A syndrome is considered to be a set of different signs and symptoms that may seem to be related to each other. For example, there are certain illnesses that may seem similar to each other because they share the same symptoms. The syndrome is often to be linked to certain diseases that may be linked to pathogens. The disease is known to be more precise but do take note that these terms are sometimes used interchangeably.
The only difference is that the disease is more specific. This is a type of illness that may be cured especially when it is caught early. If not, then disease may turn fatal. There are some diseases that can be considered deadly even if they are caught early.