Heidi Brown

The University of Arizona | UA · Division of Epidemiology and Biostatistics

Helicobacter pylori (H. pylori) is a common bacterial infection linked to gastric malignancies. While H. pylori infection and gastric cancer rates are decreasing, antibiotic resistance varies greatly by community. Little is known about resistance rates among rural Indigenous populations in the United States. From 2018 to 2021, 396 endoscopy patient...

Climate change is a major threat to human health, however the role of health in climate change communication is understudied. The goal of this study was to understand how to support individuals’ adoption of climate related mitigation and adaptation activities. We hypothesized the primary motivation for engaging in pro-environmental activities would...

Helicobacter pylori (H. pylori) is a common bacterial infection linked to gastric malignancies. While H. pylori infection and gastric cancer rates are decreasing, antibiotic resistance varies greatly by community. Little is known about resistance rates among rural Indigenous populations in the United States. From 2018 to 2021, 396 endoscopy patient...

Land surface temperature (LST) estimates often serve as urban heat islands maps and to infer human thermal comfort. Parallel to this, physiological heat balance calculations have been well documented to measure changes in body core temperature and measure risk of heat-related illness. However, there is a need for an improved spatially explicit meth...

Little is known about the epidemiology of Merkel cell carcinoma (MCC) and mucosal melanoma (MM). Using the United States (US) National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program data, we compared MCC and MM with cutaneous malignant melanoma (CMM) with respect to incidence rates and prognostic factors to better und...

Background: Helicobacter pylori (Hp) is among the most common bacterial infections in the world and one of the most common infectious agents linked to malignancy, gastric cancer (GC). Within the US there is high disparity in the rates of Hp infection and associated diseases. Hp infection is treatable, and knowledge may influence screening and trea...

Plasmodium vivax and Plasmodium falciparum cases have opposite trends in Anhui China in the past decade. Long term and seasonal trends in the transmission rate of P. falciparum in Africa has been well studied, however that of P. vivax transmitted by Anopheles sinensis in China has not been investigated. There is a lot of work on the relationship be...

It is unclear how disaster events, which are expected to increase due to climate change, will affect animal care services. Understanding the impacts they have on cat and dog populations, and how to integrate animal welfare into disaster preparedness, can facilitate disaster response and improve population health outcomes. Federal Emergency Manageme...

Using a global warming audience segmentation tool (Six Americas Super Short Survey (SASSY)) as a case study, we consider how public health can use consumer panels and online crowdsourcing markets (OCMs) in research. Through a secondary analysis, we aim to understand how consumer panels and OCMs are similar to or different from each other on demogra...

The yellow fever mosquito, Aedes aegypti, is a growing global concern. An ecological parameter necessary for vector control is the dispersal, or flight range, of mosquito vectors. Information on mosquito dispersal supports identifying optimal sampling and control strategies to limit the invasion of adult mosquitoes. Attempts around the world to und...

Green stormwater infrastructure provides environmental, economic, and health benefits as a strategy for building resilience against climate change impacts. However, it may inadvertently increase vulnerability due to improper design and construction or lack of maintenance. We engaged city stakeholders and a diverse student group to investigate possi...

Background: In Arizona Helicobacter pylori prevalence of infection among Navajo adults is about 62% and gastric cancer incidence rate is 3-4 times higher than that of the non-Hispanic White population. Aim: The aim of this study was to estimate the prevalence of specific H. pylori virulence factors (cagA and vacA) among Navajo patients undergoin...

Background: In Arizona Helicobacter pylori prevalence of infection among Navajo adults is about 62% and gastric cancer incidence rate is 3-4 times higher than that of the non-Hispanic White population. Aim: The aim of this study was to estimate the prevalence of specific H. pylori virulence factors (cagA and vacA) among Navajo patients undergoing a...

Intermittent sun exposure is the major environmental risk factor for cutaneous melanoma (CM). Cumulative sun exposure and other environmental agents, such as environmental arsenic exposure, have not shown consistent associations. Ambient ultraviolet radiation (UVR) was used to measure individual total sun exposure as this is thought to be less pron...

Purpose: Human papillomavirus (HPV) is a common sexually transmitted infection that is strongly associated with cervical cancer. A link to penile cancers has been suggested by case series. We sought to assess the strength of the association between HPV infection and penile cancer by meta-analysis. Methods: A literature search to identify populat...

Helicobacter pylori (H. pylori) is one of the most common bacterial stomach infections and is implicated in a majority of non-cardia gastric cancer. While gastric cancer has decreased in the United States (US), the incidence in the Navajo Nation is nearly four times higher than surrounding Non-Hispanic White populations. Little is known about H. py...

Trypanosoma cruzi infection leads to Chagas disease (CD), a neglected tropical infection of significant public health importance in South and Central America and other, non-endemic, countries. Pregnant women and their children are of particular importance to screen as T. cruzi can be transmitted vertically. The objective of this study was to screen...

The COVID-19 pandemic and measures against it provided a unique opportunity to understand the transmission of other infectious diseases and to evaluate the efficacy of COVID-19 prevention measures on them. Here we show a dengue epidemic in Yunnan, China during the pandemic of COVID-19 was dramatically reduced compared to non-pandemic years and, imp...

Eastern equine encephalitis (EEE) is a rare but lethal mosquito-borne zoonotic disease. Recent years have seen incursion into new areas of the USA, and in 2019 the highest number of human cases in decades. Due to the low detection rate of EEE, previous studies were unable to quantify large-scale and recent EEE ecological dynamics. We used Bayesian...

Objectives To understand how health departments implemented the response to the dual hazards of Heat Related Illness (HRI) and COVID-19 in Summer 2020. Methods We interviewed five health jurisdictions with a Building Resilience Against Climate Effects (BRACE) Framework HRI project to understand impacts to organizational roles and preparedness acti...

Background Transmission of multidrug-resistant tuberculosis (MDRTB) requires spatial proximity between infectious cases and susceptible persons. We assess activity space overlap among MDRTB cases and community controls to identify potential areas of transmission. Methods We enrolled 35 MDRTB cases and 64 TB-free community controls in Lima, Peru. C...

Mosquito surveillance data can be used for predicting mosquito distribution and dynamics as they relate to human disease. Often these data are collected by independent agencies and aggregated to state and national level portals to characterize broad spatial and temporal dynamics. These larger repositories may also share the data for use in mosquito...

Background: Injury-causing events are not randomly distributed across a landscape, but how they are associated with the features and characteristics of the places where they occur in Arizona (AZ) remains understudied. Clustering of trauma events and associations with areal sociodemographic characteristics in the greater Phoenix (PHX), AZ region ca...

p>Background. Helicobacter pylori, one of the most common bacterial infections worldwide. Chronic infections are associated with gastritis, peptic ulcer, and gastric cancer. While H. pylori infections and gastric cancer are going down in the US, certain populations continue to experience high H. pylori prevalence of infection and a significant burd...

Epidemiology is a core component of the undergraduate public health curriculum and a critical component for a healthy community and a comprehensive education. Evidence-based, collaborative instructional practices improve student success, reach diverse student populations, and improve learning outcomes. We describe the pedagogical approach of an ins...

Background: Pancreatic cancer is one of the deadliest forms of cancer, with incidence rates rising in many countries around the world. Geographic variation in pancreatic cancer incidence has not been studied extensively, especially in low- and middle-income countries. The aim of this study was to characterize the distribution of pancreatic cancer...

Background: Helicobacter pylori (Hp) is a gastric pathogen associated with development of duodenal or stomach ulcers, stomach cancer, and mucosa associated lymphoid-tissue (MALT) lymphomas. While Hp prevalence is declining in many regions, it remains the leading infectious cause of cancer worldwide. In the United States prevalence varies by geograp...

We added a vector control component to our existing abundance model to simulate intensive vector control in Puerto Rico. Removing 20–30% of gravid females in the model matches observed 60–80% reductions. The model’s capacity to reproduce vector control increases its utility for planning and evaluation strategies.

Stakeholder participation at the intersection of climate and health is essential to assess and plan for the human health impacts of current and projected climate-sensitive hazards. Using the Maricopa County Department of Public Health (MCDPH) Coalition on Climate Change and Public Health workgroup and the Climate Assessment for the Southwest (CLIMA...

The risk of a zoonotic pandemic disease threatens hundreds of millions of people. Emerging infectious diseases also threaten livestock and wildlife populations around the world and can lead to devastating economic damages. China and the USA—due to their unparalleled resources, widespread engagement in activities driving emerging infectious diseases...

We compared different diagnostic tests for Chagas disease in 150 samples in Mexico City and 146 samples in Baltimore.

The classical gravity model assumes the knowledge of origin-destination (OD) flows between places. While this is reasonable for some modes of transportation such as air travel, it presents challenges to many other applications such as road travel where the observed flow on road segments, such as annual average daily traffic (AADT), may involve traf...

Background: Chronic infection with Helicobacter pylori (H. pylori) is the strongest risk factor for distal gastric cancer. Although gastric cancer incidence has decreased, variation by race and ethnicity is observed. This study describes gastric cancer presentation and screening services among Medicare patients by race/ethnicity, place of birth, a...

Worldwide, infectious agents currently contribute to an estimated 15% of new cancer cases. Most of these (92%, or 2 million new cancer cases) are attributable to 4 infectious agents: Helicobacter pylori, human papillomavirus, and hepatitis B and C viruses. A better understanding of how infectious agents relate to the US cancer burden may assist new...

Author summary Mosquito-borne pathogens infect millions of people worldwide, and the rise in insecticide resistance is exacerbating this problem. A new generation of environmentally safe insecticides will be essential to control insecticide-resistant mosquitoes. One potential route to such novel insecticide targets is the identification of proteins...

Reproductive phenotypes associated with EOF1 gene silencing by RNAi in A. albopictus. (A) Representative eggs are shown from mosquitoes injected with dsRNA-Fluc and dsRNA-EOF1. Mosquitoes were injected with dsRNA at 1 day after adult eclosion. (B) The effect of RNAi-Fluc control or RNAi-EOF1 control on A. albopictus fecundity was examined by counti...

A confocal microscopic image of an ovariole isolated from A. aegypti mosquito. The representative image shows a developing primary follicle, a resting secondary follicle, and a germarium at 36 h PBM. Fixed follicles were stained for actin (phalloidin, green) and cell nuclei (DAPI, purple), and images were obtained by Nikon C1si confocal laser scann...

EOF1 protein is necessary for complete eggshell formation and embryonic development in A. aegypti mosquitoes. A bleach test was performed to determine viability of 4-day-old eggs from RNAi studies. Light microscopic images were taken from RNAi-Fluc and RNAi-EOF1 females immediately prior to the addition of bleach (0 min). We frequently observed tha...

Programmed shedding of follicular epithelial cells, secondary follicles, and germarium from the primary follicle occurs during late oocyte development in A. aegypti. Confocal microscopy images of representative individual follicles during mid- to late oogenesis, showing follicle development and shedding of the follicular epithelial cell layer. Ovar...

mRNA distribution of EOF1 in A. aegypti mosquito primary follicles using whole-mount FISH. (A) EOF1 mRNA transcript distributions in primary follicles were visualized by hybridizing digoxygenin-labeled RNA probes. Primary follicles isolated from ovaries of untreated female mosquitoes at 36 h PBM were fixed with 4% paraformaldehyde and hybridized wi...

Gene-specific primers used to amplify DNA templates for dsRNA synthesis. dsRNA, double-stranded RNA. (XLSX)

Reproductive phenotypes associated with EOF1 gene silencing by RNAi in A. aegypti mosquitoes. (A) Mosquitoes injected with dsRNA-EOF1 at one day after adult eclosion produced inviable eggs. (B) Mosquitoes were injected with dsRNA-EOF1 immediately after blood feeding. These females laid eggs that show no difference in fecundity and viability compare...

Eggshell enrichment and SDS-PAGE protein analysis. Representative ovaries from mosquitoes injected with dsRNA-Fluc (A) and dsRNA-EOF1 (A′). Mosquitoes were injected with dsRNA targeting EOF1 or Fluc control, and the ovaries were dissected from the injected mosquitoes at 96 h PBM. Ovaries were photographed immediately after dissection in 1× PBS. As...

Gene-specific primers used to synthesize in situ hybridization probes. (XLSX)

Numerical data used in the figures. (XLSX)

RNAi-mediated knockdown of EOF1 expression in A. aegypti ovaries. (A) Single-mosquito qPCR analysis was performed to measure the relative RNAi knockdown level of EOF1 transcript in ovaries. Mosquitoes were microinjected with 2.0 μg of dsRNA-Fluc or dsRNA-EOF1 three days prior to blood feeding, and a pair of ovaries was dissected from 13 individual...

Gene-specific primers for RNAi and qPCR. qPCR, quantitative real-time PCR; RNAi, RNA interference. (XLSX)

Research on the drivers of vaccine acceptance has expanded but most interventions fall short of coverage targets. We explored whether vaccine uptake is driven directly or indirectly by disgust with attitudes towards vaccines acting as a possible mediator. An online cross-sectional study of 1007 adults of the USA via Amazon's Mechanical Turk was con...

Background: The majority of tuberculosis transmission occurs in community settings. The primary aim of this study was to assess the association between exposure to community venues and multidrug-resistant tuberculosis (MDR-TB) disease. The secondary aim was to describe the social networks of MDR-TB cases and controls. Methods: This case-control...

Background: Emerging pathogens such as Zika, chikungunya, Ebola, and dengue viruses are serious threats to national and global health security. Accurate forecasts of emerging epidemics and their severity are critical to minimizing subsequent mortality, morbidity, and economic loss. The recent introduction of chikungunya and Zika virus to the Ameri...

Describe differences in Helicobacter pylori (H. pylori) screening among a Surveillance, Epidemiology and End Results (SEER)-Medicare elderly population by ethnicity, place of birth, and gastric cancer (GC)-related conditions, as chronic infection with H. pylori is the strongest risk factor for distal GC. Methods: We used the National Cancer Institu...

em>Background . Valley fever is a fungal infection occurring in desert regions of the U.S. and Central and South America. Environmental risk mapping for this disease is hampered by challenges with detection, case reporting, and diagnostics as well as challenges common to spatial data handling. Design and Methods. Using 12,349 individual cases in A...

Background: Seasonal influenza, though mostly self-limited in the healthy adult, may lead to severe disease and/or complications in subpopulations. Annual influenza vaccination is available in many countries with coverage goals rarely being met. We conducted a cross-sectional study of influenza vaccine uptake and explored socio-demographic, econom...

Background Helicobacter pylori infection is associated with the development of chronic gastritis, peptic ulcer disease, and gastric cancer. Current clinical recommendations are that H. pylori test-and-treat should be individualized based on comorbidities and patient preferences among populations at increased risk for certain morbidities. However, k...

Understanding the dispersal of Aedes (aegypti (L.) Diptera: Culicidae) after consuming a potentially infectious bloodmeal is an important part of controlling the spread of the arboviruses it transmits. Because of the impact on abundance, removal of oviposition sites is a key component of vector control. However, source reduction around a case may e...

We propose an improved Aedes aegypti (L.) abundance model that takes into account the effect of relative humidity (RH) on adult survival, as well as rainfall-triggered egg hatching. The model uses temperature-dependent development rates described in the literature as well as documented estimates for mosquito survival in environments with high RH, a...

Background and aims: We sought to determine current knowledge and practices among gastroenterology physicians and assess adherence to current guidelines for H. pylori management. Methods: Online surveys were distributed in 2014 to practicing gastroenterology physicians for information related to the diagnosis and treatment of H. pylori infection...

Dynamic simulation models provide vector abundance estimates using only meteorological data. However, model outcomes may heavily depend on the assumptions used to parameterize them. We conducted a sensitivity analysis for a model of Aedes aegypti (L.) abundance using weather data from two locations where this vector is established, La Margarita, Pu...

Ultraviolet radiation (UVR) has been associated with various health outcomes, including skin cancers, vitamin D insufficiency, and multiple sclerosis. Measurement of UVR has been difficult, traditionally relying on subject recall. We investigated trends in satellite-derived UVB from 1978 to 2014 within the continental United States (US) to inform U...

Little is currently known about the spatial-temporal dynamics of dengue epidemics in arid areas. This study assesses dengue outbreaks that occurred in two arid cities of Mexico, Hermosillo and Navojoa, located in northern state of Sonora. Laboratory confirmed dengue cases from Hermosillo (N=2,730) and Navojoa (N=493) were geocoded by residence and...

Aedes aegypti (L.) is one of the most important arboviral vectors worldwide. Vector control is targeted at immature and adult stages; however, eggs are resistant to desiccation and may repopulate treated areas long after treatment ceases. We investigated the effect of age on Ae. aegypti egg hatching rates using newly colonized populations (F2) from...

From 1900 through 1996, mortality from infectious diseases declined in the United States, except for a 1918 spike due to the Spanish flu pandemic.¹ Since 1996, major changes in infectious diseases have occurred, such as the introduction of human immunodeficiency virus (HIV)/AIDS and West Nile virus into the United States, advances in HIV/AIDS treat...

Recent events have thrown the spotlight on infectious disease outbreak response. We developed a data-driven method, EpiGro, which can be applied to cumulative case reports to estimate the order of magnitude of the duration, peak and ultimate size of an ongoing outbreak. It is based on a surprisingly simple mathematical property of many epidemiologi...

As the range of dengue virus (DENV) transmission expands, an understanding of community uptake of prevention and control strategies is needed both in geographic areas where the virus has recently been circulating and in areas with the potential for DENV introduction. Personal protective behaviors such as the use of mosquito repellent to limit human...

Objective: Chagas disease, a disease caused by Trypanosoma cruzi, disproportionately affects poor people throughout Latin America. In Mexico, assessments of officially reported burden have not been previously reported. To evaluate discontinuity between surveillance data and data from other sources, we used data from the Mexican Ministry of Health...

Helicobacter pylori infection is among the most prevalent infections in the world and a key cause of gastric diseases; however, its route of transmission remains unclear. This study aimed to assess the potential for fecal-oral transmission of H. pylori by leveraging its association with a disease with known etiology. Utilizing serology data from th...

While estimates of the impact of climate change on health are necessary for health care planners and climate change policy makers, models to produce quantitative estimates remain scarce. This study describes a freely available dynamic simulation model parameterized for three West Nile virus vectors, which provides an effective tool for studying vec...

Bluetongue is a Culicoides-borne viral disease of livestock. In 2006, northern Europe experienced a major outbreak of this disease with devastating effects on the livestock industry. The outbreak quickly spread over the region, primarily affecting cattle and sheep. A previous analysis of the role of vector flight and wind in the spread of this viru...

Author Summary Chikungunya is a disease transmitted by mosquitoes. Currently, there is an epidemic of chikungunya in several islands and countries in the Americas. Despite efforts at understanding and predicting spread, there have been no studies assessing the spatio-temporal spread of chikungunya in any of the Caribbean islands, mainly due to a la...

Rabies is arguably the most important viral zoonotic disease worldwide with an estimated 55,000 human deaths each year. Globally, dogs are the primary animals affected. In the United States, especially on the East Coast, raccoons and bats are the primary reservoir. However, in the southwestern United States, skunk and bat rabies play a large role....

Background This paper examines the individual factors that influence prevalence rates of canine heartworm in the contiguous United States. A data set provided by the Companion Animal Parasite Council, which contains county-by-county results of over nine million heartworm tests conducted during 2011 and 2012, is analyzed for predictive structure. Th...