What Are the Stages of Natural History of Disease?

Natural history of disease is a term that refers to the progression of a disease in an individual over time, from the initial exposure to its resolution. Understanding the natural history of a disease is essential for developing effective preventive and treatment strategies. In this article, we will explore the stages of natural history of disease.

Stage 1: Susceptibility

At this stage, an individual does not have the disease, but they are at risk of developing it. The risk factors for susceptibility can be genetic, environmental, or behavioral. For example, smoking is a risk factor for lung cancer, and a family history of breast cancer increases the likelihood of developing breast cancer.

Stage 2: Subclinical Disease

In this stage, the individual has been exposed to the disease-causing agent but has not yet developed any symptoms. For example, in tuberculosis infection, many individuals may show no symptoms despite having the bacteria in their body.

Stage 3: Clinical Disease

This stage refers to when an individual starts showing signs and symptoms of the disease. The symptoms may be mild or severe depending on various factors such as age and overall health status. The clinical presentation may vary among individuals even with the same type of illness.

Substage 1: Mild Disease

In mild cases, an individual may have only a few or no symptoms at all. They may still be able to carry out their daily activities with minimal interruption.

Substage 2: Severe Disease

In severe cases, an individual might experience intense symptoms that significantly affect their quality of life. They may need hospitalization or other medical interventions to manage their condition.

Stage 4: Recovery or Death

This stage marks the end point for any disease progression. An individual either recovers from their illness or succumbs to it. In some cases, the disease may leave long-term effects on the body, even after recovery.


The natural history of disease has several stages that an individual may go through, from susceptibility to recovery or death. Understanding these stages and the factors that influence them is crucial in developing effective preventive and treatment strategies. By recognizing the early stages of a disease, healthcare professionals can intervene early to prevent it from progressing further.