Effects of precipitation, heat, and drought on incidence and expansion of coccidioidomycosis in western USA: a longitudinal surveillance study.

BACKGROUND: Drought is an understudied driver of infectious disease dynamics. Amidst the ongoing southwestern North American megadrought, California (USA) is having the driest multi-decadal period since 800 CE, exacerbated by anthropogenic warming. In this study, we aimed to examine the influence of drought on coccidioidomycosis, an emerging infectious disease in southwestern USA. METHODS: We analysed California census tract-level surveillance data from 2000 to 2020 using generalised additive models and distributed monthly lags on precipitation and temperature. We then developed an ensemble prediction algorithm of incident cases of coccidioidomycosis per census tract to estimate the counterfactual incidence that would have occurred in the absence of drought. FINDINGS: Between April 1, 2000, and March 31, 2020, there were 81 448 reported cases of coccidioidomycosis throughout California. An estimated 1467 excess cases of coccidioidomycosis were observed in California in the 2 years following the drought that occurred between 2007 and 2009, and an excess 2649 drought-attributable cases of coccidioidomycosis were observed in the 2 years following the drought that occurred between 2012 and 2015. These increased numbers of cases more than offset the declines in cases that occurred during drought. An IQR increase in summer temperatures was associated with 2·02 (95% CI 1·84-2·22) times higher incidence in the following autumn (September to November), and an IQR increase in precipitation in the winter was associated with 1·45 (1·36-1·55) times higher incidence in the autumn. The effect of winter precipitation was 36% (25-48) stronger when preceded by two dry, rather than average, winters. Incidence in arid counties was most sensitive to precipitation fluctuations, while incidence in wetter counties was most sensitive to temperature. INTERPRETATION: In California, multi-year cycles of dry conditions followed by a wet winter increases transmission of coccidioidomycosis, especially in historically wetter areas. With anticipated increasing frequency of drought in southwestern USA, continued expansion of coccidioidomycosis, along with more intense seasons, is expected. Our results motivate the need for heightened precautions against coccidioidomycosis in seasons that follow major droughts. FUNDING: National Institutes of Health.

Regional Analysis of Coccidioidomycosis Incidence - California, 2000-2018.

Coccidioidomycosis (Valley fever) is an infection caused by the soil-dwelling fungus Coccidioides spp., which usually manifests as a mild self-limited respiratory illness or pneumonia but can result in severe disseminated disease and, rarely, death (1,2). In California, coccidioidomycosis incidence increased nearly 800% from 2000 (2.4 cases per 100,000 population) to 2018 (18.8) (2-4). The California Department of Public Health (CDPH) reports statewide and county-level coccidioidomycosis incidence annually; however, a comprehensive regional analysis has not been conducted. Using California coccidioidomycosis surveillance data during 2000-2018, age-adjusted incidence rates were calculated, and coccidioidomycosis epidemiology was described in six regions. During 2000-2018, a total of 65,438 coccidioidomycosis cases were reported in California; median statewide annual incidence was 7.9 per 100,000 population and varied by region from 1.1 in Northern and Eastern California to 90.6 in the Southern San Joaquin Valley, with the largest increase (15-fold) occurring in the Northern San Joaquin Valley. When analyzing demographic data, which was available for >99% of cases for sex and age and 59% of cases for race/ethnicity, median annual incidence was high among males (10.2) and Black persons (9.0) consistently across all regions; however, incidence varied among Hispanics and adults aged 40-59 years by region. Tracking these surveillance data at the regional level reinforced understanding of where and among what demographic groups coccidioidomycosis rates have been highest and revealed where rates are increasing most dramatically. The results of this analysis influenced the planning of a statewide coccidioidomycosis awareness campaign so that the messaging, including social media and TV and radio segments, focused not only on the general population in the areas with the highest rates, but also in areas where coccidioidomycosis is increasing at the fastest rates and with messaging targeted to groups at highest risk in those areas.

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.

Rapid Sentinel Surveillance for COVID-19 - Santa Clara County, California, March 2020.

On February 27, 2020, the Santa Clara County Public Health Department (SCCPHD) identified its first case of coronavirus disease 2019 (COVID-19) associated with probable community transmission (i.e., infection among persons without a known exposure by travel or close contact with a patient with confirmed COVID-19). At the time the investigation began, testing guidance recommended focusing on persons with clinical findings of lower respiratory illness and travel to an affected area or an epidemiologic link to a laboratory-confirmed COVID-19 case, or on persons hospitalized for severe respiratory disease and no alternative diagnosis (1). To rapidly understand the extent of COVID-19 in the community, SCCPHD, the California Department of Public Health (CDPH), and CDC began sentinel surveillance in Santa Clara County. During March 5-14, 2020, four urgent care centers in Santa Clara County participated as sentinel sites. For this investigation, county residents evaluated for respiratory symptoms (e.g., fever, cough, or shortness of breath) who had no known risk for COVID-19 were identified at participating urgent care centers. A convenience sample of specimens that tested negative for influenza virus was tested for SARS-CoV-2 RNA. Among 226 patients who met the inclusion criteria, 23% had positive test results for influenza. Among patients who had negative test results for influenza, 79 specimens were tested for SARS-CoV-2, and 11% had evidence of infection. This sentinel surveillance system helped confirm community transmission of SARS-CoV-2 in Santa Clara County. As a result of these data and an increasing number of cases with no known source of transmission, the county initiated a series of community mitigation strategies. Detection of community transmission is critical for informing response activities, including testing criteria, quarantine guidance, investigation protocols, and community mitigation measures (2). Sentinel surveillance in outpatient settings and emergency departments, implemented together with hospital-based surveillance, mortality surveillance, and serologic surveys, can provide a robust approach to monitor the epidemiology of COVID-19.

Surveillance for Coccidioidomycosis - United States, 2011-2017.

PROBLEM/CONDITION: Coccidioidomycosis (Valley fever) is an infection caused by the environmental fungus Coccidioides spp., which typically causes respiratory illness but also can lead to disseminated disease. This fungus typically lives in soils in warm, arid regions, including the southwestern United States. REPORTING PERIOD: 2011-2017. DESCRIPTION OF SYSTEM: Coccidioidomycosis has been nationally notifiable since 1995 and is reportable in 26 states and the District of Columbia (DC), where laboratories and physicians notify local and state public health departments about possible coccidioidomycosis cases. Health department staff determine which cases qualify as confirmed cases according to the definition established by Council of State and Territorial Epidemiologists and voluntarily submit basic case information to CDC through the National Notifiable Diseases Surveillance System. RESULTS: During 2011-2017, a total of 95,371 coccidioidomycosis cases from 26 states and DC were reported to CDC. The number of cases decreased from 2011 (22,634 cases) to 2014 (8,232 cases) and subsequently increased to 14,364 cases in 2017; >95% of cases were reported from Arizona and California. Reported incidence in Arizona decreased from 261 per 100,000 persons in 2011 to 101 in 2017, whereas California incidence increased from 15.7 to 18.2, and other state incidence rates stayed relatively constant. Patient demographic characteristics were largely consistent with previous years, with an overall predominance among males and among adults aged >60 years in Arizona and adults aged 40-59 years in California. INTERPRETATION: Coccidioidomycosis remains an important national public health problem with a well-established geographic focus. The reasons for the changing trends in reported cases are unclear but might include environmental factors (e.g., temperature and precipitation), surveillance artifacts, land use changes, and changes in the population at risk for the infection. PUBLIC HEALTH ACTION: Health care providers should consider a diagnosis of coccidioidomycosis in patients who live or work in or have traveled to areas with known geographic risk for Coccidioides and be aware that those areas might be broader than previously recognized. Coccidioidomycosis surveillance provides important information about the epidemiology of the disease but is incomplete both in terms of geographic coverage and data availability. Expanding surveillance to additional states could help identify emerging areas that pose a risk for locally acquired infections. In Arizona and California, where most cases occur, collecting systematic enhanced data, such as more detailed patient characteristics and disease severity, could help clarify the reasons behind the recent changes in incidence and identify additional opportunities for focused prevention and educational efforts.

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.

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.

Update on the Epidemiology of coccidioidomycosis in the United States.

The incidence of reported coccidioidomycosis in the past two decades has increased greatly; monitoring its changing epidemiology is essential for understanding its burden on patients and the healthcare system and for identifying opportunities for prevention and education. We provide an update on recent coccidioidomycosis trends and public health efforts nationally and in Arizona, California, and Washington State. In Arizona, enhanced surveillance shows that coccidioidomycosis continues to be associated with substantial morbidity. California reported its highest yearly number of cases ever in 2016 and has implemented interventions to reduce coccidioidomycosis in the prison population by excluding certain inmates from residing in prisons in high-risk areas. Coccidioidomycosis is emerging in Washington State, where phylogenetic analyses confirm the existence of a unique Coccidioides clade. Additional studies of the molecular epidemiology of Coccidioides will improve understanding its expanding endemic range. Ongoing public health collaborations and future research priorities are focused on characterizing geographic risk, particularly in the context of environmental change; identifying further risk reduction strategies for high-risk groups; and improving reporting of cases to public health agencies.

Pediatric Coccidioidomycosis: Case Series From a California Pediatric Infectious Diseases Clinic.

BACKGROUND: Coccidioidomycosis is not as well described in the pediatric population as it is in the adult population. We describe clinical findings, diagnosis and management of coccidioidomycosis in 108 pediatric patients seen in an outpatient clinic in the California Central Valley, an area endemic for coccidioidomycosis. METHODS: We reviewed medical records of a convenience sample of pediatric patients (≤17 years of age) diagnosed with coccidioidomycosis who visited an infectious diseases clinic in Madera, CA, during January 1 to October 1, 2012. We described demographic characteristics, symptoms, diagnostic testing, extent of infection (acute/pulmonary or disseminated), treatment and management. RESULTS: Of 108 patients, 90 (83%) had acute/pulmonary coccidioidomycosis and 18 (17%) had disseminated disease. The median age at diagnosis was 9 years (range, 5 months to 17 years). Only 3 (3%) patients were immunocompromised. Before coccidioidomycosis diagnosis, 72 (82%) patients received antibiotics, and 31 (29%) had at least 1 negative coccidioidomycosis serology at the time of or before diagnosis. Coccidioidomycosis was diagnosed significantly later after symptom onset among patients with disseminated (median, 57 days) than with acute/pulmonary (median, 16 days) disease (p < 0.01). A total of 104 (96%) patients received antifungal therapy, 51 (47%) visited an emergency room and 59 (55%) were hospitalized with a median stay of 44 days (range, 1-272 days). CONCLUSIONS: Substantial acute/pulmonary and disseminated coccidioidomycosis was seen among pediatric patients at this infectious disease clinic in California. In endemic areas, increased coccidioidomycosis awareness and vigilance among families and providers is necessary to facilitate early diagnosis and appropriate management.

Dust Exposure and Coccidioidomycosis Prevention Among Solar Power Farm Construction Workers in California.

OBJECTIVES: To investigate if work activities, dust exposure, and protection measures were associated with a 2011 to 2014 coccidioidomycosis outbreak among workers constructing 2 solar farms in California. METHODS: In 2013, we mailed self-administered questionnaires to employees who were onsite at the solar farms where the outbreak occurred to identify cases of clinical coccidioidomycosis and compare with asymptomatic workers by using multivariate logistic regression. RESULTS: When we compared 89 workers with clinical coccidioidomycosis to 325 asymptomatic workers, frequently being in a dust cloud or storm (odds ratio [OR] = 5.93; 95% confidence interval [CI] = 3.18, 11.06) significantly increased the odds of clinical coccidioidomycosis, whereas frequently wetting soil before soil-disturbing activity (OR = 0.42; 95% CI = 0.24, 0.75) was protective. When we controlled for being in a dust cloud or storm, frequent soil disturbance significantly increased the odds of clinical coccidioidomycosis only among those who reported wearing a respirator infrequently (OR = 2.31; 95% CI = 1.27, 4.21). CONCLUSIONS: Utilization of personal and employer-driven safety practices and increased coccidioidomycosis awareness among construction workers should be considered during the planning of any construction work in coccidioidomycosis-endemic regions to prevent occupational infections and outbreaks.