Barstow says, "Of course, there are other uses of surveillance data.
"Surveillance data is important for identifying sudden increases in disease occurrence, but it’s also important for following secular (long-term) trends and patterns of disease. For example, it would be useful to keep tabs on the frequency of cases of West Nile virus to guide decisions about mosquito control. In addition, surveillance data for HIV would be important for following long-term trends and to anticipate the needs of the population. Surveillance data is also useful for monitoring the effectiveness of prevention programs. And finally, surveillance data sometimes generate hypotheses. For example, in 1980 it was discovered that many of the cases of toxic shock syndrome occurred in menstruating women. This led to research that demonstrated that the syndrome was associated with a particular brand of tampon, and the product was promptly removed from the market."
Additional References:MA DPH Epidemiology Program