Date of this Version
N.W. van den Brink et al.
Rodents began to associate with humans at least from the early Neolithic era with the beginnings of systematic sequestering of food stores by humans (Cucchi and Vigne 2006; Reperant and Osterhaus 2014). About the year 541, the Justinian plague started amid the central granaries and crowded, unsanitary conditions of the later Roman cities. The resulting pandemic was the first documented example of the potentially devastating impact of commensal rodents on European society. The primary reservoir host and source of the plague was the black rat (Rattus rattus), which has widely thought to have disseminated from South-East Asia along land and marine trade routes (McCormick 2003). That plague spread through late Roman and early medieval Europe until the eighth century (McCormick 2003). About 600 years later, the Black Death was also vectored by R. rattus. Both pandemics were caused by Yersinia pestis, possibly infecting R. rattus via endemically infected burrowing rodents along the trade routes of Central Asia (Reperant and Osterhaus 2014); however, the strains were different between the pandemics, and the occurrences seemed to be independent (Wagner et al. 2014). R. rattus is considered to be the commensal reservoir of Y. pestis and fleas, the vectors between rats and humans, although in some Nordic countries human-to-human infections are thought also to have been important (Hufthammer and Walløe 2013). Additionally, recent assessments based on analysis of climate data suggest that R. rattus did not provide a reservoir and that overland routes were not the pathway, rather Yersinia pestis was repeatedly introduced into Europe from Asia via maritime routes (Schmid et al. 2015). Currently, the human plague is still affecting Asian and African countries, with thousands of annual casualties (Butler 2009). Rodents also carry a wide range of other bacteria as well as ecto- and endoparasites and viruses that pose a potential risk to human health (Battersby 2015).