Infectious Diseases are disorders caused by organisms — like bacteria, viruses, fungi, or parasites. Numerous organisms sleep in and on our bodies. They're normally harmless or even helpful. But under specific conditions, some organisms may cause disease. Some infectious diseases can be transferred from person to person. Some are transmitted by insects or other animals. And you’ll get others by consuming contaminated food or water or being exposed to organisms within the environment. 

Causes: Infectious diseases spread in multiple ways. In many cases, direct contact with a sick individual, either by skin-to-skin contact (including sexual contact) or by touching something another person touches, transmits the disease into a replacement host. Contact with body fluids, like blood and saliva, also spreads infectious diseases. 

Some diseases spread through droplets discharged from a sick person’s body once they cough or sneeze. These droplets linger within the air for a brief period of time, landing on a healthy person’s skin or inhaled into their lungs. 

Infectious diseases can be caused by: 

Bacteria: These single-cell organisms are responsible for illnesses such as strep throat, urinary tract infections, and tuberculosis.
Viruses: Even smaller than bacteria, viruses cause multiple diseases ranging from the common cold to AIDS. 
Fungi: Many skin diseases, like ringworm and tinea pedis, are caused by fungi. Other sorts of fungi can infect your lungs or systemic nervosum. 
Parasites: Malaria is caused by a small parasite that is transmitted by a mosquito bite. Other parasites could also be transmitted to humans from animal feces. 

Symptoms: You may undergo one or several symptoms of an infectious disease. It’s important to ascertain a doctor if you’ve got any chronic (ongoing) symptoms or symptoms that get worsen over time. Each infectious disease will have its own specific signs and symptoms. General signs and symptoms common to a variety of infectious diseases include: 

1. Fever
2. Diarrhoea
3. Fatigue
4. Muscle Aches
5. Coughing
6. Running Nose
7. Allergies