Table 6 The potential for health and demographic surveillance systems

A promising start at surveillance and monitoring of disease status at the community level derives from the increasing proliferation of Health and Demographic Surveillance System (HDSS) longitudinal data – see examples from The Gambia [140] and Tanzania [141]. To-date these systems report on the marginal distribution of diseases across multiple communities, making them a useful basis for district level health planning. They do not, but easily could, include reporting on co-infection and, more generally, co-morbidity. This is not an instance where new data collection is required. It is only an instance of carrying out more elaborate reporting of information already available. There are, of course, limitations on the level of detail that can be recovered from extant HDSS data due to the lack of extensive laboratory assessment of stool and blood samples as, for instance in a polyparasitism study in Cote d’Ivoire where up to 10 distinct intestinal parasites were identified in a single individual [108]. Nevertheless, reporting of co-infection as observed in extant HDSS systems would represent an important first step toward routinizing district level data that could be brought in for planning of more comprehensive control strategies tuned to the real needs of communities. This would also provide an important information base for ascertaining the extent to which very labor, and financially intensive, disease elimination programmes (e.g. malaria elimination) are worth the investment where a host of other conditions are likely to deserve much greater attention.