U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Document Type


Date of this Version



Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 16, No. 10, October 2010, pp. 1649-1650


Letters exchanged on role of Y. pestis in European plague Black Death.

Our colleague and mentor David E. Davis researched and wrote in his retirement after years of research and reflection on rat ecology and rodent-borne diseases (3,4). Rattus rattus is commonly recognized as the vertebrate host of fl ea-borne plague that swept through Europe in the 1300s, killing >50% of the population. Davis believed this explanation did not fit what he knew of the ecologic requirements of fleas and black rats. He studied reports of archeologic excavations and reviewed poems, medieval bestiaries, and paintings and concluded that these rats were scarce during the Black Death era.

The finding that human body lice can be bubonic plague vectors suggests a mechanism for human-to- human transmission continuing during winter in inland areas and, as suggested by the authors, could also explain total deaths in households.