Center for
Global Health

Scholar

Languages: Spanish (native), English (fluent), Portuguese (basic)

Bio statement

Ricardo Castillo, DVM, PhD, MPH is an Assistant Professor of Epidemiology at the Perelman School of Medicine at the University of Pennsylvania and the Scientific Director of the Zoonotic Diseases Research Laboratory (ZDRL), a collaborative consortium involving multiple U.S. and international institutions and employing over 30 full-time staff. He systematically applies the One Health approach to studying zoonoses in Latin America, with a focus on urban ecosystems where population growth, social inequality, and environmental change intersect to drive infectious disease risk.

Dr. Castillo is the Principal Investigator of two NIH-funded projects examining the socio-spatial dynamics of urban zoonotic diseases and optimizing mass vaccination campaigns to control epidemics. He also serves as Co-Principal Investigator on an NIH-Fogarty training grant, which strengthens research capacity in Latin America in epidemiology and implementation science for zoonotic disease control and elimination. His research integrates animal movement and population dynamics with community-based longitudinal trials to identify barriers to vaccination and to design interventions that improve coverage for both human and animal populations.

With more than 50 peer-reviewed publications in leading tropical medicine and infectious disease journals, Dr. Castillo’s work has advanced understanding of HIV, zoonotic spillover, and vaccine disparities, and has been cited in Peruvian national legislation on zoonotic disease control. His research is inherently transdisciplinary, engaging collaborators from Penn Vet, Penn Nursing, Penn Economics, and the Wharton School, as well as public health authorities and community partners in Latin America.

Trained as a veterinarian (DVM, 2007) in Peru, Dr. Castillo completed a PhD in Epidemiology and an MPH in International Health at Johns Hopkins University before joining Penn in 2017. He continues to mentor young scientists while advancing innovative, policy-relevant research at the intersection of human, animal, and environmental health.

Recent global health projects

One Health and Dog-mediated Zoonosis. The elimination and control of zoonoses such as rabies and echinococcosis require coordinated, sustained efforts at the human–animal–environment interface. Mass dog vaccination (for rabies) and regular deworming (for echinococcosis) are central strategies. Success depends on high coverage, community engagement, surveillance systems that detect transmission hotspots, and policies that integrate veterinary and public health sectors. My studies provide evidence to advance the control and elimination of these diseases in Latin America.

Climate change, migration, poverty, and infectious diseases. The biggest impact of climate change on the distribution and burden of infectious diseases might be through migration and poverty. Extreme events and loss of agriculture land forces human displacement. Poverty amplifies vulnerability of migrants by limiting access to prevention, diagnosis, and treatment, creating conditions where outbreaks spread faster and persist longer. Together, these forces challenge public health systems and demand integrated, adaptive responses. In Arequipa, Peru, we started a project to collect primary data on rural-urban migrants and understand the migration processes and their impact on populations' health.

Selected publications

Porras G, Diaz EW, De la Puente-León M, Gavidia CM, Castillo-Neyra R. Estimation of free-roaming dog populations using Google Street View: A methodological study. PLoS One. 2025;20(7):e0305154. doi:10.1371/journal.pone.0305154

Castillo-Neyra R, Ortiz-Cam L, Cañari-Casaño JL, Díaz EW, Tamayo LD, Porras G, et al. An implementation science framework to understand low coverage in mass dog rabies vaccination. PLoS Negl Trop Dis. 2025;19(7):e0012869. doi:10.1371/journal.pntd.0012869

Tidman R, Larkins A, Auplish A, Benfield C, Cleaveland S, Fahrion AS, Leopardi V, Ghimire R, Morucci K, Sila S, Castillo-Neyra R, Okello A. Evaluating cross-cutting opportunities for dog-mediated rabies control: a scoping review. Front Microbiol. 2025 Jun 18;16:1473929. doi:10.3389/fmicb.2025.1473929

Raynor B, Díaz EW, Shinnick J, Zegarra E, Monroy Y, et al. (2021) The impact of the COVID-19 pandemic on rabies reemergence in Latin America: The case of Arequipa, Peru. PLOS Neglected Tropical Diseases 15(5): e0009414. https://doi.org/10.1371/journal.pntd.0009414

Ascuña-Durand K, Salazar-Sánchez RS, Castillo-Neyra R, Ballón-Echegaray J. Relative Frequency of Blastocystis Subtypes 1, 2, and 3 in Urban and Periurban Human Populations of Arequipa, Peru. Tropical Medicine and Infectious Disease. 2020; 5(4):178. https://doi.org/10.3390/tropicalmed5040178

Salazar-Sánchez RS, Ascuña-Durand K, Ballón-Echegaray J, Vásquez-Huerta V, Martínez-Barrios E, Castillo-Neyra R. Socio-Demographic Determinants Associated with Blastocystis Infection in Arequipa, Peru [published online ahead of print, 2020 Nov 16]. Am J Trop Med Hyg. 2020;104(2):700-707. doi:10.4269/ajtmh.20-0631

Castillo-Neyra R, Buttenheim AM, Brown J, Ferrara JF, Arevalo-Nieto C, et al. (2020) Behavioral and structural barriers to accessing human post-exposure prophylaxis and other preventive practices in Arequipa, Peru, during a canine rabies epidemic. PLOS Neglected Tropical Diseases 14(7): e0008478. https://doi.org/10.1371/journal.pntd.0008478

Last Updated: 07 October 2025