The word "norovirus" often conjures up images of an outbreak among people in close quarters, such as on cruise ships. But noroviruses also infect animals, such as dogs and cats. It was recently shown that noroviruses can be transmitted from humans to dogs. Is the reverse also possible? According to a recent analysis of blood samples from humans in Italy, it might be.

Although the blood samples most commonly contained the "human" norovirus genotype (IV.1), they also contained the "animal" genotype (IV.2). This finding indicates that the evolution of human and animal noroviruses is tightly intermingled, probably as a result of a long history of social interactions between humans and domesticated pets. Transmission of norovirus from animals to humans, should it occur, would have far-reaching consequences for human health and food safety.

Study: Seroprevalence of Norovirus Genogroup IV Antibodies among Humans, Italy, 2010- 2011, Barbara Di Martino , Federica Di Profio, Chiara Ceci, Elisabetta Di Felice, Kim Y. Green, Karin Bok, Simona De Grazia, Giovanni M. Giammanco, Ivano Massirio, Eleonora Lorusso, Canio Buonavoglia, Fulvio Marsilio, and Vito Martella, Emerging Infectious Diseases, DOI: 10.3201/eid2011.131601, published 15 October 2014.