Emergent, re-emerging, or just ignored: the many lives of cat and dog parasites

Parasites of dogs and cats are changing in ways that challenge our current understanding across many scientific fields. Factors such as climate change and increased global travel are reshaping parasite distributions, favoring their introduction and emergence in new foci. Some parasites appear to have emerged in new regions, while others have switched hosts or developed resistance. Other parasites may have long been overlooked because of limited diagnostic capacity. At the same time, genetic recombination and hybridization are producing variants with altered virulence and transmission patterns. Together, these trends suggest a future in which companion animal parasitology becomes more dynamic, unpredictable, and globally interconnected, demanding stronger surveillance, improved diagnostics, and closer integration between veterinary and public health efforts. © 2026 Elsevier Ltd