This request for applications aims to expand the current network of three rural nodes and two urban nodes to incorporate one urban node in the eThekwini Metropolitan Area and one rural node in the Eastern Cape Province. The objective is to increase the population size and diversity under longitudinal surveillance by SAPRIN, thereby improving the ability of SAPRIN data to serve as triangulation for national datasets and the study of mechanisms driving the national statistics, such as rural-urban migration. SAPRIN will fund participating nodes to implement a standard surveillance protocol. Funding will follow the three-yearly funding cycle of DSI, and three-year sub-contracts will be negotiated with each node by the South African Medical Research Council. It is an open call and applicants need not have responded to the earlier Request for Expression of Interest.