Steps In The Disease Process

At this stage of the disease process, the pathogen establishes itself on or within the host.  It gains a proper niche which allows it to thrive and reproduce.  There are no symptoms and the host is absolutely unaware of the infection.  Future techniques in molecular biology may allow us to detect diseases at this early stage when it is vulnerable.  Sometimes in this stage, the host detects the disease once it is large enough and stages a successful counter-attack.

Incubation Period
The incubation period is basically the amount of time it takes the pathogen to establish itself within the host to the point where symptoms actually appear.  The incubation period depends on the disease: for most bacteria it takes 2 to 5 days, but for others like TB or leprosy it could take up to 20 or 30 years. 

Initial Symptoms
These are the first symptoms that clearly demonstrate a disease.  There is not a set group of initial symptoms because they vary greatly on the patient and which disease they may have.  Asymptomatic diseases (in which a patient has no symptoms) are extremely common, as the patient may have antibodies in production for a disease but have never been clinically diagnosed with that disease.

The acute stage is when the disease is at its fullest.  At this point, the patient is visibly ill and has true clinical symptoms.  During this stage, the intensity of the illness can be seen.  This intensity varies with the disease, the strain of the virus or pathogen, and the patient's condition.  Because of this, every single infectious disease is survivable, but all of them may also prove fatal to some people.  

Many factors determine what symptoms and outcome every disease brings.  These factors include:
  • The genetics of the host
  • The genetics of the infectious agent
  • The physical condition of the host
  • The stress encountered by the host during the disease
  • The age and sex of the host
  • The treatment of the patient
Diseases are very unpredictable because of all of these factors. They must be analyzed day by day, through statistical data. 

This is the period of the disease process in which all of the symptoms decline and the patient recovers.  There are six major paths that the recovery can take:
  • The pathogen/agent can be completely eliminated from the body, which allows the patient to return to perfect condition.
  • Sometimes, the patient can recover from the disease, but the infectious agent is still present in the body.  This is when the patient can become a carrier, which makes them capable of spreading the virulent form of the infectious agent for a certain period of time (depending upon the disease). Typohid, Herpes, and Human Papilloma Virus are certain diseases that are like this.
  • Some patients can appear to be completely recovered, however the disease could be silently progressing toward fatality.  This outcome occurs with syphilis, HIV, and tuberculosis. 
  • Some patients of herpes and hepatitis that became carriers have outbreaks of the disease during their entire lives, but they are normally never fatal.  
  • A disease can also become chronic, meaning that the victim partially recovers, but they are never truly back to their normal condition.  Symptoms of the disease are constantly present, and relapses may often occur.
  • In certain other cases, a patient may eliminate the infectious agent from their body, but the immune system is damaged to such an extent that the patient could end up developing an autoimmune disease such as rheumatoid arthritis.  An autoimmune disease is one in which the patient's body attacks its own cells.