Milder winters are allowing ticks to be more active year-round, transmitting disease such as malaria-like canine babesiosis into countries where it was once rare.
Frederic Beugnet of Merial Animal Health in Lyon, France, writes that the rare cat flea typhus may also be becoming more common in both cats and dogs.
Claudio Genchi of the University of Milan, says that summertime temperatures are becoming warm enough for the parasite roundworm dirofilaria, spread by mosquitoes, to incubate in its host.
Susan Shaw and colleagues at the University of Bristol, UK, warn that there is a real danger that warming will allow the canine leishmaniosis parasite to be spread northward by sandflies from a large population of infected dogs in the south of England.