To determine the time to appearance of antibody against hepatitis B surface antigen (anti-HBs) after clearance of hepatitis B surface antigen (HBsAg) in chronically infected individuals, we followed up 3963 cases with positive antibody against hepatitis B e antigen (anti-HBe) from 1991 to 2014. Of these, 101 (67 males, 34 females) lost HBsAg. These serocleared cases were checked every 6-month interval regarding HBsAg, anti-HBs, liver function tests, and liver sonography. Hepatitis B virus DNA was assessed at the time of seroclearance or the appearance of anti-HBs. The mean age of these patients at entry to this study was 34·4 ± 13 years. The mean follow-up duration until seroclearance of HBsAg was 6·6 ± 4·3 years. After the mean follow-up of 43·7 ± 45 months, anti-HBs appeared in 64 (63·4%) cases. The cumulative probabilities of anti-HBs appearance for 2, 5 and 10 years were 24·3%, 58% and 78·2%, respectively. The appearance of anti-HBs was associated with age ⩾35 years and seroclearance of HBsAg (hazard ratio 1·96, 95% confidence interval 1·32–3·38, P = 0·016) but not with sex. The results show that anti-HBs may develop in 78·2% of cases within 10 years of HBsAg clearance. Age ⩾35 years at HBsAg loss was associated with earlier development of anti-HBs.

Invasive pneumococcal disease (IPD), caused by infection with Streptococcus pneumoniae, has a substantial global burden. There are over 90 known serotypes of S. pneumoniae with a considerable body of evidence supporting serotype-specific mortality rates immediately following IPD. This is the first study to consider the association between serotype and longer-term mortality following IPD. Using enhanced surveillance data from the North East of England we assessed both the short-term (30-day) and longer-term (⩽7 years) independent adjusted associations between individual serotypes and mortality following IPD diagnosis using logistic regression and extended Cox proportional hazards models. Of the 1316 cases included in the analysis, 243 [18·5%, 95% confidence interval (CI) 16·4–20·7] died within 30 days of diagnosis. Four serotypes (3, 6A, 9N, 19 F) were significantly associated with overall increased 30-day mortality. Effects were observable only for older adults (⩾60 years). After extension of the window to 12 months and 36 months, one serotype was associated with significantly increased mortality at 12 months (19 F), but no individual serotypes were associated with increased mortality at 36 months. Two serotypes had statistically significant hazard ratios (HR) for longer-term mortality: serotype 1 for reduced mortality (HR 0·51, 95% CI 0·30–0·86) and serotype 9N for increased mortality (HR 2·30, 95% CI 1·29–4·37). The association with serotype 9N was no longer observed after limiting survival analysis to an observation period starting 30 days after diagnosis. This study supports the evidence for associations between serotype and short-term (30-day) mortality following IPD and provides the first evidence for the existence of statistically significant associations between individual serotypes and longer-term variation in mortality following IPD.

Anthrax is still a severe public health problem and threat to human health. A cutaneous anthrax outbreak occurred in Jiangsu Province, a non-endemic anthrax region of eastern China, from July to August 2012. Epidemiological and laboratory investigation were initiated to trace the source of infection and identify the risk factors of the outbreak. On 25 July 2012, 17 persons were exposed to a sick cow, which had been imported from northeast China a few days previously. Of the 17 exposed, eight developed symptoms between 1 and 8 days and were diagnosed as cutaneous anthrax cases. Three main genes of Bacillus anthracis were detected from both human and cow meat samples, indicating that the outbreak was associated with this infected cow. A retrospective cohort study showed that contact with blood and presence of skin damage contributed to the case infection with B. anthracis. The outbreak highlights the need to enhance quarantine for imported livestock, which should have been vaccinated prior to importation, the significance of education for high-risk individuals, and training for primary healthcare workers even in anthrax-free areas.

Vibrio cholerae O139 emerged as a causative agent of epidemic cholera in 1992 in India and Bangladesh, and was subsequently reported in China in 1993. The genetic relatedness and molecular characteristics of V. cholerae O139 in Guangdong Province, located in the southern coastal area of China, remains undetermined. In this study, we investigated 136 clinical V. cholerae O139 isolates from 1993 to 2013 in Guangdong. By conventional PCR, 123 (90·4%) isolates were positive for ctxB, ace and zot. Sequencing of the positive amplicons indicated 113 (91·7%) isolates possessed the El Tor allele of ctxB (genotype 3); seven carried the classical ctxB type (genotype 1) and three harboured a novel ctxB type (genotype 5). With respect to tcpA, 123 (90·4%) isolates were positive for the El Tor allele. In addition, pulsed-field gel electrophoresis (with NotI digestion) differentiated the isolates into clusters A and B. Cluster A contained seven of the non-toxigenic isolates from 1998 to 2000; another six non-toxigenic isolates (from 1998 and 2007) and all of the toxigenic isolates formed cluster B. Our results suggest that over a 20-year period, the predominant O139 clinical isolates have maintained a relatively tight clonal structure, although some genetic variance and shift has occurred. Our data highlight the persistence of toxigenic V. cholerae O139 in clinical settings in the southern coastal area of China.