbreak of Vibrio cholerae in Jiangxi Province].

OBJECTIVE: To study the correlation between Vibrio cholerae strains isolated from natural enviroment and fishery products and the source of infection during V. cholerae outbreaks. METHODS: Cholera toxin gene was detected by polymerase chain reaction (PCR) amplification. Pulsed-field gel electrophoresis (PFGE) was used to subtype the isolates. Results of PFGE were analyzed and clustered by BioNumerics software (Version 4.0). RESULTS: During the outbreaks, a total number of thirty O139 V. cholerae related serogroups were collected from patients, carriers, sewage and fishery products were identified and proved to be toxigenic. They could be clustered into four PFGE patterns when digested by Not I. These two V. cholerae outbreaks were caused by the same source of infection because of the following reasons: (1) PFGE patterns of the predominant strains isolated from two outbreaks were identical; (2) they were identical to the PFGE patterns of the strains isolated from the green turtle and rana catesbiana which were bought from the same wholesale store. CONCLUSION: Green turtle and rana catesbiana that were contaminated by toxigenic O139 V. cholerae strains seemed to be the source of infection causing the O139 V. cholerae outbreaks in Jiangxi province. Rapid laboratory surveillance and epidemiologic investigation were important in identifying the source of infection during the outbreaks of V. cholera.