Stages of Infection

Stages of Infection An understanding of the stages in the development of an infection is necessary to intervene and disrupt the infection cycle. An infection progresses through the following phases: Incubation period Prodromal stage Full (acute) stage of illness Convalescent period The course and severity of the infection, as well as the patient’s response, influence the type and extent of nursing care provided. Incubation Period The incubation period is the interval between the pathogen’s invasion of the body and the appearance of symptoms of infection. During this stage, the organisms are growing and multiplying. The length of incubation may vary. For example, the common cold has an incubation period of 1 to 2 days, whereas tetanus has an incubation period ranging from 2 to 21 days. Prodromal Stage A person is most infectious during the prodromal stage. Early signs and symptoms of disease are present, but these are often vague and nonspecific, ranging from fatigue and malaise to a low-grade fever. This period lasts from several hours to several days. During this phase, the patient often is unaware of being contagious. As a result, the infection spreads to other hosts. Full Stage of Illness The presence of infection-specific signs and symptoms indicates the full stage of illness. The type of infection determines the length of the illness and the severity of the manifestations. Symptoms that are limited or occur in only one body area are referred to as localized symptoms, whereas symptoms manifested throughout the entire body are referred to as systemic symptoms. Convalescent Period The convalescent period involves the recovery from the infection. Convalescence may vary according to the severity of the infection and the patient’s general condition. The signs and symptoms disappear, and the person returns to a healthy state. However, depending on the type of infection, there may be a temporary or permanent change in the patient’s previous health state even after the convalescent period. A person may continually pass through the four phases with the same infectious process, such as with herpes simplex. Although there may have been only one infectious exposure, the infection may continue to cycle through the phases. Factors Affecting the Risk for Infection The susceptibility of the host depends on various factors: Integrity of skin and mucous membranes, which protect the body against microbial invasion pH levels of the gastrointestinal and genitourinary tracts, as well as the skin, which help to ward off microbial invasion Integrity and number of the body’s white blood cells, which provide resistance to certain pathogens Age, sex, race, and heredity, which influence susceptibility–neonates and older adults appear to be more vulnerable to infection (see the accompanying box: Focus on the Older Adult) Immunizations, natural or acquired, which act to resist infection Level of fatigue, nutritional and general health status, the presence of pre-existing illnesses, previous or current treatments, and certain medications, which play a part in the susceptibility of a potential host Stress level, which if increased may adversely affect the body’s normal defense mechanisms Use of invasive or indwelling medical devices, which provide exposure to and entry for more potential sources of disease-producing organisms, particularly in a patient whose defenses are already weakened by disease Health habits that promote wellness can reduce potential risk factors, thus decreasing the susceptibility of a host. Sensible nutrition, adequate rest and exercise, stress-reduction techniques, and good personal hygiene habits can help maintain optimum bodily function and immune response. Unsafe sex practices and sharing intravenous (IV) needles are potentially dangerous, providing an opportunity for pathogens to enter a host and cause an infection.