Chapter 14 Microbio part 1

What is a disease?

An abnormal state in which the body is not functioning normally.

What is pathogenesis?

The development of disease.

What is pathology?

The study of disease, including cause, development, and effects on the body.

What are the three components studied in pathology?

• Cause of the disease

• Disease development

• Disease effects on the body

What is etiology?

The study of the cause of a disease.

What is infection?

Colonization of the body by pathogens (infectious agents).

What three steps occur during infection?

• Pathogens enter the tissue

• Penetrate host defenses

• Multiply

What is symbiosis?

A close association between two different types of organisms.

What is commensalism?

One organism benefits and the other is unaffected.

 What is mutualism?

Both organisms benefit.

What is parasitism (pathogenic)?

One organism benefits at the expense of the host.

What are opportunistic pathogens?

Normal microbiota that can cause disease under certain conditions.

What is microbial antagonism?

Competition between microbes.

What are probiotics?

 Live non-pathogenic microbes applied to or ingested into the body for positive effects.

What are transient microbiota?

Microbes present for days, weeks, or months.

What are normal microbiota?

 Microbes that permanently colonize the host.

What is mutualistic symbiosis?

The beneficial relationship between normal microbiota and the host.

What body sites harbor normal microbiota?

• Skin

• Mucus membranes

• GI tract

• Outer opening of urethra

• External genitalia

• Vagina

• External ear canal

• External eye (lids, conjunctiva)

 What host factors affect normal microbiota?

• Age

• Sex

• Diet

• Hygiene

• Temperature & pH

• Medications

• Genes

• Stress

• Host defense
  

What are four ways normal microbiota protect the host?

• Occupy niches that pathogens might occupy

• Produce acids & affect oxygen availability

• Produce bacteriocins

• Support immune system development

What vitamins do normal GI microbiota synthesize?

Vitamin K and some B vitamins.

 According to Koch’s postulates, what must be true in every case of a disease?

The same pathogen must be present.

What is the second step in Koch’s postulates?

The pathogen must be isolated and grown in pure culture.

 What is the third step in Koch’s postulates?

The cultured pathogen must cause the disease in a healthy, susceptible animal.

What is the fourth step in Koch’s postulates?

The pathogen must be isolated again from the inoculated animal and shown to be the original organism.

 What are three exceptions to Koch’s postulates?

• Some pathogens cause several disease conditions

• Some cause disease only in humans

• Some microbes have never been cultured

What is a communicable (infectious) disease?

A disease spread from one host to another.

What is a contagious disease?

A disease easily spread from one host to another.

What is a non-communicable disease?

A disease not transmitted from one host to another.

What is a symptom?

A change in body function felt by a patient.

What is a sign?

A change in the body that can be measured or observed.

What is a syndrome?

A specific group of signs and symptoms that accompany a disease.

What is prevalence?

Fraction of a population having a disease at a given time (commonality).

What is incidence?

Fraction of a population that contracts a disease during a specific time (frequency).

What is a sporadic disease?

A disease that occurs occasionally.

What is an endemic disease?

A disease constantly present in a population.

What is an epidemic disease?

A disease acquired by many hosts in a given area in a short time.

What is a pandemic disease?

A worldwide epidemic.

What is herd immunity?

Immunity in most of a population.

What is an acute disease?

A disease with rapidly developing symptoms.

What is a chronic disease?

A disease that develops slowly over a long time.

What is a subacute disease?

A disease with symptoms between acute and chronic.

What is a latent disease?

A disease with a period of no symptoms when the agent is inactive.

What are the symptom categories of COVID-19 severity?

• Asymptomatic

• Mild

• Moderate

• Severe

• Critical

What happens in mild COVID-19 cases?

Fever, dry cough, tired, muscle pain, sore throat.

What happens in moderate COVID-19?

Breathlessness, tachycardia, persistent cough, higher fever.

What happens in severe COVID-19?

Pneumonia, extreme breathlessness, chest pain, high temperature, bluish lips/face.

What happens in critical COVID-19?

SARS, inflamed alveoli, possible ventilator.

What is infection fatality ratio (IFR)?

Deaths ÷ total infected individuals during a time period.

Deaths ÷ diagnosed cases during a certain period.

What is a local infection?

An infection limited to a small area of the body.

What is a systemic infection?

 Infection throughout the body, spreading to several sites and tissues.

What is a focal infection?

A systemic infection that began as a local infection.

What is sepsis?

Extreme inflammatory syndrome in response to severe infection.

What is septicemia?

Growth of bacteria in the blood.

What is bacteremia?

Presence of bacteria in the blood.

What is toxemia?

Toxins in the blood.

What is viremia?

Viruses in the blood.

What is a primary infection?

An acute infection causing the initial illness.

What is a secondary infection?

An opportunistic infection after a primary infection.

What is a subclinical disease?

A disease with no noticeable signs or symptoms (unapparent infection).

What are predisposing factors to disease?

• Gender (short urethra in females)

• Inherited traits (e.g., sickle-cell gene)

• Climate & weather

• Fatigue

• Age

• Lifestyle

• Stress

• Chemotherapy

What are the five stages in the development of an infectious disease?

1. Incubation period

2. Prodromal period

3. Illness

4. Decline

5. Convalescence