11.2 Flashcards by MARIANNE JOYCE TAYAG

belief that normal flora benefit a host by preventing overgrowth of more harmful microbes

Microbial antagonism

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prevents potential pathogens from gaining access to our body

Normal microbial flora

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What is the specific area in the human body where microbial antagonism helps prevent infections, such as from pathogens like Candida albicans?

Vagina

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close relationship between two
different organisms

Symbiosis

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Describes the relationship between
microorganisms and their host

Symbiotic relationships

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Symbiosis means

to live together

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3 types of symbiotic relationships

– Mutualism
– Commenalism
– Parasitism

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One organism benefits, the other is unaffected (harmless)

Commensalism

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Both organisms benefit
(helpful)

Mutualism

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One organism benefits and the other is harmed (harmful)

Parasitism

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Organism don’t cause disease unless appropriate condition exists (potentially harmful)

Opportunism

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Example of mutualism

Bacteria in human colon

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Example of commensalism

Staphylococcus on skin

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Example of parasitism

Tuberculosis bacteria in human lung

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Other terms for normal microbiota

Normal flora
Indigenous microbiota

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Refers to the organisms that colonize the body’s
surfaces without normally causing disease

Normal microbiota

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2 types of normal microbiota

Resident microbiota
Transient microbiota

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Are a part of the normal microbiota throughout
life

Resident microbiota (most are commensal)

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Remain in the body for only hours to
months before disappearing

Transient microbiota

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True or False

Transient microbiota are found in the same regions as resident microbiora

True

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3 reasons why transient microbiota cannot persist in the body

– Competition from other microorganisms
– Elimination by the body’s defenses
cells
– Chemical or physical changes in the
body

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Development in the womb is generally ____
of microorganisms

free of microorganisms

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Microbiota begins to develop during the

birthing process

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one’s resident microbiota is established during?

1st months of life

Normal microbiota or other normally harmless microbes that can cause disease under certain circumstances (people with underlying conditions)

Opportunistic pathogens

Enumerate 3 Conditions that provide opportunities for pathogens

– **Immune suppression** – **Changes in the normal microbiota** – changes in relative abundance of normal microbiota may allow opportunity for a member to thrive and cause disease – **Introduction of normal microbiota into unusual site in the body**

is the invasion of the host by a pathogen

Infection

results only if the invading pathogen alters the normal functions of the body

Disease

Infection vs. Disease

• Infection is the invasion of the host by a pathogen • Disease results only if the invading pathogen alters the normal functions of the bod

Disease is also referred to as

Morbidity

• Any deviation from a condition of good health and well-being • alteration of the state of a body or of some its organs that interrupts or disturbs proper performance of bodily function

Disease

A disease condition caused by the presence or growth of infectious microorganisms or parasites

Infectious disease

Disease vs. Infectious Disease

– Disease • Any deviation from a condition of good health and well-being • alteration of the state of a body or of some its organs that interrupts or disturbs proper performance of bodily functions – Infectious Disease • A disease condition caused by the presence or growth of infectious microorganisms or parasite

the mere presence of microbes in or on the body

Contamination

results when the organism has evaded the body’s external defenses, multiplied, and become established in the body

Infection

Contamination vs. Infection

• Contamination– the mere presence of microbes in or on the body • Infection– results when the organism has evaded the body’s external defenses, multiplied, and become established in the body

The presence of an infectious agent on a body surface, on or in clothes, beddings, toys, surgical instruments or dressings, or other articles or substances including water and food

Contamination

is the entry and development or multiplication of an infectious agent in the body of man or animals

infection

T or F An infection always cause illness

False

Enumerate the 4 levels of infection (Gradients of Infection)

– Colonization (S. aureus in skin and normal nasopharynx) – Subclinical or inapparent infection (polio) – Latent infection (virus of herpes simplex) – Manifest or clinical infection

Example of colonization

S. aureus in skin and normal nasopharynx

Example of subclinical or inapparent infection

Polio

Example of latent infection

Virus of herpes simplex

It is the lodgment, development and reproduction of arthropods on the surface of the body or in the clothing

Infestation

Example of infestation

Lice, itch mite

This term could be also used to describe the invasion of the gut by parasitic worms

Infestation

What parasitic condition is an example of infestation involving the gastrointestinal tract?

Ascariasis

4 manifestations of disease

Symptoms Signs Syndrome Asymptomatic / Subclinical

subjective characteristics of disease felt only by the patient

Symptoms

objective manifestations of disease that can be observed or measured by others

Signs

group of symptoms and signs that characterize a disease or abnormal condition

Syndrome

Infections that lack symptoms

Asymptomatic or Subclinical

Study of the cause of disease / causative agent

Etiology

Theory stating that disease is caused by infections of pathogenic microorganisms

Germ theory of disease

developed a set of postulates one must satisfy to prove a particular pathogen causes a particular disease

Robert Koch

established criteria illustrating how specific microbes cause certain disease

Koch’s postulates

State Koch’s Postulates

1) same pathogen present in every case of the disease 2) pathogen must be grown in pure culture 3) pathogen isolated from pure culture must cause disease in healthy host 4) pathogen must be re-isolated from inoculated lab animal

3 Exceptions to Koch’s Postulates

– Some pathogens can’t be cultured in the laboratory – Some diseases are caused by a combination of pathogens and other cofactors – Ethical considerations prevent applying Koch’s postulates to pathogens that require a human host

from either a reservoir or portal of exit

Transmission

3 groups of infectious disease **transmission**

– Contact transmission – Vehicle transmission – Vector transmission

3 types of Contact Transmission

Direct contact Indirect contact Droplet transmission

Give examples of direct contact and diseases transmitted thru it

handshaking, kissing, sexual intercourse, bites Rabies, herpes, syphilis

Give examples of indirect contact and diseases transmitted thru it

Drinking glasses, toothbrushes, toys, punctures Common cold, pneumonia, influenza

Give examples of droplet transmission and diseases transmitted thru it

Droplets from sneezing (within 1meter) Whooping cough, strep throat

3 types of vehicle transmission

Airborne Waterborne Foodborne

Give examples of airborne and diseases transmitted thru it

Dust particles Tuberculosis, Pulmonary Anthrax, Chickenpox

Give examples of waterborne and diseases transmitted thru it

Streams, swimming pools Cholera, *Giardia* diarrhea, *Campylobacter* infections

2 types of vector transmission

Mechanical Biological

Give examples of mechanical and diseases transmitted thru it

Flies, Roaches E. coli diarrhea, salmonellosis, trachoma

Give examples of biological and diseases transmitted thru it

Lice, mites, mosquitoes, ticks Yellow fever, typhus fever, malaria

Direct transmission

1. Close Personal Contact 2. Touching, Kissing, Sex etc.

Indirect transmission

1. Fomites 2. Droplets/Airborne 3. Vehicles 4. Vectors

What is the term for **inanimate objects** that can transmit infectious agents?

Fomites

3 examples of fomites

Tissues Drinking glasses Needles

Diseases transmitted via fomites

AIDS, hepatitis

What is the term for disease transmission through contaminated **water, food, or air**?

Transmission by a medium

Enumerate 3 common media involved in vehicle-borne transmission.

Air Water Fodd

Enumerate 2 diseases transmitted through vehicles (mediums).

Plague, Cholera

What type of disease transmission occurs via **saliva or mucus** expelled during coughing, sneezing, or talking?

Droplet transmission

Enumerate 3 activities that can result in droplet transmission

Coughing Sneezing Talking

What is the maximum distance over which droplet transmission typically occurs?

Less than 1meter

Carried on Water/Mucus Droplets

Airborne transmission

What is the maximum distance over which airborne transmission typically occurs?

Greater than 1 meter

2 types of vector-borne transmission.

Mechanical vector transmission Biological vector transmission

- Passive Process - Pathogens are on the body of the vector.

Mechanical vector transmission

Example of mechanical vector transmission

Fly landing on food

disease transmitted through mechanical vector transmission

Typhoid fever

Active Process Vector must bite or scratch or sting

Biological vector transmission

Example of biological vector transmission

Mosquito bite

disease transmitted through biological vector transmission

Malaria

2 routes of transmission

Vertical Horizontal

Mother to Offspring

Vertical transmission

Animal to Animal and Person to Person

Horizontal transmission

What is the specific route of vertical transmission that occurs through the placenta?

Transplacental transmission

infection that can be transmitted from mother to child through breastfeeding

HIV

Enumerate 3 routes of vertical transmission.

Transplacental Perinatal (during birth) Breastfeeding

2 infections transmitted transplacentally

*Rubella* *Toxoplasma* *gondii*

2 infections transmitted perinatally (during delivery)

*Listeria * *monocytogenes* *Neisseria* *gonorrhoeae*

4 major types of horizontal transmission

Contact spread Common vehicle transmission Airborne transmission Vector-borne transmission

T or F Humans have more than 2 layers of separation in placenta

F (only 2)

4 different methods of classification of infectious disease

1. The body system they affect 2 The taxonomic groups of the causative agent 3. Their longevity and severity 4. How they are spread to their host

transmitted directly or indirectly from 1 host to another

Communicable diseases

easily spread from 1 person to another

Contagious diseases

not spread from 1 host to another

Non communicable disease

4 Classification of disease based on frequency of occurrence

–sporadic –endemic –epidemic –pandemic

occurs only occasionally

Sporadic disease

constantly present in the population

Endemic disease

many animals in a given area get disease in a short time period

Epidemic disease

Worldwide epidemic

Pandemic disease

incidence of specific notifiable diseases

Morbidity

Number of deaths from these disease

Mortality

those physicians are required to report

Notifiable diseases

Study of where and when diseases occur and how they are transmitted within populations

Epidemiology

2 measures used to track occurrence of disease

Incidence Prevalance

number of **new cases** of a disease in a given area during a given period of time

Incidence

number of **total cases** of a disease in a given area during a given period of time

Prevalence

4 categories of severity of disease

Acute Chronic Subacute Latent

develops quickly/lasts short time

Acute disease

develops slowly/lasts long time

Chronic disease

in between acute and chronic

Subacute disease

causative agent remains inactive for a period of time and then becomes active to produce symptoms

Latent disease

acute infection caused by initial illness

Primary infection

caused by opportunistic microbe after host immune system weakened by primary infection

Secondary infection

not cause noticeable disease

Subclinical infection

5 stages of disease development (dont forget i-draw)

• Stage 1: Incubation Period • Stage 2: Prodromal Period • Stage 3: Period of Illness • Stage 4: Period of Decline • Stage 5: Period of Convalescence

time interval between initial infection and the first appearance of any signs or symptoms

Incubation period

Early mild symptoms

Prodromal period

When disease is most acute

Period of illness

Signs and symptoms decline

Period of decline

person regains strength and body returns to prediseased state

Period of convalescence

T or F Pathogens can survive long outside of their host

Sites where pathogens are maintained as a source of infection

Reservoirs

3 types of reservoirs

Animal reservoir Human reservoir Non living reservoir

Any person, animal, arthropod, plant, soil, or substance, or a combination of these, in which an infectious agent normally lives and multiplies, on which it depends primarily for survival, and where it reproduces itself in such a manner that it can be transmitted to a susceptible host

Reservoirs

It is the natural habitat of the infectious agent

Reservoir

diseases and infections which are naturally transmitted between vertebrate animals and humans

Zoonoses

Acquire zoonoses through various routes:

– Direct contact with animal or its waste – Eating animals – Bloodsucking arthropods

are usually dead-end host to zoonotic pathogens

Humans

Enumerate the 3 types of cases involved in an outbreak.

Primary case Index case Secondary cases

Enumerate the 3 types of cases according to the spectrum of disease.

Clinical cases (Mild/Severe-Typical/Atypical) Sub-clinical cases Latent infection cases

Enumerate the 3 types of human carriers based on type.

Incubatory carrier Convalescent carrier Healthy carrier

Enumerate the types of human carriers based on duration.

Temporary carrier Chronic carrier

Enumerate the 3 portals of exit of infectious agents in human reservoirs

Urinary tract Intestinal tract Respiratory tract

is an infection that is transmissible under natural conditions from vertebrate animals to man

Zoonosis

Examples of zoonosis

- dogs (rabies), - (cats, fleas) plague - (cattle) bovine tuberculosis - rodents (leptosipirosis)

how many zoonotic diseases are known to be transmitted from animals to humans?

100

Examples of non living reservoir

Soil, water, food, and inanimate marter

Soil may harbor agents that causes

Tetanus Anthrax Coccidiodomycosis

What is a common cause of microbial contamination in water and food?

Feces or urine

defined as “a person or animal in the population or study group identified as having the particular disease, health disorder, or condition under investigation”

Case

Infected individuals who are asymptomatic but infective to others

Carriers

Some individuals will eventually develop illness while others never get sick

Carriers

may have defensive systems that protect them from illness

Healthy carriers

an infected person or animal that harbors a specific infectious agent in the absence of discernible (visible) clinical disease and serves as a potential source of infection to others.

Carriers

occurs either due to inadequate treatment or immune response, the disease agent is not completely eliminated, leading to a carrier state.

Carriers

3 elements have to occur to form a carrier state

1. The presence in the body of the disease agent. 2. The absence of recognizable symptoms and signs of disease. 3. The shedding of disease agent in the discharge or excretions.

Makes the body more susceptible to disease or alters the course of the disease

Predisposing Factors of Disease

Examples of Predisposing Factors of Disease:

• gender • age • fatigue • climate • poor nutrition

• New diseases and diseases with increasing incidences • Caused by viruses, bacteria, fungi, and protozoa

Emerging Infectious Diseases

Emerging Infectious Diseases may result from the following:

– use of antibiotics and pesticides – climatic changes –travel – lack of vaccinations – improved case reporting

Infections acquired while in a health care facility

Nosocomial infections

3 types of nosocomial infections

Exogenous Endogenous Iatrogenic

pathogen acquired from the health care environment

Exogenous

pathogen arise from normal microbiota due to factors within the health care setting

Endogenous

Nosocomial infection that results from medical procedure

Iatrogenic

Draw mo yung diagram ng perfect storm

Is the most effective way to reduce nosocomial infections

Hand washing

11.2 Flashcards

(170 cards)