users from both the public and private domains. Internet-based platforms can be used by the general public to determine local and international disease outbreaks. Consumers can also contribute their own epidemiologically relevant data to these services. Advantages Space-based tele-epidemiological initiatives, using satellites, are able to gather environmental information relevant to tracking disease outbreaks. S2E, a French multidisciplinary consortium on spatial surveillance of epidemics, has used satellites to garner relevant information on vegetation, meteorology and hydrology. This information, in concert with clinical data from humans and animals, can be used to construct predictive mathematical models that may allow for the forecasting of disease outbreaks. Web-based tele-epidemiological services are able to aggregate information from several disparate sources to provide information on disease surveillance and potential disease outbreaks. Both ProMED-mail and Healthmap collect information in several different languages to gather worldwide epidemiological information. These services are both free and allow both health care professionals and laypeople to access reliable disease outbreak information from around the world and in real-time. Disadvantages Space-based methodologies require investment of resources for the collection and management of epidemiological information; as such, these systems may not be affordable or technologically feasible for developing countries that need assistance tracking disease outbreaks. Further, the success of space-based methodologies is predicated on the collection of accurate ground-based data by qualified public health professionals. This may not be possible in developing countries because they lack basic laboratory and epidemiological resources Web-based tele-epidemiological initiatives have a unique set of challenges that are different from those experienced by space-based methodologies. HealthMap, in an effort to provide comprehensive worldwide information, contains information from a variety of sources including eyewitness accounts, online news and validated official reports. As a result, the site necessarily relies upon third party information, the veracity of which they are not liable. See also Landscape epidemiology Satellite imagery Telehealth Telematics Telemedicine Telenursing Teleophthalmology References Epidemiology Human geography Telehealth Health informatics