Progress of Disease: Infection to Recovery

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: The Different Routes of Infectious Disease Transmission

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:48 Incubation Period
  • 2:07 Prodromal Period
  • 2:50 Period of Illness
  • 3:45 Period of Decline
  • 4:24 Period of Convalescence
  • 6:32 Lesson Summary
Add to Add to Add to

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Login or Sign up


Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Artem Cheprasov
This lesson will teach you about the five basic steps of the development of disease, what they are called, and what occurs during each phase. We'll talk about the incubation and prodromal period as well as the periods of convalescence, decline, and illness.

The Steps of the Disease Process

If you live in a big city and want to try to avoid traffic jams associated with such a densely populated place, then one of your options is to ride a subway or train to get to your destination. Each stop along the way gets you closer to where you need to go.

In this lesson, we're going to take a metaphorical ride on a train that will represent our body, on a track called the disease process, from our starting point called infection, to our destination stop that's called recovery.

As we go on this ride, we'll discover the different generalized steps associated with disease progression.

The Incubation Period

At the starting point of our train ride, called infection, we get a few nasty passengers aboard our train, our body. A bunch of microbes board the train, take a seat, and begin to multiply. The train they board is our body, and the seat they take is like a cell in our body that they use for replication purposes.

Once the microbes board the train and infect our body, something known as the incubation period begins. This is the period between infection and the first signs and symptoms associated with a disease.

During the incubation period, these microbes multiply all they want, and the person may actually spread the disease-causing microorganisms without even knowing they are sick! Again, this is a symptom-less stage where microbes not only multiply inside of our body but can also spread to other people.

But, the length of the incubation period is highly variable and is dependent not only on the microorganism that invades the person but the person's immune system as well.

The Prodromal Period

Once the train leaves the infection station and proceeds through the incubation period, it reaches the next stop or stage of disease development, known as the prodromal period. This is a short stage of disease development where a person begins to feel that they are getting sick.

Basically, this is where our train's conductor, our brain, knows that something is wrong, but is not exactly sure what. Essentially, the body feels something is amiss, but the full onset of signs and symptoms associated with the disease have yet to fully hit us.

The Period of Illness

As I mentioned, the prodromal period is quite short and pretty soon progresses to our next stop, called the period of illness. This is the step in the development of a disease where a person feels the typical signs and symptoms associated with the disease. In short, this is when you are sick; that's basically what it means. Our train essentially breaks down at this stop.

This is also the stage where you can most easily transmit a communicable disease to another person. You can imagine that once we reach this stop, a lot of the microbes that infected us a couple of stops back leave the train to seek out new targets.

The very peak of an illness' intensity, where you can most easily spread around these microbes, is known as the acme point.

The Period of Decline

Once we pass the acme point, we proceed into the period of decline, which is the stage of disease development where the immune system begins to bring microbial replication under control, which leads to the lessening of clinical signs and symptoms associated with the disease.

Essentially, you can liken this phase to the train's engineers, our immune system, finally getting the upper hand in fighting off the disease-causing pathogens and fixing our body up enough to get us moving and feeling a bit better.

The Period of Convalescence

Once the train gets moving a bit better, we reach the last stop of our train ride. This is known as the period of convalescence. This is the fifth and final stage of the disease process, one where microbial replication is fully stopped and the person returns to the pre-illness state. In short, this is the stage where the person recovers from their disease.

However, that definition comes with a catch or two. In some cases, depending on the disease, the person may not proceed to the period of convalescence and may die from their disease or be disabled.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 160 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create An Account