This month, two MMWR reports highlighted three human rabies deaths in the United States. Two individuals were infected after encounters with bats(Ireland et al. 2026). In the third case, the exposure was never identified, but genetic sequencing revealed a strain associated with dogs in Haiti (Barger et al. 2026). Globally, more than 99% of human rabies cases result from bites by rabid dogs, causing approximately 60,000 deaths every year (Organization 2018).
This is particularly sobering because rabies is entirely preventable. Dog owners know that vaccines for canine rabies are highly effective, and for humans, post exposure prophylaxis saves lives when administered promptly. In fact, modeling studies show that vaccinating just 70% of dogs in a community can eliminate dog mediated rabies transmission (Organization 2018). So why, if we know how to eliminate dog rabies, does it remain a persistent threat in so many parts of the world?
Dog rabies is concentrated primarily in low and middle income countries where dog populations include free roaming owned dogs, community dogs, and strays. Vaccinating these diverse and mobile populations is both logistically difficult and economically demanding. The main global strategy is mass dog vaccination campaigns: large, usually annual efforts aiming to vaccinate as many dogs as possible over a short time (Organization 2018).
Beginning during my graduate work in the Castillo Lab at the University of Pennsylvania, and continuing today, I conduct research focusing on an ongoing dog rabies outbreak in Arequipa, Peru. Our goal is to identify strategies that maximize vaccination coverage given the city’s limited resources. Arequipa has an enormous dog population (roughly 250,000 animals!) many of which spend part of their time roaming the streets. Mass vaccination in the city relies on temporary vaccination points, where trained vaccinators set up stations and dog owners bring their pets.
In one study I contributed to, we applied algorithms traditionally used to solve “facility location problems.”(Castillo-Neyra et al. 2024) Companies like Amazon use these models to choose optimal warehouse locations. We used the same principles to determine where to place vaccination points so that the average distance residents must travel is minimized. These algorithms help ensure that logistical barriers don’t prevent people from vaccinating their dogs.
Another study examined the timing of vaccination drives. (Bellotti et al. 2025) Historically, campaigns in Arequipa were conducted in a single day or weekend, an almost impossibly compressed timeline for vaccinating a quarter million dogs. We modeled an alternative strategy: staggering the campaign so that different districts are vaccinated on successive weekends over several months. Officials worried that because dogs move freely throughout the city,(Raynor et al. 2020) infected animals from unvaccinated districts might reintroduce the virus into districts that had already completed their campaign. The model confirmed that some re-seeding would occur. However, the overall effect was still positive: staggering the campaign increased the total number of vaccinated dogs, ultimately improving rabies control despite the added complexity.
These examples represent just a few of the obstacles involved in controlling canine rabies in one city with minimal wildlife reservoirs complicating transmission. Rabies control illustrates how seemingly straightforward public health interventions can actually involve deeply complex social, biological, and logistical systems. It also demonstrates how disruptions, such as the COVID 19 pandemic (Raynor et al. 2021), can ripple through these systems, causing lasting setbacks.
References
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Citation
@online{bellotti2026,
author = {Bellotti, Brinkley},
title = {Why {Dog} {Rabies} {Persists—and} {What} {It} {Takes} to
{Eliminate} {It}},
date = {2026-01-26},
url = {https://wakeforestid.com/posts/2026-01-26-why-dog-rabies-persists/},
doi = {10.59350/p4swp-ba751},
langid = {en}
}