The signs and symptoms of a disease generally depend on the tissue or the organ which the microbe targets. For example, if in a particular disease lungs are the target, then the symptoms will be cough, breathlessness, etc. Likewise, if liver is the target for the microbes then it might lead to jaundice.
Nausea, pain, dizziness, fatigue, etc. are felt by the body while suffering from a disease and these are known as symptoms.
The change in heart rate, temperature, moisture, colour difference, etc. can be observed by the surrounding people and are termed as signs, indicating an abnormality or a disease.