Higher free-roaming dog density sustains rabies virus transmission in Haiti.

Eliminating dog-to-dog rabies virus transmission, the primary cause of > 70,000 human deaths annually, remains a challenge in over 100 countries due to the difficulty of implementing effective dog vaccination and population management programs. Despite the development of tools to optimize vaccine impact, rabies virus transmission dynamics are still not well-understood, largely due to insufficient surveillance. Utilizing data from Haiti’s advanced rabies surveillance system, we analyzed likely rabies cases, adjusted for a 5% detection rate, to estimate the true rabies burden in Haitian dogs. Our study calculated the effective reproduction number (Re) of rabies, finding strong associations between Re and free-roaming dog density, with Re falling below 1.0 when free-roaming dog density fell below 10 per km². This association suggests that denser free-roaming dog populations may perpetuate rabies transmission, providing critical insights for targeting effective vaccination efforts.