Infectious diseases are classified and categorized using several traits:

1. cause of agent
2. mode of transmission 
3. Duration of disease 
4. Location in the Body
5. severity of disease 
6. spread in population 

• Differentiate between acute, chronic, and latent infections. 

1. If it stays a long time and keeps affecting health, it's usually chronic. example HIV , TB , hepatitis infection B,C , Herpes simplex virus 

2. If it happens suddenly and ends quickly, it’s usually acute. influenza or cold 

• acute infection sudden onset, duration short time , symptom appear fast and strong.  The infection usually clear up with our without  treatment example flu or cold 
• chronic infection 
• develop slowly and long term take months or years. mild symptom and sometimes severe infection  example 
• latent infection the bacteria hid in the body without activation , it can be reactivate later when our immune system down or when taking immunocompromise treatment for example TB, herpes infection.