Nosopsyllus fasciatus

Nosopsyllus fasciatus, the northern rat flea, is a species of flea found on domestic rats and house mice. Northern rat fleas are external parasites, living by hematophagy off the blood of rodents. N. fasciatus can bite humans, but they are more common parasites of rodents. Since N. fasciatus carries the agents responsible for plague and marine typhus and can bite humans, making the species of one of concern for people. Diseases that can be spread through fleas include the plague and typhus. The rat flea is widespread due to their relationship to rodents and other vertebrates. They can be found co-infecting their host with other parasites.

It is the most widely spread of its genus, having originated in Europe, but has been transported to temperate regions worldwide. The genus, Nosopsyllus, contains sixty-eight taxa, which is then divided into four categories Nosopsyllus, Gerbillophilus, Nosinius, and Penicus.