Fig. 7. AD associated neuropathologies are found in cats and dogs.

We computed the relative number of studies reporting a pathology in humans (a, b) cats (a), and dogs (b). These percentages show that many AD-related neuropathologies in humans are also observed in companion animals. Only studies explicitly searching for the presence of a neuropathology are considered in these statistics. a, b Studied pathologies include phosphorylated tau (pTau), NFTs, CAA (i.e., meningeal, and cortical), as well as early and mature plaques. A relatively large percentage of studies report plaques, pTau, and NFTs in cats and dogs. a However, no mature plaques are reported in cats. These data are from Supplementary Data 2¹²⁵. Age distribution of neuropathologies onset across humans and carnivore species (c–e), including companion animals and e other carnivore species. We considered the age of onset of early (d) and Amyloid-β e as well as tau pathology (f) and tau (g) from data provided in Supplementary Data 2. We included all listed ages (i.e., ≥ and >), as well as data from individuals with Down syndrome. The age of early and mature plaques, as well as neurofibrillary tangles onset in Down syndrome is relatively early and their ages are highlighted with a star (Supplementary Data 2). These graphs show that companion animals and humans possess plaques and tangles. e Interestingly, mature plaques are not observed in cats and other feliforme species (see names in light grey), but they are observed in dogs and their close relatives (e.g., polar bears, sea lions). These boxplots show upper and lower quartiles, maximums, and minimums. We used adult (and not juvenile) ages to assess neuropathology onset for wild Tsushima leopard cats.