Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-30 (of 30 Records) |
Query Trace: Qiu A[original query] |
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Genetic characterization of two G8P[8] rotavirus strains isolated in Guangzhou, China, in 2020/21: evidence of genome reassortment.
Wang SJ , Chen LN , Wang SM , Zhou HL , Qiu C , Jiang B , Qiu TY , Chen SL , von Seidlein L , Wang XY . BMC Infect Dis 2022 22 (1) 579 BACKGROUND: The G8 rotavirus genotype has been detected frequently in children in many countries and even became the predominant strain in sub-Saharan African countries, while there are currently no reports from China. In this study we described the genetic characteristics and evolutionary relationship between rotavirus strains from Guangzhou in China and the epidemic rotavirus strains derived from GenBank, 2020-2021. METHODS: Virus isolation and subsequent next-generation sequencing were performed for confirmed G8P[8] specimens. The genetic characteristics and evolutionary relationship were analyzed in comparison with epidemic rotavirus sequences obtained from GenBank. RESULTS: The two Guangzhou G8 strains were DS-1-like with the closest genetic distance to strains circulating in Southeast Asia. The VP7 genes of the two strains were derived from a human, not an animal G8 rotavirus. Large genetic distances in several genes suggested that the Guangzhou strains may not have been transmitted directly from Southeast Asian countries, but have emerged following reassortment events. CONCLUSIONS: We report the whole genome sequence information of G8P[8] rotaviruses recently detected in China; their clinical and epidemiological significance remains to be explored further. |
Estimation of occupational noise-induced hearing loss using kurtosis-adjusted noise exposure levels
Zhang M , Gao X , Murphy WJ , Kardous CA , Sun X , Hu W , Gong W , Li J , Qiu W . Ear Hear 2022 43 (6) 1881-1892 OBJECTIVES: Studies have shown that in addition to energy, kurtosis plays an important role in the assessment of hearing loss caused by complex noise. The objective of this study was to investigate how to use noise recordings and audiometry collected from workers in industrial environments to find an optimal kurtosis-adjusted algorithm to better evaluate hearing loss caused by both continuous noise and complex noise. DESIGN: In this study, the combined effects of energy and kurtosis on noise-induced hearing loss (NIHL) were investigated using data collected from 2601 Chinese workers exposed to various industrial noises. The cohort was divided into three subgroups based on three kurtosis (β) levels (K 1 : 3 ≤ β ≤ 10, K 2 : 10 <β ≤ 50, and K 3 : β > 50). Noise-induced permanent threshold shift at test frequencies 3, 4, and 6 kHz (NIPTS 346 ) was used as the indicator of NIHL. Predicted NIPTS 346 was calculated using the ISO 1999 model for each participant, and the actual NIPTS was obtained by correcting for age and sex using non-noise-exposed Chinese workers (n = 1297). A kurtosis-adjusted A-weighted sound pressure level normalized to a nominal 8-hour working day (L Aeq,8h ) was developed based on the kurtosis categorized group data sets using multiple linear regression. Using the NIPTS 346 and the L Aeq.8h metric, a dose-response relationship for three kurtosis groups was constructed, and the combined effect of noise level and kurtosis on NIHL was investigated. RESULTS: An optimal kurtosis-adjusted L Aeq,8h formula with a kurtosis adjustment coefficient of 6.5 was established by using the worker data. The kurtosis-adjusted L Aeq,8h better estimated hearing loss caused by various complex noises. The analysis of the dose-response relationships among the three kurtosis groups showed that the NIPTS of K 2 and K 3 groups was significantly higher than that of K 1 group in the range of 70 dBA ≤ L Aeq,8h < 85 dBA. For 85 dBA ≤ L Aeq,8h ≤ 95 dBA, the NIPTS 346 of the three groups showed an obvious K 3 > K 2 > K 1 . For L Aeq,8h >95 dBA, the NIPTS 346 of the K 2 group tended to be consistent with that of the K 1 group, while the NIPTS 346 of the K 3 group was significantly larger than that of the K 1 and K 2 groups. When L Aeq,8h is below 70 dBA, neither continuous noise nor complex noise produced significant NIPTS 346 . CONCLUSIONS: Because non-Gaussian complex noise is ubiquitous in many industries, the temporal characteristics of noise (i.e., kurtosis) must be taken into account in evaluating occupational NIHL. A kurtosis-adjusted L Aeq,8h with an adjustment coefficient of 6.5 allows a more accurate prediction of high-frequency NIHL. Relying on a single value (i.e., 85 dBA) as a recommended exposure limit does not appear to be sufficient to protect the hearing of workers exposed to complex noise. |
Recent incarceration among individuals infected with hepatitis A virus during person-to-person community outbreaks, United States, 2016-2020
Hagan LM , Montgomery MP , Lauro PL , Cima M , Stringer G , Kupferman NM , Leapley A , Gandhi AP , Nims D , Iberg Johnson J , Bouton L , Burkholder C , Grilli GA , Kittle T , Hansen K , Sievers MM , Newman AP , Albertson JP , Taylor B , Pietrowski M , Stous S , Qiu-Shultz Z , Jones C , Barbeau B , Nicolai LA , McCombs K , Chan M , Cooley L , Gupta N , Nelson N . Public Health Rep 2022 138 (4) 333549221108413 OBJECTIVES: Although many people who are incarcerated have risk factors for hepatitis A virus (HAV) infection, the proportion of hepatitis A cases among people with a recent incarceration is unknown. We examined the relationship between recent incarceration and HAV infection during community-based, person-to-person outbreaks to inform public health recommendations. METHODS: The Centers for Disease Control and Prevention surveyed health departments in 33 jurisdictions reporting person-to-person HAV outbreaks during 2016-2020 on the number of outbreak-associated cases, HAV-infected people recently incarcerated, and HAV-associated hospitalizations and deaths. RESULTS: Twenty-five health departments reported 18 327 outbreak-associated hepatitis A cases during January 11, 2016-January 24, 2020. In total, 2093 (11.4%) HAV-infected people had been recently incarcerated. Of those with complete data, 1402 of 1462 (95.9%) had been held in a local jail, and 1513 of 1896 (79.8.%) disclosed hepatitis A risk factors. Eighteen jurisdictions reported incarceration timing relative to the exposure period. Of 9707 cases in these jurisdictions, 991 (10.2%) were among recently incarcerated people; 451 of 688 (65.6%) people with complete data had been incarcerated during all (n = 55) or part (n = 396) of their exposure period. CONCLUSIONS: Correctional facilities are important settings for reaching people with risk factors for HAV infection and can also be venues where transmission occurs. Providing HAV vaccination to incarcerated people, particularly people housed in jails, can be an effective component of community-wide outbreak response. |
United Against Rabies Forum: The One Health Concept at Work.
Tidman R , Thumbi SM , Wallace R , de Balogh K , Iwar V , Dieuzy-Labaye I , Song J , Shadomy S , Qiu Y , Torres G , Hutchison J , Abela-Ridder B , Bote K , Beeching S , Cronin K , Trees A . Front Public Health 2022 10 854419 Human deaths from rabies are preventable and can be eliminated by applying a systematic One Health approach. However, this ancient disease still threatens the lives of millions of people in up to 150 countries and kills an estimated 59, 000 people every year. Rabies today is largely a disease of poverty, almost always linked to dog bites, with most deaths occurring in neglected communities in Africa and Asia. The disease places an immense economic burden on its victims, a cost that far outweighs the investment needed to control it. A global framework for rabies elimination in humans is set out in Zero by 30: The Global Strategic Plan to end human deaths from dog-mediated rabies by 2030. Despite the existence of proven control strategies and agreement on the path to eliminating human rabies deaths, mortality numbers from rabies remain high, and COVID-19 has set back efforts even further. But COVID-19 has also highlighted the value of a One Health approach to zoonotic disease and pandemic prevention. Rabies control programs offer a practical route to building One Health capacities that can also address other zoonotic threats, including those with pandemic potential. The United Against Rabies Forum aims to accelerate progress on rabies elimination while applying a One Health approach. The Forum promotes cross-sector collaboration among stakeholders and supports countries in their rabies elimination efforts. Increased political engagement and resource mobilization, both internationally and nationally, will be needed to achieve global rabies goals and can also make One Health implementation a reality. |
Novel and extendable genotyping system for human respiratory syncytial virus based on whole-genome sequence analysis.
Chen J , Qiu X , Avadhanula V , Shepard SS , Kim DK , Hixson J , Piedra PA , Bahl J . Influenza Other Respir Viruses 2021 16 (3) 492-500 BACKGROUND: Human respiratory syncytial virus (RSV) is one of the leading causes of respiratory infections, especially in infants and young children. Previous RSV sequencing studies have primarily focused on partial sequencing of G gene (200-300 nucleotides) for genotype characterization or diagnostics. However, the genotype assignment with G gene has not recapitulated the phylogenetic signal of other genes, and there is no consensus on RSV genotype definition. METHODS: We conducted maximum likelihood phylogenetic analysis with 10 RSV individual genes and whole-genome sequence (WGS) that are published in GenBank. RSV genotypes were determined by using phylogenetic analysis and pair-wise node distances. RESULTS: In this study, we first statistically examined the phylogenetic incongruence, rate variation for each RSV gene sequence and WGS. We then proposed a new RSV genotyping system based on a comparative analysis of WGS and the temporal distribution of strains. We also provide an RSV classification tool to perform RSV genotype assignment and a publicly accessible up-to-date instance of Nextstrain where the phylogenetic relationship of all genotypes can be explored. CONCLUSIONS: This revised RSV genotyping system will provide important information for disease surveillance, epidemiology, and vaccine development. |
Multiple Variants of SARS-CoV-2 in a University Outbreak After Spring Break - Chicago, Illinois, March-May 2021.
Doyle K , Teran RA , Reefhuis J , Kerins JL , Qiu X , Green SJ , Choi H , Madni SA , Kamal N , Landon E , Albert RC , Pacilli M , Furtado LE , Hayden MK , Kunstman KJ , Bethel C , Megger L , Fricchione MJ , Ghinai I . MMWR Morb Mortal Wkly Rep 2021 70 (35) 1195-1200 To prevent transmission of SARS-CoV-2, the virus that causes COVID-19, colleges and universities have implemented multiple strategies including testing, isolation, quarantine, contact tracing, masking, and vaccination. In April 2021, the Chicago Department of Public Health (CDPH) was notified of a large cluster of students with COVID-19 at an urban university after spring break. A total of 158 cases of COVID-19 were diagnosed among undergraduate students during March 15-May 3, 2021; the majority (114; 72.2%) lived in on-campus dormitories. CDPH evaluated the role of travel and social connections, as well as the potential impact of SARS-CoV-2 variants, on transmission. Among 140 infected students who were interviewed, 89 (63.6%) reported recent travel outside Chicago during spring break, and 57 (40.7%) reported indoor social exposures. At the time of the outbreak, undergraduate-aged persons were largely ineligible for vaccination in Chicago; only three of the students with COVID-19 (1.9%) were fully vaccinated. Whole genome sequencing (WGS) of 104 specimens revealed multiple distinct SARS-CoV-2 lineages, suggesting several nearly simultaneous introductions. Most specimens (66; 63.5%) were B.1.1.222, a lineage not widely detected in Chicago before or after this outbreak. These results demonstrate the potential for COVID-19 outbreaks on university campuses after widespread student travel during breaks, at the beginning of new school terms, and when students participate in indoor social gatherings. To prevent SARS-CoV-2 transmission, colleges and universities should encourage COVID-19 vaccination; discourage unvaccinated students from travel, including during university breaks; implement serial COVID-19 screening among unvaccinated persons after university breaks; encourage masking; and implement universal serial testing for students based on community transmission levels. |
Food recalls associated with foodborne disease outbreaks, United States, 2006-2016
Qiu Q , Dewey-Mattia D , Subramhanya S , Cui Z , Griffin PM , Lance S , Lanier W , Wise ME , Crowe SJ . Epidemiol Infect 2021 149 1-24 About 800 foodborne disease outbreaks are reported in the United States annually. Few are associated with food recalls. We compared 226 outbreaks associated with food recalls with those not associated with recalls during 2006-2016. Recall-associated outbreaks had, on average, more illnesses per outbreak and higher proportions of hospitalisations and deaths than non-recall-associated outbreaks. The top confirmed aetiology for recall-associated outbreaks was Salmonella. Pasteurised and unpasteurised dairy products, beef and molluscs were the most frequently implicated foods. The most common pathogen-food pairs for outbreaks with recalls were Escherichia coli-beef and norovirus-molluscs; the top pairs for non-recall-associated outbreaks were scombrotoxin-fish and ciguatoxin-fish. For outbreaks with recalls, 48% of the recalls occurred after the outbreak, 27% during the outbreak, 3% before the outbreak, and 22% were inconclusive or had unknown recall timing. Fifty per cent of recall-associated outbreaks were multistate, compared with 2% of non-recall-associated outbreaks. The differences between recall-associated outbreaks and non-recall-associated outbreaks help define the types of outbreaks and food vehicles that are likely to have a recall. Improved outbreak vehicle identification and traceability of rarely recalled foods could lead to more recalls of these products, resulting in fewer illnesses and deaths. |
Evaluating the effectiveness of earplugs in preventing noise-induced hearing loss in an auto parts factory in China
Gong W , Zhao L , Li L , Morata TC , Qiu W , Feng HA , Zhu B . Int J Environ Res Public Health 2021 18 (13) A survey was administered to 385 noise-exposed workers from an auto parts factory and 1268 non-noise-exposed health department employees in China. Individual 8 h A-weighted equiva-lent sound levels (LAeq,8h), earplug personal attenuation ratings (PARs), and pure-tone audiometric tests were performed. The average LAeq,8h of noise-exposed workers was 87 dB (A) with a mean PAR of 7 dB. The prevalence of high-frequency hearing loss was 65% for noise-exposed workers and 33% for the non-noise-exposed employees. The use of earplugs had no observable effect on the prevalence of high-frequency hearing loss of the study participants (OR 0.964, 95% CI 0.925–1.005, p = 0.085). No significant relationship between the effectiveness offered by earplug use and high-frequency hearing thresholds at 3, 4, and 6 kHz was found (t = −1.54, p = 0.125). The mandatory requirement of earplug use without individualized training on how to wear HPDs correctly had no detectable effect on the prevention of hearing loss at the auto parts factory. The hearing conservation program at the surveyed factory was not effective. Periodic hearing tests, earplug fit testing, expanding the offer of different types of hearing protection, and employee education about the importance of protecting their hearing were recommended to the occupational health and safety program. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. |
Genomic analysis of Clostridioides difficile in two regions of the United States reveals a diversity of strains and limited transmission.
Pecora N , Holzbauer S , Wang X , Gu Y , Taffner S , Hatwar T , Hardy D , Dziejman M , D'Heilly P , Pung K , Guh A , Qiu X , Gill S , Dumyati G . J Infect Dis 2021 225 (1) 121-129 BACKGROUND: The distribution of Clostridioides difficile strains and transmission dynamics in the United States are not well defined. Whole genome sequencing (WGS) across two CDC Emerging Infections Program C. difficile infection (CDI) surveillance regions (Minnesota and New York) was performed to identify predominant multilocus sequence types (MLSTs) in community and healthcare-associated disease and assess transmission. METHODS: C. difficile isolates from CDI cases over three months between 2016 and 2017 underwent WGS. Cases were residents of the catchment area without a positive C. difficile test in the preceding 8 weeks. Cases were epidemiologically classified as healthcare (HCA) or community (CA) associated. RESULTS: Of 422 isolates, 212 (50.2%) were HCA and 203 (48.1%) were CA. Predominant MLSTs were ST42 (9.3%), ST8 (7.8%), and ST2 (8.1%). MLSTs associated with HCA-CDI included ST1 (76%), ST53 (83.3%), ST43 (80.0%), while those associated with CA-CDI included ST3 (76.9%), and ST41 (77.8%). ST1 was more frequent in NY than MN (10.8% vs 3.1%). Thirty three pairs were closely related genomically, 14 of which had potential patient-patient transmission supported by chart review. DISCUSSION: The genomic epidemiology of C. difficile across two regions of the US indicates the presence of a diverse strain profile and limited direct transmission. |
Burden and etiology of moderate and severe diarrhea in children less than 5years of age living in north and south of China: Prospective, population-based surveillance
Zhou HL , Bessey T , Wang SM , Mo ZJ , Barclay L , Wang JX , Zhang CJ , Ma JC , Qiu C , Zhao G , Li RC , Zhao YL , Jiang B , Wang XY . Gut Pathog 2021 13 (1) 33 BACKGROUND: Diarrhea remains the leading cause of childhood illness in China. Better understanding of burden and etiology of diarrheal diseases is important for development of effective prevention measures. METHODS: Population-based diarrhea surveillance was conducted in Sanjiang (southern China) year-round and Zhengding (northern China) in autumn/winter. Stool specimens were collected from children < 5 years of age experiencing diarrhea. The TaqMan Array Card (TAC), based on multiplex real-time PCR, was applied to detect multiple enteric microbial agents simultaneously. Results using these methods were compared to those derived from conventional PCR assays. RESULTS: During the study period, 6,380 children in Zhengding and 3,581 children in Sanjiang < 5 years of age participated. Three hundred and forty (31.2%) and 279 (22.9%) diarrhea episodes were identified as moderate-to-severe in the two counties, with incidence of 60.4 and 88.3 cases per 1,000 child-years in Zhengding and Sanjiang, respectively. The five most frequently detected bacterial and viral agents in Sanjiang were adenovirus, enterovirus, enteroaggregative Escherichia coli (EAEC), rotavirus, and sapovirus all the year round, while the most common viral agents in Zhengding were rotavirus, followed by astrovirus and adenovirus during the cool season. Compared to conventional PCR assay, the average incremental detection via the TAC method was twofold. CONCLUSION: Our study demonstrated high diversity and prevalence of multiple major bacterial and viral agents, including rotavirus and calicivirus, among children in China. Further studies are needed to define the public health significance of neglected but frequently detected pathogens such as EAEC, enterotoxigenic E. coli, Campylobacter, adenovirus, and enterovirus. |
Kurtosis: a new tool for noise analysis
Qiu W , Murphy WJ , Suter A . Acoust Today 2020 16 (4) 39-47 Hearing loss due to high-level noise exposure remains a significant occupational health hazard that continues to increase in prevalence in industrial and military work environments despite government-mandated hearing conservation programs. The underlying assumption in current noise standards is that hearing loss over an 8-hour A-weighted equivalent continuous exposure level (often abbreviated as LAeq,8h) can be predicted by the equal energy hypothesis. This method assumes equivalent effects on hearing for a 3 dB increase or decrease in exposure intensity with a halving or doubling of exposure duration, respectively. In other words, equal amounts of hearing loss are expected regardless of how the noise exposure levels have occurred over time. The equal energy hypothesis is the basis of most noise standards and guidelines in the United States and internationally. Although this approach is generally considered appropriate for steady-state noise, it is not adequate for complex noise (Hamernik and Qiu, 2001). Some Background: Consensus has been lacking on the use of simple energy averaging to predict the effects of noise on hearing. In the United States, some government agencies use a modification consisting of a 5 dB trading relationship, whereas others use the internationally accepted 3 dB rule. Use of the 3 dB rule has been recommended by the National Institute of Occupational Safety and Health (NIOSH) since 1998, which recommendation has been validated based on additional, more recent research (Suter, 2017). Another issue with using a simple energy metric is the inability of sound energy averaging to account for the increased hazard of noise with impulsive components. Although intermittences in noise exposures may have been considered helpful to hearing in the past, this no longer seems to be the case with complex noise exposures, which are found frequently in manufacturing industries. Because the additional hazards from impulsive noise were already recognized, the earliest version of the International Standards Organization (ISO) 1999 standard (1971) suggested a 10 dB adjustment to the average exposure level when impulsive noise is superimposed on a background of continuous noise. At a 1981 meeting of noise experts in Southampton, UK, some participants proposed keeping the 10 dB adjustment, with others wanting to change it to 5 dB, and a third group proposing just using simple energy averaging (Personal Observation, Suter, 1981). The resulting report concluded that hearing conservation programs should be initiated at a 5 dB lower level as a precautionary measure whenever there are impulsive noise conditions (von Gierke et al., 1981). Consequently, the 1990 version of the standard contained a note suggesting a 5 dB correction but even that disappeared without explanation in later iterations of the ISO 1999 standard (2013). Since then, more evidence has emerged regarding the hazard to hearing from complex noise environments relative to continuous noise environments. Complex or Non-Gaussian Noise: A steady-state, continuous noise exposure typically has a normal or Gaussian amplitude distribution (see background in Figure 1). However, the temporal pattern of noise exposures often varies significantly in work environments. A complex noise environment may be described as Gaussian background noise punctuated by a series of high-level transient noises resulting in a non-Gaussian distribution (as shown in Figure 1). These transients can be brief, high-level noise bursts, impulses, or impacts with varying interpeak intervals, peak levels, and peak durations. Industrial workers are often exposed to complex noise environments. Examples include jobs involving maintenance work, metalworking, and power tools, such as impact wrenches and nail guns. Over the past several decades, a number of studies using animal models have shown that exposure to complex noise produces more hearing damage than an equivalent energy exposure to continuous Gaussian noise, in terms of both behavioral hearing loss and sensory cell loss (e.g., Lei et al., 1994). These results, along with similar findings from human data in industrial settings, have demonstrated that although acoustic energy and exposure duration are necessary metrics, they are not sufficient to evaluate the hearing loss from complex non-Gaussian noise exposure. Because many noise environments can be characterized by the same equivalent energy and spectra, a metric that describes the temporal structure of an exposure would be a useful adjunct to the equivalent sound pressure level metric. The kurtosis of a sample distribution is such a metric. |
Notes from the field: First case in the United States of Neisseria gonorrhoeae harboring emerging mosaic penA60 allele, conferring reduced susceptibility to cefixime and ceftriaxone
Picker MA , Knoblock RJ , Hansen H , Bautista I , Griego R , Barber L , Bendik W , Lam K , Adelman E , Qiu-Shultz Z , Raphael BH , Pham CD , Kersh EN , Weinstock H , St Cyr SB . MMWR Morb Mortal Wkly Rep 2020 69 (49) 1876-1877 In November 2019, the Southern Nevada Public Health Laboratory of the Southern Nevada Health District (SNHD) identified a male urethral gonococcal isolate later demonstrating reduced susceptibility to cefixime (minimum inhibitory concentration [MIC] = 2.0 μg/mL) and ceftriaxone (MIC = 1.0 μg/mL) but susceptible to azithromycin (MIC = 0.25 μg/mL). Molecular testing by CDC in the United States revealed the emerging mosaic penA60 allele, first identified in Japan in 2016 (1), which confers reduced susceptibility to cephalosporins and increases the risk for treatment failure. The penA60 allele has been identified in China (2), Canada (3,4), Denmark (5), Australia (6), France (7), and the United Kingdom (8). The Nevada case is the first identified case of a Neisseria gonorrhoeae isolate harboring the mosaic penA60 allele reported in the United States. |
New metrics needed in the evaluation of hearing hazard associated with industrial noise exposure
Zhang M , Xie H , Zhou J , Sun X , Hu W , Zou H , Zhou L , Li J , Zhang M , Kardous CA , Morata TC , Murphy WJ , Zhang JH , Qiu W . Ear Hear 2020 42 (2) 290-300 OBJECTIVES: To evaluate (1) the accuracy of the International Organization for Standardization (ISO) standard ISO 1999 [(2013), International Organization for Standardization, Geneva, Switzerland] predictions of noise-induced permanent threshold shift (NIPTS) in workers exposed to various types of high-intensity noise levels, and (2) the role of the kurtosis metric in assessing noise-induced hearing loss (NIHL). DESIGN: Audiometric and shift-long noise exposure data were acquired from a population (N = 2,333) of screened workers from 34 industries in China. The entire cohort was exclusively divided into subgroups based on four noise exposure levels (85 ≤ LAeq.8h < 88, 88 ≤ LAeq.8h < 91, 91 ≤ LAeq.8h < 94, and 94 ≤ LAeq.8h ≤ 100 dBA), two exposure durations (D ≤ 10 years and D > 10 years), and four kurtosis categories (Gaussian, low-, medium-, and high-kurtosis). Predicted NIPTS was calculated using the ISO 1999 model for each participant and the actual measured NIPTS was corrected for age and sex also using ISO 1999. The prediction accuracy of the ISO 1999 model was evaluated by comparing the NIPTS predicted by ISO 1999 with the actual NIPTS. The relation between kurtosis and NIPTS was also investigated. RESULTS: Overall, using the average NIPTS value across the four audiometric test frequencies (2, 3, 4, and 6 kHz), the ISO 1999 predictions significantly (p < 0.001) underestimated the NIPTS by 7.5 dB on average in participants exposed to Gaussian noise and by 13.6 dB on average in participants exposed to non-Gaussian noise with high kurtosis. The extent of the underestimation of NIPTS by ISO 1999 increased with an increase in noise kurtosis value. For a fixed range of noise exposure level and duration, the actual measured NIPTS increased as the kurtosis of the noise increased. The noise with kurtosis greater than 75 produced the highest NIPTS. CONCLUSIONS: The applicability of the ISO 1999 prediction model to different types of noise exposures needs to be carefully reexamined. A better understanding of the role of the kurtosis metric in NIHL may lead to its incorporation into a new and more accurate model of hearing loss due to noise exposure. |
Burden of viral gastroenteritis in children living in rural China: population-based surveillance.
Wang JX , Zhou HL , Mo ZJ , Wang SM , Hao ZY , Li Y , Zhen SS , Zhang CJ , Zhang XJ , Ma JC , Qiu C , Zhao G , Jiang B , Jiang X , Li RC , Zhao YL , Wang XY . Int J Infect Dis 2019 90 151-160 BACKGROUND: Despite the considerable disease burden caused by the disease, rotavirus vaccine has not been introduced into routine national immunization schedule, and norovirus vaccines are being developed without a comprehensive understanding of gastroenteritis epidemiology. To bridge this knowledge gap, we investigated the disease burden of viral gastroenteritis in rural China. METHODS: Between October 2011 and December 2013, population-based surveillance was conducted in Zhengding and Sanjiang counties in China. Stool samples were collected from children <5 years of age with diarrhea. All specimens were tested for rotaviruses, noroviruses, sapoviruses, enteric adenoviruses, and astroviruses. RESULTS: The most common pathogen causing diarrhea was rotavirus (54.7 vs 45.6 cases/1,000 children/year in Zhengding and Sanjiang, respectively), followed by norovirus (28.4 vs 19.3 cases/1,000 children/year in Zhengding and Sanjiang, respectively). The highest incidence of these viruses was observed in children 6-18 months of age. Among the 5 viral pathogens, rotaviruses caused the most severe illness, followed by noroviruses. CONCLUSION: Rotavirus and norovirus are the 2 most important viral pathogens causing childhood diarrhea in both northern and southern China; they should be the major targets for viral gastroenteritis prevention strategies among children in China. |
A signature of circulating inflammatory proteins and development of end-stage renal disease in diabetes
Niewczas MA , Pavkov ME , Skupien J , Smiles A , Md Dom ZI , Wilson JM , Park J , Nair V , Schlafly A , Saulnier PJ , Satake E , Simeone CA , Shah H , Qiu C , Looker HC , Fiorina P , Ware CF , Sun JK , Doria A , Kretzler M , Susztak K , Duffin KL , Nelson RG , Krolewski AS . Nat Med 2019 25 (5) 805-813 Chronic inflammation is postulated to be involved in the development of end-stage renal disease in diabetes, but which specific circulating inflammatory proteins contribute to this risk remain unknown. To study this, we examined 194 circulating inflammatory proteins in subjects from three independent cohorts with type 1 and type 2 diabetes. In each cohort, we identified an extremely robust kidney risk inflammatory signature (KRIS), consisting of 17 proteins enriched in tumor necrosis factor-receptor superfamily members, that was associated with a 10-year risk of end-stage renal disease. All these proteins had a systemic, non-kidney source. Our prospective study findings provide strong evidence that KRIS proteins contribute to the inflammatory process underlying end-stage renal disease development in both types of diabetes. These proteins point to new therapeutic targets and new prognostic tests to identify subjects at risk of end-stage renal disease, as well as biomarkers to measure responses to treatment of diabetic kidney disease. |
Feline herpesvirus vectored-rabies vaccine in cats: A dual protection
Chen T , Zhou X , Qi Y , Mi L , Sun X , Zhang S , Liu Y , Olson V , Qiu W , Wu X , Hu R . Vaccine 2019 37 (16) 2224-2231 In China, cats cause about 5% of human rabies cases. Rabies control in cats plays a role in achieving the ultimate goal of elimination of dog rabies-mediated human deaths. However, there is no cat-specific rabies vaccine in China yet. In this study, we constructed a recombinant rabies vaccine by using a felid herpesvirus 1 (FHV-1) isolate, and deleted the gI/E in the FHV-1 and replaced the region with a glycoprotein (G) of rabies virus (RABV) strain BD06 through homologous recombination. The recombinant virus FHV-RVG was recovered and purified, and the expression of RABV glycoprotein was verified by indirect immunofluorescent assay. For potency in cats, each animal was inoculated intranasally with 1ml FHV-RVG at 10(6.5) TCID50. Blood samples were collected at defined intervals for antibody titration. The animals were challenged by herpes and rabies after completion of vaccination on day 180 and day 194, respectively. Our results demonstrated all vaccinated cats generated antibodies against both FHV-1 and RABV, and reached an arbitrary protective titer>0.5IU/ml for rabies viral neutralizing antibody (VNA) by day 14 post inoculation (dpi) and titer peaked on 30 dpi with VNA at 24.5+/-10.23IU/ml. All vaccinated cats presented no clinical signs of FHV-1 infection and survived rabies challenge, while the control cats had severe rhinotracheitis and died from rabies after challenge. All this demonstrated that the FHV-based recombinant vaccine is effective in protection against both FHV-1 and RABV infections. |
Use of the kurtosis statistic in an evaluation of the effects of noise and solvent exposures on the hearing thresholds of workers: An exploratory study
Fuente A , Qiu W , Zhang M , Xie H , Kardous CA , Campo P , Morata TC . J Acoust Soc Am 2018 143 (3) 1704 The aim of this exploratory study was to examine whether the kurtosis metric can contribute to investigations of the effects of combined exposure to noise and solvents on human hearing thresholds. Twenty factory workers exposed to noise and solvents along with 20 workers of similar age exposed only to noise in eastern China were investigated using pure-tone audiometry (1000-8000 Hz). Exposure histories and shift-long noise recording files were obtained for each participant. The data were used in the calculation of the cumulative noise exposure (CNE) and CNE adjusted by the kurtosis metric for each participant. Passive samplers were used to measure solvent concentrations for each worker exposed to solvents over the full work shift. Results showed an interaction between noise exposure and solvents for the hearing threshold at 6000 Hz. This effect was observed only when the CNE level was adjusted by the kurtosis metric. |
Computation of â„› in age-structured epidemiological models with maternal and temporary immunity
Feng Z , Han Q , Qiu Z , Hill AN , Glasser JW . Discrete Continuous Dyn Syst Ser B 2016 21 (2) 399-415 For infectious diseases such as pertussis, susceptibility is determined by immunity, which is chronological age-dependent. We consider an age-structured epidemiological model that accounts for both passively acquired maternal antibodies that decay and active immunity that wanes, permitting reinfection. The model is a 6-dimensional system of partial differential equations (PDE). By assuming constant rates within each age-group, the PDE system can be reduced to an ordinary differential equation (ODE) system with aging from one age-group to the next. We derive formulae for the effective reproduction number â„› and provide their biological interpretation in some special cases. We show that the disease-free equilibrium is stable when â„› < 1 and unstable if â„› > 1. |
Clinical characteristics, virulence factors and molecular typing of methicillin-resistant Staphylococcus aureus infections in Shenzhen City, China
Hu L , Li Y , Lu Y , Klena JD , Qiu Y , Lin Y , Jiang M , Shi X , Chen L , Liu X , Ma H , Cheng J , Wu S , Kan B , Hu Q . Epidemiol Infect 2016 144 (14) 1-9 Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a serious hospital and community-acquired infection and some strains are associated with greater severity. We investigated the clinical variability and molecular characteristics of MRSA infections in Shenzhen, China through a study at nine sentinel hospitals from January to December 2014. MRSA infections were classified as community-associated (CA-MRSA), healthcare-associated (HA-MRSA), and healthcare-associated community-onset (HACO-MRSA). In total, 812 MRSA isolates were collected and 183 of these were selected for further study. Patients with HA-MRSA infections were generally of greater age compared to other groups. Distinct body site and clinical presentations were evident in infected patients, e.g. CA-MRSA (skin and soft tissue, 53%), HA-MRSA (respiratory tract, 22%; surgical site, 20%; trauma wounds, 20%) and HACO-MRSA (mastitis, 47%). In contrast to HA-MRSA, other categories of strains were significantly more susceptible to gentamicin, sulfamethoxazole/trimethoprim, and tetracycline. No resistance to vancomycin or linezolid was recorded. The predominant clonal lineage within each strain category was CC59-t437-SCCmec IV/V-agr I (CA, 51.4%; HA, 28.9%; HACO, 52.9%) which exhibited characteristics of a traditional CA clone together with agr I which is more often associated with HA clones. In conclusion, for the three categories of MRSA infections, there were significant differences in clinical characteristics of patients, but the predominant clone in each category shared a similar genetic background which suggests that transmission of MRSA strains has occurred between the community and hospitals in Shenzhen. |
Label-free and continuous-flow ferrohydrodynamic separation of HeLa cells and blood cells in biocompatible ferrofluids
Zhao W , Zhu T , Cheng R , Liu Y , He J , Qiu H , Wang L , Nagy T , Querec TD , Unger ER , Mao L . Adv Funct Mater 2015 26 (22) 3990-3998 In this study, a label-free, low-cost, and fast ferrohydrodynamic cell separation scheme is demonstrated using HeLa cells (an epithelial cell line) and red blood cells. The separation is based on cell size difference, and conducted in a custom-made biocompatible ferrofluid that retains the viability of cells during and after the assay for downstream analysis. The scheme offers moderate-throughput (≈106 cells h-1 for a single channel device) and extremely high recovery rate (>99%) without the use of any label. It is envisioned that this separation scheme will have clinical applications in settings where rapid cell enrichment and removal of contaminating blood will improve efficiency of screening and diagnosis such as cervical cancer screening based on mixed populations in exfoliated samples. |
Risk factors for Vibrio parahaemolyticus infection in a southern coastal region of China
Liao Y , Li Y , Wu S , Mou J , Xu Z , Cui R , Klena JD , Shi X , Lu Y , Qiu Y , Lin Y , Xie X , Ma H , Li Z , Yu H , Varma JK , Ran L , Hu Q , Cheng J . Foodborne Pathog Dis 2015 12 (11) 881-6 OBJECTIVES: The objectives of the study were to identify dietary and medical risk factors for Vibrio parahaemolyticus (VP) infection in the coastal city Shenzhen in China. METHODS: In April-October 2012, we conducted a case-control study in two hospitals in Shenzhen, China. Laboratory-confirmed VP cases (N = 83) were matched on age, sex, and other social factors to healthy controls (N = 249). Subjects were interviewed using a questionnaire on medical history; contact with seawater; clinical symptoms and outcome; travel history over the past week; and dietary history 3 days prior to onset. Laboratory tests were used to culture, serotype, and genotype VP strains. We used logistic regression to calculate the odds ratios for the association of VP infection with potential risk factors. RESULTS: In multivariate analysis, VP infection was associated with having pre-existing chronic disease (adjusted odds ratio [aOR], 6.0; 95% confidence interval [CI], 1.5-23.7), eating undercooked seafood (aOR, 8.0; 95% CI, 1.3-50.4), eating undercooked meat (aOR, 29.1; 95% CI, 3.0-278.2), eating food from a street food vendor (aOR, 7.6; 95% CI, 3.3-17.6), and eating vegetable salad (aOR, 12.1; 95% CI, 5.2-28.2). CONCLUSIONS: Eating raw (undercooked) seafood and meat is an important source of VP infection among the study population. Cross-contamination of VP in other food (e.g., vegetables and undercooked meat) likely plays a more important role. Intervention should be taken to lower the risks of cross-contamination with undercooked seafood/meat, especially targeted at people with low income, transient workers, and people with medical risk factors. |
Etiology of diarrhea among children under the age five in China: results from a five-year surveillance
Yu J , Jing H , Lai S , Xu W , Li M , Wu J , Liu W , Yuan Z , Chen Y , Zhao S , Wang X , Zhao Z , Ran L , Wu S , Klena JD , Feng L , Li F , Ye X , Qiu Y , Wang X , Yu H , Li Z , Yang W . J Infect 2015 71 (1) 19-27 OBJECTIVES: Diarrhea is a leading cause of morbidity and mortality for children, although sparse data is available on the etiology of diarrhea in China. This study was conducted to determine main causes that underlie childhood diarrhea and related diseases. METHOD: Surveillance data for diarrhea was collected from 213 participating hospitals between 2009 and 2013. These stool specimens, from children aged 0-59 months, were then analyzed for a panel of etiological agents consisting of 5 viruses, 8 bacteria and 3 protozoa. The proportion of children who tested positive for each pathogen was calculated and seasonal patterns for major organisms were determined. RESULTS: Pathogens were identified in 44.6% of the 32,189 samples from children with diarrhea. The most commonly detected pathogens were rotavirus (29.7% of cases), norovirus (11.8%), Diarrheagenic Escherichia coli (DEC; 5.0%), adenovirus (4.8%), non-typhoidal Salmonella (NTS; 4.3%), and Shigella spp. (3.6%). A strong seasonal pattern was observed for these organisms, including rotavirus (winter), norovirus (autumn), and DEC, NTS, and Shigella (summer). CONCLUSION: A wide range of enteropathogens were detected in this five-year surveillance study; rotavirus and norovirus were most common among children under the age five. These findings should serve as robust evidence for public health entities when planning and developing national intervention programs in China. |
Recalibration of the limiting antigen avidity EIA to determine mean duration of recent infection in divergent HIV-1 subtypes
Duong YT , Kassanjee R , Welte A , Morgan M , De A , Dobbs T , Rottinghaus E , Nkengasong J , Curlin ME , Kittinunvorakoon C , Raengsakulrach B , Martin M , Choopanya K , Vanichseni S , Jiang Y , Qiu M , Yu H , Hao Y , Shah N , Le LV , Kim AA , Nguyen TA , Ampofo W , Parekh BS . PLoS One 2015 10 (2) e0114947 BACKGROUND: Mean duration of recent infection (MDRI) and misclassification of long-term HIV-1 infections, as proportion false recent (PFR), are critical parameters for laboratory-based assays for estimating HIV-1 incidence. Recent review of the data by us and others indicated that MDRI of LAg-Avidity EIA estimated previously required recalibration. We present here results of recalibration efforts using >250 seroconversion panels and multiple statistical methods to ensure accuracy and consensus. METHODS: A total of 2737 longitudinal specimens collected from 259 seroconverting individuals infected with diverse HIV-1 subtypes were tested with the LAg-Avidity EIA as previously described. Data were analyzed for determination of MDRI at ODn cutoffs of 1.0 to 2.0 using 7 statistical approaches and sub-analyzed by HIV-1 subtypes. In addition, 3740 specimens from individuals with infection >1 year, including 488 from patients with AIDS, were tested for PFR at varying cutoffs. RESULTS: Using different statistical methods, MDRI values ranged from 88-94 days at cutoff ODn = 1.0 to 177-183 days at ODn = 2.0. The MDRI values were similar by different methods suggesting coherence of different approaches. Testing for misclassification among long-term infections indicated that overall PFRs were 0.6% to 2.5% at increasing cutoffs of 1.0 to 2.0, respectively. Balancing the need for a longer MDRI and smaller PFR (<2.0%) suggests that a cutoff ODn = 1.5, corresponding to an MDRI of 130 days should be used for cross-sectional application. The MDRI varied among subtypes from 109 days (subtype A&D) to 152 days (subtype C). CONCLUSIONS: Based on the new data and revised analysis, we recommend an ODn cutoff = 1.5 to classify recent and long-term infections, corresponding to an MDRI of 130 days (118-142). Determination of revised parameters for estimation of HIV-1 incidence should facilitate application of the LAg-Avidity EIA for worldwide use. |
Emergence and prevalence of non-H2S-producing Salmonella enterica serovar Senftenberg isolates belonging to a novel sequence type 1751 in China
Yi S , Xie J , Liu N , Li P , Xu X , Li H , Sun J , Wang J , Liang B , Yang C , Wang X , Hao R , Wang L , Wu Z , Zhang J , Wang Y , Huang L , Sun Y , Klena JD , Meng J , Qiu S , Song H . J Clin Microbiol 2014 52 (7) 2557-65 Salmonella enterica serovar Senftenberg is a common non-typhoidal Salmonella serotype which causes human Salmonella infections worldwide. In this study, 182 S. Senftenberg isolates including 17 atypical non-H2S-producing isolates were detected in China from 2005-2011. The microbiological and genetic characteristics of the non-H2S-producing and selected H2S-producing isolates were determined by using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and clustered regularly interspaced short palindromic repeat (CRISPR) analysis. The phs operons were amplified and sequenced. The 17 non-H2S-producing and 36 H2S-producing isolates belonged to 7 sequence types (STs) including 3 new STs: ST1751, ST1757 and ST1758. Fourteen (14/17) of the non-H2S-producing isolates belonged to ST1751 and had the distinct PFGE patterns. All 17 non-H2S-producing isolates had a nonsense mutation at position 1621 of phsA. H2S-producing and non-H2S-producing S. Senftenberg were isolated from the same stool sample from three patients; isolates from the same patients displayed the same antimicrobial susceptibility, ST, and PFGE pattern, but could be discriminated based on CRISPR spacers. Non-H2S-producing S. Senftenberg isolates belonging to ST1751 have been prevalent in Shanghai, China. It's possible that these emerging organisms will disseminate further because they are difficult to detect. Thus, we should strengthen the surveillance for the spread of this atypical S. Senftenberg variant. |
Outbreak of campylobacteriosis associated with a long-distance obstacle adventure race - Nevada, October 2012
Zeigler M , Claar C , Rice D , Davis J , Frazier T , Turner A , Kelley C , Capps J , Kent A , Hubbard V , Ritenour C , Tuscano C , Qiu-Shultz Z , Leaumont CF . MMWR Morb Mortal Wkly Rep 2014 63 (17) 375-8 On October 12, 2012, the Nellis Air Force Base Public Health Flight (Nellis Public Health), near Las Vegas, Nevada, was notified by the Mike O'Callaghan Federal Medical Center (MOFMC) emergency department (ED) of three active-duty military patients who went to the ED during October 10-12 with fever, vomiting, and hemorrhagic diarrhea. Initial interviews by clinical staff members indicated that all three patients had participated October 6-7 in a long-distance obstacle adventure race on a cattle ranch in Beatty, Nevada, in which competitors frequently fell face first into mud or had their heads submerged in surface water. An investigation by Nellis Public Health, coordinated with local and state health officials, identified 22 cases (18 probable and four confirmed) of Campylobacter coli infection among active-duty service members and civilians. A case-control study using data provided by patients and healthy persons who also had participated in the race showed a statistically significant association between inadvertent swallowing of muddy surface water during the race and Campylobacter infection (odds ratio = 19.4; p<0.001). Public health agencies and adventure race organizers should consider informing race attendees of the hazards of inadvertent ingestion of surface water. |
Detection of recent HIV-1 infection using a new Limiting-Antigen Avidity Assay: potential for HIV-1 incidence estimates and avidity maturation studies
Duong YT , Qiu M , De AK , Jackson K , Dobbs T , Kim AA , Nkengasong JN , Parekh BS . PLoS One 2012 7 (3) e33328 BACKGROUND: Accurate and reliable laboratory methods are needed for estimation of HIV-1 incidence to identify the high-risk populations and target and monitor prevention efforts. We previously described a single-well limiting-antigen avidity enzyme immunoassay (LAg-Avidity EIA) to detect recent HIV-1 infection. METHODS: We describe here further optimization and characterization of LAg-Avidity EIA, comparing it to the BED assay and a two-well avidity-index (AI) EIA. Specimen sets included longitudinal sera (n = 393), collected from 89 seroconverting individuals from 4 cohorts representing 4 HIV-1 subtypes, and sera from AIDS patients (n = 488) with or without TB co-infections from 3 different cohorts. Ninety seven HIV-1 positive specimens were purchased commercially. The BED assay, LAg-Avidity EIA, AI-EIA and HIV serology were performed, as needed. RESULTS: Monitoring quality control specimens indicated high reproducibility of the LAg-Avidity EIA with coefficient of variation of <10% in the dynamic range. The LAg-Avidity EIA has an overall mean duration of recency (omega) of 141 days (95% CI 119-160) at normalized optical density (ODn) cutoff of 1.0, with similar omega in different HIV-1 subtypes and populations (132 to 143 days). Antibody avidity kinetics were similar among individuals and subtypes by both the LAg-Avidity EIA and AI-EIA compared to the HIV-IgG levels measured by the BED assay. The false recent rate among individuals with AIDS was 0.2% with the LAg-Avidity EIA, compared to 2.9% with the BED assay. Western blot profiles of specimens with increasing avidity confirm accurate detection of recent HIV-1 infections. CONCLUSIONS: These data demonstrate that the LAg-Avidity EIA is a promising assay with consistent omega in different populations and subtypes. The assay should be very useful for 1) estimating HIV-1 incidence in cross-sectional specimens as part of HIV surveillance, 2) identifying risk factors for recent infections, 3) measuring impact of prevention programs, and 4) studying avidity maturation during vaccine trials. |
Quality assurance in the HIV/AIDS laboratory network of China
Jiang Y , Qiu M , Zhang G , Xing W , Xiao Y , Pan P , Yao J , Ou CY , Su X . Int J Epidemiol 2010 39 Suppl 2 ii72-8 BACKGROUND: In 2009, there were 8273 local screening laboratories, 254 confirmatory laboratories, 35 provincial confirmatory central laboratories and 1 National AIDS Reference Laboratory (NARL) in China. These laboratories were located in Center for Disease Control and Prevention (CDC) facilities, hospitals, blood donation clinics, maternal and child health (MCH) hospitals and border health quarantine health-care facilities. METHODS: The NARL and provincial laboratories provide quality assurance through technical, bio-safety and managerial training; periodic proficiency testing; on-site supervisory inspections; and commercial serologic kit evaluations. RESULTS: From 2002 to 2009, more than 220 million HIV antibody tests were performed at screening laboratories, and all reactive and indeterminate samples were confirmed at confirmatory laboratories. The use of highly technically complex tests, including CD4 cell enumeration, viral load, dried blood spot (DBS)-based early infant diagnosis (EID), drug resistance (DR) genotyping, HIV-1 subtyping and incidence assays, have increased in recent years and their performance quality is closely monitored. CONCLUSION: China has made significant progress in establishing a well-coordinated HIV laboratory network and QA systems. However, the coverage and intensity of HIV testing and quality assurance programmes need to be strengthened so as to ensure that more infected persons are diagnosed and that they receive timely prevention and treatment services. |
Prevalence and molecular identification of Cryptosporidium spp. in pigs in Henan, China
Wang R , Qiu S , Jian F , Zhang S , Shen Y , Zhang L , Ning C , Cao J , Qi M , Xiao L . Parasitol Res 2010 107 (6) 1489-94 The distribution and public health significance of Cryptosporidium species/genotypes in pigs differ among geographic areas and studies. To characterize the prevalence of cryptosporidiosis in pigs in Henan, China, a total of 1,350 fecal samples from 14 farms in ten prefectures in Henan Province were examined. The overall prevalence of Cryptosporidium was 8.2% (111/1,350), with the highest infection rate (79/383 or 20.6%) in 1-2-month-old piglets and the lowest infection rates in 3-6-month-old pigs. Cryptosporidium-positive samples from 108 animals were analyzed by polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis of the small subunit rRNA gene, and 35 were further analyzed by DNA sequencing of the PCR products. Two Cryptosporidium species/genotype were identified, including Cryptosporidium suis (94/108) and the Cryptosporidium pig genotype II (14/108). C. suis infection was more common in younger piglets whereas the pig genotype II was relatively common in older pigs. These findings suggest that pigs are not a major source of zoonotic Cryptosporidium in the study area. |
Genetic polymorphisms of Echinococcus tapeworms in China as determined by mitochondrial and nuclear DNA sequences
Nakao M , Li T , Han X , Ma X , Xiao N , Qiu J , Wang H , Yanagida T , Mamuti W , Wen H , Moro PL , Giraudoux P , Craig PS , Ito A . Int J Parasitol 2010 40 (3) 379-85 The genetic polymorphisms of Echinococcus spp. in the eastern Tibetan Plateau and the Xinjiang Uyghur Autonomous Region were evaluated by DNA sequencing analyses of genes for mitochondrial cytochrome c oxidase subunit 1 (cox1) and nuclear elongation factor-1 alpha (ef1a). We collected 68 isolates of Echinococcus granulosus sensu stricto (s.s.) from Xinjiang and 113 isolates of E. granulosus s. s., 49 isolates of Echinococcus multilocularis and 34 isolates of Echinococcus shiquicus from the Tibetan Plateau. The results of molecular identification by mitochondrial and nuclear markers were identical, suggesting the infrequency of introgressive hybridization. A considerable intraspecific variation was detected in mitochondrial cox1 sequences. The parsimonious network of cox1 haplotypes showed star-like features in E. granulosus s. s. and E. multilocularis, but a divergent feature in E. shiquicus. The cox1 neutrality indexes computed by Tajima's D and Fu's Fs tests showed high negative values in E. granulosus s. s. and E. multilocularis, indicating significant deviations from neutrality. In contrast, the low positive values of both tests were obtained in E. shiquicus. These results suggest the following hypotheses: (i) recent founder effects arose in E. granulosus and E. multilocularis after introducing particular individuals into the endemic areas by anthropogenic movement or natural migration of host mammals, and (ii) the ancestor of E. shiquicus was segregated into the Tibetan Plateau by colonising alpine mammals and its mitochondrial locus has evolved without bottleneck effects. |
Direct fibrogenic effects of dispersed single-walled carbon nanotubes on human lung fibroblasts
Wang L , Mercer RR , Rojanasakul Y , Qiu A , Lu Y , Scabilloni JF , Wu N , Castranova V . J Toxicol Environ Health A 2010 73 (5) 410-22 Nanomaterials, including single-walled carbon nanotubes (SWCNT), are being developed for a variety of commercial products. However, adverse health effects attributed to these new materials are not well understood. Recent reports showed that exposure of mice to dispersed SWCNT (DSWCNT) produced a rapid and progressive interstitial lung fibrosis without persistent inflammation. To understand the mechanism underlying this unusual fibrogenicity of DSWCNT, the present investigation focused on the direct bioactivity of DSWCNT using a cell culture of lung fibroblasts that represent a major cell type resident in the lung interstitium and responsible for the production of collagen matrix. At concentrations relevant to those used in vivo, in vitro exposure of lung fibroblasts to DSWCNT stimulated cell proliferation and induced collagen production without producing cell damage. One of the major matrix metalloproteinases (MMP), MMP-9, which is known to be involved in lung fibrosis, was also elevated by DSWCNT treatment both in vitro and in vivo. Taken together, these results suggest that direct stimulation of fibroblasts by DSWCNT translocated into the interstitium may play a significant role in DSWCNT-induced lung fibrosis. Our data also suggest that the dispersion status and/or size of the SWCNT structures is a critical factor in determining nanoparticle fibrogenicity and that MMP-9 may be involved in the fibrogenic process. The results obtained may aid in the development of in vitro models for rapid screening of the potential fibrogenicity of carbon nanotubes, which are lacking and urgently needed. |
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