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As SARS-CoV-2, the virus that causes COVID-19, continues to circulate globally, high levels of vaccine- and infection-induced immunity and the availability of effective treatments and prevention tools have substantially reduced the risk for medically significant COVID-19 illness (severe acute illness and post-COVID-19 conditions) and associated hospitalization and death (1). These circumstances now allow public health efforts to minimize the individual and societal health impacts of COVID-19 by focusing on sustainable measures to further reduce medically significant illness as well as to minimize strain on the health care system, while reducing barriers to social, educational, and economic activity (2). Individual risk for medically significant COVID-19 depends on a person's risk for exposure to SARS-CoV-2 and their risk for developing severe illness if infected (3). Exposure risk can be mitigated through nonpharmaceutical interventions, including improving ventilation, use of masks or respirators indoors, and testing (4). The risk for medically significant illness increases with age, disability status, and underlying medical conditions but is considerably reduced by immunity derived from vaccination, previous infection, or both, as well as timely access to effective biomedical prevention measures and treatments (3,5). CDC's public health recommendations change in response to evolving science, the availability of biomedical and public health tools, and changes in context, such as levels of immunity in the population and currently circulating variants. CDC recommends a strategic approach to minimizing the impact of COVID-19 on health and society that relies on vaccination and therapeutics to prevent severe illness; use of multicomponent prevention measures where feasible; and particular emphasis on protecting persons at high risk for severe illness. Efforts to expand access to vaccination and therapeutics, including the use of preexposure prophylaxis for persons who are immunocompromised, antiviral agents, and therapeutic monoclonal antibodies, should be intensified to reduce the risk for medically significant illness and death. Efforts to protect persons at high risk for severe illness must ensure that all persons have access to information to understand their individual risk, as well as efficient and equitable access to vaccination, therapeutics, testing, and other prevention measures. Current priorities for preventing medically significant illness should focus on ensuring that persons 1) understand their risk, 2) take steps to protect themselves and others through vaccines, therapeutics, and nonpharmaceutical interventions when needed, 3) receive testing and wear masks if they have been exposed, and 4) receive testing if they are symptomatic, and isolate for ≥5 days if they are infected.

This analysis reveals patterns that may inform future prevention strategies., Shiga toxin–producing Escherichia coli (STEC) cause substantial and costly illnesses. Leafy greens are the second most common source of foodborne STEC O157 outbreaks. We examined STEC outbreaks linked to leafy greens during 2009–2018 in the United States and Canada. We identified 40 outbreaks, 1,212 illnesses, 77 cases of hemolytic uremic syndrome, and 8 deaths. More outbreaks were linked to romaine lettuce (54%) than to any other type of leafy green. More outbreaks occurred in the fall (45%) and spring (28%) than in other seasons. Barriers in epidemiologic and traceback investigations complicated identification of the ultimate outbreak source. Research on the seasonality of leafy green outbreaks and vulnerability to STEC contamination and bacterial survival dynamics by leafy green type are warranted. Improvements in traceability of leafy greens are also needed. Federal and state health partners, researchers, the leafy green industry, and retailers can work together on interventions to reduce STEC contamination.

Enteric pathogens, such as non-typhoidal Salmonella, Campylobacter and Escherichia coli, can reside in the intestinal tract of many animals, including livestock, companion animals, small mammals and reptiles. Often, these animals can appear healthy; nonetheless, humans can become infected after direct or indirect contact, resulting in a substantial illness burden. An estimated 14% of the 3.2 million illnesses that occur in the United States of America (USA) each year from such enteric pathogens are attributable to animal contact. Surveillance for enteric pathogens in the USA includes the compilation and interpretation of both laboratory and epidemiologic data. However, the authors feel that a collaborative, multisectoral and transdisciplinary - or One Health - approach is needed for data collection and analysis, at every level. In addition, they suggest that the future of enteric illness surveillance lies in the development of improved technologies for pathogen detection and characterisation, such as genomic sequencing and metagenomics. In particular, using whole-genome sequencing to compare genetic sequences of enteric pathogens from humans, food, animals and the environment, can help to predict antimicrobial resistance among these pathogens, determine their genetic relatedness and identify outbreaks linked to a common source. In this paper, the authors describe three recent, multi-state human enteric illness outbreaks linked to animal contact in the USA and discuss how integrated disease surveillance was essential to outbreak detection and response. Additional datasharing between public health and animal health laboratories and epidemiologists at the local, national, regional and international level may help to improve surveillance for emerging animal and human health threats and lead to new opportunities for prevention.

Background Produce-associated outbreaks of Shiga toxin–producing Escherichia coli (STEC) were first identified in 1991. In April 2018, New Jersey and Pennsylvania officials reported a cluster of STEC O157 infections associated with multiple locations of a restaurant chain. The Centers for Disease Control and Prevention (CDC) queried PulseNet, the national laboratory network for foodborne disease surveillance, for additional cases and began a national investigation. Methods A case was defined as an infection between 13 March and 22 August 2018 with 1 of the 22 identified outbreak-associated E. coli O157:H7 or E. coli O61 pulsed-field gel electrophoresis pattern combinations, or with a strain STEC O157 that was closely related to the main outbreak strain by whole-genome sequencing. We conducted epidemiologic and traceback investigations to identify illness subclusters and common sources. A US Food and Drug Administration–led environmental assessment, which tested water, soil, manure, compost, and scat samples, was conducted to evaluate potential sources of STEC contamination. Results We identified 240 case-patients from 37 states; 104 were hospitalized, 28 developed hemolytic uremic syndrome, and 5 died. Of 179 people who were interviewed, 152 (85%) reported consuming romaine lettuce in the week before illness onset. Twenty subclusters were identified. Product traceback from subcluster restaurants identified numerous romaine lettuce distributors and growers; all lettuce originated from the Yuma growing region. Water samples collected from an irrigation canal in the region yielded the outbreak strain of STEC O157. Conclusions We report on the largest multistate leafy greens–linked STEC O157 outbreak in several decades. The investigation highlights the complexities associated with investigating outbreaks involving widespread environmental contamination.

Unpasteurized milk can contain harmful bacteria such as Listeria monocytogenes. In 2016, the US Food and Drug Administration notified the Centers for Disease Control and Prevention (Atlanta, GA) that L. monocytogenes isolated from unpasteurized chocolate milk from a Pennsylvania dairy was closely related, by whole-genome sequencing, to L. monocytogenes isolates collected from blood specimens of 2 patients (in California and Florida) in 2014. The California and Florida patients consumed unpasteurized milk from the Pennsylvania dairy. Both were >65 yr old and were hospitalized in 2014; the Florida patient died. Isolates from the 2 patients had indistinguishable pulsed-field gel electrophoresis patterns and were closely related by whole-genome multilocus sequence typing analysis (by 2 alleles) to the isolate from unpasteurized chocolate milk produced by the Pennsylvania dairy in 2015. Together, epidemiologic and laboratory information indicated a common origin. This is the first multistate listeriosis outbreak linked to unpasteurized milk in the United States detected using whole-genome multilocus sequence analysis.

Background Nontyphoidal Salmonella causes ~1 million food-borne infections annually in the United States. We began investigating a multistate outbreak of Salmonella serotype Agona infections in April 2011. Methods A case was defined as infection with the outbreak strain of Salmonella Agona occurring between 1 January and 25 August 2011. We developed hypotheses through iterative interviews. Product distribution analyses and traceback investigations were conducted. The Food and Drug Administration (FDA) tested papayas from Mexico for Salmonella. Results We identified 106 case patients from 25 states. Their median age was 21 years (range, 1-91). Thirty-nine of 61 case patients (64%) reported Hispanic/Latino ethnicity; 11 of 65 (17%) travelled to Mexico before illness. Thirty-two of 56 case patients (57%) reported papaya consumption. Distribution analyses revealed that three firms, including Distributor A, distributed papaya to geographic areas that aligned with both the location and timing of illnesses. Traceback of papayas purchased by ill persons in four states identified Distributor A as the common supplier. FDA testing isolated the outbreak strain from a papaya sample collected at distributor A and from another sample collected at the US-Mexico border, destined for distributor A. FDA isolated Salmonella species from 62 of 388 papaya import samples (16%). The investigation led to a recall of fresh, whole papayas from Distributor A and an FDA import alert for all papayas from Mexico. Conclusions This is the first reported Salmonella outbreak in the United States linked to fresh, whole papayas. The outbreak highlights important issues regarding the safety of imported produce.

Key Points Question Are pet store puppies a source of extensively drug-resistant Campylobacter jejuni infection in the US? Findings This survey study identified 168 cases from public health reports of Campylobacter infections with an epidemiologic or molecular link to pet store puppies from 2011 to 2020; 97% of patients reported contact with a dog, of whom 88% reported contact with a pet store puppy. Isolates were resistant to 7 antibiotic classes, including all recommended treatment agents. Meaning Extensively drug-resistant C jejuni strains have emerged as a cause of illness among pet store customers, employees, and visitors; infections caused by these strains cannot be treated with commonly recommended oral antibiotics., Importance Extensively drug-resistant Campylobacter jejuni infections cannot be treated with any commonly recommended antibiotics and pose an increasing public health threat. Objectives To investigate cases of extensively drug-resistant C jejuni associated with pet store puppies and describe the epidemiologic and laboratory characteristics of these infections. Design, Setting, and Participants In August 2017, health officials identified, via survey, patients with C jejuni infections who reported contact with puppies sold by pet stores. In conjunction with state and federal partners, the Centers for Disease Control and Prevention investigated cases of culture-confirmed C jejuni infections in US patients with an epidemiologic or molecular association with pet store puppies between January 1, 2016, and February 29, 2020. Available records from cases occurring before 2016 with genetically related isolates were also obtained. Main Outcomes and Measures Patients were interviewed about demographic characteristics, health outcomes, and dog exposure during the 7 days before illness onset. Core genome multilocus sequence typing was used to assess isolate relatedness, and genomes were screened for resistance determinants to predict antibiotic resistance. Isolates resistant to fluoroquinolones, macrolides, and 3 or more additional antibiotic classes were considered to be extensively drug resistant. Cases before 2016 were identified by screening all sequenced isolates submitted for surveillance using core genome multilocus sequence typing. Results A total of 168 patients (median [interquartile range] age, 37 [19.5-51.0] years; 105 of 163 female [64%]) with an epidemiologic or molecular association with pet store puppies were studied. A total of 137 cases occurred from January 1, 2016, to February 29, 2020, with 31 additional cases dating back to 2011. Overall, 117 of 121 patients (97%) reported contact with a dog in the week before symptom onset, of whom 69 of 78 (88%) with additional information reported contact with a pet store puppy; 168 isolates (88%) were extensively drug resistant. Traceback investigation did not implicate any particular breeder, transporter, distributer, store, or chain. Conclusions and Relevance Strains of extensively drug-resistant C jejuni have been circulating since at least 2011 and are associated with illness among pet store customers, employees, and others who come into contact with pet store puppies. The results of this study suggest that practitioners should ask about puppy exposure when treating patients with Campylobacter infection, especially when they do not improve with routine antibiotics, and that the commercial dog industry should take action to help prevent the spread of extensively drug-resistant C jejuni from pet store puppies to people., This survey study investigates the epidemiologic, laboratory, and traceback findings associated with persistent, extensively drug-resistant strains of Campylobacter jejuni associated with US pet store puppies.

SUMMARYSalmonella is a leading cause of bacterial foodborne illness. We report the collaborative investigative efforts of US and Canadian public health officials during the 2013–2014 international outbreak of multiple Salmonella serotype infections linked to sprouted chia seed powder. The investigation included open-ended interviews of ill persons, traceback, product testing, facility inspections, and trace forward. Ninety-four persons infected with outbreak strains from 16 states and four provinces were identified; 21% were hospitalized and none died. Fifty-four (96%) of 56 persons who consumed chia seed powder, reported 13 different brands that traced back to a single Canadian firm, distributed by four US and eight Canadian companies. Laboratory testing yielded outbreak strains from leftover and intact product. Contaminated product was recalled. Although chia seed powder is a novel outbreak vehicle, sprouted seeds are recognized as an important cause of foodborne illness; firms should follow available guidance to reduce the risk of bacterial contamination during sprouting.

Public health officials investigate outbreaks to control them, to prevent additional illnesses, and to learn how to prevent similar outbreaks in the future. The process the public health community uses to detect, investigate, and control enteric (intestinal) disease outbreaks from food, water, and other sources involves certain procedural steps. These include detecting a possible outbreak, defining and finding cases, generating hypotheses about likely sources, testing the hypotheses and evaluating evidence, finding contamination sources, controlling the outbreak, and determining when the outbreak is over. Investigating outbreaks of acute enteric diseases can be a dynamic and complex undertaking involving multiple public health and regulatory partners in different jurisdictions. This chapter provides an overview of the investigation process with an emphasis on multijurisdictional foodborne illness investigations in the United States.

On 27 April 2015, Washington health authorities identified Escherichia coli O157:H7 infections associated with dairy education school field trips held in a barn 20–24 April. Investigation objectives were to determine the magnitude of the outbreak, identify the source of infection, prevent secondary illness transmission and develop recommendations to prevent future outbreaks. Case-finding, hypothesis generating interviews, environmental site visits and a case–control study were conducted. Parents and children were interviewed regarding event activities. Odds ratios (OR) and 95% confidence intervals (CI) were computed. Environmental testing was conducted in the barn; isolates were compared to patient isolates using pulsed-field gel electrophoresis (PFGE). Sixty people were ill, 11 (18%) were hospitalised and six (10%) developed haemolytic uremic syndrome. Ill people ranged in age from P = 0.04). Barn samples yielded E. coli O157:H7 with PFGE patterns indistinguishable from patient isolates. This investigation provided epidemiological, laboratory and environmental evidence for a large outbreak of E. coli O157:H7 infections from exposure to a contaminated barn. The investigation highlights the often overlooked risk of infection through exposure to animal environments as well as the importance of handwashing for disease prevention. Increased education and encouragement of infection prevention measures, such as handwashing, can prevent illness.

While most human Salmonella infections result from exposure to contaminated foods, an estimated 11% of all Salmonella infections are attributed to animal exposures, including both direct animal handling and indirect exposures such as cleaning cages and handling contaminated pet food. This report describes the epidemiologic, environmental and laboratory investigations conducted in the United States as part of the response to an international outbreak of tetracycline-resistant Salmonella enterica serotype I 4,[5],12:i:- infections with over 500 illnesses occurring from 2008 to 2010. This investigation found that illness due to the outbreak strain was significantly associated with exposure to pet reptiles and frozen feeder rodents used as food for pet reptiles. Salmonella isolates indistinguishable from the outbreak strain were isolated from a frozen feeder mice-fed reptile owned by a case patient, as well as from frozen feeder mice and environmental samples collected from a rodent producing facility (Company A). An international voluntary recall of all Company A produced frozen feeder animals sold between May 2009 and July 2010 occurred. Only 13% of cases in our investigation were aware of the association between Salmonella infection and mice or rats. Consumers, the pet industry, healthcare providers and veterinarians need to be aware of the potential health risk posed by feeder rodents, whether live or frozen. Frozen feeder rodent producers, suppliers and distributors should follow the animal food labelling requirements as described in 21 CFR §501.5, and all packages of frozen feeder rodents should include safe handling instructions. Persons should wash their hands thoroughly with soap and water after handling live or frozen feeder rodents, as well as reptiles or anything in the area where the animals live. Continued opportunities exist for public health officials, the pet industry, veterinarians and consumers to work together to prevent salmonellosis associated with pet food, pets and other animals.

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.

SUMMARYIn 2008, nationwide investigations of a Salmonella serotype Saintpaul outbreak led first to consumer warnings for Roma and red round tomatoes, then later for jalapeño and serrano peppers. In New Mexico, where there were a large number of cases but no restaurant-based clusters, the NM Department of Health and the Indian Health Service participated with CDC in individual-level and household-level case-control studies of infections in New Mexico and the Navajo Nation. No food item was associated in the individual-level study. In the household-level study, households with an ill member were more likely to have had jalapeño peppers present during the exposure period and to have reported ever having serrano peppers in the household. This report illustrates the complexity of this investigation, the limitations of traditional individual-level case-control studies when vehicles of infection are ingredients or commonly eaten with other foods, and the added value of a household-level study.

SUMMARYIn November 2009, we initiated a multistate investigation of Salmonella Montevideo infections with pulsed-field gel electrophoresis pattern JIXX01.0011. We identified 272 cases in 44 states with illness onset dates ranging from 1 July 2009 to 14 April 2010. To help generate hypotheses, warehouse store membership card information was collected to identify products consumed by cases. These records identified 19 ill persons who purchased company A salami products before onset of illness. A case-control study was conducted. Ready-to-eat salami consumption was significantly associated with illness (matched odds ratio 8·5, 95% confidence interval 2·1–75·9). The outbreak strain was isolated from company A salami products from an environmental sample from one manufacturing plant, and sealed containers of black and red pepper at the facility. This outbreak illustrates the importance of using membership card information to assist in identifying suspect vehicles, the potential for spices to contaminate ready-to-eat products, and preventing raw ingredient contamination of these products.

Raw produce is an increasingly recognized vehicle for salmonellosis. We investigated a nationwide outbreak that occurred in the United States in 2008.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.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 ∞) 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 jalapeño 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, jalapeño peppers were implicated in all three clusters with implicated ingredients, and jalapeño 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 jalapeño peppers collected in Texas and in agricultural water and serrano peppers on a Mexican farm. Tomato tracebacks did not converge on a source.Although an epidemiologic association with raw tomatoes was identified early in this investigation, subsequent epidemiologic and microbiologic evidence implicated jalapeño and serrano peppers. This outbreak highlights the importance of preventing raw-produce contamination.

OBJECTIVE: Human Salmonella infections associated with dry pet food have not been previously reported. We investigated such an outbreak of Salmonella Schwarzengrund and primarily affecting young children. PATIENTS AND METHODS: Two multistate case-control studies were conducted to determine the source and mode of infections among case-patients with the outbreak strain. Study 1 evaluated household exposures to animals and pet foods, and study 2 examined risk factors for transmission among infant case-patients. Environmental investigations were conducted. RESULTS: Seventy-nine case-patients in 21 states were identified; 48% were children aged 2 years or younger. Case-households were significantly more likely than control households to report dog contact (matched odds ratio [mOR]: 3.6) and to have recently purchased manufacturer X brands of dry pet food (mOR: 6.9). Illness among infant case-patients was significantly associated with feeding pets in the kitchen (OR: 4.4). The outbreak strain was isolated from opened bags of dry dog food produced at plant X, fecal specimens from dogs that ate manufacturer X dry dog food, and an environmental sample and unopened bags of dog and cat foods from plant X. More than 23 000 tons of pet foods were recalled. After additional outbreak-linked illnesses were identified during 2008, the company recalled 105 brands of dry pet food and permanently closed plant X. CONCLUSIONS: Dry dog and cat foods manufactured at plant X were linked to human illness for a 3-year period. This outbreak highlights the importance of proper handling and storage of pet foods in the home to prevent human illness, especially among young children.

Author(s): Hagan, Holly; Pouget, Enrique R; Williams, Ian T; Garfein, Richard S; Strathdee, Steffanie A; Hudson, Sharon M; Latka, Mary H; Ouellet, Lawrence J | Abstract: Background. In studies of hepatitis C virus (HCV) seroconversion in injection drug users (IDUs), some have questioned whether underreporting of syringe sharing, a stigmatized behavior, has led to misattribution of HCV risk to other injection-related behaviors. Methods. IDUs aged 15–30 years who were seronegative for human immunodeficiency virus and HCV antibodies were recruited into a prospective study in 5 US cities. Behavioral data were collected via computer-assisted self-interviewing to reduce socially desirable reporting. Hazard ratios (HRs) were estimated to assess associations between behavior and HCV seroconversion. Because the shared use of cookers, cottons, and rinse water was highly correlated, a summary variable was created to represent drug preparation equipment sharing. Results. Among 483 IDUs who injected during the period covered by the follow-up assessments, the incidence of HCV infection was 17.2 cases per 100 person years; no HIV seroconversions occurred. Adjusting for confounders, the shared use of drug preparation equipment was significantly associated with HCV seroconversion (adjusted HR, 2.66; 95% confidence interval, 1.03–23.92), but syringe sharing was not (adjusted HR, 0.91). We estimated that 37% of HCV seroconversions in IDUs were due to the sharing of drug preparation equipment. Conclusions. Associations between sharing drug preparation equipment and HCV seroconversion are not attributable to underascertainment of syringe sharing. Avoiding HCV infection will require substantial reductions in exposure to all sources of contaminated blood.

Long-term follow-up studies of populations that received recombinant hepatitis B (HB) vaccination beginning at birth are limited.Micronesian adolescents who had received 3 doses of recombinant HB vaccine (Recombivax 5 microg at birth, 2.5 microg at 2 months, 2.5 microg ug at 6 months) and tested negative for antibody to HB core antigen (anti-HBc) 2 years after primary vaccination (baseline testing) were followed up 15 years after primary vaccination. After testing for anti-HBc, HB surface antigen (HBsAg), and antibody to HBsAg (anti-HBs), participants received a booster dose of HB vaccine. An anamnestic response was defined as an increase in anti-HBs concentrations to a levelor = 10 mIU/mL 14 days postbooster.Of the 105 participants, 42 (40.0%) had anti-HBs concentrationsor = 10 mIU/mL on baseline testing. At 15 years, 8 (7.6%) were anti-HBc positive; none were HBsAg positive. Of the remaining 97, 7 (7.3%) had anti-HBs concentrationsor = 10 mIU/mL. Of the 96 who received a booster dose, 46 (47.9%) had an anamnestic response; final antibody concentrations were 10-99 mIU/mL for 17 (17.7%) and100 mIU/mL for 29 (30.2%). Participants with anti-HBs concentrationsor = 10 mIU/mL on baseline testing were more likely to have an anamnestic response at 15 years [26/39 (66.7%) versus 20/57 (35.1%); P = 0.003].Fifteen years after primary vaccination starting at birth, 8% of participants had evidence of past HB virus infection, but none had chronic infection. Absence of an anamnestic response to an additional vaccine dose, seen in half of participants, might indicate waning immunity.

Objective To examine hepatitis C virus (HCV) seroprevalence among injection drug users in 4 US cities from 1994 through 2004. Methods Demographic characteristics, behaviors, and prevalence of HCV antibody among 5088 injection drug users aged 18-40 years from Baltimore, Maryland; Chicago, Illinois; Los Angeles, California; and New York, New York, enrolled in 3 related studies--Collaborative Injection Drug User Study (CIDUS) I (1994-1996), CIDUS II (1997-1999), and CIDUS III/Drug User Intervention Trial (2002-2004)--were compared using the chi(2) and Mantel-Haenszel tests of significance. Trends over time were assessed by logistic regression. Results Prevalence of HCV infection was 65%, 35%, and 35% in CIDUS I, CIDUS II, and CIDUS III, respectively. The adjusted prevalence odds ratio (OR) of being HCV antibody positive increased with the number of years of injection drug use (OR, 1.93 [95% confidence interval {CI}, 1.68-2.21] for each year of injecting within the first 2 years; OR, 1.09 [95% CI, 1.07-1.11] for each year of injecting beyond the first 2 years). Significant decreases were observed in the prevalence of HCV antibody between CIDUS I and CIDUS III in Baltimore (OR, 0.30; 95% CI, 0.20-0.43) and Los Angeles (OR, 0.17; 95% CI, 0.09-0.31) and among people of races other than black in Chicago (OR, 0.12; 95% CI, 0.08-0.17). No decrease in prevalence was seen in New York (OR, 1.04; 95% CI, 0.69-1.58) or among blacks in Chicago (OR, 0.55; 95% CI, 0.16-1.90). Conclusion Although regional differences exist, our data suggest that the incidence of HCV infection among injection drug users in the United States decreased from 1994 through 2004.

OBJECTIVES: Most U.S. studies of acute liver failure (ALF) patients have been conducted at tertiary care liver transplantation centers. The aim of this study was to conduct population-based surveillance for ALF. METHODS: We conducted population-based surveillance for ALF within the 8 counties comprising Metropolitan Atlanta between November 2000 and October 2004. ALF cases were defined as the presence of coagulopathy, any grade of hepatic encephalopathy within 26 wk of illness onset, and no history of underlying liver disease. A questionnaire was administered and medical records were reviewed to determine clinical features, etiologies, and outcomes. RESULTS: A total of 65 cases were enrolled, yielding an annualized incidence for all causes of ALF of 5.5 (95% Cl 4.3-7.0) per million. Acetaminophen (APAP)-related ALF was the most common (41%) etiology in adults while ALF of undetermined etiology was most common (38%) in children, followed by APAP-related ALF (25%). Unintentional APAP overdose was the most common type (61%) of APAP-related cause. Blacks were more likely than other races to have ALF of undetermined etiology (32% vs 11%). Overall mortality was 40%, with 27 (42%) surviving with supportive care alone and 8 (12%) requiring orthotopic liver transplantation. CONCLUSIONS: Our population-based study suggests approximately 1,600 ALF cases occur in the United States each year. Consistent with findings from studies conducted exclusively at liver transplantation centers, APAP-related ALF was the most common etiology. Increased awareness of APAP-related ALF in the medical community may limit future cases. More research is warranted into ALF of undetermined etiology, especially in children.

We used molecular epidemiologic techniques to document patient-to-patient transmission of hepatitis B virus (HBV) between 2 outpatient oral surgery patients operated on 161 min apart. Serological testing of 25 (93%) of 27 patients operated on after the source patient revealed that 19 (76%) of 25 were previously immune to HBV; no additional cases were identified. We found no deficiencies in infection control practices. Transmission may have been limited by the high prevalence (64%) of patients vaccinated against HBV. To our knowledge, this is the first documented case of patient-to-patient transmission of a bloodborne pathogen in a dental setting in the United States.

SUMMARYOn 23 May 2011, CDC identified a multistate cluster of Salmonella Heidelberg infections and two multidrug-resistant (MDR) isolates from ground turkey retail samples with indistinguishable pulsed-field gel electrophoresis patterns. We defined cases as isolation of outbreak strains in persons with illness onset between 27 February 2011 and 10 November 2011. Investigators collected hypothesis-generating questionnaires and shopper-card information. Food samples from homes and retail outlets were collected and cultured. We identified 136 cases of S. Heidelberg infection in 34 states. Shopper-card information, leftover ground turkey from a patient's home containing the outbreak strain and identical antimicrobial resistance profiles of clinical and retail samples pointed to plant A as the source. On 3 August, plant A recalled 36 million pounds of ground turkey. This outbreak increased consumer interest in MDR Salmonella infections acquired through United States-produced poultry and played a vital role in strengthening food safety policies related to Salmonella and raw ground poultry.

Aim To identify risk factors for acute hepatitis B virus (HBV) infection among Wyoming methamphetamine injectors. Design A case–control study conducted in the setting of an outbreak. Setting A county in central Wyoming, United States. Participants Cases were identified through surveillance and contact tracing and were defined as Natrona County, Wyoming, residents who were either symptomatic or confirmed serologically to be acutely infected with HBV during January–August, 2003. Controls were susceptible to HBV infection. All participants identified themselves as methamphetamine injectors. Measurements Participants were administered a survey that inquired about risk factors for HBV infection, including drug use practices and sexual behaviors. Controls were also tested serologically for acute HBV infection. Findings Among the 18 case-patients and 49 controls who participated in the study, sharing water used to prepare injections and/or rinse syringes was associated with HBV infection (94% of case-participants versus 44% of controls; OR = 21.9, 95% CI: 2.7, 177.8), as was sharing cotton filters (89% of case-participants versus 52% of controls; OR = 7.4, 95% CI: 1.5, 35.6); sharing syringes was not statistically associated. In logistic regression models adjusted for age, sex, and interview site, sharing rinse water and sharing cotton remained statistically associated. Conclusions Methamphetamine use has become increasingly prevalent in the United States. Our findings highlight the need for awareness of risks associated with injection drug use and sharing behaviors. Enhanced hepatitis B vaccination programs and educational campaigns that target methamphetamine injectors specifically, including those living in rural areas, should be developed and implemented.

Hepatitis E virus (HEV) is an enterically transmitted RNA virus that causes both epidemic and sporadic cases of acute hepatitis. Despite sero-surveys showing antibody to HEV in up to 36% of the US population, acute hepatitis E has been reported among individuals with no history of international travel only three times in the United States. We report a case of apparently locally-acquired hepatitis E that occurred in El Paso, Texas that was 98% similar to a previously isolated HEV found in swine in the United States. Like the three previous cases, a thorough investigation found no conclusive sources of infection. Active case surveillance found no additional cases.

Objectives:To determine whether hepatitis B virus (HBV) transmission occurred among patients visiting a physician's office and to evaluate potential transmission mechanisms.Design:Serologic survey, retrospective cohort study, and observation of infection control practices.Setting:Private medical office.Patients:Those visiting the office between March 1 and December 26, 2001.Results:We identified 38 patients with acute HBV infection occurring between February 2000 and February 2002. The cohort study, limited to the 10 months before outbreak detection, included 91 patients with serologic test results and available charts representing 18 case-patients and 73 susceptible patients. Overall, 67 patients (74%) received at least one injection during the observation period. Case-patients received a median of 14 injections (range, 2-25) versus 2 injections (range, 0-17) for susceptible patients (P < .001). Acute infections occurred among 18 (27%) of 67 who received at least one injection versus none of 24 who received no injections (RR, 13.6; CI95, 2.4-undefined). Risk of infection increased 5.2-fold (CI95, 0.6-47.3) for those with 3 to 6 injections and 20.0-fold (CI95, 2.8-143.5) for those with more than 6 injections. Typically, injections consisted of doses of atropine, dexamethasone, vitamin B12, or a combination of these mixed in one syringe. HBV DNA genetic sequences of 24 patients with acute infection and 4 patients with chronic infection were identical in the 1,500-bp region examined. Medical staff were seronegative for HBV infection markers. The same surface was used for storing multidose vials, preparing injections, and dismantling used injection equipment.Conclusion:Administration of unnecessary injections combined with failure to separate clean from contaminated areas and follow safe injection practices likely resulted in patient-to-patient HBV transmission in a private physician's office.

In the United States, transmission of viral hepatitis from health care-related exposures is uncommon and primarily recognized in the context of outbreaks. Transmission is typically associated with unsafe injection practices, as exemplified by several recent outbreaks that occurred in ambulatory health care settings. To prevent transmission of bloodborne pathogens, health care workers must adhere to standard precautions and follow fundamental infection-control principles, including safe injection practices and appropriate aseptic techniques. These principles and practices need to be made explicit in institutional policies and reinforced through in-service education for all personnel involved in direct patient care, including those in ambulatory care settings. The effectiveness of these measures should be monitored as part of the oversight process. In addition, prompt reporting of suspected health care-related cases coupled with appropriate investigation and improved monitoring of surveillance data are needed to accurately characterize and prevent health care-related transmission of viral hepatitis.

Hepatitis C virus (HCV) has emerged as a major public health problem among injection drug users. In this analysis we examine whether disinfection of syringes with bleach has a potentially protective effect on anti-HCV seroconversion.We conducted a nested case-control study comparing 78 anti-HCV seroconverters with 390 persistently anti-HCV seronegative injection drug users. These data come from the Second Collaborative Injection Drug Users Study, a prospective cohort study that recruited injection drug users from five U.S. cities between 1997 and 1999. We used conditional logistic regression to determine the effect of bleach disinfection of syringes on anti-HCV seroconversion.Participants who reported using bleach all the time had an odds ratio (OR) for anti-HCV seroconversion of 0.35 (95% confidence interval = 0.08-1.62), whereas those reporting bleach use only some of the time had an odds ratio of 0.76 (0.21-2.70), when compared with those reporting no bleach use.These results suggest that bleach disinfection of syringes, although not a substitute for use of sterile needles or cessation of injection, may help to prevent HCV infection among injection drug users.

We collected data during postexposure antimicrobial prophylaxis campaigns and from a prophylaxis program evaluation 60 days after start of antimicrobial prophylaxis involving persons from six U.S. sites where Bacillus anthracis exposures occurred. Adverse events associated with antimicrobial prophylaxis to prevent anthrax were commonly reported, but hospitalizations and serious adverse events as defined by Food and Drug Administration criteria were rare. Overall adherence during 60 days of antimicrobial prophylaxis was poor (44%), ranging from 21% of persons exposed in the Morgan postal facility in New York City to 64% of persons exposed at the Brentwood postal facility in Washington, D.C. Adherence was highest among participants in an investigational new drug protocol to receive additional antibiotics with or without anthrax vaccine--a likely surrogate for anthrax risk perception. Adherence of

We have studied the occurrence, stage specificity and cellular location of key molecules associated with microtubules in Plasmodium falciparum merozoites. Antibodies to gamma tubulin, conventional kinesin and cytoplasmic dynein were used to determine the polarity of merozoite microtubules (mt), the stage specificity of the motor proteins and their location during merozoite development. We conclude that the minus ends of the mts are located at their apical pole. Kinesin was present throughout the lifecycle, appearing as a distinct crescent at the apex of developing merozoites. The vast majority of cytoplasmic dynein reactivity occurred in late merogony, also appearing at the merozoite apex. Destruction of mt with dinitroanilines did not affect the cellular location of kinesin or dynein. In invasion assays, dynein inhibitors reduced the number of ring stage parasites. Our results show that both conventional kinesin and cytoplasmic dynein are abundant, located at the negative pole of the merozoite mt and, intriguingly, appear there only in very late merogony, prior to merozoite release and invasion.

The prevalence, risk factors, and prevention opportunities of hepatitis C virus (HCV) infection were studied in a large sample of 698 young adult injection drug users (IDUs) in Chicago, 18-30 years old. Participants were recruited between 1997 and 1999 by using street outreach, targeted advertising, and chain-referral methods. HCV infection prevalence was 27% and was strongly associated with both age and duration of injecting (P

TT virus (TTV) is a recently discovered infectious agent originally obtained from transfusion-related hepatitis. However, the causative link between the TTV infection and liver disease remains uncertain. Recent studies demonstrated that genome sequences of different TTV strains are significantly divergent. To assess genetic heterogeneity of the TTV genome in more detail, a sequence analysis of PCR fragments (271 bp) amplified from open reading frame 1 (ORF1) was performed. PCR fragments were amplified from 5 to 40% of serum specimens obtained from patients with different forms of hepatitis who reside in different countries (e.g., China, Egypt, Vietnam, and the United States) and from normal human specimens obtained from U.S. residents. A total of 170 PCR fragments were sequenced and compared to sequences derived from the corresponding TTV genome region deposited in GenBank. Genotypes 2 and 3 were found to be significantly more genetically related than any other TTV genotype. Moreover, three sequences were shown to be almost equally related to both genotypes 2 and 3. These observations suggest a merger of genotypes 2 and 3 into one genotype, 2/3. Additionally, five new groups of TTV sequences were identified. One group represents a new genotype, whereas the other four groups were shown to be more evolutionary distant from all known TTV sequences. The evolutionary distances between these four groups were also shown to be greater than between TTV genotypes. The phylogenetic analysis suggested that these four new genetic groups represent closely related yet different viral species. Thus, TTV exists as a “swarm” of at least five closely related but different viruses. These observations suggest a high degree of genetic complexity within the TTV population. The finding of the additional TTV-related species should be taken into consideration when the association between TTV infections and human diseases of unknown etiology is studied.

Although hepatitis C virus (HCV) infection is the most common chronic blood-borne infection in the United States, the annual incidence of new infections has decreased by more than 80% since 1989 to approximately 36,000 new infections by 1996. The Third National Health and Nutrition Examination Survey (NHANES III) revealed that an estimated 3.9 million US citizens (1.8%) have been infected with HCV. Of these, approximately 2.7 million persons are chronically infected with HCV. Population-based studies indicate that 40% of chronic liver disease is HCV related. Chronic hepatitis C results in an estimated 8,000 to 10,000 deaths each year. Because the prevalence of HCV infection is approximately threefold higher among persons now between 30 and 49 years of age, the number of deaths resulting from HCV-related liver disease could increase substantially during the next 10 to 20 years, as this cohort reaches the ages at which complications from chronic liver disease typically occur. Most people who develop chronic infection may not even be aware that they have been infected, because acute disease is commonly benign. However, infected persons can transmit the disease to others and are at risk for developing chronic liver disease. HCV is transmitted primarily through direct percutaneous exposures to blood. In the United States, blood transfusion accounted for a substantial proportion of HCV infections before 1990, when routine testing began, but now accounts for only a small percentage. Injection drug use is currently the major risk factor for acute HCV infection. Prevention and control of HCV infection in the United States must focus not only on reduction of transmission in groups at high risk of infection (e.g., injection drug users) but also on the early identification of persons with chronic infection.

Background We investigated a large, foodborne outbreak of hepatitis A that occurred in February and March 1997 in Michigan and then extended the investigation to determine whether it was related to sporadic cases reported in other states among persons who had consumed frozen strawberries, the food suspected of causing the outbreak. Methods The cases of hepatitis A were serologically confirmed. Epidemiologic studies were conducted in the two states with sufficient numbers of cases, Michigan and Maine. Hepatitis A virus RNA detected in clinical specimens was sequenced to determine the relatedness of the virus from outbreak-related cases and other cases. Results A total of 213 cases of hepatitis A were reported from 23 schools in Michigan and 29 cases from 13 schools in Maine, with the median rate of attack ranging from 0.2 to 14 percent. Hepatitis A was associated with the consumption of frozen strawberries in a case–control study (odds ratio for the disease, 8.3; 95 percent confidence interval, 2.1 to 33) ...

SUMMARYWe investigated an outbreak of 396Salmonella entericaserotype I 4,5,12:i:- infections to determine the source. After 7 weeks of extensive hypothesis-generation interviews, no refined hypothesis was formed. Nevertheless, a case-control study was initiated. Subsequently, an iterative hypothesis-generation approach used by a single interviewing team identified brand A not-ready-to-eat frozen pot pies as a likely vehicle. The case-control study, modified to assess this new hypothesis, along with product testing indicated that the turkey variety of pot pies was responsible. Review of product labels identified inconsistent language regarding preparation, and the cooking instructions included undefined microwave wattage categories. Surveys found that most patients did not follow the product's cooking instructions and did not know their oven's wattage. The manufacturer voluntarily recalled pot pies and improved the product's cooking instructions. This investigation highlights the value of careful hypothesis-generation and the risks posed by frozen not-ready-to-eat microwavable foods.

Foodborne diseases cause an estimated 48 million illnesses each year in the United States, including 9.4 million caused by known pathogens. Foodborne disease outbreak surveillance provides valuable insights into the agents and foods that cause illness and the settings in which transmission occurs. CDC maintains a surveillance program for collection and periodic reporting of data on the occurrence and causes of foodborne disease outbreaks in the United States. This surveillance system is the primary source of national data describing the numbers of illnesses, hospitalizations, and deaths; etiologic agents; implicated foods; contributing factors; and settings of food preparation and consumption associated with recognized foodborne disease outbreaks in the United States.1998-2008.The Foodborne Disease Outbreak Surveillance System collects data on foodborne disease outbreaks, defined as the occurrence of two or more cases of a similar illness resulting from the ingestion of a common food. Public health agencies in all 50 states, the District of Columbia, U.S. territories, and Freely Associated States have primary responsibility for identifying and investigating outbreaks and use a standard form to report outbreaks voluntarily to CDC. During 1998-2008, reporting was made through the electronic Foodborne Outbreak Reporting System (eFORS).During 1998-2008, CDC received reports of 13,405 foodborne disease outbreaks, which resulted in 273,120 reported cases of illness, 9,109 hospitalizations, and 200 deaths. Of the 7,998 outbreaks with a known etiology, 3,633 (45%) were caused by viruses, 3,613 (45%) were caused by bacteria, 685 (5%) were caused by chemical and toxic agents, and 67 (1%) were caused by parasites. Among the 7,724 (58%) outbreaks with an implicated food or contaminated ingredient reported, 3,264 (42%) could be assigned to one of 17 predefined commodity categories: fish, crustaceans, mollusks, dairy, eggs, beef, game, pork, poultry, grains/beans, oils/sugars, fruits/nuts, fungi, leafy vegetables, root vegetables, sprouts, and vegetables from a vine or stalk. The commodities implicated most commonly were poultry (18.9%; 95% confidence interval [CI] = 17.4-20.3) and fish (18.6%; CI = 17.2-20), followed by beef (11.9%; CI = 10.8-13.1). The pathogen-commodity pairs most commonly responsible for outbreaks were scombroid toxin/histamine and fish (317 outbreaks), ciguatoxin and fish (172 outbreaks), Salmonella and poultry (145 outbreaks), and norovirus and leafy vegetables (141 outbreaks). The pathogen-commodity pairs most commonly responsible for outbreak-related illnesses were norovirus and leafy vegetables (4,011 illnesses), Clostridium perfringens and poultry (3,452 illnesses), Salmonella and vine-stalk vegetables (3,216 illnesses), and Clostridium perfringens and beef (2,963 illnesses). Compared with the first 2 years of the study (1998-1999), the percentage of outbreaks associated with leafy vegetables and dairy increased substantially during 2006-2008, while the percentage of outbreaks associated with eggs decreased.Outbreak reporting rates and implicated foods varied by state and year, respectively; analysis of surveillance data for this 11-year period provides important information regarding changes in sources of illness over time. A substantial percentage of foodborne disease outbreaks were associated with poultry, fish, and beef, whereas many outbreak-related illnesses were associated with poultry, leafy vegetables, beef, and fruits/nuts. The percentage of outbreaks associated with leafy vegetables and dairy increased during the surveillance period, while the percentage associated with eggs decreased.Outbreak surveillance data highlight the etiologic agents, foods, and settings involved most often in foodborne disease outbreaks and can help to identify food commodities and preparation settings in which interventions might be most effective. Analysis of data collected over several years of surveillance provides a means to assess changes in the food commodities associated most frequently with outbreaks that might occur following improvements in food safety or changes in consumption patterns or food preparation practices. Prevention of foodborne disease depends on targeted interventions at appropriate points from food production to food preparation. Efforts to reduce foodborne illness should focus on the pathogens and food commodities causing the most outbreaks and outbreak-associated illnesses, including beef, poultry, fish, and produce.

Background Shiga toxin-producing Escherichia coli (STEC) O157:H7 is the causal agent for more than 96,000 cases of diarrheal illness and 3,200 infection-attributable hospitalizations annually in the United States. Materials and methods We defined a confirmed case as a compatible illness in a person with the outbreak strain during 10/07/2011-11/30/2011. Investigation included hypothesis generation, a case-control study utilizing geographically-matched controls, and a case series investigation. Environmental inspections and tracebacks were conducted. Results We identified 58 cases in 10 states; 67% were hospitalized and 6.4% developed hemolytic uremic syndrome. Any romaine consumption was significantly associated with illness (matched Odds Ratio (mOR) = 10.0, 95% Confidence Interval (CI) = 2.1-97.0). Grocery Store Chain A salad bar was significantly associated with illness (mOR = 18.9, 95% CI = 4.5-176.8). Two separate traceback investigations for romaine lettuce converged on Farm A. Case series results indicate that cases (64.9%) were more likely than the FoodNet population (47%) to eat romaine lettuce (p-value = 0.013); 61.3% of cases reported consuming romaine lettuce from the Grocery Store Chain A salad bar. Conclusions This multistate outbreak of STEC O157:H7 infections was associated with consumption of romaine lettuce. Traceback analysis determined that a single common lot of romaine lettuce harvested from Farm A was used to supply Grocery Store Chain A and a university campus linked to a case with the outbreak strain. An investigation at Farm A did not identify the source of contamination. Improved ability to trace produce from the growing fields to the point of consumption will allow more timely prevention and control measures to be implemented.

Objective. To describe the pattern of immunization in the cohort of children who entered public schools in Virginia in 1992. Design. This was a historic cohort study using stratified cluster sampling. Three strata were created based on the socioeconomic status (SES) of the children in the catchment area of each public school in Virginia. Setting. The random sample included public elementary schools throughout Virginia. Participants. Immunization records were obtained for a randomly selected cohort of 2519 first-grade children in Virginia. Outcome Measures. Age at completion of recommended childhood vaccines was determined from birth to school entry by SES, race, and population density. Provider practices were assessed by ascertaining missed opportunities for simultaneous administration of vaccinations according to recommended schedules. Results. Although immunization completion rates were high at school entry, low levels of immunization coverage were found in all areas of Virginia at 24 months of age regardless of SES (as measured by per capita income), population density, or race. However, under-immunization was more severe for poor children in urban areas (42.3% of children in low-SES urban areas were age-appropriately immunized at 24 months of age versus 64.0% in children in high-SES rural areas). By multivariate logistic regression, race and gender were not predictors of which children were appropriately immunized at 2 years of age after adjusting for the following: SES, population density, receiving the first DTP (diphtheria, tetanus, and pertussis) or OPV (oral polio) vaccination after 3 months of age, and failure to have the first DTP administered simultaneously with the first OPV or the second DTP administered simultaneously with the second OPV. Receiving the first DTP or OPV vaccination after 3 months of age and failure to have the first and second DTP and OPV administered simultaneously were the strongest predictors of not being age-appropriately immunized at 2 years of age. The effect of failure to vaccinate simultaneously on predicting vaccination coverage at 2 years of age was strongly modified by SES. Children who attended schools located in census tracts with per capita incomes less than $10 600 and who did not have the first and second doses of DTP and OPV administered simultaneously were 33.19 times more likely not to be age-appropriately immunized at 2 years of age compared with children who attended schools located in census tracts with per capita incomes greater than $18 800 and who received the first and second doses of DTP and OPV simultaneously (95% confidence interval: 18.29 to 60.22). Conclusions. Although beginning the immunization schedule at the recommended age was crucial to appropriate vaccination later in life, provider practices were important predictors of under-immunization. Failure to administer vaccinations simultaneously strongly influenced poorer children in Virginia. Serious delays in vaccine administration were observed not only for poor children in urban areas, but also in all areas of Virginia before school entry.

Importance This large outbreak of foodborne salmonellosis demonstrated the complexity of investigating outbreaks linked to poultry products. The outbreak also highlighted the importance of efforts to strengthen food safety policies related to Salmonella in chicken parts and has implications for future changes within the poultry industry. Objective To investigate a large multistate outbreak of multidrug resistant Salmonella Heidelberg infections. Design Epidemiologic and laboratory investigations of patients infected with the outbreak strains of Salmonella Heidelberg and traceback of possible food exposures. Setting United States. Outbreak period was March 1, 2013 through July 11, 2014 Patients A case was defined as illness in a person infected with a laboratory-confirmed Salmonella Heidelberg with 1 of 7 outbreak pulsed-field gel electrophoresis (PFGE) XbaI patterns with illness onset from March 1, 2013 through July 11, 2014. A total of 634 case-patients were identified through passive surveillance; 200/528 (38%) were hospitalized, none died. Results Interviews were conducted with 435 case-patients: 371 (85%) reported eating any chicken in the 7 days before becoming ill. Of 273 case-patients interviewed with a focused questionnaire, 201 (74%) reported eating chicken prepared at home. Among case-patients with available brand information, 152 (87%) of 175 patients reported consuming Company A brand chicken. Antimicrobial susceptibility testing was completed on 69 clinical isolates collected from case-patients; 67% were drug resistant, including 24 isolates (35%) that were multidrug resistant. The source of Company A brand chicken consumed by case-patients was traced back to 3 California production establishments from which 6 of 7 outbreak strains were isolated. Conclusions Epidemiologic, laboratory, traceback, and environmental investigations conducted by local, state, and federal public health and regulatory officials indicated that consumption of Company A chicken was the cause of this outbreak. The outbreak involved multiple PFGE patterns, a variety of chicken products, and 3 production establishments, suggesting a reservoir for contamination upstream from the production establishments. Sources of bacteria and genes responsible for resistance, such as farms providing birds for slaughter or environmental reservoir on farms that raise chickens, might explain how multiple PFGE patterns were linked to chicken from 3 separate production establishments and many different poultry products.

In 2010, 41 patients ill with Escherichia coli O157:H7 isolates determined to be indistinguishable by pulsed-field gel electrophoresis were identified among residents of five Southwestern U.S. states. A majority of patients reported consuming complimentary samples of aged raw-milk Gouda cheese at national warehouse chain store locations; sampling Gouda cheese was significantly associated with illness (odds ratio, 9.0; 95 % confidence interval, 1.7 to 47). Several Gouda samples yielded the O157:H7 outbreak strain, confirming the food vehicle and source of infections. Implicated retail food-sampling operations were inconsistently regulated among affected states, and sanitation deficiencies were common among sampling venues. Inspection of the cheese manufacturer indicated deficient sanitation practices and insufficient cheese curing times. Policymakers should continue to reexamine the adequacy and enforcement of existing rules intended to ensure the safety of raw-milk cheeses and retail food sampling. Additional research is necessary to clarify the food safety hazards posed to patrons who consume free food samples while shopping.

Background Monitoring disease incidence and transmission patterns is important to characterize groups at risk for hepatitis C virus (HCV) infection. Clinical cases generally represent about 20% to 30% of all newly acquired infections. Methods We used sentinel surveillance to determine incidence and transmission patterns for acute hepatitis C in the United States using data from 25 years of population-based surveillance in the general community. Acute cases of hepatitis C were identified from 1982 through 2006 by a stimulated passive surveillance system in 4 to 6 US counties. Cases were defined by a discrete onset of symptoms, alanine aminotransferase (ALT) levels greater than 2.5 times the upper limit of normal (×ULN), negative findings for serologic markers for acute hepatitis A and B, and positive findings for antibody to HCV or HCV RNA. Incidence and frequency of reported risk factors were the main outcome measures. Results Of 2075 patients identified, the median age was 31 years, 91.5% had ALT values greater than 7 × ULN, 77.3% were jaundiced, 22.5% were hospitalized, and 1.2% died. Incidence averaged 7.4 per 100 000 individuals (95% confidence interval [CI], 6.4-8.5 per 100 000) during 1982 to 1989 then declined averaging 0.7 per 100 000 (95% CI, 0.5-1.0 per 100 000) during 1994 to 2006. Among 1748 patients interviewed (84.2%), injection drug use (IDU) was the most commonly reported risk factor. The average number of IDU-related cases declined paralleling the decline in incidence, but the proportion of IDU-related cases rose from 31.8% (402 of 1266) during 1982 to 1989 to 45.6% (103 of 226) during 1994 to 2006. Among IDU-related cases reported during 1994 to 2006, 56 of 61 individuals (91.8%) had been in a drug treatment program and/or incarcerated. Conclusions The incidence of acute HCV declined substantially over the 25 years of population-based surveillance. Despite declines, IDU is the most common risk factor for new HCV infection.

Background: Three patients attending a hemodialysis unit were diagnosed with acute hepatitis C virus (HCV) infection. We investigated the scope and mode of transmission. Methods: Patients and staff were tested to determine HCV infection status; all HCV-RNA-positive sera underwent quasispecies analysis to assess genetic relatedness. Staff practices were evaluated via interviews and observations. A cohort study was performed to assess risk factors for incident HCV infection. Results: HCV infection was documented at time of hire or unit admission for 2 staff and 12 patients (prevalent case-patients). Seven (13%) of 52 patients HCV susceptible at admission to the unit subsequently acquired HCV infection (incident case-patients). Analysis of HCV quasispecies from the hyper variable region 1 identified 2 separate clusters each containing 3 incident case-patients and 1 prevalent case-patient. Incident case-patients received a higher median number of intravenous medications per dialysis session compared to susceptible patients (2.1 vs 1.8, p-value = 0.0606). Only one incident case-patient received dialysis on the same machine as their genetically related prevalent case-patient. Preparation of injection medications at the dialysis station on a mobile medication cart, and failures to clean environmental surfaces between patients were infection control breaches identified as likely modes of HCV transmission. Conclusions: Epidemiologic and laboratory data revealed transmission of HCV among patients at the same dialysis unit. Transmission was most likely related to infection control breaches. Our findings reinforce the risk of patient-to-patient HCV transmission in hemodialysis units when staff fails to adhere to recommended infection control practices.

BACKGROUND: In May 2008, PulseNet detected a multistate outbreak of Salmonella enterica serotype Saintpaul infections. Initial investigations identified an epidemiologic association between illness and consumption of raw tomatoes, yet cases continued. In mid-June, we investigated two clusters of outbreak strain infections in Texas among patrons of Restaurant A and two establishments of Restaurant Chain B to determine the outbreak's source. METHODOLOGY/PRINCIPAL FINDINGS: We conducted independent case-control studies of Restaurant A and B patrons. Patients were matched to well controls by meal date. We conducted restaurant environmental investigations and traced the origin of implicated products. Forty-seven case-patients and 40 controls were enrolled in the Restaurant A study. Thirty case-patients and 31 controls were enrolled in the Restaurant Chain B study. In both studies, illness was independently associated with only one menu item, fresh salsa (Restaurant A: matched odds ratio [mOR], 37; 95% confidence interval [CI], 7.2-386; Restaurant B: mOR, 13; 95% CI 1.3-infinity). The only ingredient in common between the two salsas was raw jalapeño peppers. Cultures of jalapeño peppers collected from an importer that supplied Restaurant Chain B and serrano peppers and irrigation water from a Mexican farm that supplied that importer with jalapeño and serrano peppers grew the outbreak strain. CONCLUSIONS/SIGNIFICANCE: Jalapeño peppers, contaminated before arrival at the restaurants and served in uncooked fresh salsas, were the source of these infections. Our investigations, critical in understanding the broader multistate outbreak, exemplify an effective approach to investigating large foodborne outbreaks. Additional measures are needed to reduce produce contamination.

INTRODUCTION: Ribavirin, with interferons or pegylated interferons, is used to treat chronic hepatitis C. Ribavirin is contraindicated in pregnancy (FDA Pregnancy Category X) and in men whose partners may become pregnant. In 2003, the Ribavirin Pregnancy Registry was established to monitor pregnancy exposures to ribavirin and to evaluate the potential human teratogenicity of prenatal exposure. METHODS: This voluntary registry enrolls pregnant women who have been exposed to ribavirin during pregnancy or during the six months prior to conception either directly, by taking ribavirin, or indirectly through sexual contact with a man taking ribavirin. Women are followed until delivery; live born infants are followed for one year. The Registry aims to enroll 131 live births following direct (maternal) exposure to ribavirin and 131 live births following indirect (male) exposures. RESULTS: After more than five years of operation, the Registry has enrolled 49 live births with direct exposure and 69 live births following indirect exposure. Six outcomes with birth defects have been reported. All were among live born infants: torticollis (2), hypospadias (1), polydactyly and a neonatal tooth (1), glucose-6-phosphate dehydrogenase deficiency (1), ventricular septal defect and cyst of 4th ventricle of the brain (1). Three received direct exposures ([6.1% (95% CI: 1.2, 16.9)], three were exposed indirectly [4.3% (95% CI: 0.9, 12.2)]. CONCLUSIONS: Although current enrollment is far short of the required sample size, preliminary findings have not detected a signal indicating human teratogenicity for ribavirin. However, findings must be interpreted with caution concerning direct or indirect prenatal ribavirin exposures. Birth Defects Research (Part A), 2010. © 2010 Wiley-Liss, Inc.

To evaluate the impact of routine hepatitis B (HB) vaccination on the prevalence of chronic hepatitis B virus (HBV) infection among children in Pacific Island countries where HBV infection was highly endemic, we conducted HB serosurveys during 2000 to 2007 among women of childbearing age born before implementation of HB vaccination and among children born after its implementation.Serum specimens were collected from children aged 2 to 6 years and their mothers in Chuuk, Federated States of Micronesia in 2000, children aged 2 to 9 years and their mothers in Pohnpei, Federated States of Micronesia in 2005, and 5- to 9-year-old children and prenatal clinic patients in 2007 in Republic of the Marshall Islands (RMI). Specimens were tested for HB surface antigen (HBsAg) and antibodies to HB core antigen (total anti-HBc). HB vaccination coverage was determined from health department vaccination registries. We defined chronic HBV infection as the presence of HBsAg.Birthdose and 3 dose HB vaccination coverage was 48% and 87%, respectively, in Chuuk, 87% and 90% in Pohnpei, and 49% and 93% in RMI. Chronic HBV infection prevalence among children was 2.5% (9/362) in Chuuk, 1.5% (7/478) in Pohnpei and 1.8% (6/331) in RMI. Chronic HBV infection prevalence among women was 9.2% (21/229) in Chuuk, 4.4% (10/229) in Pohnpei, and 9.5% (11/116) in RMI.Hepatitis B vaccination has resulted in a substantial decline in chronic infection in children in the Pacific Islands. HB vaccine effectiveness is high in this region, despite challenges in providing HB vaccine at birth and completing vaccination series on schedule.

We investigated 4 hepatitis C virus (HCV) infection outbreaks at hemodialysis units to identify practices associated with transmission. Apparent failures to follow recommended infection control precautions resulted in patient-to-patient HCV transmission, through cross-contamination of the environment or intravenous medication vials. Fastidious attention to aseptic technique and infection control precautions are essential to prevent HCV transmission.

Background: There was an increase in perinatal hepatitis B virus (HBV) infections in one Arkansas county that disproportionately affected Marshallese infants. Methods: An estimated 6000 to 10,000 Marshallese, from the Pacific island nation of the Marshall Islands where HBV is highly endemic, live in one Arkansas county. We conducted a retrospective review of hospital and health department records from 2003 to 2005 in that county. We compared maternal screening for hepatitis B surface antigen (HBsAg) between Marshallese and non-Marshallese. We also reviewed birth and immunization records for infants born to HBsAg-positive mothers to evaluate postexposure prophylaxis (PEP). Results: Ten percent (n = 41) of Marshallese births and 0.1% (n = 15) of non-Marshallese births were to HBsAg-positive women. Among those born to HBsAg-positive women, Marshallese and non-Marshallese infants were equally likely to receive PEP with hepatitis B vaccine (98% vs. 100%; P[r] = 0.98) and hepatitis B immune globulin (HBIG) ≤12 hours after birth (88% vs. 87%; P = 0.91). Approximately 57% (n = 32) of all infants born to HBsAg-positive women were tested for perinatal HBV infection. The proportion of Marshallese (17%) and non-Marshallese (13%) infants who tested positive for HBsAg at ages 9 to 25 months was similar (P = 0.78). Receiving HBIG >12 hours after birth was the only factor significantly associated with infection. Conclusions: Although HBV infection was more prevalent among Marshallese compared with non-Marshallese women, there were no differences in infant receipt of PEP and perinatal HBV infection. Delivery hospitals in this county had standing orders to administer hepatitis B vaccine to all newborns, which likely provided a safety net to prevent perinatal HBV transmission in this high-risk population.

Objective.A hospital discovered a lapse in the reprocessing procedures for transrectal ultrasound-guided prostate biopsy equipment. An investigation was initiated to assess the risks of transmission of hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and bacteria during prostate biopsies.Methods.We offered testing for HBV, HCV, and HIV infection to patients who had undergone prostate biopsies from January 30, 2003, through January 27, 2006. We reviewed their medical records and obtained information on the reprocessing procedures that were in use at the time for the prostate biopsy equipment.Setting.A healthcare facility in Maine.Results.Of the 528 patients exposed to improperly reprocessed prostate biopsy equipment, none tested positive for HIV or HCV. Sixteen patients (3%) tested positive for past HBV infection but had no prebiopsy HBV serologic test results available (ie, transmission from improperly reprocessed biopsy equipment was possible), and 11 (2%) had evidence of postbiopsy bacterial infections. The number of cases of HBV and bacterial infections were within reported ranges for this population and were not clustered in time. Review of the reprocessing procedures in use at the time revealed that the manufacturer-recommended brushes for cleaning the reusable biopsy needle guide were never used. Brushes did not come with the equipment and had to be ordered separately.Conclusions.Despite the lack of evidence of pathogen transmission in this investigation, it is critical to review the manufacturer's reprocessing recommendations and to establish appropriate procedures to avert potential pathogen transmission and subsequent patient concerns. This investigation provides a better understanding of the risks associated with improperly reprocessed transrectal ultrasound prostate biopsy equipment and serves as a methodologic tool for future investigations.