Lecture 7: Principles of Infectious Disease Flashcards
(29 cards)
Normal Microbiota
Sum of microorganisms that colonize the body’s surface without normally causing disease
Resident Microbiota
- part of normal microbiota throughout life
- usually commensal
- upper respiratory tract, digestive tract, urinary tract
Transient Microbiota
may be present for only hours to months and are found in same regions as resident microbiota, but cannot persist in the body
Acquisition of Normal Microbiota
- Development in the womb is free of microbiota (Axenic)
- Microbiota begins to develop during the birthing process
- much of ones resident microbiota is established during the first months of life
Opportunistic Pathogens
- part of normal microbiota that can cause disease under certain conditions:
- Immune suppression
- Changes in the normal microbitoa
- introduction of normal microbiota into unusual sites of the body
Periotinitis
- Microbes in an unusual body site
- when the appendix bursts and bacteria gets into the system
Disease
Abnormal medical condition associated with specific symptoms and signs
Infection
Invasion and colonization of a host organisms body by a pathogen
-Inf diseases result only if the invading pathogen alters the normal functions of the body
Pathology
study of disease
Etiology
study of the cause of disease
Pathogenesis
development of disease
Categories of Disease
Hereditary, Congenital, Degenerative, Nutritional
Symptom
- Change in body function that is felt by a patient as a result of disease
- Subjective manifestation
- Headache, Pain
Sign
- Change in a body that can be measured or observed as a result of disease
- Objective manifestation
- Rash or Swelling
Syndrome
Specific group of signs and symptoms that accompany a disease
Germ Theory of Disease
Claims that disease can be caused by infections of pathogenic microorgansims
Koch Postulates
To prove a specific microbe causes a specific disease:
- suspected germ must be present in every case of the disease
- germ must be isolated and grown in pure culture
- cultured form must cause the disease when its inolculated into healthy experimental host
- Same germ must be reisolated from the diseased experimental host
Infectious Diseases can be classified by:
- Taxonomic groups of the causative agent
- Severity and duration (chronic vs. acute)
- How they spread to their host
- Systemic vs. local
- effects they have on populations
Stages of Infectious Diseases
- Incubation Period- No signs or Symptoms
- Prodromal Period- Vague, genreal Symptoms
- Illness- most severe signs, symptoms
- Decline- declining signs and symptoms
- Convalescence: no signs or symptoms
Disease can be distinguished as:
Acute, Chronic, Subacute, Latent, Asymptomatic
Reservoires
sites at which infectious agents remain viable and from which infection of individuals can occur
-most pathogens can’t survive for long outside of their host
3 general types of carriers
Human (Active or healthy) Carriers, Animals, Nonliving matter
Human carriers
Active: individuals who have an infectious disease
Healthy: asymptomatic themselves, but infective to others
Animal Carriers
Zoonosies
Zoonotic disease aquired through direct contact with animals or their waste, eating animals, blood sucking arthropods
-reverse zoonosis (humans back to animals) has been seen, but more rare
