LAUSR

How acute pathogens persist and what curtails their epidemic growth in the absence of acquired immunity remains unknown. Canine rabies is a fatal zoonosis that circulates endemically at low prevalence among domestic dogs in low- and middle-income countries. We traced rabies transmission in a population of 50,000 dogs in Tanzania from 2002 to 2016 and applied individual-based models to these spatially resolved data to investigate the mechanisms modulating transmission and the scale over which they operate. Although rabies prevalence never exceeded 0.15%, the best-fitting models demonstrated appreciable depletion of susceptible animals that occurred at local scales because of clusters of deaths and dogs already incubating infection. Individual variation in rabid dog behavior facilitated virus dispersal and cocirculation of virus lineages, enabling metapopulation persistence. These mechanisms have important implications for prediction and control of pathogens that circulate in spatially structured populations. Description The madness of dogs Rabies is a deadly zoonotic disease that causes tens of thousands of deaths every year, mainly among African and Asian children. It is usually transmitted to humans by dogs, and once symptoms appear, it is inevitably fatal. Despite control efforts, rabies continues to circulate at very low prevalence in Serengeti district, Tanzania, where Mancy et al. have been tracking cases in several species for more than a decade to understand the dynamics of the virus. Highly resolved genetic data allowed the authors to trace transmission networks, from which individual dog behavior emerges as a key factor (see the Perspective by Antolin). Some infected dogs may travel long distances and introduce new lineages into neighboring communities, whereas others may simply bite other animals. Because dogs are mobile, culling fails, and the only resort is fully comprehensive dog vaccination. —CA Individual variation in rabid dog behavior ensures virus dispersal and cocirculation of lineages, enabling persistence at low prevalence.