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EMeRGenS is an NIH-funded research project at the University of California San Diego (UCSD). We plan to use dynamic mathematical modeling to predict and effectively respond to emerging substance use epidemic threats and associated HIV, HCV, and fatal overdose incidence.



The overdose epidemic in the United States has followed an exponential curve since 1979 with no sign of abating. On the contrary, a series of political, economic and technological factors are fueling drug use epidemics in the country. Technological advances have led to an explosion in the emergence of powerful synthetic substances that can be produced with minimal equipment. Inequalities, poor mental health services, and other social issues contribute to an increased susceptibility to drug use disorders. Improved transport and communication infrastructure, including the internet, facilitates the emergence of drug markets. As a result, polysubstance use is diversifying presenting new health risks and new challenges for treatment. In 2017, over 70,000 people died of an overdose and HIV outbreaks were identified in two cities of Massachusetts. Curbing these alarming trends requires preemptive epidemic preparedness and the latter should be based on a rigorous and systematic assessment of the factors influencing drug use epidemics. These factors, however, are dynamic and interacting.


We will use an emerging infectious disease framework and dynamic mathematical modeling methods to predict emerging drug use epidemics in the United States. Mathematical modeling has been used extensively to forecast emerging and reemerging infectious disease epidemics because it allows us to mechanistically represent the different factors determining disease transmission and their dynamics over time. We will develop a mathematical model of drug use in the United States which represents current patterns of drug use across the country and associated HIV, HCV and overdose incidence. It will explicitly represent heterogeneity in susceptibility to drug use disorders in the population, social networks and the influence of drug markets, law enforcement and healthcare services on drug use and associated health outcomes.


We will investigate the value of internet data (Google searches, social media, news) in providing real-time estimates of substance use patterns and associated health harms to complement our models' parameterization and inform timely modeling scenarios.

We will also use online marketing strategies which harness interest for a topic, as expressed by internet searches, to promote harm reduction intervertions among communities identified by our models as being at rish for an impending emerging susbstance use epidemic. 





Annick Bórquez, MSc, PhD

Annick Bórquez, MSc, PhD, is an HIV and substance use epidemiologist at the division of Infectious Diseases and Global Public Health at UCSD. Her research seeks to improve the health of marginalized populations through developing, applying and integrating mathematical modeling, cost effectiveness and qualitative methods. Her focus is on addressing intersecting epidemics of substance use disorders, overdose, HIV, HCV and other associated health harms, with a focus on social and structural determinants of health. She has led multiple studies to inform intervention and policy planning in HIV and substance use among people who inject drugs, justice involved populations, female sex workers, men who have sex with men and transgender women in a range of settings, including Mexico, Peru, West and Sub-Saharan Africa, India, Russia and the United States.
Dr. Bórquez has a background in medical microbiology from the University of Edinburgh and holds an MSc. and a PhD. in epidemiology from the department of Infectious Disease Epidemiology at Imperial College London. 

She is the principal investigator of this NIDA Avenir grant to adapt emerging infectious diseases methods including internet/big data analysis and mathematical modeling, to the field of substance use to predict and respond to emerging substance use epidemics in the United States.


Melanie Nicholls, PhD, LCSW

Melanie Nicholls Ph.D., LCSW is a therapist and new faculty member at San Diego State University. She received her Ph.D in the SDSU-UCSD Joint Doctoral Program in Interdisciplinary Research on Substance Use. Her research focuses on the barriers and facilitators for opioid use disorder treatment with an emphasis on implementation science. Her clinical background is primarily in substance use and severe and persistent mental illnesses. She is interested in research on improving the implementation of evidence-based practices in substance use and mental health treatment.


Marsa Rayani, MSc, BSc, PhD

Marsa is a Ph.D. holder in Information and Systems Engineering from Concordia University, Canada, awarded in 2022. She also possesses an M.Sc. in Computer Science from University Putra Malaysia (2008) and a B.Sc. in Computer Software Engineering from Iran (2012). Currently, she serves as a Postdoctoral Fellow at the University of California, San Diego, specializing in Machine Learning for predicting substance use in the field of public health research. With a research focus on machine learning, public health, algorithm design, and architecture design, Marsa's favorite topics align with her expertise. Driven by a deep-rooted passion for innovation and pushing technological boundaries, Marsa is devoted to effecting positive change in the lives of individuals and communities through her work in public health research.

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Alexandra Almeida, PhD 

Alexandra Almeida is a Ph.D. candidate in the SDSU-UCSD Joint Doctoral Program in Interdisciplinary Research on Substance Use and works as a researcher at FIOCRUZ/Brazil. Her current research focuses on the syndemic of substance use, HIV, and HCV, and Natural Language Processing methods for improving the understanding of chronic and transmissible diseases and related surveillance systems. She is a statistician with a previous Ph.D. in Epidemiology and Public Health from Sérgio Arouca National School of Public Health/FIOCRUZ, Brazil.

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Makaya Funk-White, Doctoral Student 

Makaya Funk-White is a current doctoral student in the UCSD/SDSU Joint Doctoral Program studying Interdisciplinary Research on Substance Use. Prior to that she earned both her bachelors and her masters degrees in Social Work at San Diego State University. Her research interests lie in studying the relationship between older adults and substance use, substance use and cognition, and policy research. She currently has a diversity supplement awarded by the NIA studying brain age and alcohol use in older adults. 

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Thomas Patton, MSc, PhD

Tom Patton is a Postdoctoral Fellow in the NIH T32 Training Program in Substance Use, HIV, and Related Infections at the University of California, San Diego (UCSD). He received an MSc in Health Economics and a Ph.D. in Economics from the University of York (UK). He previously worked as a Research Fellow at the Centre for Health Economics, University of York. His main research interest is in the development of economic evaluations for the assessment of policy interventions aimed at reducing the harms of opioid use disorder.   

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Sharon Park, BA

Sharon is a Program Coordinator for UCSD's Division of Infectious Diseases and Global Public Health. She supports multiple principal investigators working on a variety of research topics including HIV transmission networks, injection drug use, ethno-epidemiology along the US-Mexican border. She received her B.A. in Economics from the University of California Berkeley. 



Gabriel Carrasco-Escobar, MPH

Gabriel Carrasco-Escobar completed his master degree in Epidemiology and Biostatistics at Universidad Peruana Cayetano Heredia (UPCH), Peru, and is currently in the Public Health Doctoral Program at the University of California, San Diego (UCSD), USA. His research is focused on the Epidemiology of Tropical Diseases and the intersection with environmental determinants in resource-limited settings. He is particularly interested in epidemiological, spatial and remote sensing methods to understand the distribution and determinants of tropical diseases. In the most recent years, his work was focused on the role of human population mobility in the malaria epidemiology in the Amazon region and the micro-geographic landscape composition as regulator for Malaria transmission dynamics.

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Rocio Carrasco-Hernandez, MSc, PhD

Dr. Rocio Carrasco-Hernandez is a multidisciplinary researcher. Originally from Mexico City, she coursed an BSc and an MSc in Biology, working with research projects on the ecophysiology of plants and microorganisms in volcanic soils and then modelling the ecological niche of bovine rabies disease, using landscape and environmental variables. She then completed a PhD in Environmental Sciences in Manchester, UK; working with physical models of solar radiation in urban environments. Back to Mexico, she obtained a 2yr postdoctoral position at the Faculty of Medicine, UNAM, to study geographical relations that may affect HIV risk among transwomen. Now entering the field of molecular epidemiology, Dr. Carrasco-Hernandez attempts to understand some geographical patterns governing HIV transmission networks, as well as some structural properties of the genetic sequences which may explain the formation of large transmission clusters within a population.

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Derek Johnson, PhD

Derek Johnson is a post-doctoral student at UCSD researching the use of novel data to predict and assess emerging substance abuse. He received his Ph.D. in epidemiology from the University of Alabama at Birmingham and has completed a postdoctoral program in global health at Tufts University. He has previously worked for Médecins Sans Frontières where he worked on HIV related projects in Uganda and Myanmar.


Charles Marks, MPH

Charles Marks is a doctoral student in the SDSU-UCSD Joint Doctoral Program in Interdisciplinary Research on Substance Use and works as a graduate research assistant for PRIMER. Their current research focuses on developing dynamic models of injection initiation which can be utilized to understand various factors related to injection initiation as well as to inform initiation prevention measures. Generally, they are interested in utilizing critical social theory to inform public health policy research addressing health inequities.

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Kaiming Bi, PhD

Kaiming Bi is a post-doctoral researcher in the Division of Infectious Diseases and Global Public Health at UCSD. Before joining UCSD, he received his bachelor's degree in Mathematics at Northeastern University in China and received his Ph.D. degree in Industrial Engineering at Kansas State University. His research background includes disease modeling, simulation, optimal control, and machine learning. Currently, his research interest focus on the modeling of opioid-related drug transmission.

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Anh Vo, BS, BA

Anh Vo is a research assistant at UCSD's Division of Infectious Diseases and Global Public Health. Anh's current research focuses on developing mathematical models examining underlying patterns or seasonality of drug epidemics, as well as how the recent COVID-19 pandemic affects and informs changes in drug use. She is also working concurrently on projects that seek to use dynamic modeling to optimize HIV prevention portfolios targeting people who inject drugs. Anh has received her B.S. in Public Health and B.A. in Global Health at UCSD, and her primary interests lie in exploring emerging issues in infectious disease by leveraging biostatistics and mathematical modeling.


Consider joining our research team - follow this link to view our current job postings! 

Our Findings

Publications pertaining to the prediction of drug-related epidemics: 

Drug checking in the fentanyl era: Utilization and interest among people who inject drugs in San Diego, California.

Bailey K, Abramovitz D, Artamonova I, Davidson P, Stamos-Buesig T, Vera CF, Patterson TL, Arredondo J, Kattan J, Bergmann L, Thihalolipavan S, Strathdee SA, Borquez A. Int J Drug Policy. 2023 Jun 7;118:104086. doi: 10.1016/j.drugpo.2023.104086. Epub ahead of print. PMID: 37295217.

"A lotta people switched playing hard ball to playing Russian roulette": Experiences with rising overdose incidence caused by drug supply changes during the COVID-19 pandemic in the San Diego-Tijuana border metroplex.

Valasek CJ, Streuli SA, Pines HA, Strathdee SA, Borquez A, Bourgois P, Stamos-Buesig T, Vera CF, Harvey-Vera A, Bazzi AR. Drug Alcohol Depend Rep. 2023 Mar 28;7:100154. doi: 10.1016/j.dadr.2023.100154. PMID: 37089868; PMCID: PMC10113744.


Fentanyl, Heroin, and Methamphetamine-Based Counterfeit Pills Sold at Tourist-Oriented Pharmacies in Mexico: An Ethnographic and Drug Checking Study.

Friedman J, Godvin M, Molina C, Romero R, Borquez A, Avra T, Goodman-Meza D, Strathdee S, Bourgois P, Shover CL.  medRxiv [Preprint]. 2023 May 31:2023.01.27.23285123. doi: 10.1101/2023.01.27.23285123. Update in: Drug Alcohol Depend. 2023 Jun 9;249:110819. PMID: 36747647; PMCID: PMC9901047.


Characterizing Help-Seeking Searches for Substance Use Treatment From Google Trends and Assessing Their Use for Infoveillance: Longitudinal Descriptive and Validation Statistical Analysis.

Patton T, Abramovitz D, Johnson D, Leas E, Nobles A, Caputi T, Ayers J, Strathdee S, Bórquez A. J Med Internet Res. 2022 Dec 1;24(12):e41527. doi: 10.2196/41527. PMID: 36454620; PMCID: PMC9756118.


A stakeholder-driven framework for measuring potential change in the health risks of people who inject drugs (PWID) during the COVID-19 pandemic.

Bradley H, Austin C, Allen ST, Asher A, Bartholomew TS, Board A, Borquez A, Buchacz K, Carter A, Cooper HLF, Feinberg J, Furukawa N, Genberg B, Gorbach PM, Hagan H, Huriaux E, Hurley H, Luisi N, Martin NK, Rosenberg ES, Strathdee SA, Jarlais DCD. Int J Drug Policy. 2022 Dec;110:103889. doi: 10.1016/j.drugpo.2022.103889. Epub 2022 Oct 17. PMID: 36343431; PMCID: PMC9574463.


Commentary on Savinkina et al.: Reforming drug 'detox' centers-what will it entail and where do we begin?

Borquez A. Addiction. 2022 Sep;117(9):2462-2463. doi: 10.1111/add.15985. PMID: 35916376.

Illicit Substance Use and the COVID-19 Pandemic in the United States: A Scoping Review and Characterization of Research Evidence in Unprecedented Times.

Vo AT, Patton T, Peacock A, Larney S, Borquez A. Int J Environ Res Public Health. 2022 Jul 21;19(14):8883. doi: 10.3390/ijerph19148883. PMID: 35886734; PMCID: PMC9317093.


Fatal overdose: Predicting to prevent.

Borquez A, Martin NK. Int J Drug Policy. 2022 Jun;104:103677. doi: 10.1016/j.drugpo.2022.103677. Epub 2022 May 9. PMID: 35550852; PMCID: PMC9347029.


Using Economic Evaluation to Inform Responses to the Opioid Epidemic in the United States: Challenges and Suggestions for Future Research.

Patton T, Revill P, Sculpher M, Borquez A. Subst Use Misuse. 2022;57(5):815-821. doi: 10.1080/10826084.2022.2026969. Epub 2022 Feb 14. PMID: 35157549; PMCID: PMC8969147.


Identifying Counties at Risk of High Overdose Mortality Burden Throughout the Emerging Fentanyl Epidemic in the United States: A Predictive Statistical Modeling Study. The Lancet Public Health

Marks C, Abramovitz D, Donnelly C, Carrasco G. Carrasco-Hernández R, Ciccarone D, González-Izquierdo A, Martin NK, Strathdee S, Smith D, Bórquez A. The Lanncet Public Health 2021. DOI:


Methodological approaches for the prediction of opioid use-related epidemics in the United States: a narrative review and cross-disciplinary call to action.

Marks C, Carrasco-Escobar G, Carrasco-Hernandez R, Johnson D, Ciccarone D, Strathdee SA, Smith D, Bórquez A. Transl Res. 2021 Mar 30:S1931-5244(21)00081-5. doi: 10.1016/j.trsl.2021.03.018. PMID: 33798764.

Other publications associated with the EMERGENS grant: 


Estimating the impact of a police education program on hepatitis C virus transmission and disease burden among people who inject drugs in Tijuana, Mexico: A dynamic modeling analysis.

Rivera Saldana CD, Abramovitz D, Beletsky L, Borquez A, Kiene S, Marquez LK, Patton T, Strathdee S, Zúñiga ML, Martin NK, Cepeda J. Addiction. 2023 Apr 11. doi: 10.1111/add.16203. Epub ahead of print. PMID: 37039246.

Prison-based interventions are key to achieving HCV elimination among people who inject drugs in New South Wales, Australia: A modelling study.

Stone J, Lim AG, Dore GJ, Borquez A, Geddes L, Gray R, Grebely J, Hajarizadeh B, Iversen J, Maher L, Valerio H, Martin NK, Hickman M, Lloyd AR, Vickerman P. Liver Int. 2023 Mar;43(3):569-579. doi: 10.1111/liv.15469. Epub 2022 Nov 14. PMID: 36305315; PMCID: PMC10308445.

Good2Go: perceptions and impact of a community-based comprehensive sexual health screening program in San Diego, California.

Hoenigl M, Smith LR, Egger M, Mittal ML, Borquez A, Little SJ. AIDS. 2022 Nov 15;36(14):2083-2085. doi: 10.1097/QAD.0000000000003335. PMID: 36305189; PMCID: PMC9623468.

Modelling the contribution of incarceration and public health oriented drug law reform to HCV transmission and elimination among PWID in Tijuana, Mexico.

Saldana CDR, Beletsky L, Borquez A, Kiene SM, Marquez LK, Strathdee SA, Zúñiga ML, Cepeda J, Martin NK. Int J Drug Policy. 2022 Dec;110:103878. doi: 10.1016/j.drugpo.2022.103878. Epub 2022 Oct 12. PMID: 36242829; PMCID: PMC9841890.

Network-level HIV risk norms are associated with individual-level HIV risk and harm reduction behaviors among people who inject drugs: a latent profile analysis.

Shrader CH, Borquez A, Vasylyeva TI, Chaillon A, Artamanova I, Harvey-Vera A, Vera CF, Rangel G, Strathdee SA, Skaathun B. AIDS Behav. 2023 Feb;27(2):484-495. doi: 10.1007/s10461-022-03783-6. Epub 2022 Aug 8. PMID: 35939177; PMCID: PMC9358371.

Hepatitis C elimination among people who inject drugs in Mexico during the COVID-19 pandemic.

Márquez LK, Borquez A, Fleiz C, Magis-Rodríguez C, Rangel G, Strathdee SA, Martin NK. Gac Med Mex. 2022;158(2):110-113. English. doi: 10.24875/GMM.M22000650. PMID: 35763823.

Modeling the population-level impact of opioid agonist treatment on mortality among people accessing treatment between 2001 and 2020 in New South Wales, Australia.

Chaillon A, Bharat C, Stone J, Jones N, Degenhardt L, Larney S, Farrell M, Vickerman P, Hickman M, Martin NK, Bórquez A. Addiction. 2022 May;117(5):1338-1352. doi: 10.1111/add.15736. Epub 2021 Dec 4. PMID: 34729841; PMCID: PMC9299987.

Assessing HIV and overdose risks for people who use drugs exposed to compulsory drug abstinence programs (CDAP): A systematic review and meta-analysis.

Vo AT, Magana C, Hickman M, Borquez A, Beletsky L, Martin NK, Cepeda JA. Int J Drug Policy. 2021 Oct;96:103401. doi: 10.1016/j.drugpo.2021.103401. Epub 2021 Aug 11. PMID: 34389218; PMCID: PMC9027650.

Municipal police support for harm reduction services in officer-led referrals of people who inject drugs in Tijuana, Mexico.

Baker P, Arredondo J, Borquez A, Clairgue E, Mittal ML, Morales M, Rocha-Jimenez T, Garfein R, Oren E, Pitpitan E, Strathdee SA, Beletsky L, Cepeda JA. Harm Reduct J. 2021 Jul 26;18(1):76. doi: 10.1186/s12954-021-00513-4. PMID: 34311765; PMCID: PMC8313001.

Overlapping Key Populations and HIV Transmission in Tijuana, Mexico: A Modelling Analysis of Epidemic Drivers.

Fraser H, Borquez A, Stone J, Abramovitz D, Brouwer KC, Goodman-Meza D, Hickman M, Patterson TL, Silverman J, Smith L, Strathdee SA, Martin NK, Vickerman P. AIDS Behav. 2021 Nov;25(11):3814-3827. doi: 10.1007/s10461-021-03361-2. Epub 2021 Jul 3. PMID: 34216285; PMCID: PMC8560668.

Impact of cumulative incarceration and the post-release period on syringe-sharing among people who inject drugs in Tijuana, Mexico: a longitudinal analysis.

Rivera Saldana CD, Beletsky L, Borquez A, Kiene SM, Strathdee SA, Zúñiga ML, Martin NK, Cepeda J. Addiction. 2021 Feb 23. doi: 10.1111/add.15445. PMID: 33620749.

Preferences and acceptability of law enforcement initiated referrals for people who inject drugs: a mixed methods analysis.

Olgin GK, Bórquez A, Baker P, Clairgue E, Morales M, Bañuelos A, Arredondo J, Harvey-Vera A, Strathdee S, Beletsky L, Cepeda JA. Subst Abuse Treat Prev Policy. 2020 Oct 2;15(1):75. doi: 10.1186/s13011-020-00319-w. PMID: 33008431; PMCID: PMC7530855.

What is needed to achieve HCV microelimination among HIV-infected populations in Andalusia, Spain: a modeling analysis.

Skaathun B, Borquez A, Rivero-Juarez A, Mehta SR, Tellez F, Castaño-Carracedo M, Merino D, Palacios R, Macías J, Rivero A, Martin NK. . BMC Infect Dis. 2020 Aug 8;20(1):588. doi: 10.1186/s12879-020-05285-z. PMID: 32770955; PMCID: PMC7414743.

Opioid agonist treatment scale-up and the initiation of injection drug use: A dynamic modeling analysis.

Marks C, Borquez A, Jain S, Sun X, Strathdee SA, Garfein RS, Milloy MJ, DeBeck K, Cepeda JA, Werb D, Martin NK.

PLoS Med. 2019 Nov 26;16(11):e1002973. doi: 10.1371/journal.pmed.1002973. eCollection 2019 Nov. 

Free PMC Article

Responding to global stimulant use: challenges and opportunities.

Farrell M, Martin NK, Stockings E, Bórquez A, Cepeda JA, Degenhardt L, Ali R, Tran LT, Rehm J, Torrens M, Shoptaw S, McKetin R.  Lancet (London, England). 2019 November 2;394(10209):1652-1667. PubMed PMID: 31668409; PubMed Central PMCID: PMC6924572; DOI: 10.1016/S0140-6736(19)32230-5.

Integrating HIV preexposure prophylaxis and harm reduction among men who have sex with men and transgender women to address intersecting harms associated with stimulant use: a modelling study.

Bórquez A, Rich K, Farrell M, Degenhardt L, McKetin R, Tran LT, Cepeda J, Silva-Santisteban A, Konda K, Cáceres CF, Kelly S, Altice FL, Martin NK. Journal of the International AIDS Society. 2020 June;23 Suppl 1:e25495. PubMed PMID: 32562365; DOI: 10.1002/jia2.25495.

Modelling integrated antiretroviral treatment and harm reduction services on HIV and overdose among people who inject drugs in Tijuana, Mexico.

Cepeda JA, Bórquez A, Magana C, Vo A, Rafful C, Rangel G, Medina-Mora ME, Strathdee S, Martin NK. Journal of the International AIDS Society. 2020 June;23 Suppl 1:e25493. PubMed PMID: 32562375; DOI: 10.1002/jia2.25493.

Abstracts and Conference Proceedings

CPDD 2022 (Minneapolis), oral presentation: Predicting County-Level Overdose Death Rates Amid the Escalating Overdose Crisis in the United States: A Statistical Modeling Approach Predicting Deaths Through 2022. 06/18/22

CPDD 2022 (Minneapolis), poster presentation: Analyzing quality of life measures collected in people with opioid use disorder from the NIDA Data Share initiative: the implications for cost-effectiveness evidence in resource allocation decisions. 06/20/22

CPDD 2021 (virtual) poster presentation and Invited oral presentation at the annual research symposium of the National Drug and Alcohol Research Center (NDARC) of the University of New South Wales, Australia. Modeling the population-level impact of opioid agonist treatment on mortality among people accessing treatment between 2001 and 2020 in New South Wales, Australia. 10/21/2021

CPDD 2021 (virtual), poster presentation: The contribution of drug sharing to the prescription opioids’ epidemic: a dynamic modeling study

CPDD conference, Florida (virtual) 2020, poster presentation: Trends in Internet Search Behavior for Substance Use Treatment: A Measure of Health Seeking Behavior and oral presentation: Predicting Counties At-Risk of a Synthetic Opioid Overdose Outbreak: A Statistical Modeling Approach

Our Findings
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