2.2.1  Measures targeting the reservoir of infection

During your community practice, the prevention and control measures you will undertake depend on the type of reservoir. In this section we will discuss measures for tackling human and animal reservoirs. When you encounter an infected person, you should undertake the measures described below.

Diagnosis and treatment

First, you should be able to diagnose and treat cases of the disease, or refer the patient for treatment at a higher health facility. There are two ways to identify an infected individual: when a patient comes to you (Box 2.3, on the next page, describes how you should approach a patient in order to identify a case), and by screening (discussed below). Identifying and treating cases as early as possible, reduces the severity of the disease for the patient, avoiding progression to complications, disability and death; and it also reduces the risk of transmission to others.

Box 2.3  Approaches to the diagnosis of a case

  • The first step is to ask about the main complaints of the patient.
  • Then ask about the presence of other related symptoms and risk factors.
  • Examine the patient physically to detect signs of any diseases you suspect.
  • Finally, refer the patient for laboratory examinations if available (e.g. blood examination for malaria).


Issues related to HIV/AIDS will be further discussed in Study Sessions 20–30 later in this Module.

Screening refers to the detection of an infection in an individual who does not show any signs or symptoms of the disease. It is carried out using specific tests called screening tests. Screening will help you to detect an infection early and organise appropriate treatment so as to reduce complications and prevent transmission to others. An example of screening that may be familiar to you is screening the blood of pregnant women for HIV infection.


You will learn further details about tuberculosis in Study Sessions 13–17 of this Module.

Following detection of an infectious disease, you may need to separate patients from others to prevent transmission to healthy people. This is called isolation. It is not indicated for every infection, but it is important to isolate people with highly severe and easily transmitted diseases. For example, an adult case of active pulmonary tuberculosis (‘pulmonary’ means in the lungs) should be kept in isolation in the first two weeks of the intensive phase of treatment. The isolation period lasts until the risk of transmission from the infected person has reduced or stopped. The period and degree of isolation differs between different diseases, as you will learn in later study sessions.


How to report communicable diseases will be discussed in Study Session 41 of this Module.

Cases of communicable diseases should be reported to a nearby health centre or woreda Health Office periodically, using the national surveillance guidelines.

Animal reservoirs

When infected animals are the reservoir involved in the transmission of communicable diseases, different measures can be undertaken against them. The type of action depends on the animal reservoir, and ranges from treatment to destroying the infected animal, depending on the usefulness of the animal and the availability of treatment. For example to prevent and control a rabies outbreak, the measures to be taken are usually to destroy all stray dogs in the area, and vaccinate pet dogs if the owner can afford this protection and the vaccine is available.

2.2  General approaches in the prevention and control of communicable diseases

2.2.2  Measures targeting the mode of transmission