HealthMap.org is an online map tool that locates any reports of disease from a selection of news sources.  Available in multiple languages, HealthMap is a great use of the Google Maps API.  In fact, HealthMap is funded by Google, which explains why they are so dependent on the Google Maps data.

HealthMap brings together disparate data sources to achieve a unified and comprehensive view of the current global state of infectious diseases and their effect on human and animal health. This freely available Web site integrates outbreak data of varying reliability, ranging from news sources (such as Google News) to curated personal accounts (such as ProMED) to validated official alerts (such as World Health Organization). Through an automated text processing system, the data is aggregated by disease and displayed by location for user-friendly access to the original alert. HealthMap provides a jumping-off point for real-time information on emerging infectious diseases and has particular interest for public health officials and international travelers.

They also recently launched an iPhone app called Outbreaks Near Me, available for free in the iTunes app store.  The app allows you to view the maps from your iPhone and get alerts for outbreaks in your area.