About

I'm an Assistant Professor at the University of California San Diego in the Herbert Wertheim School of Public Health and Human Longevity Sciences. My research focuses on the relationships between climate change and human health.

Research topics

• Internal medicine
• Medicine
• Environmental health
• Meteorology
• Environmental science
• Intensive care medicine
• Immunology
• Ecology
• Geography

Selected publications

• Regional Increases in Incidence of Coccidioidomycosis (Valley Fever) — Arizona, 2005–2022

  MMWR Morbidity and Mortality Weekly Report · 2026-02-19 · 1 citations

  articleOpen access

  Incidence of coccidioidomycosis (Valley fever), a fungal infection caused by inhalation of Coccidioides species spores, has increased substantially across the southwestern United States in association with increasing aridity, warming temperatures, and precipitation volatility.Arizona and California report >95% of U.S. coccidioidomycosis cases, and incidence in Arizona has increased statewide.Patterns within Arizona's distinct climatological regions have not been characterized, especially in regions outside the known zone of persistently high levels of disease occurrence (hyperendemicity) in the southwest Sonoran Desert region.In this study, surveillance data reported to the Arizona Department of Health Services since 2005 were used to calculate coccidioidomycosis incidence within six ecological regions.During 2005-2022, annual incidence approximately doubled in Arizona, with >95% of cases reported from the Sonoran Desert region.Although the Plateaus and Mojave Desert regions (in the northern parts of the state) reported <1.5% of Arizona cases during this period, these regions experienced the highest relative increases in incidence from the 2005-2007 period to the 2020-2022 period.During 2020-2022, coccidioidomycosis incidence in the Plateaus region was 6.61 times the incidence during 2005-2007 (95% CI = 4.22-10.30),and in the Mojave Desert region, incidence was 4.50 times that during 2005-2007 (95% CI = 3.45-5.89).The Plateau and Mojave regions also reported the highest relative increases in incidence from the 2014-2016 period to the 2020-2022 period.Large relative incidence increases in northern regions, including cooler and wetter regions generally considered less suitable for Coccidioides species establishment and transmission, necessitate targeted public health messaging in these areas and support ongoing investigation into the causes of these increases.* Based on the earliest date among the following: symptom onset, specimen collected for laboratory testing, laboratory test results finalized for a specimen, diagnosis, case reported to the county, entered into the Medical Electronic Disease Surveillance Intelligence System (MEDSIS), reported to ADHS, or submitted to the state.Event date definitions are outlined in Arizona Department of Health Services' User Training Guide | MEDSIS.

  PublisherOA PDFDOI

• A global research and evaluation agenda for centering health and equity in city Climate Action Plans

  PLOS Climate · 2026-04-15

  articleOpen access

  City climate policy is one of the most powerful levers that can address environmental, health and equity challenges simultaneously. Yet large gaps exist in research and evaluation of city Climate Action Plans (CAPs) to guide and improve their impact, especially regarding public health and equity. We propose a conceptual framework and a global, interdisciplinary research agenda to ensure CAPs deliver on their full potential for climate, health, and justice.

  PublisherDOI

• Temperature extremes impact mortality and morbidity differently

  Science Advances · 2025-07-30 · 15 citations

  articleOpen access

  Increased temperature-related mortality is expected to significantly contribute to future economic damages from climate change, with declines in cold-related deaths outweighed by increases in heat-related deaths. While temperature-mortality relationships are well-documented, the effects of climate change on morbidity are less understood. Using data on emergency department (ED) visits, hospital admissions, mortality, and daily temperatures across California from 2006 to 2017, we find distinct differences in the temperature-response functions of these health outcomes, influenced by age distribution and underlying causes of morbidity and mortality. These differential responses fundamentally shape the burden of future climate change: We project that while future warming will increase ED visits, mortality will decrease due to fewer cold extremes. These results underscore the need to quantify temperature-morbidity responses to fully understand and anticipate the health impacts of climate change and suggest that local declines in mortality due to warming can mask economically meaningful increases in temperature-driven morbidity and health care utilization.

  PublisherDOI

• Prolonged coccidioidomycosis transmission seasons in a warming California: a Markov state transition model of shifting disease dynamics

  Journal of The Royal Society Interface · 2025-02-01 · 5 citations

  articleOpen access

  Coccidioidomycosis, an emerging fungal disease in the southwestern United States, exhibits pronounced seasonal transmission, yet the influence of current and future climate on the timing and duration of transmission seasons remains poorly understood. We developed a distributed-lag Markov state transition model to estimate the effects of temperature and precipitation on the timing of transmission season onset and end, analysing reported coccidioidomycosis cases ( n = 72 125) in California from 2000 to 2023. Using G-computation substitution estimators, we examined how hypothetical changes in seasonal meteorology impact transmission season timing. Transitions from cooler, wetter conditions to hotter, drier conditions were found to significantly accelerate season onset. Dry conditions (10th percentile of precipitation) in the spring shifted season onset an average of 2.8 weeks (95% CI: 0.43–3.58) earlier compared with wet conditions (90th percentile of precipitation). Conversely, transitions back to cooler, wetter conditions hastened season end, with dry autumn conditions extending the season by an average of 0.69 weeks (95% CI: 0.37–1.41) compared with wet conditions. When dry conditions occurred in the spring and autumn, the transmission season extended by 3.70 weeks (95% CI: 1.23–4.22). With prolonged dry seasons expected in California with climate change, our findings suggest this shift will extend the period of elevated coccidioidomycosis risk.

  PublisherOA PDFDOI

• Estimating the Exposure–Response Relationship between Fine Mineral Dust Concentration and Coccidioidomycosis Incidence Using Speciated Particulate Matter Data: A Longitudinal Surveillance Study

  Environmental Health Perspectives · 2025-01-01 · 12 citations

  articleOpen access

  BACKGROUND: spp. spores, is an emerging infectious disease that is increasing in incidence throughout the southwestern US. The pathogen is soil-dwelling, and spore dispersal and human exposure are thought to co-occur with airborne mineral dust exposures, yet fundamental exposure-response relationships have not been conclusively estimated. OBJECTIVES: We estimated associations between fine mineral dust concentration and coccidioidomycosis incidence in California from 2000 to 2017 at the census tract level, spatiotemporal heterogeneity in exposure-response, and effect modification by antecedent climate conditions. METHODS: We acquired monthly census tract-level coccidioidomycosis incidence data and modeled fine mineral dust concentrations from 2000 to 2017. We fitted zero-inflated distributed-lag nonlinear models to estimate overall exposure-lag-response relationships and identified factors contributing to heterogeneity in exposure-responses. Using a random-effects meta-analysis approach, we estimated county-specific and pooled exposure-responses for cumulative exposures. RESULTS: (95% CI: 1.04, 1.12)] months before estimated disease onset, with the highest exposures being particularly associated. The cumulative exposure-response relationship varied significantly by county [lowest IRR, western Tulare: 1.05 (95% CI: 0.54, 2.07); highest IRR, San Luis Obispo: 3.01 (95% CI: 2.05, 4.42)]. Season of exposure and prior wet winter were modest effect modifiers. DISCUSSION: Lagged exposures to fine mineral dust were strongly associated with coccidioidomycosis incidence in the endemic regions of California from 2000 to 2017. https://doi.org/10.1289/EHP13875.

  PublisherDOI

• Choice of Downscaled Climate Product Matters: Projections of Valley Fever Seasonality in a Warming Climate

  GeoHealth · 2025-12-31

  articleOpen access

  Downscaled climate projections provide valuable information needed to better understand the impacts of climate change on health outcomes and to inform adaptation and mitigation strategies at local to regional scales. Because downscaled climate products vary in their representations of fine-scale spatiotemporal patterns, due to of multiple interacting factors, epidemiologic analyses need to consider how differences across downscaling approaches impact projections of health impacts into the future. We evaluate the projected seasonality of coccidioidomycosis in response to projected temperature and precipitation estimated using global climate models from CMIP6 included in California's Fifth Climate Change Assessment, downscaled using two approaches: (a) dynamical downscaling using the Weather Research and Forecasting model; and (b) hybrid statistical downscaling using the Localized Constructed Analogs approach. Our results indicate that by end of century, coccidioidomycosis transmission is projected to start earlier, end later, and last longer across the California endemic region; however, the magnitude of these changes varies by downscaling method. Specifically, LOCA2-hybrid projected a season onset that is 4.2 weeks earlier and an end that is 4.1 weeks later than historical conditions, while the dynamical approach projected a 4 week earlier onset and a 3.8 week later end compared to the historical period. Overall, the LOCA2-hybrid product estimates that the transmission season will last about 0.3 weeks longer than what is projected using dynamical downscaling by end of century. This analysis highlights the sensitivity of coccidioidomycosis seasonality projections to choice of downscaling product, underscoring the need to account for these differences in mitigation and adaptation planning.

  PublisherOA PDFDOI

• Recent and Forecasted Increases in Coccidioidomycosis Incidence Linked to Hydroclimatic Swings, California, USA

  Emerging infectious diseases · 2025-03-18 · 12 citations

  articleOpen access

  In 2023, California reported near-record high coccidioidomycosis cases after a dramatic transition from drought to heavy precipitation. Using an ensemble model, we forecasted 12,244 cases statewide during April 1, 2024-March 31, 2025, a 62% increase over cases reported 2 years before and on par with case counts for 2023.

  PublisherDOI

• Fallowed agricultural lands dominate anthropogenic dust sources in California

  Communications Earth & Environment · 2025-04-26 · 10 citations

  articleOpen access

  Abstract Air pollution remains a major problem in many parts of California, significantly impacting public health and regional climate. However, the contribution of anthropogenic dust from agricultural sources, among major pollutants in California’s semi-arid Central Valley, remains largely unclear. Here, we used the Cropland Data Layer from the U.S. Department of Agriculture to identify crop types and land use/cover and leveraged satellite-derived estimates of major dust events between 2008 and 2022 over California. We identified fallowed land—an unplanted agricultural land parcel—as a key anthropogenic dust source in California. Specifically, we find that the Central Valley accounts for about 77% of total fallowed land areas in California, where they are associated with about 88% of major anthropogenic dust events. We also find that the geographic coverage of these fallowed lands expanded between 2008 and 2022 with associated increasing anthropogenic dust activities. Additionally, these anthropogenic dust activities are sensitive to the drought severity over the fallowed lands, with potential cumulative effects on downstream dust burden during prolonged multi-year drought conditions. Overall, our results have important implications for public health, including increased risk for Valley fever and for regional climates, such as increases in extreme precipitation and snowmelt over the Sierra Nevada.

  PublisherOA PDFDOI

• Geographic Differences in Asthma ED Visit Hot Spots In Children Compared to Adults

  Journal of Allergy and Clinical Immunology · 2025-02-01

  articleOpen access
  PublisherOA PDFDOI

• Coccidioidomycosis seasonality in California: climate determinants and spatiotemporal variability of seasonal dynamics, 2000-2021

  ISEE Conference Abstracts · 2024-07-31

  articleOpen access1st authorCorresponding

  Author(s): Heaney, Alexandra K; Campo, Simon K; Head, Jennifer R; Collender, Phillip; Weaver, Amanda; Sondermeyer Cooksey, Gail; Yu, Alexander; Jain, Seema; Vugia, Duc; Bhattachan, Abinash; Taylor, John; Remais, Justin V

  PublisherDOI

Frequent coauthors

• Justin V. Remais

  University of California, Berkeley

  22 shared

• Jennifer R. Head

  University of Michigan–Ann Arbor

  16 shared

• John W. Taylor

  10 shared

• Jia Coco Liu

  Meta (United States)

  10 shared

• Sophie Phillips

  9 shared

• Jon Zelner

  University of Michigan–Ann Arbor

  9 shared

• Philip A. Collender

  University of California, Berkeley

  9 shared

• Duc J. Vugia

  8 shared

Education

• PhD, Environmental Health Sciences

  Columbia University Mailman School of Public Health

  2019

• BA, Human Biology

  Stanford University

  2014