Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
Records 1-23 (of 23 Records) |
Query Trace: Nguyen TA[original query] |
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An outbreak investigation of Salmonella Weltevreden illnesses in the United States linked to frozen precooked shrimp imported from India - 2021
Jenkins E , Cripe J , Whitney BM , Greenlee T , Schneider B , Nguyen TA , Pightling A , Manetas J , Abraham A , Fox T , Mickelsen N , Priddy C , McMullen S , Crosby A , Viazis S . J Food Prot 2024 100360 ![]() ![]() In 2021, the U.S. Food and Drug Administration (FDA), Centers for Disease Control and Prevention (CDC), and state partners investigated a multi-state sample-initiated retrospective outbreak investigation (SIROI) consisting of a cluster of nine Salmonella Weltevreden illnesses associated with frozen, pre-cooked shrimp imported from India. Import surveillance testing identified Salmonella Weltevreden recovered from a cooked shrimp sample from Supplier B. In total, nine patients with clinical isolates highly related via whole genome sequencing were reported in four states with illness onset dates between February 26 and July 17, 2021. Epidemiologic data was gathered by state partners for seven patients, whom all reported exposure to shrimp. Five patients reported consuming shrimp cocktail from the same retailer. A traceback investigation for five of the six patients converged on Supplier B. This evidence demonstrated that the outbreak of Salmonella Weltevreden illnesses was caused by the consumption of cooked, ready-to-eat shrimp manufactured by Supplier B. At the time of the investigation, outbreak and recall information was shared with Indian competent authorities. In March 2022, a follow up inspection of Supplier B's facility in India was conducted, and insanitary conditions and practices were observed. This outbreak investigation highlighted the importance of multidisciplinary national and international public health partnerships. The lessons learned from this investigation should continue to inform investigational activities and food safety guidance for industry. |
Genetic diversity in Salmonella enterica in outbreaks of foodborne and zoonotic origin in the USA in 2006-2017
Trees E , Carleton HA , Folster JP , Gieraltowski L , Hise K , Leeper M , Nguyen TA , Poates A , Sabol A , Tagg KA , Tolar B , Vasser M , Webb HE , Wise M , Lindsey RL . Microorganisms 2024 12 (8) ![]() ![]() Whole genome sequencing is replacing traditional laboratory surveillance methods as the primary tool to track and characterize clusters and outbreaks of the foodborne and zoonotic pathogen Salmonella enterica (S. enterica). In this study, 438 S. enterica isolates representing 35 serovars and 13 broad vehicle categories from one hundred epidemiologically confirmed outbreaks were evaluated for genetic variation to develop epidemiologically relevant interpretation guidelines for Salmonella disease cluster detection. The Illumina sequences were analyzed by core genome multi-locus sequence typing (cgMLST) and screened for antimicrobial resistance (AR) determinants and plasmids. Ninety-three of the one hundred outbreaks exhibited a close allele range (less than 10 allele differences with a subset closer than 5). The remaining seven outbreaks showed increased variation, of which three were considered polyclonal. A total of 16 and 28 outbreaks, respectively, showed variations in the AR and plasmid profiles. The serovars Newport and I 4,[5],12:i:-, as well as the zoonotic and poultry product vehicles, were overrepresented among the outbreaks, showing increased variation. A close allele range in cgMLST profiles can be considered a reliable proxy for epidemiological relatedness for the vast majority of S. enterica outbreak investigations. Variations associated with mobile elements happen relatively frequently during outbreaks and could be reflective of changing selective pressures. |
An Overview of Foodborne Sample-Initiated Retrospective Outbreak Investigations and Interagency Collaboration in the United States.
Wellman A , Bazaco M , Blessington T , Pightling A , Dwarka A , Hintz L , Wise ME , Gieraltowski L , Conrad A , Nguyen TA , Hise K , Viazis S , Beal J . J Food Prot 2023 86 (6) 100089 ![]() ![]() Foodborne outbreak investigations have traditionally included the detection of a cluster of illnesses first, followed by an epidemiologic investigation to identify a food of interest. The increasing use of whole genome sequencing (WGS) subtyping technology for clinical, environmental, and food isolates of foodborne pathogens, and the ability to share and compare the data on public platforms, present new opportunities to identify earlier links between illnesses and their potential sources. We describe a process called sample-initiated retrospective outbreak investigations (SIROI) used by federal public health and regulatory partners in the United States. SIROIs begin with an evaluation of the genomic similarity between bacterial isolates recovered from food or environmental samples and clusters of clinical isolates while subsequent and parallel epidemiologic and traceback investigations are initiated to corroborate their connection. SIROIs allow for earlier hypothesis generation, followed by targeted collection of information about food exposures and the foods and manufacturer of interest, to confirm a link between the illnesses and their source. This often leads to earlier action that could reduce the breadth and burden of foodborne illness outbreaks. We describe two case studies of recent SIROIs and present the benefits and challenges. Benefits include insight into foodborne illness attribution, international collaboration, and opportunities for enhanced food safety efforts in the food industry. Challenges include resource intensiveness, variability of epidemiologic and traceback data, and an increasingly complex food supply chain. SIROIs are valuable in identifying connections among small numbers of illnesses that may span significant time periods; detecting early signals for larger outbreaks or food safety issues associated with manufacturers; improving our understanding of the scope of contamination of foods; and identifying novel pathogen/commodity pairs. |
Investigations of possible multistate outbreaks of Salmonella, Shiga toxin-producing Escherichia coli, and Listeria monocytogenes infections - United States, 2016
Marshall KE , Nguyen TA , Ablan M , Nichols MC , Robyn MP , Sundararaman P , Whitlock L , Wise ME , Jhung MA . MMWR Surveill Summ 2020 69 (6) 1-14 PROBLEM/CONDITION: Salmonella, Shiga toxin-producing Escherichia coli (STEC), and Listeria monocytogenes are the leading causes of multistate foodborne disease outbreaks in the United States. Responding to multistate outbreaks quickly and effectively and applying lessons learned about outbreak sources, modes of transmission, and risk factors for infection can prevent additional outbreak-associated illnesses and save lives. This report summarizes the investigations of multistate outbreaks and possible outbreaks of Salmonella, STEC, and L. monocytogenes infections coordinated by CDC during the 2016 reporting period. PERIOD COVERED: 2016. An investigation was considered to have occurred in 2016 if it began during 2016 and ended on or before March 31, 2017, or if it began before January 1, 2016, and ended during March 31, 2016-March 31, 2017. DESCRIPTION OF SYSTEM: CDC maintains a database of investigations of possible multistate foodborne and animal-contact outbreaks caused by Salmonella, STEC, and L. monocytogenes. Data were collected by local, state, and federal investigators during the detection, investigation and response, and control phases of the outbreak investigations. Additional data sources used for this report included PulseNet, the national molecular subtyping network based on isolates uploaded by local, state, and federal laboratories, and the Foodborne Disease Outbreak Surveillance System (FDOSS), which collects information from state, local, and territorial health departments and federal agencies about single-state and multistate foodborne disease outbreaks in the United States. Multistate outbreaks reported to FDOSS were linked using a unique outbreak identifier to obtain food category information when a confirmed or suspected food source was identified. Food categories were determined and assigned in FDOSS according to a classification scheme developed by CDC, the Food and Drug Administration (FDA), and the U.S. Department of Agriculture Food Safety and Inspection Service (FSIS) in the Interagency Food Safety Analytics Collaboration. A possible multistate outbreak was determined by expert judgment to be an outbreak if supporting data (e.g., temporal, geographic, demographic, dietary, travel, or food history) suggested a common source. A solved outbreak was an outbreak for which a specific kind of food or animal was implicated (i.e., confirmed or suspected) as the source. Outbreak-level variables included number of illnesses, hospitalizations, cases of hemolytic uremic syndrome (HUS), and deaths; the number of states with illnesses; date of isolation for the earliest and last cases; demographic data describing patients associated with a possible outbreak (e.g., age, sex, and state of residence); the types of data collected (i.e., epidemiologic, traceback, or laboratory); the outbreak source, mode of transmission, and exposure location; the name or brand of the source; whether the source was suspected or confirmed; whether a food was imported into the United States; the types of regulatory agencies involved; whether regulatory action was taken (and what type of action); whether an outbreak was publicly announced by CDC via website posting; beginning and end date of the investigation; and general comments about the investigation. The number of illnesses, hospitalizations, cases of HUS, and deaths were characterized by transmission mode, pathogen, outcome (i.e., unsolved, solved with suspected source, or solved with confirmed source), source, and food or animal category. RESULTS: During the 2016 reporting period, 230 possible multistate outbreaks were detected and 174 were investigated. A median of 24 possible outbreaks was under investigation per week, and investigations were open for a median of 37 days. Of these 174 possible outbreaks investigated, 56 were excluded from this analysis because they occurred in a single state, were linked to international travel, or were pseudo-outbreaks (e.g., a group of similar isolates resulting from laboratory media contamination rather than infection in patients). Of the remaining 118 possible multistate outbreaks, 50 were determined to be outbreaks and 39 were solved (18 with a confirmed food source, 10 with a suspected food source, 10 with a confirmed animal source, and one with a suspected animal source). Sprouts were the most commonly implicated food category in solved multistate foodborne outbreaks (five). Chicken was the source of the most foodborne outbreak-related illnesses (134). Three outbreaks involved novel food-pathogen pairs: flour and STEC, frozen vegetables and L. monocytogenes, and bagged salad and L. monocytogenes. Eleven outbreaks were attributed to contact with animals (10 attributed to contact with backyard poultry and one to small turtles). Thirteen of 18 multistate foodborne disease outbreaks with confirmed sources resulted in product action, including 10 outbreaks with recalls, two with market withdrawals, and one with an FSIS public health alert. Twenty outbreaks, including 11 foodborne and nine animal-contact outbreaks, were announced to the public by CDC via its website, Facebook, and Twitter. These announcements resulted in approximately 910,000 webpage views, 55,000 likes, 66,000 shares, and 5,800 retweets. INTERPRETATION: During the 2016 reporting period, investigations of possible multistate outbreaks occurred frequently, were resource intensive, and required a median of 37 days of investigation. Fewer than half (42%) of the 118 possible outbreaks investigated were determined to have sufficient data to meet the definition of a multistate outbreak. Moreover, of the 50 outbreaks with sufficient data, approximately three fourths were solved. PUBLIC HEALTH ACTION: Close collaboration among CDC, FDA, FSIS and state and local health and agriculture partners is central to successful outbreak investigations. Identification of novel outbreak sources and trends in sources provides insights into gaps in food safety and safe handling of animals, which helps focus prevention strategies. Summarizing investigations of possible multistate outbreaks can provide insights into the investigative process, improve future investigations, and help prevent illnesses. Although identifying and investigating possible multistate outbreaks require substantial resources and investment in public health infrastructure, they are important in determining outbreak sources and implementing prevention and control measures. |
High hepatitis C virus infection among female sex workers in Viet Nam: strong correlation with HIV and injection drug use
Le LN , O'Connor S , Tran TH , Maher L , Kaldor J , Sabin K , Tran HV , Tran QD , Ho VAT , Nguyen TA . Western Pac Surveill Response J 2019 10 (3) 9-18 Objective: The World Health Organization's guidelines on viral hepatitis testing and treatment recommend prioritizing high prevalence groups. Hepatitis C virus (HCV) infection disproportionately affects people who inject drugs and men who have sex with men, but data on female sex workers (FSW) are limited. The study aimed to determine active HCV infection and risk factors associated with HCV exposure among Vietnamese FSW. Methods: We surveyed 1886 women aged >/= 18 years from Haiphong, Hanoi and Ho Chi Minh City who had sold sex in the last month. We tested for HCV antibody and HCV core antigen as markers for exposure to HCV and active infection, respectively. Results: Across these provinces, high prevalence of HCV exposure (8.8-30.4%) and active infection (3.6-22.1%) were observed. Significant associations with HCV exposure were HIV infection (aOR = 23.7; 95% CI: 14.8-37.9), injection drug use (aOR = 23.3; 95% CI: 13.1-41.4), history of compulsory detention (aOR = 2.5; 95% CI: 1.4-4.2) and having more than 10 sex clients in the last month (aOR = 1.9; 95% CI: 1.2-3.2). Among FSW who reported never injecting drugs, HIV infection (aOR = 24.2; 95% CI: 14.8-39.4), a history of non-injection drug use (aOR = 3.3, CI: 1.8-5.7), compulsory detention (aOR = 2.2; 95% CI: 1.2-4.0) and having over 10 sex clients in the last month (aOR = 2.2, 95% CI: 1.3-3.7) were independently associated with HCV exposure. Discussion: FSW have elevated HCV risks through sex- and drug-related pathways. These findings highlight the need to offer FSW-targeted HCV interventions and ensure their access to HIV prevention and treatment. |
National health information systems for achieving the Sustainable Development Goals
Suthar AB , Khalifa A , Joos O , Manders EJ , Abdul-Quader A , Amoyaw F , Aoua C , Aynalem G , Barradas D , Bello G , Bonilla L , Cheyip M , Dalhatu IT , De Klerk M , Dee J , Hedje J , Jahun I , Jantaramanee S , Kamocha S , Lerebours L , Lobognon LR , Lote N , Lubala L , Magazani A , Mdodo R , Mgomella GS , Monique LA , Mudenda M , Mushi J , Mutenda N , Nicoue A , Ngalamulume RG , Ndjakani Y , Nguyen TA , Nzelu CE , Ofosu AA , Pinini Z , Ramirez E , Sebastian V , Simanovong B , Son HT , Son VH , Swaminathan M , Sivile S , Teeraratkul A , Temu P , West C , Xaymounvong D , Yamba A , Yoka D , Zhu H , Ransom RL , Nichols E , Murrill CS , Rosen D , Hladik W . BMJ Open 2019 9 (5) e027689 OBJECTIVES: Achieving the Sustainable Development Goals will require data-driven public health action. There are limited publications on national health information systems that continuously generate health data. Given the need to develop these systems, we summarised their current status in low-income and middle-income countries. SETTING: The survey team jointly developed a questionnaire covering policy, planning, legislation and organisation of case reporting, patient monitoring and civil registration and vital statistics (CRVS) systems. From January until May 2017, we administered the questionnaire to key informants in 51 Centers for Disease Control country offices. Countries were aggregated for descriptive analyses in Microsoft Excel. RESULTS: Key informants in 15 countries responded to the questionnaire. Several key informants did not answer all questions, leading to different denominators across questions. The Ministry of Health coordinated case reporting, patient monitoring and CRVS systems in 93% (14/15), 93% (13/14) and 53% (8/15) of responding countries, respectively. Domestic financing supported case reporting, patient monitoring and CRVS systems in 86% (12/14), 75% (9/12) and 92% (11/12) of responding countries, respectively. The most common uses for system-generated data were to guide programme response in 100% (15/15) of countries for case reporting, to calculate service coverage in 92% (12/13) of countries for patient monitoring and to estimate the national burden of disease in 83% (10/12) of countries for CRVS. Systems with an electronic component were being used for case reporting, patient monitoring, birth registration and death registration in 87% (13/15), 92% (11/12), 77% (10/13) and 64% (7/11) of responding countries, respectively. CONCLUSIONS: Most responding countries have a solid foundation for policy, planning, legislation and organisation of health information systems. Further evaluation is needed to assess the quality of data generated from systems. Periodic evaluations may be useful in monitoring progress in strengthening and harmonising these systems over time. |
High HIV prevalence and risk among male clients of female sex workers in Hanoi and Ho Chi Minh City, Vietnam
Nadol P , Hoang TV , Le LV , Nguyen TA , Kaldor J , Law M . AIDS Behav 2017 21 (8) 2381-2393 In Vietnam's concentrated HIV epidemic, female sex workers (FSWs) are at increased risk for acquiring and transmitting HIV, largely through their male clients. A high proportion of males in Vietnam report being clients of FSWs. Studying HIV-related risk factors and prevalence among male clients is important, particularly given the potential for male clients to be a 'bridge' of HIV transmission to the more general population or to sex workers. Time-location sampling was used to identify FSW in Hanoi and Ho Chi Minh City, Vietnam's largest cities, in 2013-2014. Recruited FSWs were asked to refer one male client to the study. Demographic and risk behavior data were collected from FSWs and male clients by administered questionnaires. Biologic specimens collected from male clients were tested for HIV and opiates. Sampling weights, calculated based on the FSWs probability of being selected for enrolment, were applied to prevalence estimates for both FSWs and male clients. Logistic regression models were developed to obtain odds ratios for HIV infection among male clients. A total of 804 male clients were enrolled. Overall, HIV prevalence among male clients was 10.2%; HIV prevalence was 20.7% (95% confidence interval (CI) 15.0-27.9%) among those reporting a history of illegal drug use and 32.4% (95% CI 20.2-47.7%) among those with opioids detected in urine. HIV prevalence among male clients did not differ across 'bridging' categories defined by condom use with FSWs and regular partners over the previous 6 months. HIV among male clients was associated with a reported history of illegal drug use (OR 3.76; 95% CI 1.87-7.56), current opioid use (OR 2.55; 95% CI 1.02-6.36), and being referred by an FSW who self-reported as HIV-positive (OR 5.37; 95% CI 1.46-19.75). Self-reported HIV prevalence among enrolled FSWs was 2.8%. Based on HIV test results of male clients and self-reported status from FSWs, an estimated 12.1% of male client-FSW pairs were sero-discordant. These results indicate high HIV prevalence among male clients of FSWs, particularly among those with a history of drug use. Programs to expand HIV testing, drug-use harm reduction, and HIV treatment for HIV-infected male clients of FSWs should be considered as key interventions for controlling the HIV epidemic in Vietnam. |
Multistate outbreak of human Salmonella Typhimurium infections linked to live poultry from agricultural feed stores and mail-order hatcheries, United States 2013
Anderson TC , Nguyen TA , Adams JK , Garrett NM , Bopp CA , Baker JB , McNeil C , Torres P , Ettestad PJ , Erdman MM , Brinson DL , Gomez TM , Barton Behravesh C . One Health 2016 2 144-149 Live poultry-associated salmonellosis is an emerging public health issue in the United States. Public and animal health officials collaborated to investigate one of the largest (356 cases, 39 states) of these outbreaks reported to date. A case was defined as illness in a person infected with the outbreak strain of Salmonella Typhimurium with illness onset between 1 March and 22 October 2013. The median patient age was seven years (range: < 1–87 years); 58% of ill persons were children ≤ 10 years, 51% were female, 25% were hospitalized; 189 (76%) of 250 patients reported live poultry exposure in the week before illness; and 149 (95%) of 157 reported purchasing live poultry from agricultural feed stores. Traceback investigations identified 18 live poultry sources, including 16 mail-order hatcheries. Environmental sampling was conducted at two mail-order hatcheries. One (2.5%) of 40 duplicate samples collected at one hatchery yielded the outbreak strain. Live poultry are an important source of human salmonellosis, particularly among children, highlighting the need for educational campaigns and comprehensive interventions at the mail-order hatchery and agricultural feed store levels. Prevention and control efforts depend on a One Health approach, involving cooperation between public and animal health officials, industry, health professionals, and consumers. |
Outbreaks of human salmonella infections associated with live poultry, United States, 1990-2014
Basler C , Nguyen TA , Anderson TC , Hancock T , Behravesh CB . Emerg Infect Dis 2016 22 (10) 1705-11 Backyard poultry flocks have increased in popularity concurrent with an increase in live poultry-associated salmonellosis (LPAS) outbreaks. Better understanding of practices that contribute to this emerging public health issue is needed. We reviewed outbreak reports to describe the epidemiology of LPAS outbreaks in the United States, examine changes in trends, and inform prevention campaigns. LPAS outbreaks were defined as ≥2 culture-confirmed human Salmonella infections linked to live poultry contact. Outbreak data were obtained through multiple databases and a literature review. During 1990-2014, a total of 53 LPAS outbreaks were documented, involving 2,630 illnesses, 387 hospitalizations, and 5 deaths. Median patient age was 9 years (range <1 to 92 years). Chick and duckling exposure were reported by 85% and 38% of case-patients, respectively. High-risk practices included keeping poultry inside households (46% of case-patients) and kissing birds (13%). Comprehensive One Health strategies are needed to prevent illnesses associated with live poultry. |
Laboratory, environmental, and epidemiologic investigation and regulatory enforcement actions in response to an outbreak of Salmonella bredeney infections linked to peanut butter
Viazis S , Beal JK , Monahan C , Lanier WA , Kreil KR , Melka DC , Boden WD , Dion JL , Miller ZA , Nguyen TA , Gieraltowski LB , Zink DL . Open Forum Infect Dis 2015 2 (3) ofv114 BACKGROUND: In September 2012, the Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), and state and local partners investigated an outbreak of Salmonella enterica serovar Bredeney linked to peanut butter (PB). METHODS: A case was defined as infection with the outbreak strain of Salmonella Bredeney between June 1, 2012 and October 31, 2012. Food exposure questionnaires were analyzed by the CDC to determine the food vehicle. The FDA reviewed production information from Retail Chain A's sole supplier of PB, Company A. The PB samples collected from case-patients and Company A were tested for Salmonella. Results. Forty-two case-patients from 20 states were identified. Of 33 case-patients from whom food exposure information was obtained, 25 (76%) shopped at Retail Chain A and 25 (100%) purchased Company A PB. Three state health departments isolated the outbreak strain from opened jars of PB collected from case-patients. The FDA investigators identified multiple deficiencies in current Good Manufacturing Practices (cGMPs) in Company A's manufacturing facility and determined that internal controls were insufficient to prevent shipment of contaminated product. The FDA isolated the outbreak strain of Salmonella Bredeney from implicated product collected at the firm and the environment of the firm's food production facility. CONCLUSIONS: Timely laboratory, investigational, and epidemiologic data led to the voluntary recall of PB by Company A. The FDA suspended Company A's food facility registration, prohibiting the firm from introducing food into interstate commerce. This outbreak underscores the need for effective preventive controls, including robust internal environmental monitoring programs, appropriate action in response to contamination findings, and an improved understanding of food safety at the managerial and corporate levels. |
Sampling males who inject drugs in Haiphong, Vietnam: comparison of time-location and respondent-driven sampling methods
Tran HV , Le LV , Johnston LG , Nadol P , Van Do A , Tran HT , Nguyen TA . J Urban Health 2015 92 (4) 744-57 Accurate measurements of HIV prevalence and associated risk factors among hidden and high-risk groups are vital for program planning and implementation. However, only two sampling methods are purported to provide representative estimates for populations without sampling frames: time-location sampling (TLS) and respondent-driven sampling (RDS). Each method is subject to potential biases and questionable reliability. In this paper, we evaluate surveys designed to estimate HIV prevalence and associated risk factors among people who inject drugs (PWID) sampled through TLS versus RDS. In 2012, males aged ≥16 years who reported injecting drugs in the previous month and living in Haiphong, Vietnam, were sampled using TLS or RDS. Data from each survey were analyzed to compare HIV prevalence, related risk factors, socio-demographic characteristics, refusal estimates, and time and expenditures for field implementation. TLS (n = 432) and RDS (n = 415) produced similarly high estimates for HIV prevalence. Significantly lower proportions of PWID sampled through RDS received methadone treatment or met an outreach worker. Refusal estimates were lower for TLS than for RDS. Total expenditures per sample collected and number of person-days of staff effort were higher for TLS than for RDS. Both survey methods were successful in recruiting a diverse sample of PWID in Haiphong. In Vietnam, surveys of PWID are conducted throughout the country; although the refusal estimate was calculated to be much higher for RDS than TLS, RDS in Haiphong appeared to sample PWID with less exposure to services and required fewer financial and staff resources compared with TLS. |
Correlates of HIV infection among female sex workers in Vietnam: injection drug use remains a key risk factor
Le LV , Nguyen TA , Tran HV , Gupta N , Duong TC , Tran HT , Nadol P , Sabin K , Maher L , Kaldor JM . Drug Alcohol Depend 2015 150 46-53 OBJECTIVE: Women who sell sex and use drugs have dual risks for HIV infection. Despite increasing reports of drug use among female sex workers (FSW) in Vietnam, FSW HIV interventions remain focused mainly on sexual risk reduction. We assessed the impact of drug use and inconsistent condom use on HIV infection among FSW in Vietnam, which few studies have quantified. METHODS: We surveyed 5298 women aged ≥18 years who had sold sex in the past month from ten geographically dispersed provinces. We performed multivariate logistic regression on data from provinces with high (≥10%) or low (<10%) HIV prevalence among FSW. RESULTS: Compared to FSW who never used illicit drugs, the odds of HIV infection among FSW who had ever injected drugs and those who reported non-injection drug use were 3.44 (CI 2.32-5.09) and 1.76 (CI 1.14-2.71), respectively, in high-prevalence provinces. FSW who always used condoms with clients had lower odds of HIV infection than those who did not (AOR=0.71; CI 0.52-0.98). In low-prevalence provinces lifetime injection drug use (AOR 22.05, CI 12.00-40.49), but not non-injecting drug use or inconsistent condom use, was significantly associated with HIV infection. CONCLUSIONS: Because injection drug use and inconsistent condom use were key risk factors for HIV infection in high-prevalence provinces, drug injection risk reduction should be as much a focus of HIV prevention as sexual risk reduction. Where HIV prevalence remains low in FSW, a more general emphasis on harm reduction for all drug users will benefit FSW. |
Notes from the field: multistate outbreak of human Salmonella infections linked to live poultry from a mail-order hatchery in Ohio - February-October 2014
Basler C , Forshey TM , Machesky K , Erdman CM , Gomez TM , Brinson DL , Nguyen TA , Behravesh CB , Bosch S . MMWR Morb Mortal Wkly Rep 2015 64 (9) 258 In early 2014, five clusters of human Salmonella infections were identified through PulseNet, the national molecular subtyping network for foodborne disease surveillance. Many ill persons in each of these clusters reported contact with live poultry, primarily chicks and ducklings, from a single mail-order hatchery; therefore, the clusters were merged into a single investigation. During February 3-October 14, 2014, a total of 363 persons infected with outbreak strains of Salmonella serotypes Infantis, Newport, and Hadar were reported from 43 states and Puerto Rico, making it the largest live poultry-associated salmonellosis outbreak reported in the United States. |
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. |
Outbreak of Salmonella Newport infections linked to cucumbers - United States, 2014
Angelo KM , Chu A , Anand M , Nguyen TA , Bottichio L , Wise M , Williams I , Seelman S , Bell R , Fatica M , Lance S , Baldwin D , Shannon K , Lee H , Trees E , Strain E , Gieraltowski L . MMWR Morb Mortal Wkly Rep 2015 64 (6) 144-7 In August 2014, PulseNet, the national molecular subtyping network for foodborne disease surveillance, detected a multistate cluster of Salmonella enterica serotype Newport infections with an indistinguishable pulse-field gel electrophoresis (PFGE) pattern (XbaI PFGE pattern JJPX01.0061). Outbreaks of illnesses associated with this PFGE pattern have previously been linked to consumption of tomatoes harvested from Virginia's Eastern Shore in the Delmarva region and have not been linked to cucumbers or other produce items. To identify the contaminated food and find the source of the contamination, CDC, state and local health and agriculture departments and laboratories, and the Food and Drug Administration (FDA) conducted epidemiologic, traceback, and laboratory investigations. A total of 275 patients in 29 states and the District of Columbia were identified, with illness onsets occurring during May 20-September 30, 2014. Whole genome sequencing (WGS), a highly discriminating subtyping method, was used to further characterize PFGE pattern JJPX01.0061 isolates. Epidemiologic, microbiologic, and product traceback evidence suggests that cucumbers were a source of Salmonella Newport infections in this outbreak. The epidemiologic link to a novel outbreak vehicle suggests an environmental reservoir for Salmonella in the Delmarva region that should be identified and mitigated to prevent future outbreaks. |
Findings from integrated behavioral and biologic survey among males who inject drugs (MWID) - Vietnam, 2009-2010: evidence of the need for an integrated response to HIV, hepatitis B virus, and hepatitis C virus
Nadol P , O'Connor S , Duong H , Le LV , Thang PH , Tram TH , Ha HT , McConnell MS , Partridge J , Kaldor J , Law M , Nguyen TA . PLoS One 2015 10 (2) e0118304 INTRODUCTION: Given the overlapping modes of transmission of HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV), understanding the burden and relationship of these infections is critical for an effective response. Representative data on these infections among males who inject drugs (MWID), the key high-risk population for HIV in Vietnam, are currently lacking. METHODS: Data and stored specimens from Vietnam's 2009-2010 Integrated Biologic and Behavioral Survey, a cross-sectional study among high-risk populations, were used for this analysis. Plasma samples were tested for HIV, HBV, and HCV using commercial assays. A questionnaire was administered to provide demographic, behavior, and service-uptake information. Provincial-level analyses were conducted to profile MWID enrollees and to provide estimates on the prevalence of HIV, HBV, and HCV infection. RESULTS: Among 3010 MWID sampled across 10 provinces, the median (range) HIV prevalence was 28.1% (1.0%-55.5%). Median prevalence for current HBV infection (HBsAg+) was 14.1% (11.7%-28.0%), for previous exposure to HBV (total anti-HBc+) was 71.4% (49.9%-83.1%), and for current or past HCV infection (HCV Ag/Ab+) was 53.8% (10.9%-80.8%). In adjusted analysis, HBsAg+ (aOR: 2.09, 1.01-4.34) and HCV Ag/Ab+ (aOR: 19.58, 13.07-29.33) status were significantly associated with HIV infection; the association with total anti-HBc+ approached significance (aOR: 1.29, 0.99-1.68). CONCLUSION: The prevalence and association between HIV, HBV, and HCV are high among MWID in Vietnam. These findings indicate the need for integrated policies and practice that for the surveillance, prevention, screening, and treatment of both HIV and viral hepatitis among MWID in Vietnam. |
Salmonellosis and meat purchased at live-bird and animal-slaughter markets, United States, 2007-2012
Imanishi M , Anderson TC , Routh J , Brown C , Conidi G , Glenn L , Reddy V , Waechter H , Malavet M , Nyaku M , Bohm S , Bidol S , Arends K , Saupe A , Higa J , Nguyen TA , Pringle J , Behravesh CB , Bosch S . Emerg Infect Dis 2014 20 (1) 167-9 Salmonella spp. cause ≈1.2 million human illnesses annually in the United States (1). Infections are primarily acquired through exposure to contaminated food or infected animals (1,2). Since 2007, state and local health departments and the Centers for Disease Control and Prevention have investigated multiple salmonellosis outbreaks linked to meat purchased at live-bird markets (LBMs) and live-animal markets (LAMs), where poultry and livestock are sold for onsite slaughter. These markets typically operate in large cities and serve populations of diverse ethnic backgrounds (3). | | In 2007, an outbreak involving 62 case-patients infected with 1 of 3 S. enterica serotype Schwarzengrund strains was investigated in Massachusetts; 61% were children <5 years of age, including 14 (23%) infants <1 year of age, and 96% were Asian (Table). A case-patient was defined as a person infected with S. enterica who had a pulsed-field gel electrophoresis XbaI restriction enzyme pattern indistinguishable from the outbreak strain. Exposure to poultry purchased at LBMs was reported, and environmental sampling at an implicated LBM identified 6 S. enterica serotypes, including 1 outbreak strain. |
Multistate outbreak of human Salmonella infections linked to live poultry from a mail-order hatchery in Ohio - March-September 2013
Basler C , Forshey TM , Machesky K , Erdman MC , Gomez TM , Nguyen TA , Behravesh CB . MMWR Morb Mortal Wkly Rep 2014 63 (10) 222 In early 2013, four clusters of human Salmonella infections were identified through PulseNet, the national molecular subtyping network for foodborne bacteria. Many of the ill persons in these four clusters reported contact with live poultry, primarily chicks and ducklings, from a single mail-order hatchery; therefore, these investigations were merged. During March 4-October 9, 2013, a total of 158 persons infected with outbreak strains of Salmonella serotypes Infantis, Lille, Newport, and Mbandaka were reported from 30 states. |
Multistate outbreak of Escherichia coli O145 infections associated with romaine lettuce consumption, 2010
Taylor EV , Nguyen TA , Machesky KD , Koch E , Sotir MJ , Bohm SR , Folster JP , Bokanyi R , Kupper A , Bidol SA , Emanuel A , Arends KD , Johnson SA , Dunn J , Stroika S , Patel MK , Williams I . J Food Prot 2013 76 (6) 939-44 Non-O157 Shiga toxin-producing Escherichia coli (STEC) can cause severe illness, including hemolytic uremic syndrome (HUS). STEC O145 is the sixth most commonly reported non-O157 STEC in the United States, although outbreaks have been infrequent. In April and May 2010, we investigated a multistate outbreak of STEC O145 infection. Confirmed cases were STEC O145 infections with isolate pulsed-field gel electrophoresis patterns indistinguishable from those of the outbreak strain. Probable cases were STEC O145 infections or HUS in persons who were epidemiologically linked. Case-control studies were conducted in Michigan and Ohio; food exposures were analyzed at the restaurant, menu, and ingredient level. Environmental inspections were conducted in implicated food establishments, and food samples were collected and tested. To characterize clinical findings associated with infections, we conducted a chart review for case patients who sought medical care. We identified 27 confirmed and 4 probable cases from five states. Of these, 14 (45%) were hospitalized, 3 (10%) developed HUS, and none died. Among two case-control studies conducted, illness was significantly associated with consumption of shredded romaine lettuce in Michigan (odds ratio [OR] = undefined; 95% confidence interval [CI] = 1.6 to undefined) and Ohio (OR = 10.9; 95% CI = 3.1 to 40.5). Samples from an unopened bag of shredded romaine lettuce yielded the predominant outbreak strain. Of 15 case patients included in the chart review, 14 (93%) had diarrhea and abdominal cramps and 11 (73%) developed bloody diarrhea. This report documents the first foodborne outbreak of STEC O145 infections in the United States. Current surveillance efforts focus primarily on E. coli O157 infections; however, non-O157 STEC can cause similar disease and outbreaks, and efforts should be made to identify both O157 and non-O157 STEC infections. Providers should test all patients with bloody diarrhea for both non-O157 and O157 STEC. |
Prevalence of cryptococcal antigenemia and cost-effectiveness of a cryptococcal antigen screening program - Vietnam
Smith RM , Nguyen TA , Ha HT , Thang PH , Thuy C , Xuan Lien T , Bui HT , Le TH , Struminger B , McConnell MS , Fanfair RN , Park BJ , Harris JR . PLoS One 2013 8 (4) e62213 BACKGROUND: An estimated 120,000 HIV-associated cryptococcal meningitis (CM) cases occur each year in South and Southeast Asia; early treatment may improve outcomes. The World Health Organization (WHO) recently recommended screening HIV-infected adults with CD4<100 cells/mm(3) for serum cryptococcal antigen (CrAg), a marker of early cryptococcal infection, in areas of high CrAg prevalence. We evaluated CrAg prevalence and cost-effectiveness of this screening strategy in HIV-infected adults in northern and southern Vietnam. METHODS: Serum samples were collected and stored during 2009-2012 in Hanoi and Ho Chi Minh City, Vietnam, from HIV-infected, ART-naive patients presenting to care in 12 clinics. All specimens from patients with CD4<100 cells/mm(3) were tested using the CrAg lateral flow assay. We obtained cost estimates from laboratory staff, clinicians and hospital administrators in Vietnam, and evaluated cost-effectiveness using WHO guidelines. RESULTS: Sera from 226 patients [104 (46%) from North Vietnam and 122 (54%) from the South] with CD4<100 cells/mm(3) were available for CrAg testing. Median CD4 count was 40 (range 0-99) cells/mm(3). Nine (4%; 95% CI 2-7%) specimens were CrAg-positive. CrAg prevalence was higher in South Vietnam (6%; 95% CI 3-11%) than in North Vietnam (2%; 95% CI 0-6%) (p = 0.18). Cost per life-year gained under a screening scenario was $190, $137, and $119 at CrAg prevalences of 2%, 4% and 6%, respectively. CONCLUSION: CrAg prevalence was higher in southern compared with northern Vietnam; however, CrAg screening would be considered cost-effective by WHO criteria in both regions. Public health officials in Vietnam should consider adding cryptococcal screening to existing national guidelines for HIV/AIDS care. |
A national outbreak of Salmonella serotype Tennessee infections from contaminated peanut butter: a new food vehicle for salmonellosis in the United States
Sheth AN , Hoekstra M , Patel N , Ewald G , Lord C , Clarke C , Villamil E , Niksich K , Bopp C , Nguyen TA , Zink D , Lynch M . Clin Infect Dis 2011 53 (4) 356-62 BACKGROUND: Salmonella serotype Tennessee is a rare cause of the estimated 1 million cases of salmonellosis occurring annually in the United States. In January 2007, we began investigating a nationwide increase in Salmonella Tennessee infections. METHODS: We defined a case as Salmonella Tennessee infection in a patient whose isolate demonstrated 1 of 3 closely related pulsed-field gel electrophoresis patterns and whose illness began during the period 1 August 2006 through 31 July 2007. We conducted a case-control study in 22 states and performed laboratory testing of foods and environmental samples. RESULTS: We identified 715 cases in 48 states; 37% of isolates were from urine specimens. Illness was associated with consuming peanut butter more than once a week (matched odds ratio [mOR], 3.5 [95% confidence interval {95% CI}, 1.4-9.9]), consuming Brand X peanut butter (mOR, 12.1 [95% CI, 3.6-66.3]), and consuming Brand Y peanut butter (mOR, 9.1 [95% CI, 1.0-433]). Brands X and Y were produced in 1 plant, which ceased production and recalled products on 14 February 2007. Laboratories isolated outbreak strains of Salmonella Tennessee from 34 Brands X and Y peanut butter jars and 2 plant environmental samples. CONCLUSIONS: This large, widespread outbreak of salmonellosis is the first linked to peanut butter in the United States; a nationwide recall resulted in outbreak control. Environmental contamination in the peanut butter plant likely caused this outbreak. This outbreak highlights the risk of salmonellosis from heat-processed foods of nonanimal origin previously felt to be low risk for Salmonella contamination. |
2008 outbreak of Salmonella Saintpaul infections associated with raw produce
Barton Behravesh C , Mody RK , Jungk J , Gaul L , Redd JT , Chen S , Cosgrove S , Hedican E , Sweat D , Chavez-Hauser L , Snow SL , Hanson H , Nguyen TA , Sodha SV , Boore AL , Russo E , Mikoleit M , Theobald L , Gerner-Smidt P , Hoekstra RM , Angulo FJ , Swerdlow DL , Tauxe RV , Griffin PM , Williams IT . N Engl J Med 2011 364 (10) 918-27 BACKGROUND: Raw produce is an increasingly recognized vehicle for salmonellosis. We investigated a nationwide outbreak that occurred in the United States in 2008. METHODS: We defined a case as diarrhea in a person with laboratory-confirmed infection with the outbreak strain of Salmonella enterica serotype Saintpaul. Epidemiologic, traceback, and environmental studies were conducted. RESULTS: Among the 1500 case subjects, 21% were hospitalized, and 2 died. In three case-control studies of cases not linked to restaurant clusters, illness was significantly associated with eating raw tomatoes (matched odds ratio, 5.6; 95% confidence interval [CI], 1.6 to 30.3); eating at a Mexican-style restaurant (matched odds ratio, 4.6; 95% CI, 2.1 to infinity) and eating pico de gallo salsa (matched odds ratio, 4.0; 95% CI, 1.5 to 17.8), corn tortillas (matched odds ratio, 2.3; 95% CI, 1.2 to 5.0), or salsa (matched odds ratio, 2.1; 95% CI, 1.1 to 3.9); and having a raw jalapeno pepper in the household (matched odds ratio, 2.9; 95% CI, 1.2 to 7.6). In nine analyses of clusters associated with restaurants or events, jalapeno peppers were implicated in all three clusters with implicated ingredients, and jalapeno or serrano peppers were an ingredient in an implicated item in the other three clusters. Raw tomatoes were an ingredient in an implicated item in three clusters. The outbreak strain was identified in jalapeno peppers collected in Texas and in agricultural water and serrano peppers on a Mexican farm. Tomato tracebacks did not converge on a source. CONCLUSIONS: Although an epidemiologic association with raw tomatoes was identified early in this investigation, subsequent epidemiologic and microbiologic evidence implicated jalapeno and serrano peppers. This outbreak highlights the importance of preventing raw-produce contamination. |
Transmission risk factors and treatment of pediatric shigellosis during a large daycare center-associated outbreak of multidrug resistant shigella sonnei: Implications for the management of shigellosis outbreaks among children
Arvelo W , Hinkle CJ , Nguyen TA , Weiser T , Steinmuller N , Khan F , Gladbach S , Parsons M , Jennings D , Zhu BP , Mintz E , Bowen A . Pediatr Infect Dis J 2009 28 (11) 976-80 BACKGROUND: Shigellosis outbreaks in daycare centers result in substantial disease and economic burdens in the United States. The emergence of multidrug resistant Shigella strains raises questions regarding control of transmission within daycare centers and treatment for children. From May to October 2005, 639 Shigella sonnei cases were reported in northwest Missouri, mostly among persons exposed to daycare centers. METHODS: We conducted a case-control investigation among licensed daycare centers (LDCs) in northwest Missouri to determine transmission risk factors, tested isolates for antimicrobial resistance, and described treatment practices. Case LDCs had secondary attack rates of shigellosis ≥2% (range, 2%-25%) and control LDCs ≤2% (range, 0%-1.3%). We interviewed LDC staff and performed on-site inspections. Thirty-one outbreak isolates were tested for antimicrobial resistance. We interviewed physicians and reviewed health department outbreak-related treatment data. RESULTS: We enrolled 18 case and 21 control LDCs. LDCs with ≥1 sink in every room (odds ratio [OR]: 0.1; 95% confidence interval [CI]: 0.02-0.5) or a diapering station in every room (OR: 0.1; 95% CI: 0.01-0.6) were less likely to be case-LDCs. Resistance to ampicillin and trimethoprim-sulfamethoxazole was found in 90% of the outbreak strains. Among 210 children treated with antimicrobial agents, azithromycin was used in 92 (44%) while a fluoroquinolone was used in 11 (5%) children. CONCLUSIONS: During a large daycare center-associated shigellosis outbreak, strains were highly resistant to ampicillin and trimethoprim-sulfamethoxazole. Children were frequently treated with azithromycin and occasionally fluoroquinolones. Appropriate handwashing and diapering infrastructure are necessary to minimize spread of shigellosis within daycare centers, and could reduce use of antimicrobial agents. |
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