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BACKGROUND: Measles outbreaks often require labor- and resource-intense response. A border-area measles outbreak occurred in Yunnan province that required outbreak response immunization for its containment. We report results of our investigation into the outbreak and the health sector costs of the response activities, with the goal of providing evidence for policy makers when considering the full value of vaccines and of measles elimination. METHODS: We conducted case investigations to determine sources of infection and routes of transmission. Costs of outbreak response activities incurred by health sector were determined through retrospective interviews and record reviews of staff. RESULTS: In total, 67 measles cases were confirmed, including 4 cases imported from Myanmar. Among the 33 cases aged between 8 months and 14 y old, 22 (66∙7%) had received 2 doses of MCV; 2 (6∙0%) had received 1 dose of MCV; 9 (27∙3%) had not received MCV. The first 4 cases had been infected in Myanmar, and we identified 8 transmission clusters with a total of 62 cases. Transmission among Yunnan province residents occurred in schools, family settings, and at gatherings. The overall cost to control the outbreak was $214,774, for a per-case cost of $3,206. The outbreak response vaccination campaign accounted for 64% of the total outbreak costs. CONCLUSIONS: Despite high population immunity among Yunnan province children and adolescents, an import-related measles outbreak occurred among individuals who were not vaccinated or had vaccine failure in the across-border area. The economic cost of the outbreak was substantial. Investment in a sensitive measles surveillance system to detect outbreaks in a timely manner, maintaining high population immunity to measles, and reinforcing cross-border collaboration with neighboring countries support achieving and sustaining measles elimination in the border areas of China.

Objective: This study aimed to investigate HBsAg positive rates and risk factors of HBV infection among the children less than 15 years old in Yunnan province, a remote southwest part of mainland China. Methods: Multi-stage sampling was used to randomly select study subjects from 9,360,000 individuals. Hepatitis B vaccine inoculation rate and HBsAg positive rate were investigated, and then propensity score and generalized linear mixed model (GLMMs) were applied to the case-control study. Results: The average HBsAg positive rate was 1.81%, with 1.2% in urban areas and 2.4% in rural areas. Rate of first-dose-in-time in urban areas was 77.7%, obviously higher than 49.5% in rural areas (χ2 = 2811.71, P

The incidence of measles in Yunnan Province among vaccine target-age children has decreased markedly after attaining and sustaining high 2-dose coverage of measles containing vaccine (MCV) through routine immunization services and supplementary immunization activities (SIAs). Most cases of measles now occur among adults. In 2015, we investigated a measles outbreak among adults to determine transmission patterns and the potential role of nosocomial transmission.We enhanced measles surveillance using retrospective active case search. We conducted case investigations to determine sources of infection and routes of transmission; laboratory testing included serologic and molecular diagnostic methods.Twenty-two outbreak-associated cases of measles were identified; most (86.36%) were among individuals 20 to 39 years of age (range, 7 months to 43 years). We interviewed 19 individuals who had acquired measles. The first 3 cases were infected in Tibet; 12 (63%) were hospital-acquired infections; 2 (11%) were community-acquired; and 2 (11%) were family-contact cases. We conducted outbreak response immunization (ORI) that provided MCV without regard to vaccination status; 10,596 residents between 20 and 40 years of age were vaccinated. A serological survey conducted during the ORI showed that 84% of the 20-40 year-olds were immune to measles prior to vaccination. Post-vaccination serological testing showed 100% were immune.Despite high population immunity among children and adolescents, imported measles virus transmission occurred among adults in a provincial cross-border area. Nosocomial transmission and measles immunity gaps among adults poses a threat to measles elimination and highlights the strategy of targeting adults during ORI to outbreaks with adult-to-adult transmission.

Objective To investigate the relationship between the failure of prevention of hepatitis B virus Mother-to-Child transmission and HBV serological pattern, viral load as well as HBV genotypes. Methods 2765 pairs of mother-infant matched samples were collected. These pregnant women were HBsAg positive and delivered at hospital from January 1st, 2011 to June 30th, 2011. Of these samples, 26 pairs of sera samples were randomly selected from 114 pairs of samples which failed in the prevention of hepatitis B virus Mother-to-Child transmission. Serological tests, viral load and genotype detection were performed for further analysis. Additionally, the selected subjects were followed and tested again in 2014. Results HBeAg positive rates were 76.92% and 69.23% in mother group and infant group respectively, showed no statistical difference. The average HBV DNA levels were >2 × 10 5 IU/ml in both mother group and infant group. Genotype analysis revealed that 11 pairs of mother-infant matched samples belonged to C gene type and another 11 pairs were B gene type. Different genotypes were observed in 4 pairs of mother-infant matched samples. Conclusion HbeAg positive and high HBV DNA level were two major risk factors of HBV mother to child transmission. Additionally, nosocomial infection was another potential way of HBV vertical transmission, especially in remote area of Yunnan province.

Background Japanese encephalitis (JE) is a leading cause of childhood viral encephalitis both at global level and in China. Vaccination is recommended as a key strategy to control JE. In China most JE cases have been reported in southwest provinces, which include Yunnan. In this study, we quantify the epidemiological shift of JE in Yunnan Province from 2005 to 2017, covering before and after the introduction of JE vaccination into routine Expanded Program on Immunization (EPI) in 2007. Methods We used routinely collected data in the case-based JE surveillance system from 2005 through 2017 in Yunnan. Cases were reported from hospital and county-level Centers for Disease Control in line with the National JE Surveillance Guideline. Epidemiological data were extracted, analysed and presented in appropriate ways. Immunization coverage was estimated from actual JE doses administered and new births for each year. Results A total 4780 JE cases (3077 laboratory-confirmed, 1266 clinical and 437 suspected) were reported in the study period. Incidence of JE (per 100 000 population) increased from 0.95 in 2005 to 1.69 in 2007. With increase in vaccination coverage, incidence rates decreased steadily from 1.16 in 2009 to 0.17 in 2017. However, seasonality remained similar across the years, peaking in June–September. Banna (bordering Myanmar and Laos), Dehong (bordering Myanmar), and Zhaotong (an inland prefecture) had the highest incidence rates of 2.3, 1.9, and 1.6, respectively. 97% of all cases were among local residents. As vaccination coverage increased (and incidence decreased), proportion of JE cases among children Conclusions The 13-year JE surveillance data in Yunnan Province showed dramatic decrease of total incidence and a shift from children to adults. Improving vaccination coverage, including access to adults at risk, and strengthening the JE surveillance system is needed to further control or eliminate JE in the province.

Background: A recent measles importation-related outbreak in the China-Myanmar border region required outbreak response immunization to stop the outbreak, raising the question of measles immunity in the area. We conducted two measles serological surveys to develop a seroepidemiological profile of native Chinese citizens and registered Myanmar immigrants to identify strategies to promote measles elimination in the border region. Methods: We conducted a clinic-based measles serosurvey of Myanmar registered immigrants (n = 300) and a population-based serosurvey of Chinese Lincang residents (n = 355). Serum samples were tested with enzyme-linked immunosorbent assays to assess immunity to measles. Results: We found that Myanmar immigrants had a seropositivity rate of 85.3% (95% CI: 81.3–89.4) with a GMT of 924.9 mIU/ml, and Lincang Chinese nationals had a seropositivity rate of 94.6% (95% CI:92.3–97.0) with a GMT of 1363.3 mIU/ml. Myanmar children 2–6 years of age and 7–14 years of age were more likely to be susceptible to measles than same-aged Chinese children: odds ratios 23.00 (95% CI: 5.10–103.69, P < .001) and 7.95 (95% CI: 1.66–38.01,P = .009), respectively. Conclusions: We recommend conducting a catch-up vaccination program for Myanmar children ≤15 years old.

Recently, we reported that the frequency of hepatitis C virus (HCV) genotypes and subtypes has rapidly changed among intravenous drug users (IDUs) in Yunnan Province over the last 5 years; this is especially true for subtype 6a which has increased in frequency from 5 to 15%. Here, we assessed 120 HCV-positive plasma samples from the general population (GP). HCV NS5B fragments were amplified and sequenced by PCR. We identified four HCV genotypes (1, 2, 3 and 6) and seven HCV subtypes (1b, 2a, 3a, 3b, 6a, 6n, and 6k) in this population. Genotype 3 was predominant, with a distribution frequency of 0.484, followed by genotype 1 (0.283), genotype 6 (0.133) and genotype 2 (0.100). HCV subtypes 3b (frequency 0.292) and 1b (frequency 0.283) were the most common subtypes. A comparison of the current data with previous results reported for IDUs showed that the distribution frequencies of genotypes 1, 2 and 6 were significantly different between patients in the GP and IDUs (P

Enterovirus B83 (EV-B83) is a recently identified member of enterovirus species B. It is a rarely reported serotype and up to date, only the complete genome sequence of the prototype strain from the United States is available. In this study, we describe the complete genomic characterization of an EV-B83 strain 246/YN/CHN/08HC isolated from a healthy child living in border region of Yunnan Province, China in 2008. Compared with the prototype strain, it had 79.6% similarity in the complete genome and 78.9% similarity in the VP1 coding region, reflecting the great genetic divergence among them. VP1-coding region alignment revealed it had 77.2–91.3% with other EV-B83 sequences available in GenBank. Similarity plot analysis revealed it had higher identity with several other EV-B serotypes than the EV-B83 prototype strain in the P2 and P3 coding region, suggesting multiple recombination events might have occurred. The great genetic divergence with previously isolated strains and the extremely rare isolation suggest this serotype has circulated at a low epidemic strength for many years. This is the first report of complete genome of EV-B83 in China.

SUMMARYEscherichia albertiiis a newly emerging enteric pathogen that has been associated with gastroenteritis in humans. Recently,E. albertiihas also been detected in healthy and sick birds, animals, chicken meat and water. In the present study, the prevalence and characteristics of theeae-positive, lactose non-fermentingE. albertiistrains in retail raw meat in China were evaluated. Thirty isolates of such strains ofE. albertiiwere identified from 446 (6·73%) samples, including duck intestines (21·43%, 6/28), duck meat (9·52%, 2/21), chicken intestines (8·99%, 17/189), chicken meat (5·66%, 3/53), mutton meat (4·55%, 1/22) and pork meat (2·44%, 1/41). None was isolated from 92 samples of raw beef meat. Strains were identified asE. albertiiby phenotypic properties, diagnostic PCR, sequence analysis of the 16S rRNA gene, and housekeeping genes. Five intimin subtypes were harboured by these strains. All strains possessed the II/III/V subtype group of thecdtBgene, with two strains carrying another copy of the I/IV subtype group. Pulsed-field gel electrophoresis showed high genetic diversity ofE. albertiiin raw meats. Our findings indicate thatE. albertiican contaminate various raw meats, posing a potential threat to public health.