Phases of an infectious disease

    Specialists in the field say that an infectious disease is a pathology caused by organisms that colonize the host. Infectious diseases are also characterized by the fact that they have three stages of development.

     In this article I will tell you what are the stages of development of an infectious disease.

     The first period is called the pre-pathogenic period, and this period refers to the time when people are healthy, ie are in balance with the environment, are in circumstances of physical, mental and social well-being. During this period, people need to know that there is an interaction between the agent, the environment and the host. For this interaction to take place, the presence of the three elements mentioned above is required, otherwise there would be no incubation of a future disease.

     This period represents risk factors for the host when the three elements are unbalanced, because the infection occurs, they can be: endogenous (genetic, immune and mental conditions) or exogenous, refers to the ecological environment on which the agent depends. Therefore, infectious diseases are spread by exogenous risk factors.

     The second period is called the pathogenic or subclinical period, and this period corresponds to the time interval between the invasion by an infectious agent and the appearance of the first signs or symptoms of the infectious disease. If the transmission vehicle is a vector, its incubation time must also be taken into account. Specialists say that this period refers to the time interval between the penetration of the infectious agent into the vector until the vector becomes contagious.

     The incubation period is classified as follows:

  • The symptoms of people suffering from this problem come within 10 days of infection. In this case the period is called the short period.
  • In the intermediate period: the time interval between infection and the manifestation of symptoms is between 2 and 4 weeks.
  • And last but not least, the long incubation period. During this period, the symptoms appear one month after the transmission of the infectious agent.

     People also need to know that a clinical picture refers to the set of symptoms and signs of a disease, ie the perceptible change in the body or its functions that reveals its presence. The clinical picture allows us to diagnose the infectious disease.

     Specialists in the field also say that certain diseases do not present a clinical picture, ie they are asymptomatic. Although there was an infection, the host does not suffer from any symptoms of the disease caused by the infection with the parasitism of the microorganism.

     During this period there is a first manifestation of non-specific signs and symptoms, called secondary symptoms, these are not typical of a specific disease, but are subsequent to other signs of the disease, such as fever.

     After these first manifestations, specific or pathognomonic symptoms appear, characteristic of a certain disease, from this clinical sign an exact diagnosis can be made.

     During convalescence, people suffering from this problem must go through the symptoms of the clinical picture until complete recovery of health. It is a gradual period of recovery of health after suffering from the infectious disease, in this case.

     Knowing the characteristics of the three phases of a disease allows us to anticipate the diagnosis. The pre-pathogenic phase or the incubation phase is a key factor that determines the ability to spread and virulence of an infectious disease. Therefore, it is vitally important to study and know these characteristics, especially of those infectious diseases with epidemic potential.