Emergence of dengue virus 4 genotype II in Guangzhou, China, 2010: survey and molecular epidemiology of one community outbreak.

BACKGROUND: The re-emergence of dengue virus 4 (DENV-4) has become a public health concern in South America, Southeast Asia and South Asia. However, it has not been known to have caused a local outbreak in China for the past 20 years. The purpose of this study was to elucidate the epidemiology of one local community outbreak caused by DENV-4 in Guangzhou city, China, in 2010; and to determine the molecular characteristics of the genotype II virus involved. CASE PRESENTATIONS: During September and October of 2010, one imported case, a Guangzhou resident who travelled back from Thailand, resulted in 18 secondary autochthonous cases in Guangzhou City, with an incidence rate of 5.53 per 10,000 residents. In indigenous cases, 14 serum samples tested positive for IgM against DENV and 7 for IgG from a total of 15 submitted serum samples, accompanied by 5 DENV-4 isolates. With identical envelope gene nucleotide sequences, the two isolates (D10168-GZ from the imported index case and Guangzhou 10660 from the first isolate in the autochthonous cases) were grouped into DENV-4 genotype II after comparison to 32 previous DENV-4 isolates from GenBank that originated from different areas. CONCLUSIONS: Based on epidemiological and phylogenetic analyses, the outbreak, which was absent for 20 years after the DENV-4 genotype I outbreak in 1990, was confirmed as DENV-4 genotype II and initially traced to the imported index case, a Guangzhou resident who travelled back from Thailand.

[Etiologic detection and epidemiological analysis of one suspected case of diphtheria in Guangdong province].

OBJECTIVE: To clarify the diagnosis of one suspected case of diphtheria in Guangdong province by epidemiological analysis and etiologic detection. METHODS: On July 6th 2010, the corynebacterium diphtheria was detected from the nasal secretions of one nasopharyngeal carcinoma patient in a college-town hospital in Guangzhou City, Guangdong Province. The patient and the close contacts were asked to participate in the epidemiological survey; and their nasopharyngeal swabs (3 samples) and the nasal secretions of the patient (1 sample) were collected. The bacteria of the samples were isolated and cultured by blood plate and agar loefflera. The smears of positive strains were dyed and identified by BioMerieux API Coryne biochemical card. Gene tox of ß-Corynebacteriophage, Corynebacterium diphtheriae was tested by PCR method, the aliphatic acid was analyzed by gas chromatography method and the Corynebacterium diphtheriae (CMCC 38009) was selected as positive control. RESULTS: The patient had not gone out, neither had been visited. The patient denied history of vaccines or the immunizations. From the survey on patient's family members and close contacts, no similar symptoms had been found. One strain of Corynebacterium diphtheriae was isolated from the patient's nasal secretions, Gram positive and shape diversified. After cultured by agar loefflera and Gram-dyed and Neisser-dyed, one end or both two ends of the strain showed typical metachromatic granule. API Coryne was identified to Corynebacterium diphtheriae mitis/belfanti (99.4%). The result of gas chromatography method also indicated Corynebacterium diphtheriae. No Corynebacterium diphtheriae was isolated from the nasopharyngeal swabs, neither of the patient nor of the close contacts. The gene tox of ß-Corynebacteriophage, Corynebacterium diphtheriae was negative according to the PCR test. CONCLUSION: The isolated Corynebacterium diphtheriae did not produce toxin as there was no biological structure gene of toxin. The patient was a health carrier of nontoxic Corynebacterium diphtheriae.

Evaluation of live attenuated S79 mumps vaccine effectiveness in mumps outbreaks: a matched case-control study.

BACKGROUND: Mumps virus infection is a potentially serious viral infection of childhood and early adulthood. In China, live attenuated S(79) mumps vaccine has been licensed for pediatric use since 1990. The objective of this study was to determine the effectiveness of live attenuated S(79) mumps vaccine against clinical mumps in outbreaks. METHODS: Cases were selected from mumps outbreaks in schools in Guangzhou between 2004 and 2005. Each case was matched by gender, age and classroom. Vaccination information was obtained from Children's EPI Administrative Computerized System. Vaccine effectiveness (VE) was calculated for 1 or 2 doses of S(79) vaccine with 95% confidence intervals (CI). RESULTS: One hundred and ninety-four cases and 194 controls were enrolled into the study. VE of the S(79) mumps vaccine for 1 dose versus 0 confer protection 80.4% (95% CI, 60.0%-90.4%) and VEs against mumps in outbreaks for 1 dose of mumps vaccine are similar among those children aged 4-9 years and aged over 10 years old. CONCLUSION: The live attenuated S(79) mumps vaccine can be effective in preventing clinical mumps outbreaks.

[Avian influenza virus infection in people occupied in poultry fields in Guangzhou city].

OBJECTIVE: To conduct serological investigation on H5N1/H9N2/H7N7 infection among people occupied in poultry fields. METHODS: Serum samples were collected from people working in live poultry and none-poultry retailing food markets, poultry wholesaling, large-scale poultry breading factories and in small-scale farms, wide birds breeding, swine slaughtering houses and from normal population. Antibodies of H5, H9 and H7 with hemagglutination inhibition and neutralization tests were tested and analyzed. Logistic regression and chi(2) test were used. RESULTS: Among 2881 samples, 4 were positive to H5-Ab (0.14%), 146 were positive to H9-Ab (5.07%) and the prevalence of H9 among people from live poultry retailing (14.96%) was the highest. Prevalence rates of H9 were as follows: 8.90% in people working in the large-scale poultry breading factories, 6.69% in the live poultry wholesaling business, 3.75% in the wide birds breeding, 2.40% in the swine slaughtering, 2.21% in the non-poultry retailing, 1.77% in the rural poultry farmers and 2.30% in normal population. None was positive to H7-Ab among 1926 poultry workers. CONCLUSION: The H5 prevalence among people was much lower than expected, but the H9 prevalence was higher. None of the populations tested was found positive to H7-Ab. There was a higher risk of AIV infection in live poultry retailing, wholesaling and large-scale breading businesses, with the risk of live poultry retailing the highest. The longer the service length was, the higher the risk existed.

[A cross sectional survey on serum lipid level and its influencing factors in children aged 3-14 years in Guangdong province].

OBJECTIVE: To investigate the serum levels of cholesterol, triglyceride and high density lipoprotein cholesterol in children aged 3-14 years and its influencing factors. METHODS: The cross-sectional survey study population was a representative sample from Guangdong province obtained by multi-stage randomized cluster sampling. Serum lipids in 6188 children aged > or = 3 years were assayed using automatic biochemical instrument. The data of social and demographic status were collected by face-to-face interview, and height and weight were obtained by physical examination. RESULTS: The age-standardized and region-weighted means of serum total cholesterol (TC), triglyceride (TG), and high density lipoprotein cholesterol (HDL-C) were 0.80 mmol/L, 3.50 mmol/L and 1.28 mmol/L, respectively. For the mean of TG, there was no difference between metropolitan and middle city, nor between rich county and poor county. For TC, it was the highest in metropolitan, and there was no difference between rich and poor county. For HDL-C, the difference existed between every two regions. The age-standardized and region-weighted prevalence of high TG, high TC and low HDL-C were 2.2%, 2.1% and 8.0%, respectively. Metropolitan, rich county, low weight and age between 7.0-9.9 years are protecting factors for high TG, and the number of family between 3-4, age between 7.0-9.9, metropolitan, middle city and poor county are risk factors for high TC. Male, family income per year between 800-9999 RMB, middle city, rich county are protecting factors for low HDL-C. CONCLUSION: The prevalence of abnormal serum lipid was still low compared with other regions in China. The region, number of family member, age and sex may be the important factors influencing on serum lipid levels.