chapter 14

Pathology

Study of disease

Etiology

Cause of disease

Endemic disease

Present in population

Epidemic

Many people short period

Predisposing factors

Gender, inherited traits, climate, fatigue, age, lifestyle, nutrition, chemotherapy, lack of vaccination

Septicemia

Blood poisoning; bacteria

John snow

Cholera

Nightingale

Sanitation

Nonliving reservoir

Soil and water

Latent disease

Inactive then active

Acute disease

Develop rapidly only a short time

Human microbiome project

Analyze his relationships with microbial communities on the body and human health

Mortality rates

Number of deaths related to disease within a population

Morbidity rates

Number of people affected by disease in a population

Notifiable infectious diseases

Diseases with physicians report occurrence

Descriptive epidemiology

Collection and analysis of data-snow- cholera

Analytical epidemiology

Analyze a particular disease to determine its probable cause-nightingale-sanitation

Experimental epidemiology

Hypothesis and controlled experiments- Semmelweis-sepsis

Epidemiology

Where and when diseases Occur and how they are transmitted through populations

Microbial antagonism

is a competition between microbes

Symbiosis

is the relationship between normal microbiota and the host

Commensalism

One organism benefits, the other is unaffected

Mutualism

Both organisms benefit

Parasitism

One organism benefits, the other has the expense

Modern transportation infectious diseases

Zika virus and west Nile encephalitis

Insect vectors infectious diseases

Aedes aegypti

Animal control infectious diseases

Lyme disease

Public health failure

Bioterrorism

Ecological disaster

Coccidioidomycosis

Genetic recombination disease

E. Coli

Evolution of new strains diseases

Vibrio cholerae

Weather patterns

Hantavirus

Emerging infectious disease

Show a potential to increase: vector borne

Standard precautions

Minimum practices

Transmission based precautions

For suspected infections: contact, droplet, and airborne precautions

Healthcare associated infections

Microorganisms, compromised host, chain of transmission

Compromised host

Resistance to infection is impaired by disease

nosocomial infections

Infection after receiving treatment in a health care facility

Mechanical transmission

Arthropod carries pathogen on feet

Biological pathogens

Pathogen reproduces; bites or feces

Vehicle transmission

Airborne, waterborne, foodborne

Symptoms

Changes in body function from disease

Sign

Changes in body that can be observed

Syndrome

Group of signs

Communicable disease

Disease has spread from one host to another

Incidence

number of people who develop a disease during a particular time period

Prevalence

number of people who develop a disease at a specified time, regardless of when it first appeared

Sporadic disease

Occur occasionally

Endemic disease

Constantly present

Chronic disease

Symptoms Develop slowly

Subacute disease

Between acute and chronic

Latent disease

Inactive for period but activate later with symptoms

Herd immunity

Immunity in most of population

Local infection

pathogens are limited to a small area of the body

Systemic infection

Infection throughout the body

Focal infection

Systemic infection that started as local infection

Droplet transmission

transmission via airborne droplets less than 1 meter

Indirect contact transmission

spread to a host by a non living object called a fomite

Congenital transmission

Mother to fetus or newborn at birth

Direct contact transmission

Close association between infected and host

Carriers ( human reservoirs )

In apparent infections

Zoonoses (animal reservoirs)

Animals to humans

Toxemia; viremia

Toxins and viruses in blood

subclinical disease

No signs of disease

incubation period

Interval between infection and first signs

Prodomal period

Short period after incubation; early mild symptoms

Period of illness

Most severe

Period of convalescence

Body returns to its normal state

Koch postulates 1

Pathogen must be present in every case

Koch postulate 2

Must be isolated from host and grown in culture

Koch postulates 3

Pathogen from pure culture must cause disease when it’s innoculated in healthy animal

Koch postulates 4

Must be isolated from innoculated animal and shown in original organism

Koch postulates exceptions

Some pathogens cause several conditions, some cause disease in humans, never been cultured