The aim of this special edition of International Migration is to bring about discussion between those conducting research in Diaspora Studies and the Anthropology of Public Health and Medicine. Historically, international migration has been associated with the transport of disease. Regardless of the evidence, metaphors of plague, and infection have circulated and been used to marginalise and keep out diaspora communities in host countries in an effort to ‘exclude filth’. Migrants have been referred to in terms such as the ‘Asiatic menace’ indicating a virus-like threat to local populations. We look at the impact the traces of these images have on current host nations’ perceptions of diaspora communities and also ask what impact does this have on the diasporic communities’ self-perceptions, if any? Does this affect conceptions of belonging, or feed into continuing dialogues of displacement? The movement of people has long been associated with the spread of disease and infections. In light of this, we are concerned with the role of medical knowledge and practices in relation to diaspora communities, and how these discourses have contributed to the perception of diaspora populations by host societies, and helped shape wider questions of belonging and citizenship. We aim to look at these questions in their historical context, both in their continuities and discontinuities, emphasising the importance of this to an understanding of current practices. Circuits of migration, and connected medical practices are taking new forms, where, on the one hand migrants are still associated with disease and pollution, but on the other migrants are also increasingly staffing the infrastructure of western public health services. At the same time, the west can no longer lay claim to ‘superior’ biomedical provision. These shifts signal new directions in the relationship between medical discourse and diasporic ‘others’, giving rise to a contradictory language of migrants being seen as both a threat, and a solution to the ‘health of the nation’.