Manifestation Of Disease

Local Infection

Pathogens are limited to a small surface area of the body

• Ex: paper cut

Systemic Infection

An infection throughout the body

Focal Infection

Systemic infection that began as a local infection

Primary Infection

Acute infection that causes the initial illness

Secondary Infection

Opportunistic infection after primary infection

Acute Disease

Symptoms develop and recede rapidly

Chronic Disease

Continual organism production over a long period of time

• ex: Hepatitis B. Virus

Latent Disease

Disease with a period of no symptoms when the microbe is inactive

• ex: Herpes

Symptom

A change in body function that is felt by the patient as a result of the disease

• ex: achy, weak, fever

Sign

A change in body that can be measured of observed as a result of disease

• ex: rash, fever

Syndrome

A specific group of signs and symptoms that accompany the disease

Latency

Period of dormancy seen in some chronic infections

Sequelae

Long term or permanent damage to your organs or tissues

1. Incubation Phase

The time from the initial contact with the infectious agent to the appearance of symptoms

2. Podromal Stage

1-2 days of early symptoms appearing

3. Acute phase

Infectious agent multiplies at high levels, exhibits great toxicity, becomes well established in host

4. Period of Convalescence (If our immune system is winning)

Patient’s immune system begins to respond to the infection and signs and symptoms begin to decline

5. Continuation Phase

Either organisms lingers for months and years or organisms is gone but symptoms continue

Reservoirs for Pathogens

Humans, animals, and nonliving components of Earth (dirt, water, sand)

Asymptotic Carriers

Infected but show no symptoms

Incubating carriers

Spread the infection through the incubating period

Convalescent Carriers

Recuperating patients without symptoms and continues to spread pathogens

Chronic Carriers

Individuals who shelter the infectious agent for long periods after recovery because of latency of the microbe

Passive Carriers

Medical personnel deal with contaminated secretions/blood risk picking up pathogens and passing it to others

Vertical Transfer

Disease is passed from parent to offspring

Horizontal Transfer

Disease is spread throughout population from one individual to another

Modes of Transmission

• Direct contact, indirect contact, vector transmission

Direct Contact

Occurs between skin or mucous membranes if the infected and soon to be infected

• ex: spread by kissing

Indirect Contact

Infected host to intermediate conveyor to another host

Fomite or Vehicle

Inanimate objects harbor and transmit pathogens to new host

Vector Transmission

Living organisms that transmit disease but doesn’t get sick

Biological Vector Transmission

Injecting saliva, defecating, blood

Mechanical Vector Transmission

Transferred by the legs or body by the vector (not internalized)

Nosocomial Infection

Infections acquired at the hospital

Factors Contributing to Noscomial Infections

• Collection point of pathogens, compromised host, chain of transmission

Etiology

Study of the cause of the infection

Epidemiology

Study of frequency and distribution of disease and other health related factors in a defined population

Name Two Organizations for Disease Control

Center for Disease Control and Prevention (CDC) and World Health Organization (WHO)

Florence Nightingale

Laid the foundations of modern epidemiology during the Crimean War

Mortality Rate

Number of people that die in a particular disease

Notifiable Disease

Diseases in which physicians are required by law to report to the Public Health Service

Endemic

A disease that is constantly present in a certain population

Epidemic

Large increase in number of cases in a certain area

Pandemic

World wide epidemic

Sporadic

Occasional cases at irregular intervals in random locales

Point-Source Epidemic

Infectious agent comes from single source and all of its victims were exposed at that source at the same time

Common-Source Epidemic

Results from common exposure to a single source of infection over a period of time

Propagated Epidemic

Results from an infectious agent that is communicable from person to person and is sustained over time in a population