Could Urban Ports Be a Site of Introduction for Foreign Rats and Their Diseases?
A recent study on urban rats in Vancouver revealed the presence of an ear mange mite, Notoedres muris in almost half the rats collected at an international shipping port. The mite was only found in rats at the port, and not in any of the > 700 rats collected in the areas surrounding the port. Since N. muris is only transmitted through direct contact among rats, the presence of the mite at the port likely represents an importation event. Historically, international shipping has been responsible for importation and rats and their diseases into new areas. This is one of the ways that bubonic plague spread around the world, for example. Although, N. muris is not a health risk to people, it suggests that Canadian ports could be a site for introduction of more noxious, rat-borne pathogens in the future. Check out the Vancouver Rat Project Website (www.vancouverratproject.com) for more details.