Microbiology ch 14

The study of disease

The study of the cause of a disease

The development of disease

Colonization of the body by pathogens

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

it can be present for days, weeks or months

-can be washed off 

Bacteria on the body that permanently colonizze the host.

The relationship between normal microbiota and the host.

When one organism benefits and the other is unaffected 

When both organisms benefit

When one organism benefits at the expense of the other.

Some normal microbiota are opportunistic pathogens

A competition between microbes. 

• it protects the host by:
• -occupying niches that pathogens might occupy
• -producing acids
• -producing bateriocins
•  

They are live microbes applied to or ingested into the body, intended to exert a beneficial effect 

• 1-The same pathogen must be present in every case of the disease.
• 2-The pathogen must be isolated from the disease's host and grown in pure culture.
• 3-The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible lab animal.
• 4-The pathogen must be isolated from the inoculated animal and must be shown to be the orginal pathogen.  

• Koch's postulates are used to prove the causse of an infectious disease.
• -some pathogens can cause several disease conditions
• -some pathogens cause disease only in humans  

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

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

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

A disease that is spread from one host to another.

A disease that is easily spread from one host to another

A disease that is not transmitted from one host to another. 

Fraction of a population that contracts a disease during a specific time.

Fraction of a population havig a specific disease at a given time. 

Disease that occuurs occasionally in a population.

Disease constantly present in a population

Disease acquired by many hosts in a given area in a short time.

Worldwide epidemic

immunity in most of a population

Symptoms develop rapidly

Disease develops slowly

Symptoms between acute and chronic

Disease with a period of no symptoms when the causative agent is inactive 

Pathogens are limited to a small area of the body

An infection throughout the body

Systemic infection that began as a local infection

Toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infection. 

Bacteria in the blood

Growth of bacteria in the blood 

Toxins in the blood

Viruses in the blood

Acute infection that cuases the initial illness

Opportunistic infection after a primary (predisposing) infection

No noticeable signs or symptoms (inapparent infection) 

• -make body more susceptible to disease
• *Short urethra in females
• *Inherited traits, such as the sickle cell gene
• *Climate and weather
• *Age
• *Fatigue
• *Lifestyle
• *Chemotherapy 

• Continual sources of infection
• -Human: AIDs, gonorrhea
•      -Carriers may have inapparent infections or latent diseases

• -Animal: Rabies, Lyme disease
•    -some zoonoses may be transmitted to humans
• -Nonliving: Botulism, tetanus
•    -soil 

Direct: Requires close association between infected and susceptible host

Spread by fomites

Transmission via airborne droplets

Transmission by an inanimate reservoir  

(food, water, air)  

• Arthropods, especially fleas, ticks, and mosquitoes
• -transmit diease by 2 general methods:
•      1-mechanical transmission
•      2-Biological transmission 

Arthropod carries pathogen on feet

Pathogen reproduces in vector

• -Are acquired as a result of a hospital stay
• -Affect 5-15% of all hospital patients 

Coagulase-negative staphylococci

Diseases that are new, increasing in incidence, or showing a potential to increase in the near future. 

John Snow

Collection and analysis of a data 

-John Snow 

Comparison of a diseased group and a healthy group

-Florence Nightingale 

Controlled experiments

-Ignaz Semmelweis 

Health care workers report specified disease to local, state, and national offices

Physicians are required to report occurence

Incidence of a specific notifiable disease

Deaths from notifiable diseases

Number of people affected in relation to the total population in a given time period

Number of deaths from a disease in relation to the population in a given time 

• -Genetic recombination
•       *E.coli, avian influenza  (H5N1)

• -Evolution of new strains
• -Inappropriate use of antibiotics and pesticides
•    *antibiotic-resistant strains
• -Change in weather patterns
•    *hantavirus 

• -Modern transportation
•        *West Nile virus
• -Ecological disaster, war, and expanding human settlement
•    *coccidiodomycocis
• -Animal control measures
•     *lyme disease
• -Public health Failure
•    *diphtheria 

The study of where and when diseases occur. 

Centers for Disease Control and Prevention

Collects and analyzes epidemiological information in the United States