Peripheral countries are at a disadvantage with respect to the construction of scientific knowledge, which is mostly carried out by a small number of traditional core loci countries. However, in a few cases, groups of scientists are able to break through exclusion barriers. Sometimes they tackle relevant issues, share values and procedures with core loci representatives, and take part in heated controversies: in short, they participate in the construction of legitimate science. These scientists form 'centres of excellence' in scientifically marginal countries. In this paper, contextual conditions involving the emergence, establishment and decline of such enterprises are discussed, on the basis of examples drawn from the history of Chagas disease (Cd). In this history, we see a major discovery established, deconstructed and re-established. Quantitative analyses of publications on Cd over 70 years show the relation between the choice of different types of journals and methodological approaches, and the legitimation strategies adopted by different groups of practitioners. It also shows the outcomes of such strategies in terms of production concentration, emergence of new authors and growth of institutional work. This story shows that it is important for the pioneers to establish a different intellectual culture in their local environment. Unless they do so, and gain its acceptance among their immediate colleagues, the enterprise cannot preserve its status as a centre of excellence.
