Baiqing Dong

Prevalence and Genetic Diversity of Coronaviruses in Bats from China

ABSTRACT Coronaviruses can infect a variety of animals including poultry, livestock, and humans and are currently classified into three groups. The interspecies transmissions of coronaviruses between different hosts form a complex ecosystem of which little is known. The outbreak of severe acute respiratory syndrome (SARS) and the recent identification of new coronaviruses have highlighted the necessity for further investigation of coronavirus ecology, in particular the role of bats and other wild animals. In this study, we sampled bat populations in 15 provinces of China and reveal that approximately 6.5% of the bats, from diverse species distributed throughout the region, harbor coronaviruses. Full genomes of four coronavirues from bats were sequenced and analyzed. Phylogenetic analyses of the spike, envelope, membrane, and nucleoprotein structural proteins and the two conserved replicase domains, putative RNA-dependent RNA polymerase and RNA helicase, revealed that bat coronaviruses cluster in three different groups: group 1, another group that includes all SARS and SARS-like coronaviruses (putative group 4), and an independent bat coronavirus group (putative group 5). Further genetic analyses showed that different species of bats maintain coronaviruses from different groups and that a single bat species from different geographic locations supports similar coronaviruses. Thus, the findings of this study suggest that bats may play an integral role in the ecology and evolution of coronaviruses.

Antimicrobial Drug Resistance of Salmonella enterica Serovar Typhi in Asia and Molecular Mechanism of Reduced Susceptibility to the Fluoroquinolones

ABSTRACT This study describes the pattern and extent of drug resistance in 1,774 strains of Salmonella enterica serovar Typhi isolated across Asia between 1993 and 2005 and characterizes the molecular mechanisms underlying the reduced susceptibilities to fluoroquinolones of these strains. For 1,393 serovar Typhi strains collected in southern Vietnam, the proportion of multidrug resistance has remained high since 1993 (50% in 2004) and there was a dramatic increase in nalidixic acid resistance between 1993 (4%) and 2005 (97%). In a cross-sectional sample of 381 serovar Typhi strains from 8 Asian countries, Bangladesh, China, India, Indonesia, Laos, Nepal, Pakistan, and central Vietnam, collected in 2002 to 2004, various rates of multidrug resistance (16 to 37%) and nalidixic acid resistance (5 to 51%) were found. The eight Asian countries involved in this study are home to approximately 80% of the worlds typhoid fever cases. These results document the scale of drug resistance across Asia. The Ser83→Phe substitution in GyrA was the predominant alteration in serovar Typhi strains from Vietnam (117/127 isolates; 92.1%). No mutations in gyrB, parC, or parE were detected in 55 of these strains. In vitro time-kill experiments showed a reduction in the efficacy of ofloxacin against strains harboring a single-amino-acid substitution at codon 83 or 87 of GyrA; this effect was more marked against a strain with a double substitution. The 8-methoxy fluoroquinolone gatifloxacin showed rapid killing of serovar Typhi harboring both the single- and double-amino-acid substitutions.

Serologic survey of pandemic (H1N1) 2009 virus, Guangxi Province, China.

Suggested citation for this article: Chen H, Wang Y, Liu W, Zhang J, Dong B, Fan X, et al. Serologic survey of pandemic (H1N1) 2009 virus, Guangxi Province, China [letter]. Emerg Infect Dis [serial on the Internet]. 2009 Nov [date cited]. Available from http://www.cdc.gov/EID/content/15/11/1849.htm

Detection of diverse astroviruses from bats in China.

Astroviruses infect humans and many different animal species and are associated with gastroenteritis. Recent studies first detected the virus from bat species in Hong Kong. To understand astrovirus distribution in the wider region further, we examined the prevalence of this virus family in bat specimens collected from a large geographical region of mainland China. We collected 500 anal swabs from 20 bat species in 51 natural habitats from 11 provinces of China and tested these for astroviruses. Our study revealed a remarkably high genetic diversity of astroviruses; five monophyletic groups were identified in bats, including two novel groups. Evidence for varying degrees of host restriction for astroviruses from bats has been found. Phylogenetic analyses also provided insight into the inter-species transmission of Mamastrovirus.

Detection of a novel and highly divergent coronavirus from asian leopard cats and Chinese ferret badgers in Southern China.

ABSTRACT Since an outbreak of severe acute respiratory syndrome (SARS) was averted in 2004, many novel coronaviruses have been recognized from different species, including humans. Bats have provided the most diverse assemblages of coronaviruses, suggesting that they may be the natural reservoir. Continued virological surveillance has proven to be the best way to avert this infectious disease at the source. Here we provide the first description of a previously unidentified coronavirus lineage detected from wild Asian leopard cats (Prionailurus bengalensis) and Chinese ferret badgers (Melogale moschata) during virological surveillance in southern China. Partial genome analysis revealed a typical coronavirus genome but with a unique putative accessory gene organization. Phylogenetic analyses revealed that the envelope, membrane, and nucleoprotein structural proteins and the two conserved replicase domains, putative RNA-dependent RNA polymerase and RNA helicase, of these novel coronaviruses were most closely related to those of group 3 coronaviruses identified from birds, while the spike protein gene was most closely related to that of group 1 coronaviruses from mammals. However, these viruses always fell into an outgroup phylogenetic relationship with respect to other coronaviruses and had low amino acid similarity to all known coronavirus groups, indicating that they diverged early in the evolutionary history of coronaviruses. These results suggest that these viruses may represent a previously unrecognized evolutionary pathway, or possibly an unidentified coronavirus group. This study demonstrates the importance of systematic virological surveillance in market animals for understanding the evolution and emergence of viruses with infectious potential.

Vaginal Douching, Condom Use, and Sexually Transmitted Infections Among Chinese Female Sex Workers

Background and Objective: Vaginal douching has been hypothesized to increase a womans risk for human immunodeficiency virus (HIV) infection. However, data on the prevalence of this practice and its association with condom use and sexually transmitted infections (STIs) are limited. Study: A cross-sectional survey among 454 female sex workers (FSWs) in a Chinese county. Results: Vaginal douching was reported by 64.7% of the women. The prevalence of self-reported history of STI and that of current STI was 19.4% and 41.5%, respectively. Fifteen percent of the women reported consistent use of condoms with their clients and 8.4% with their regular partners. Vaginal douching was significantly associated with decreased use of condoms (with clients: OR = 0.31; with regular partner(s): OR = 0.22) and increased rate of self-reported STI history (OR = 1.95). However, there was no direct relation between douching and current STI. Over one third of the women believed that douching can prevent STI/HIV. Conclusion: Vaginal douching exposes FSWs to a high risk of STI/HIV. Medical professional and public health workers should correct womens misconception about the effectiveness of douching and discourage women from douching through educational activities.

The Use of Typhoid Vaccines in Asia: The DOMI Experience

BACKGROUND Two currently licensed typhoid vaccines have been evaluated in Asia, yet few Asian countries have considered including typhoid vaccines in their vaccination programs. The Diseases of the Most Impoverished (DOMI) Program was initiated to provide evidence to decide on the introduction of typhoid vaccines in Asian countries. METHODS The centerpiece of the program is a multidisciplinary demonstration project with Vi vaccine in 5 Asian countries. The project includes epidemiologic, economic, sociobehavioral, and policy studies. RESULTS Policy makers want evidence on which to base their vaccine-related decisions. The DOMI Program has provided updated information on the typhoid fever burden at several Asian sites. Cost-of-illness studies found high costs to governments and individuals. Sociobehavioral studies indicated a positive attitude toward typhoid vaccines. The results of the demonstration projects indicate that mass-immunization campaigns are feasible and acceptable. CONCLUSIONS The DOMI Program has begun to provide momentum for the evidence-based, rational introduction of typhoid vaccines into the public health programs of several Asian countries.

Suitable Disk Antimicrobial Susceptibility Breakpoints Defining Salmonella enterica Serovar Typhi Isolates with Reduced Susceptibility to Fluoroquinolones

ABSTRACT Infections with Salmonella enterica serovar Typhi isolates that have reduced susceptibility to ofloxacin (MIC ≥ 0.25 μg/ml) or ciprofloxacin (MIC ≥ 0.125 μg/ml) have been associated with a delayed response or clinical failure following treatment with these antimicrobials. These isolates are not detected as resistant using current disk susceptibility breakpoints. We examined 816 isolates of S. Typhi from seven Asian countries. Screening for nalidixic acid resistance (MIC ≥ 16 μg/ml) identified isolates with an ofloxacin MIC of ≥0.25 μg/ml with a sensitivity of 97.3% (253/260) and specificity of 99.3% (552/556). For isolates with a ciprofloxacin MIC of ≥0.125 μg/ml, the sensitivity was 92.9% (248/267) and specificity was 98.4% (540/549). A zone of inhibition of ≤28 mm around a 5-μg ofloxacin disc detected strains with an ofloxacin MIC of ≥0.25 μg/ml with a sensitivity of 94.6% (246/260) and specificity of 94.2% (524/556). A zone of inhibition of ≤30 mm detected isolates with a ciprofloxacin MIC of ≥0.125 μg/ml with a sensitivity of 94.0% (251/267) and specificity of 94.2% (517/549). An ofloxacin MIC of ≥0.25 μg/ml and a ciprofloxacin MIC of ≥0.125 μg/ml detected 74.5% (341/460) of isolates with an identified quinolone resistance-inducing mutation and 81.5% (331/406) of the most common mutant (carrying a serine-to-phenylalanine mutation at codon 83 in the gyrA gene). Screening for nalidixic acid resistance or ciprofloxacin and ofloxacin disk inhibition zone are suitable for detecting S. Typhi isolates with reduced fluoroquinolone susceptibility.

Trends and disease burden of enteric fever in Guangxi province, China, 1994-2004

OBJECTIVE To determine the burden of enteric fever through trends in morbidity and mortality, bacterial species and antimicrobial resistance in Guangxi, a southern, subtropical, coastal province of China with a disproportionally large burden of enteric fever. METHODS Data on morbidity and mortality caused by enteric fever between 1994 and 2004 were extracted from the Guangxi Center for Disease Control and Prevention. Laboratory-based surveillance and outbreak investigations were integrated with reports of notifiable infectious diseases to estimate the bacterial species-specific incidence of enteric fever. To adjust for underreporting, survey data were collected from three prefectures that represent the hyper-, moderate- and low-endemic regions of Guangxi province. FINDINGS In Guangxi province, enteric fever incidence rate varied over the study period, with a peak of 13.5 cases per 100 000 population in 1995 and a low of 6.5 in 2003. The disease occurred most frequently during the summer and autumn months and in the group aged 10-49 years. The incidence of enteric fever varied by region within Guangxi province. During the 11-year period covered by the study, 61 outbreaks of enteric fever were reported, and Salmonella paratyphi A (SPA) became the predominant causative agent in the province. CONCLUSION Prospective studies may provide a better understanding of the reason for the shifting epidemiology of enteric fever in Guangxi province. Given the emergence of resistance to first- and second-line antimicrobials for the treatment of enteric fever, a bivalent vaccine against both SPA and S. typhi would facilitate for disease control.

Non‐typhoidal Salmonella rates in febrile children at sites in five Asian countries

There is increased recognition of non‐typhoidal Salmonella (NTS) as a major cause of severe febrile illness in sub‐Saharan Africa. However, little is known about community‐based incidence of NTS in Asia. In a multicentre, community‐based prospective Salmonella surveillance study, we identified a total of six NTS cases: three in Karachi, Pakistan, one in Kolkata, India, and two in North Jakarta, Indonesia. No NTS cases were identified in Hechi, People’s Republic of China, and Hue, Viet Nam. Three cases were in children under 3 years, and one case was in a child aged 10 years and one in a child aged 15 years. Only one case was an adult (29 years). The highest incidence of NTS infection was in Karachi (7.2 culture‐proven NTS cases per 100 000 person years in age group of 2–15 years). However, in comparison with sub‐Saharan Africa, the NTS burden in Asia appears rather limited.