ernesto rojas sanchez pipetting in the OHI lab

From Costa Rica to California

Ernesto Rojas Sánchez Embarks on a New Chapter in Epidemiology

by Eunah Preston
June 24, 2025

When Dr. Ernesto Rojas Sánchez first heard about UC Davis, he was a third-year veterinary student at the Universidad Nacional de Costa Rica (UNA-CR). That’s when Dr. Pat Conrad, at the time the Associate Dean for Global Programs at the UC Davis School of Veterinary Medicine, visited his university to give a series of talks on infectious diseases in California and the One Health approach. Her presentation, which included research on toxoplasmosis in marine mammals and a roundtable discussion “Imagine what you can do and contribute as a veterinarian”, left a lasting impression. That initial connection would ultimately set Ernesto on a path that led him all the way to Davis.

Ernesto Rojas Sanchez standing in front of the OHI sign in graduation regalia — *Ernesto Rojas Sánchez standing in front of the One Health Institute building at UC Davis School of Veterinary Medicine. Photo Credit: Ernesto Rojas Sánchez*

“I knew I wanted to learn more about how a world-leading institution like UC Davis applies the One Health approach to address complex challenges”, Ernesto said. He kept in touch with Dr. Conrad, who recognized his passion and potential and connected him with Dr. Woutrina Smith at the One Health Institute. That introduction proved pivotal. Dr. Smith brought Ernesto into her lab and became a key mentor, guiding his development as a researcher and One Health professional. This connection marked the beginning of his UC Davis journey, and he soon joined the 2022 Rx One Health Field Institute, his first immersive experience with the university. From there, doors began to open.

Building a Foundation in One Health Research

Enrolled in the UC Davis School of Veterinary Medicine’s Master of Preventive Veterinary Medicine (MPVM) program, Ernesto immersed himself in interdisciplinary research and collaborative projects that spanned laboratory work, field research, and global health partnerships. He worked closely with Dr. Smith, who became a mentor across every facet of his experience, from the lab bench to the field to the data set analysis. Other mentors included Andrea Packham and Magdalena Plancarte from the One Health Institute Laboratory, UC Davis professors Drs. Brian Bird, Jane Sykes, Karen Shapiro, Devinn Sinnott, and Jennifer Cassano, along with Drs. Cara Field and Padraig Duginan from The Marine Mammal Center (TMMC),and Dr. Melissa Miller from California Department of Fish and Wildlife.

sherman trap demonstration at Rx One Health Field Institute — L-R: Taksoo Kim, Ernesto Rojas Sánchez, and Brian Bird discussing wildlife trap types as part of Rx One Health Field Institute at Clover Valley Ranch, CA. Photo Credit: Eunah Preston/OHI

Ernesto also participated in several key programs and initiatives, including the UC Davis Students for One Health Club, the UCD SVM Global Programs Committee, the Clover Valley Water & Wildlife project, and research efforts focused on coccidioidomycosis through both UC Davis Health and the School of Veterinary Medicine.

Clover Valley field research team — L-R: Sarah Smith, Ariel Loredo, and Ernesto Rojas Sánchez conducting hantavirus field research in Clover Valley Ranch, CA. Photo Credit: Brian Bird/OHI

Reflecting on the Last Three Years

A standout memory from his time at UC Davis is a collaborative visit to TMMC. This visit marked the first time where members of a large-scale study around Sarcocystis neurona infection in California sea lions got to be together in-person: “It made everything feel more connected.” As someone who had been processing and testing samples collected by members of the TMMC team, Ernesto appreciated putting the faces to the names of his collaborators.

The Marine Mammal Center research team — Left (L-R): Woutrina Smith, Ernesto Rojas Sánchez, Andrea Packham, Magdalena Plancarte, Cara Field outside The Marine Mammal Center in Sausalito, CA; Right: Ernesto Rojas Sánchez at The Marine Mammal Center in Sausalito, CA. Photo Credit: Dr. Woutrina Smith

One of the biggest takeaways from his MPVM experience was the value of organization in research, a lesson he attributes to his time in Dr. Smith’s lab. “The hardworking people around me and the high level of organization at The One Health Institute Laboratory deeply influenced how I approach my work today—whether it’s doing lab work, analyzing data, managing a project, mentoring other students, or any other simple or complex task,” he said.

Sea otter serum sample testing positive for Sarcocystis neurona — Sea otter serum sample testing positive for *Sarcocystis neurona* using the indirect fluorescent antibody test (IFAT) at 400× magnification. Photo Credit: Ernesto Rojas Sánchez

The Journey Continues at UC Davis

Fueled by a genuine passion for research, especially when it has an impact in improving patients' health, helps clinicians as well as public health, Ernesto approaches each day with motivation and curiosity – energy that carried him through the completion of his MPVM degree at UC Davis this year. Last summer he also began his PhD in the Graduate Group of Epidemiology at UC Davis. His primary advisor will be Dr. Jane Sykes, with continued mentorship from Dr. Woutrina Smith and new guidance from Dr. Beatriz Martinez-Lopez. He plans to continue his research on epidemiology of coccidioidomycosis in California, a complex One Health issue at the intersection of human, animal, and environmental health.