Wastewater Surveillance for Norovirus, California, USA.

Norovirus is a leading cause of acute gastroenteritis and imposes a substantial disease burden. In California, USA, norovirus surveillance is limited. We evaluated correlations between wastewater norovirus concentrations and available public health surveillance data. Wastewater surveillance for norovirus genotype GII in California provided timely, localized, and actionable data for public health authorities.

Trends of Enterovirus D68 Concentrations in Wastewater, California, USA, February 2021-April 2023.

In this retrospective study, we measured enterovirus D68 (EV-D68) genomic RNA in wastewater solids longitudinally at 2 California, USA, wastewater treatment plants twice per week for 26 months. EV-D68 RNA was undetectable except when concentrations increased from mid-July to mid-December 2022, which coincided with a peak in confirmed EV-D68 cases.

Risk Factors for Non-O157 Shiga Toxin-Producing Escherichia coli Infections, United States.

Shiga toxin-producing Escherichia coli (STEC) causes acute diarrheal illness. To determine risk factors for non-O157 STEC infection, we enrolled 939 patients and 2,464 healthy controls in a case-control study conducted in 10 US sites. The highest population-attributable fractions for domestically acquired infections were for eating lettuce (39%), tomatoes (21%), or at a fast-food restaurant (23%). Exposures with 10%-19% population attributable fractions included eating at a table service restaurant, eating watermelon, eating chicken, pork, beef, or iceberg lettuce prepared in a restaurant, eating exotic fruit, taking acid-reducing medication, and living or working on or visiting a farm. Significant exposures with high individual-level risk (odds ratio >10) among those >1 year of age who did not travel internationally were all from farm animal environments. To markedly decrease the number of STEC-related illnesses, prevention measures should focus on decreasing contamination of produce and improving the safety of foods prepared in restaurants.

Large Community Outbreak of Legionnaires Disease Potentially Associated with a Cooling Tower - Napa County, California, 2022.

Legionnaires disease is a serious infection acquired by inhalation of water droplets from human-made building water systems that contain Legionella bacteria. On July 11 and 12, 2022, Napa County Public Health (NCPH) in California received reports of three positive urinary antigen tests for Legionella pneumophila serogroup 1 in the town of Napa. By July 21, six Legionnaires disease cases had been confirmed among Napa County residents, compared with a baseline of one or two cases per year. NCPH requested assistance from the California Department of Public Health (CDPH) and CDC to aid in the investigations. Close temporal and geospatial clustering permitted a focused environmental sampling strategy of high-risk facilities which, coupled with whole genome sequencing results from samples and investigation of water system maintenance, facilitated potential linking of the outbreak with an environmental source. NCPH, with technical support from CDC and CDPH, instructed and monitored remediation practices for all environmental locations that tested positive for Legionella. The investigation response to this community outbreak illustrates the importance of interdisciplinary collaboration by public health agencies, laboratory support, timely communication with the public, and cooperation of managers of potentially implicated water systems. Timely identification of possible sources, sampling, and remediation of any facility testing positive for Legionella is crucial to interrupting further transmission.

Correlation between wastewater and COVID-19 case incidence rates in major California sewersheds across three variant periods.

Monitoring for COVID-19 through wastewater has been used for adjunctive public health surveillance, with SARS-CoV-2 viral concentrations in wastewater correlating with incident cases in the same sewershed. However, the generalizability of these findings across sewersheds, laboratory methods, and time periods with changing variants and underlying population immunity has not been well described. The California Department of Public Health partnered with six wastewater treatment plants starting in January 2021 to monitor wastewater for SARS-CoV-2, with analyses performed at four laboratories. Using reported PCR-confirmed COVID-19 cases within each sewershed, the relationship between case incidence rates and wastewater concentrations collected over 14 months was evaluated using Spearman's correlation and linear regression. Strong correlations were observed when wastewater concentrations and incidence rates were averaged (10- and 7-day moving window for wastewater and cases, respectively, ρ = 0.73-0.98 for N1 gene target). Correlations remained strong across three time periods with distinct circulating variants and vaccination rates (winter 2020-2021/Alpha, summer 2021/Delta, and winter 2021-2022/Omicron). Linear regression revealed that slopes of associations varied by the dominant variant of concern, sewershed, and laboratory (ß = 0.45-1.94). These findings support wastewater surveillance as an adjunctive public health tool to monitor SARS-CoV-2 community trends.

Estimating Relative Abundance of 2 SARS-CoV-2 Variants through Wastewater Surveillance at 2 Large Metropolitan Sites, United States.

Monitoring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) is critical for public health management of coronavirus disease. Sequencing is resource-intensive and incompletely representative, and not all isolates can be sequenced. Because wastewater SARS-CoV-2 RNA concentrations correlate with coronavirus disease incidence in sewersheds, tracking VOCs through wastewater is appealing. We developed digital reverse transcription PCRs to monitor abundance of select mutations in Alpha and Delta VOCs in wastewater settled solids, applied these to July 2020-August 2021 samples from 2 large US metropolitan sewersheds, and compared results to estimates of VOC abundance from case isolate sequencing. Wastewater measurements tracked closely with case isolate estimates (Alpha, rp 0.82-0.88; Delta, rp 0.97). Mutations were detected in wastewater even at levels <5% of total SARS-CoV-2 RNA and in samples available 1-3 weeks before case isolate results. Wastewater variant monitoring should be strategically deployed to complement case isolate sequencing.

Preliminary Incidence and Trends of Infections Caused by Pathogens Transmitted Commonly Through Food - Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2016-2021.

To evaluate progress toward prevention of enteric infections in the United States, the Foodborne Diseases Active Surveillance Network (FoodNet) conducts active population-based surveillance for laboratory-diagnosed infections caused by Campylobacter, Cyclospora, Listeria, Salmonella, Shiga toxin-producing Escherichia coli (STEC), Shigella, Vibrio, and Yersinia at 10 U.S. sites. This report summarizes preliminary 2021 data and describes changes in annual incidence compared with the average annual incidence for 2016-2018, the reference period for the U.S. Department of Health and Human Services' (HHS) Healthy People 2030 goals for some pathogens (1). During 2021, the incidence of infections caused by Salmonella decreased, incidence of infections caused by Cyclospora, Yersinia, and Vibrio increased, and incidence of infections caused by other pathogens did not change. As in 2020, behavioral modifications and public health interventions implemented to control the COVID-19 pandemic might have decreased transmission of enteric infections (2). Other factors (e.g., increased use of telemedicine and continued increase in use of culture-independent diagnostic tests [CIDTs]) might have altered their detection or reporting (2). Much work remains to achieve HHS Healthy People 2030 goals, particularly for Salmonella infections, which are frequently attributed to poultry products and produce, and Campylobacter infections, which are frequently attributed to chicken products (3).

Inadequate Refrigeration of Some Commercial Foods Is a Continued Cause of Foodborne Botulism in the United States, 1994-2021.

Foodborne botulism is a rapidly progressive potentially fatal paralyzing illness caused by the consumption of botulinum neurotoxin, which is most commonly produced by Clostridium botulinum. Refrigeration is the primary barrier to botulinum neurotoxin production in many processed foods. C. botulinum toxin production has occurred and caused botulism in the United States when foods that were not processed to destroy spores of C. botulinum were stored in an anaerobic environment and not properly refrigerated. We identified 37 cases, including 4 deaths, that occurred during 1994-2021 in the United States from 13 events associated with inadequate refrigeration of commercially produced products. In 11 events, the patient stored the product unrefrigerated at home; in 2 events, a product was kept unrefrigerated at the store before the consumer purchased it. In three events, refrigeration instructions were inadequate or not easily accessible (one label printed on outer but not inner packaging, one label not clearly visible, and one label was not in English). The number of people affected per event ranged from 1 to 16. Using enhanced cost estimates for foodborne botulism cases from a published economic model, these events were estimated to cost >$79M. Potential solutions to this recurring problem include the addition of a secondary barrier, such as an acidifier, to prevent botulinum toxin production, and better labeling to convey risks of refrigerated foods that have not been processed to destroy spores of C. botulinum and to decrease the occurrence of improper storage and handling.

Epidemiology of Brucellosis in California, 1993-2017: A Continuing Foodborne Disease Risk for Older Latinos.

BACKGROUND: Brucellosis is a severe occupational or foodborne zoonosis throughout much of the world. Although eradicated from domestic cattle in the United States, brucellosis remains a disease risk to people through acquisition and consumption of animal products from endemic countries. METHODS: Cases of human brucellosis reported through the California public health disease surveillance network were reviewed for 1993 to 2017. RESULTS: From 1993 to 2017, 492 cases of brucellosis were reported in California residents. Persons aged >65 years represented less than 20% of cases, but incidence in this age group (0.94 cases per 1 000 000 population per year) was more than twice the incidence in persons aged <19 years (0.44). Incidence was 10 to 20 times greater among Latinos compared with non-Latinos across all age groups and both sexes. Brucella melitensis was identified in 80% of patients for whom cultured Brucella were identified to the species level. Of 187 case patients who reported consuming specifically unpasteurized dairy products, more than 90% reported acquiring these products from outside of the United States, most commonly from Mexico. In the latter half of the study period (2006-2017), 73% of Latino case patients who reported consuming dairy products mentioned specifically Mexican-style soft cheese (queso fresco). CONCLUSIONS: This study underscores the continuing serious health threat of brucellosis for Latinos in California, particularly older men, and the need for targeted public health messaging on preventing the risk presented by importation and consumption of unpasteurized dairy products from outside of the United States, principally Mexico.

West Nile Virus-Associated Hospitalizations, California, 2004-2017.

BACKGROUND: West Nile virus (WNV) is the most commonly reported mosquito-borne disease in the USA. California reports more WNV disease than any other state. METHODS: We identified WNV-associated hospitalizations from 2004 through 2017 in California and estimated hospitalization incidence using Patient Discharge Data. We described demographic, geographic, and clinical characteristics of WNV hospitalizations; identified risk factors for in-hospital death; and tabulated hospitalization charges. RESULTS: From 2004 through 2017, 3109 Californians were hospitalized with WNV (median, 214 patients/year; range, 72-449). The majority were male (1983; 63.8%) and aged ≥60 years (1766; 56.8%). The highest median annual hospitalization rate (0.88 hospitalizations/100 000 persons) was in the Central Valley, followed by southern California (0.59 hospitalizations/100 000 persons). Most patients (2469; 79.4%) had ≥1 underlying condition, including hypertension, cardiovascular disease, diabetes, chronic kidney disease, or immunosuppression due to medications or disease. Median hospitalization length of stay was 12 days (interquartile range, 6-23 days). During hospitalization, 1317 (42%) patients had acute respiratory failure and/or sepsis/septic shock, 772 (24.8%) experienced acute kidney failure, and 470 (15.1%) had paralysis; 272 (8.8%) patients died. Nearly 47% (1444) of patients were discharged for additional care. During these 14 years, $838 680 664 (mean $59.9 million/year) was charged for WNV hospitalizations, 73.9% through government payers at a median charge of $142 321/patient. CONCLUSIONS: WNV-associated hospitalizations were substantial and costly in California. Hospitalization incidence was higher in males, elderly persons, and patients with underlying conditions. WNV persists as a costly and severe public health threat in California.

Coccidioidomycosis outbreak among inmate wildland firefighters: California, 2017.

BACKGROUND: In California, state prison inmates are employed to fight wildfires, which involves performing soil-disrupting work. Wildfires have become more common, including areas where Coccidioides, the soil-dwelling fungus that causes coccidioidomycosis, proliferates. However, work practices that place wildland firefighters at risk for coccidioidomycosis have not been investigated. METHODS: On August 17, 2017, the California Department of Public Health was notified of a cluster of coccidioidomycosis cases among Wildfire A inmate wildland firefighters. We collected data through medical record abstraction from suspected case-patients and mailed a survey assessing potential job task risk factors to Wildfire A inmate firefighters. We described respondent characteristics and conducted a retrospective case-control investigation to assess coccidioidomycosis risk factors. RESULTS: Among 198 inmate firefighters who worked on Wildfire A, 112 (57%) completed the survey. Of 10 case-patients (four clinical and six laboratory-confirmed), two were hospitalized. In the case-control analysis of 71 inmate firefighters, frequently cutting fire lines with a McLeod tool (odds ratio [OR]: 5.5; 95% confidence interval [CI]: 1.1-37.2) and being in a dust cloud or storm (OR: 4.3; 95% CI: 1.1-17.4) were associated with illness. Two of 112 inmate firefighters reported receiving coccidioidomycosis training; none reported wearing respiratory protection on this wildfire. CONCLUSIONS: Wildland firefighters who use hand tools and work in dusty conditions where Coccidioides proliferates are at risk for coccidioidomycosis. Agencies that employ them should provide training about coccidioidomycosis and risk reduction, limit dust exposure, and implement respiratory protection programs that specify where respirator use is feasible and appropriate.

Foodborne Botulism Outbreak Associated With Commercial Nacho Cheese Sauce From a Gas Station Market.

BACKGROUND: Botulism is a rare and potentially fatal paralytic disease caused by botulinum neurotoxin (BoNT). In April 2017, 4 California residents from 2 adjacent counties were hospitalized with suspected foodborne botulism, precipitating an investigation by state and local public health departments in California. METHODS: We interviewed suspected botulism patients and their families, inspected the suspect establishment, and collected suspect food. We tested patient sera, stool, and gastric aspirates using mouse bioassay for BoNT and/or culture for Clostridium botulinum. We tested suspect food and environmental samples for BoNT and confirmed presumptive positives using direct mouse bioassay and culture. We performed whole-genome sequencing on food and clinical isolates. RESULTS: From April 2017 through May 2017, 10 patients in the Sacramento area were hospitalized with laboratory-confirmed botulism; 7 required mechanical ventilation, and 1 died. Of 9 patients with information, all had visited Gas Station X before illness onset, where 8 reported consuming a commercial cheese sauce. BoNT/A and/or BoNT/A-producing C. botulinum were detected from each patient and from leftover cheese sauce. Clostridium botulinum isolates from 4 patients were closely related to cheese sauce isolates by whole-genome high-quality single-nucleotide polymorphism analysis. No other botulism cases associated with this cheese sauce were reported elsewhere in the United States. CONCLUSIONS: This large foodborne botulism outbreak in California was caused by consumption of commercial cheese sauce dispensed at a gas station market. The epidemiologic and laboratory evidence confirmed the cheese sauce as the outbreak source. The cheese sauce was likely locally contaminated, although the mechanism is unclear.

Valley Fever (Coccidioidomycosis) Awareness - California, 2016-2017.

Valley fever (coccidioidomycosis) is endemic in the southwestern United States and caused by inhalation of Coccidioides spp. fungal spores from soil or dust; 97% of U.S. Valley fever cases are reported from Arizona and California (1). In California, Valley fever incidence increased 213% from 2014 to 2018 (2). In 2016, the California Department of Public Health (CDPH) added three questions to the adult California Behavioral Risk Factor Surveillance System (BRFSS) survey to better understand whether Californians had heard of Valley fever, knew the environmental risk where they live, and knew who is at risk for severe disease. A total of 2,893 BRFSS respondents aged ≥18 years answered at least one Valley fever question. Using the weighted California population, 42.4% of respondents reported general awareness of Valley fever; awareness was lowest among adults aged 18-44 years (32.9%) and Hispanic persons (26.4%). In addition, despite higher percentages reporting awareness of Valley fever, only 25.0% of persons living in a high-incidence region and 3.0% of persons living in a moderate-incidence region were aware that they lived in areas where Coccidioides spp. exist. Among persons with one or more risk factors for severe disease, 50.8% reported having heard about Valley fever, but only 3.5% knew they were at increased risk for severe disease. The findings from this survey helped to inform a statewide Valley fever awareness campaign implemented during 2019-2020 and to guide outreach to persons living in high- and moderate-incidence regions in California and potentially other southwestern states or who are at risk for severe disease.

Preliminary Incidence and Trends of Infections with Pathogens Transmitted Commonly Through Food - Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2016-2019.

To evaluate progress toward prevention of enteric illnesses, the Foodborne Diseases Active Surveillance Network (FoodNet) of CDC's Emerging Infections Program monitors the incidence of laboratory-diagnosed infections caused by eight pathogens transmitted commonly through food at 10 U.S. sites.* This report summarizes preliminary 2019 data and describes changes in incidence compared with that during 2016-2018. The incidence of enteric infections caused by these eight pathogens reported by FoodNet sites in 2019 continued to increase or remained unchanged, indicating progress in controlling major foodborne pathogens in the United States has stalled. Campylobacter and Salmonella caused the largest proportion of illnesses; trends in incidence varied by Salmonella serotype. Widespread adoption of whole genome sequencing (WGS) of bacteria has improved the ability to identify outbreaks, emerging strains, and sources of pathogens. To maximize the potential of WGS to link illnesses to particular sources, testing of isolates by clinical and public health laboratories is needed. Reductions in Salmonella serotype Typhimurium suggest that targeted interventions (e.g., vaccinating chickens and other food animals) might decrease human infections. Reducing contamination during food production, processing, and preparation will require more widespread implementation of known prevention measures and of new strategies that target particular pathogens and serotypes.

Preliminary Incidence and Trends of Infections with Pathogens Transmitted Commonly Through Food - Foodborne Diseases Active Surveillance Network, 10 U.S. Sites, 2015-2018.

Foodborne diseases represent a major health problem in the United States. The Foodborne Diseases Active Surveillance Network (FoodNet) of CDC's Emerging Infections Program monitors cases of laboratory-diagnosed infection caused by eight pathogens transmitted commonly through food in 10 U.S. sites.* This report summarizes preliminary 2018 data and changes since 2015. During 2018, FoodNet identified 25,606 infections, 5,893 hospitalizations, and 120 deaths. The incidence of most infections is increasing, including those caused by Campylobacter and Salmonella, which might be partially attributable to the increased use of culture-independent diagnostic tests (CIDTs). The incidence of Cyclospora infections increased markedly compared with 2015-2017, in part related to large outbreaks associated with produce (1). More targeted prevention measures are needed on produce farms, food animal farms, and in meat and poultry processing establishments to make food safer and decrease human illness.

Epidemiology of coccidioidomycosis among children in California, 2000-2016.

We calculated population-based incidence of coccidioidomycosis from the 2000-2016 California surveillance data and compared children (≤17 years) with adults (≥18 years). During that time, the annual pediatric incidence per 100,000 increased from 0.8 in 2000 to 5.2 in 2016, while the adult annual rate increased from 3.2 in 2000 to 16.2 in 2016. Pediatric incidence was higher among children in the 12-17-year age group and among residents of endemic counties. Rates by sex were similar from infancy until adolescence when rates in males became substantially higher than females and remained so into older age; reasons for this are unclear.

Occupational coccidioidomycosis surveillance and recent outbreaks in California.

Workers in Coccidioides-endemic areas performing soil-disturbing work or exposed to windy and dusty conditions are at increased risk for coccidioidomycosis. Four occupational coccidioidomycosis outbreaks from 2007 to 2014 in California are described, involving construction workers in a number of excavation projects and an outdoor filming event involving cast and crew. These outbreaks highlight the importance of identifying industries and occupations at high risk for coccidioidomycosis, conducting targeted occupational health surveillance to assess the burden of illness, developing and implementing prevention strategies, and setting research priorities.

Molecular typing of clinical and environmental isolates of Cryptococcus gattii species complex from southern California, United States.

BACKGROUND: Two species complexes (SC) cause the majority of human Cryptococcus infections: Cryptococcus neoformans SC and Cryptococcus gattii SC. Infection is typically thought to be acquired following environmental exposure. In an urban setting, parks and other public spaces are a likely source of contact with C. gattii SC. OBJECTIVES: The goals of this study were to describe the genetic diversity of C. gattii SC in the California environment, to determine the extent of environmental exposure in publicly accessed areas and to correlate the genotypes of environmental C. gattii SC isolates with those from patients in southern California. METHODS: Specimens from trees and soil from 13 parks and public areas of seven California counties were examined for C. gattii SC isolates. Isolates were sequence typed and compared to sequence types from human clinical isolates from the same area. RESULTS: Multilocus sequence typing identified C. gattii sensu stricto (VGI molecular type) as well as Cryptococcus bacillisporus (VGIII molecular type). Several C. bacillisporus but none of the C. gattii sensu stricto isolates shared sequence types with human clinical isolates from southern California. CONCLUSIONS: C. gattii SC colonies exist in some California public parks. The presence of identical STs in environmental and human isolates of C. bacillisporus is suggestive of an arboreal origin of human infections. Two new tree species were documented as hosts for C. gattii SC in California, adding to the four species previously identified.

Differences Among Incidence Rates of Invasive Listeriosis in the U.S. FoodNet Population by Age, Sex, Race/Ethnicity, and Pregnancy Status, 2008-2016.

Listeria monocytogenes is a foodborne pathogen that disproportionally affects pregnant females, older adults, and immunocompromised individuals. Using U.S. Foodborne Diseases Active Surveillance Network (FoodNet) surveillance data, we examined listeriosis incidence rates and rate ratios (RRs) by age, sex, race/ethnicity, and pregnancy status across three periods from 2008 to 2016, as recent incidence trends in U.S. subgroups had not been evaluated. The invasive listeriosis annual incidence rate per 100,000 for 2008-2016 was 0.28 cases among the general population (excluding pregnant females), and 3.73 cases among pregnant females. For adults ≥70 years, the annual incidence rate per 100,000 was 1.33 cases. No significant change in estimated listeriosis incidence was found over the 2008-2016 period, except for a small, but significantly lower pregnancy-associated rate in 2011-2013 when compared with 2008-2010. Among the nonpregnancy-associated cases, RRs increased with age from 0.43 (95% confidence interval: 0.25-0.73) for 0- to 14-year olds to 44.9 (33.5-60.0) for ≥85-year olds, compared with 15- to 44-year olds. Males had an incidence of 1.28 (1.12-1.45) times that of females. Compared with non-Hispanic whites, the incidence was 1.57 (1.18-1.20) times higher among non-Hispanic Asians, 1.49 (1.22-1.83) among non-Hispanic blacks, and 1.73 (1.15-2.62) among Hispanics. Among females of childbearing age, non-Hispanic Asian females had 2.72 (1.51-4.89) and Hispanic females 3.13 (2.12-4.89) times higher incidence than non-Hispanic whites. We observed a higher percentage of deaths among older patient groups compared with 15- to 44-year olds. This study is the first characterizing higher RRs for listeriosis in the United States among non-Hispanic blacks and Asians compared with non-Hispanic whites. This information for public health risk managers may spur further research to understand if differences in listeriosis rates relate to differences in consumption patterns of foods with higher contamination levels, food handling practices, comorbidities, immunodeficiencies, health care access, or other factors.