Data collection is based on self-reporting through Monday-morning electronic reports using a standard form. The from is enquiring about possible exposure to persons suffering from RTI or GTI, and possible own symptoms of the same diseases during the preceding 7 day period (including weekends and other holidays). The form will require daily records offering all possible combinations of the following categories: healthy-with symptoms, working normally-day off, own disease-child ill-other reason for day off.