(M) Theory of Disease Causation Flashcards by Geno Alinsub

T or F

Disease and other health events do not occur randomly in a population

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But disease/other health events are more likely to occur in some members of the population than others because of ?

Risk factors

that may not be distributed randomly in the population

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T or F

One important use of epidemiology is to identify the factors that place some members at lesser risk than others.

F (Greater risk)

lame

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What are the factors for Risk of disease

theres 3

Host
Agent
Environment

ayan 3

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Risk of Disease Is Not Equal

Components of Host

Age affects risk
Immunity
Stress

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Why extreme ages are more vulnerable to diseases?

because of their immune system

mas mavaba

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Risk of Disease Is Not Equal

what are the 2 factors under immunity?

Exposure
Vaccination

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Risk of Disease Is Not Equal

Components of Agent

Variability in agents
DIfferent agents
Viral

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Risk of Disease Is Not Equal

Components of Environment

Season
Politics

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How do risk factor works together

What are the 5 relations of Agent, Host and Environment

use this card to familiarze i guess

B is a proxy for A risk Factor for O
A and B are overlapping Risk Factors for O
A and B are independent risk factors for O
B mediates the effect of A on O
A moderates the effect of B on O

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How Do We Identify Important Risk Factors?

what apporach are used?

Epidemiologic Approach

uses Decriptive and Analytic

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How Do We Identify Important Risk Factors?

T or F

we Summarize disease occurince in sample

F (in population)

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How Do We Identify Important Risk Factors? T or F

Compare risk of disease among animals with different exposures

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How Do We Identify Important Risk Factors? T or F

measure comparison with disease occurence

F (associations)

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Causes of Disease

Any (blank) that leads to new cases of disease

Exposure

Knowing the exposure can lead us preventing the disease

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Two basic philosophies about causation of infectious diseases

Presence of an agent → disease (Direct)
Agent alone is not sufficient to produce disease (Need other factors)

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The occurrence of disease follows certain biologic laws which apply to both communicable and non-communicable diseases, what are the 2 laws?

disease results from an imbalance between a disease agent and man
the nature and extent of the imbalance depends on the **nature and characteristics of the host and the agent. **

The characteristics of the two are influenced considerably by the conditions of their environment.

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First recognized criteria for establishing cause

Henle-Koch Postulates

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Henle-Koch Postulates - T or F

The organism is found in all disease cases.

e.g All of TB-positive should have mycobacterium tuberculosis

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Henle-Koch Postulates - T or F

The organism is found in other individuals as a non-pathogenic parasite.

F (NOT FOUND)

You will not see the mycobacterium tuberculosis sa ibang tao na hindi TB-positive

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Henle-Koch Postulates - T or F

It must be possible to produce a pure, sustainable culture of the organism.

The organism can be CULTURED or ISOLATED

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Henle-Koch Postulates - T or F

It must be possible to experimentally reproduce the same disease in a susceptible host.

If the cultured/isolated organism were passed to another, the other should be positive from the disease

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Henle-Koch Postulates - T or F

One Agent → Two Disease

F (one disease)

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was Henle-Koch postulates debunked?

yeah it was

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# Problems with Koch’s Postulates - T or F Doesn’t directly relate to non-infectious diseases

T | You cannot isolate organism from a diabetic patient

# Problems with Koch’s Postulates - T or F Every exposed individual becomes infected

F (NOT EVERY) | It depends with the immunity of the person

# Problems with Koch’s Postulates - T or F Not all infected individuals develop disease.

T ## Footnote * TB-exposure and TB-infected – no manifestation * TB-Postive – manifested

# Problems with Koch’s Postulates - T or F Possible to recover infectious agents from all infected individuals or even all disease cases.

F (Not possible) | Some virus cannot be isolated

Did Koch identify THE cause?

Partly but not all

What is the conclusion for the henle-koch postulate

Conclusion: The epidemiologic concept maintains that **there can be no single cause of disease**.

# These 3 factors: contribute to the occurrence of disease

Agent, Host, and Environment

Models assist with in understanding and describing complex causal relationships

* Web of causation * Path models * Venn Diagrams * Rothman Pie (Necessary, sufficient, and component causes)

a susceptible host (the person at risk for the disease), a disease agent (the proximate cause), and an environmental context for the interaction between host and agent.

The Epidemiological Triad

# The Epidemiological Triad the person at risk for the disease

host

# The Epidemiological Triad proximate cause

disease **agent**

# The Epidemiological Triad context for the interaction between host and agent.

environmental

Disease results from the interaction between the agent and the susceptible host in an environment that supports transmission of the agentfrom a source to that host

The Epidemiological Triad

– the aggregate of all external conditions and influence affecting the life and development of an organism, human behaviour or society

Environment

if u see this card

study the epidemiologic lever ## Footnote ● towards the agent - the agent has more of an ability to cause a disease ● towards the host - increased amount of ways a person is susceptible to a disease e.g. sleepless nights, unhealthy diet, consumption of unhealthy food ● towards the environment - plays a key role in how the agent and host are affected by a disease, where it is likely to spread, and its current location

# Epidemiological Triad Biologic, nutrients, chemical, physical, and mechanical

Agent

balance depends on age, race, sex, habits, customs, genetic factor, personality defense mechanism

Human

# Epidemiologic Lever - T or F Agent, host, and environmental factors interrelate in a variety of complex ways to produce disease.

# Epidemiologic Lever - T or F Different diseases require the same balances and interactions of these three components.

F (different)

# Epidemiologic Lever - T or F Development of appropriate, practical, and effective public health measures to control or prevent disease usually requires assessment of all three components and their interactions.

T | Even if one factor is addressed- that is a partial solution

designed to be shaped like a seesaw with the environment being the base, the host being on one side and the agent being on the other.

epidemiological lever

When the teeter-totter is balanced

the equilibrium state

what signifies a balanced epidemiological lever?

this state signifies that **everything is healthy**

# Imbalance considered as the agent having more of an ability to cause a disease on man

Imbalance towards the agent

# Imbalance the amount of ways a person is susceptible to a disease increased

Imbalance towards the host

# Imbalance Environment plays a key role in how the agent and host are affected by a disease, and where the disease is most likely to spread and where itis currently located

Imbalance towards the environment

# Conclusion for The Epidemiological Triad While the epidemiologic triad serves as a useful model for many diseases, it has proven inadequate for?

non-communicable diseases | BEST USED: Epidemiologic diseases

this model has shapes that overlaps with other

Venn Diagram

de-emphasizes the agent as the sole cause of disease while emphasizing the interplay of physical, biological, and social environments. It also brings genetics into the mix

The Wheel of Causation

Like the Wheel of Causation,this in explaining disease. deemphasizes the agent in explaining disease Provides for multifactorial causes that traverse various pathways. Can be highly intricate and complex

Web of Causation

what model are like with the web of causation?

Wheel of Causation

how many factors web of causation provides

multifactorial

if u see this card

hanapan niyo si euly crush, yung moreno pls pls

# Web of Causation TOF. Easy and not complex

F (Can be highly intricate and complex)

# Wider Application of the Web devised to enhance search for understanding communicable disease

Epidemiologic Triad

# Wider Application of the Web devised to enhance understanding of non-communicable diseases /chronic diseases – can also be applied to communicable diseases

Web of Causation

use this card to see the example for wider application of the web

→ One interesting communicable disease example involves unanticipated consequences of economic development, and more particularly Trypanosomiasis or “sleeping sickness” that spread across Africa in the wake of new roads. → The agent was carried behind trucks by its vector, the tsetse fly, with fly bites being the mode of disease transmission. → in the Philippines, an ades mosquito was stuck in a luggage and then was brought to Taiwan.

this model is used sometimes in range of diseases and has a sequence before a disease manifest

Path Model (Causal Sequence)

this model has this 3 components: * Component Cause * Sufficient Cause * Necessary Cause

Causal Pies (Rothman, 1976)

# Causal Pie Any causal factor (Host, Agent, Env.

Component cause

Set of component causes that is capable of causing disease

Sufficient cause

# T or F Once all of the sufficient causes are present, disease WILL occur

Component cause that is REQUIRED for disease to occur

Necessary cause

# Causal Pies The complete pie, which might be considered a causal pathway is called

Sufficient Casue

# Causal Pies component cause can overlap?

yes they can! they may or may not obirlap

# T or F A single component cause is a rarely a sufficient cause by itself.

T ## Footnote For example, even exposure to a highly infectious agent such as measles virus does not in variably result in measles disease.

# Causal Pies - T or F an agent that is usually harmless in healthy persons may cause devastating disease under different conditions.

T ## Footnote i.e. Pneumocystis carinii is an organism that harmlessly colonizes the respiratory tract of some healthy persons, but can cause potentially lethal pneumonia in persons whose immune systems have been weakened by human immunodeficiency virus (HIV).

# Causal Pies - T or F Note that public health action does not depend on the identification of every component cause

T | kahit single component lang ma block goods na pero ## Footnote pero this does mean na may others parin na pwede ma infect okay? oka

# Causal Pies Disease prevention can be accomplished by?

blocking any single component of a sufficient cause | at least through that pathway. ## Footnote For example, the elimination of smoking (component B) would prevent lung cancer from sufficient causes I and II, although some lung cancer would still occur through sufficient cause III.

# Modern concepts of disease Bradford–Hill criteria Strong associations with higher risk ratios are more likely to be causal than a weak association – higher risk ratio, the more stronger it is

Strength of Association

# Modern concepts of disease Bradford–Hill criteria consistently finding an association a putative cause and a disease outcome in multiple studies by different investigators

Consistency

# Modern concepts of disease Bradford–Hill criteria If a factor is only associated With a specific disease It was said to be specific and considered more likely to be causal

Specificity

# Modern concepts of disease Bradford–Hill criteria The causal factor should precede the outcome it is proposed to be causing; nauuna exposure before sakit

Temporality

# Modern concepts of disease Bradford–Hill criteria A dose-response association IS supportive of a causal relationship; dependent sa amount na na consume

Biological Gradient

# Modern concepts of disease Bradford–Hill criteria Is the association biologically plausible?

Plausibility

# Modern concepts of disease Bradford–Hill criteria The proposed causal association should not contradict current scientific knowledge

Coherence

# Modern concepts of disease Bradford–Hill criteria A causal association is more likely if it is supported by results from controlled, randomized trials

experimental

# Modern concepts of disease Bradford–Hill criteria A causal association may be more likely If there are other examples of causal associations for analogous exposures and outcomes

Analogy

factor in epidemiological triad: any element, substance, or force whether living or non-living, the presence or absence of which can initiate or perpetuate a disease process.

agent

Types of Agents

* **Non-living, living and borderline** (bacteria, virus, parasites, prions) * ** Physical, Chemical and Mechanical** in nature (i.e. extremes of temperatures, light, electricity, physical trauma, etc.) * * **Exogenous** (i.e. common poisons), or **endogenous** – luob ng katawan (i.e. accumulation of toxic products of metabolism in acidosis of diabetes) * * **Nutrients** (deficiency agents and excess agents)

deficiency of Vitamin B

Beriberi

iron deficiency

Anemia

over-eating

Obesity

Components of Inherent Characteristics

Physical features, biologic requirements, chemical make-up, viability, and resistance.

# Inherent Characteristics: morphology, motility, presence or absence of capsules, whether the infecting agent comes in the form of spores or cysts, or whether they need to be in their vegetative forms to cause infection

Physical Features

# Inherent Characteristics: Refer to the things needed by the agent to survive

Biologic requirements

# Characteristics of Agents of Diseases: Inherent Characteristics * Aerobic/ anaerobic * Partial carbon dioxide tension * Production of endotoxins or exotoxins | Remove one of these, organism will not survive

Biologic requirements

# Characteristics of Agents of Diseases: Components of Characteristics directly related to man

* Infectivity * Pathogenicity * Virulence * Antigenicity

# Characteristics of Agents of Diseases: directly related to man the ability to gain access and adapt to the human host to the extent of finding lodgement and multiplication.

Infectivity

# Characteristics of Agents of Diseases: directly related to man measures the ability of an agent when lodged in the body to set up a specific reaction, local or general, clinical or subclinical .

Pathogenicity

# Characteristics directly related to man refers to the severity of the reaction produced and is usually measured in terms of fatality.

Virulence

# Characteristics of Agents of Diseases: directly related to man the ability to stimulate the host to produce antibodies.

Antigenicity ## Footnote e.g. immunizing effects of smallpox, dengue, whooping cough, measles, chickenpox, etc

# Characteristics of Agents of Diseases: Components of Characteristics of agent in relation to the environment.

* Reservoirs of infections * Source of infection * Modes of transmission

# Characteristics of Agents of Diseases: in relation to the environment man, animal, plants, soil, or inanimate organic matter in which an infectious agent lives and multiplies and depends primarily for survival, reproducing itself in such manner that it can be transmitted to a susceptible host.

Reservoirs of infections

# T or F Man himself is the most frequent reservoir of infectious agents pathogenic to man

True ## Footnote e.g.intestinal parasites, typhoid, influenza, scabies, cholera, poliomyelitis, diphtheria, etc.)

# Reservoir Tetanus and fungi

Soil

# Reservoir rabies, tularemia, anthrax, plague, and typhus

Animal

# Characteristics of Agents of Diseases: in relation to the environment the thing, person, object or substance, from which an infectious agent passes immediately to a host.

Source of infection

# Source of Infection - T or F Transfer is often direct from reservoir to host in which case the reservoir is also the source of infection

T ## Footnote (i.e. measles, chickenpox, smallpox, enteric infections).

# Source of Infection - T or F The source may be at any point in the chain of transmission as a vehicle, vector, intermediate animal host, or contaminated articles;

T (e.g) contaminated water (typhoid ,cholera); beef (tanea saginata) infective mosquito (in malaria and filaria) The reservoir is an infected person.

# Characteristics of Agents of Diseases: in relation to the environment the mechanisms by which an infectious agent is transported from reservoir to susceptible human host.

Modes of transmission

Modes of transmission types:

* Direct * Indirect * Airborne

# Modes of Transmission Direct and essentially immediate transfer of infectious agents to a receptive portal of entry through which human or animal infection may take place.

Direct Transmission

# Direct contact or not touching, biting, kissing or sexual intercourse

Direct

# Direct contact or not projection (droplets spread) of droplet spray onto the conjunctiva or onto the mucous membrane of the eye, nose or mouth during sneezing, coughing, spitting, singing or talking | (usually limited to a distance of about 1 meter or less).

Direct

# Indirect Transmission Contaminated inanimate materials or object (formites) such as toys, handkerchiefs, soiled clothes, bedding, cooking or eating utensils, surgical instruments or dressings (indirect contact); water, food, milk, biological products including blood, serum, plasma, tissues or organs

Vehicle-Borne -- MAIN POINT: USES MEDIUM OKUR

# Modes of Transmission: Indirect Transmission Any substance serving as an intermediate means by which an infectious agent is transported and introduced into a susceptible host through a suitable portal of entry. The agent may or may not have multiplied or developed in or on the vehicle before being transmitted.

Vehicle-Borne

# Indirect Transmission: Vector Borne Includes simple mechanical carriage by a crawling or flying insect through soiling of its feet or proboscis, or by passage of organisms through its gastrointestinal tract. This does not require multiplication or development of the organism.

Mechanical (Vector Borne)

# Indirect Transmission: Vector Borne multiplication, cyclic development, or a combination of these (cyclopropagative) is required before the arthropod can transmit the infective form of the agent to man.

Biological (Vector Borne) ## Footnote kindly proceed with the lecture notes nalang for the following explanation, its too long to put here

# Modes of Transmission: Indirect Transmission Kinds under Vector Borne

1. Mechanical 2. Biological 3. Airborne

The dissemination of microbial aerosols to a suitable portal of entry, usually the respiratory tract.

Airborne

If u see this card

please go over the explanation for Indirect Transmission | lahat basahin wag bobo

# Modes of Transmission: Airborne suspensions of particles in the air consisting partially or wholly of microorganism

Microbial aerosols

# Airborne Does microbial Aerosols remain suspended?

They may remain suspended in the air for long periods of time, some retaining and others losing infectivity or virulence. ## Footnote example of maam here are the TB myobecterium naka suspend sa hangin even for days kaya naka negative pressure ang rooms ng patients

# Indirect Transmission: Airborne Size of particles easily drawn into the alveoli of the lungs and may be retained there

1-to 5 um

# T or F Not considered as airborne are droplets and other large particles which promptly settle down (direct transmission).

T | malaki kasi, ahahahah malaki

# Indirect Transmission: Airborne what are the other types under airborne

1. Droplet Nuclie 2. Dust

# Airborne sually the small residues which result from evaporation of fluid from droplets emitted by an infected host.

Droplet nuclei

# T or F Mechanical Nuclei may be created purposely by a variety of atomizing devices, or accidentally as in microbiology laboratories or in abattoirs, rendering plants or autopsy rooms

F (Droplet Nuclei)

# Airborne The small particles of widely varying size which may arise from soil (as, for example, fungus spores separated from dry soil by wind or mechanical agitation), clothes, bedding, or contaminated floors.

Dust

an individual exposed to the agent. He is susceptible to the agent ofthe disease, and if a proper condition for parasitism is fulfilled, he affords subsistence orlodgement to the agent, and thus becomes infected. (Patient)

Host

# The Host Factor of Disease - T or F A contact and a suspect will not become a host of the disease. A carrier cannot in a way be classified as a host

F (A contact and a suspect MAY eventually become a host of the disease. A carrier CAN in a way be classified also as a host) | contact and a suspect MAY eventually become a host of the disease.

# The Host Factor of Disease In parasitology what happens?

distinction is made between a definitive host and an intermediate host

# The Host Factor of Disease - T or F In certain illnesses, man is definitive (final stage) host and in other illnesses, man is the intermediate host.

T | (e.g. malaria where the sexual stage of the parasite develops)

# The Host Factor of Disease what is the primary point of interest in epidemiology?

what happens to the host ## Footnote whether it gets sick or not, whether it becomes a carrier, a source, or a reservoir.

Enumerate the characteristics of the host | not familliariza, enumerate

* Age * SEX (^0^) * Race * Habits, Customs and Religion * Faith in the Quack Doctor * Food Habits, Drinking Habits, Midwifery Practices * Exposure to the Agent

# T or F Certain diseases have a predilection for specific age groups

T (i.e. whooping cough and measles occur more frequently in children (absence of immunity) ## Footnote Study the tables sankyu

# Sex - T or F All diseases are sex-linked

F (CERTAIN lang) ## Footnote not all ulol.

Genetic traits for hemophilia are carried by the

Females

# Sex - Hemophilia disease is manifested in the

male offspring

# Sex these are the difference of male and female in terms of boday

anatomical and hysiological states differences | may pekpek babae, lalaki titi ## Footnote penis and vagina

# Sex - T or F there are certain diseases found in females only and not found in males, and vice-versa.

True | kasi wala namang ovary lalaki (male at birth), bobo

# T or F There are diseases peculiar to certain races

T | denica im watching u

ickle cell anemia is peculiar to?

Negr0es

Asians (may lahi na black) | sabi to ni maam polly ah

cardiovascular disease

Sunburn is most common among

Whites -- they dont have the melanin for difference in skin pigmentation

syndrome, almost exclusively described for Filipino

Bangungot | culturally related

# The Host Factor of Disease: Characteristics of the Host play a major role in the determination of incidence of disease and even the degree of fatality of the disease.

Habits, Customs and Religion

why Muslims does not have taeniasis solium?

because Muslims don’t eat pork. | tape worm that are found in pork - taeniasis solium

Not common to find **teaniasis saginata ** among

Hindus | Beef tape worm

If u see this card

please read the example of Characteristics of the Host – Habits, Customs and Religion | thanks okay? okay

# Characteristics of the Host – Faith in the Quack Doctor Delayed bringing patients to the physician. This is more striking in the case of deliveries. When the physician is called it is usually a very difficult case already, and the “BLANK” has already unintentionally inflicted serious damage on the woman in labor and on the child inside. | answer the blank

Hilot

the severance of the umbilical cord using a bamboo stick, which etnic group?

Muslims in Sulu

he severance of the umbilical cord using a bamboo stick which is very sharp many cases of?

tetanus of the new-born

# Faith in the Quack Doctor - T or F The practice of the “hilot” of leaving a long stump of the umbilical cord (about 1 foot long) on the other hand has helped a lot in the prevention of tetanus

T ## Footnote since if the rural health personnel are called within a few hours after delivery, they can still prevent the successful entry of the spores by simply cutting the cord and leaving only a 1” to 1.5” stump.

Attitude of the other members of the family to the sick person (do not practice separation and boiling of utensils for fear that the sick person will have hurt feelings because his relatives consider him as a dirty person)

Characteristics of the Host – Food Habits

During the 1961-62 epidemics in a province in Mindanao it was observed that when a person is admitted to the hospital or to the hydration center, the entire family had to be admitted together with him. Inside the room, the family cooks and eats.

Characteristics of the Host – Food Habits, Drinking Habits, Midwifery Practices

Habits of sleeping outdoors or indoors are important considerations in malaria transmission and may present problems in controls if the vector is an outdoor biter

Characteristics of the Host – Food Habits, Drinking Habits, Midwifery Practices

# Characteristics of the Host – Exposure to the Agent: Nature of the work or the conditions of work

Occupation

# Characteristics of the Host – Exposure to the Agent: Occupation Ergonomics

backaches

# Exposure to the Agent filariasis, hence the incidence of hydroceles

Abaca planters

# Exposure to the Agent pterygium

Fishing

# Exposure to the Agent Pearl diving

burst ear drums

# T or F - Exposure to agents The stagnant movement of population which appears seasonal in many instances coinciding with the planting and harvesting season are important determinants in the spread of disease

F (movement lang)

enumerate the Defense Mechanisms of the Host

* Specific Anatomical Defenses * Immunity (Passive and Active) * Inherent Insusceptibility * Resistance * Tolerance * Premunition * Allergy * State of Nutrition | SIIR To PAS

Defense Mechanisms of the Host: Physical refer to the structure of the bodY

Specific Anatomical Defenses | please read the examples

Defense Mechanisms of the Host: Specific Anatomical Defenses the reaction of the body to injury (inflammation), and the secretion of adrenaline during periods of stress

Specific defenses

# Defense Mechanisms of the Host: is one who possesses specific protective antibodies or cellular immunity as a result of previous infection or immunization, or is so conditioned by such previous specific experience, as to respond adequately with production of antibodies sufficient in either instance to protect from illness following exposure to the specific infectious agent of the disease.

Immunity

# T or F Immunity is relative; ordinarily effective protection may be overwhelmed by an excessive dose of the infectious agent or an unusual portal of entry.

Two classification of immunity

Natural and Acquired

# Defense Mechanisms of the Host: Types of Immunity attained either naturally by maternal transfer or artificially by inoculation of specific protective antibodies

Passive Immunity

Attained either naturally by infection, with or without clinical manifestations, or artificially by inoculation of fractions or products of the infectious agent, or the agent itself in killed modified or variant form

Active Immunity

Defense mechanism of host: is the ability to resist disease independently of antibodies or specifically developed tissue responses

Inherent Insusceptibility

# Tor F Inherent insusceptibility are not genetic/acquired and not permanent/temporary

F (ARE GENETIC/ACQUIRED AND ARE PERMANENT/TEMPORARY)

Defense Mechanisms of the Host: Immunity the sum of body mechanisms which interpose barriers to progress of invasion of infectious agents

Resistance

what includes in resistance?

* immunity * inherent susceptibility

Defense Mechanisms of the Host: term applied to the condition whereby the infectious agent can be demonstrated from the individual, and yet the person does not show clinical manifestation as should be expected.

Tolerance

# Defense Mechanisms of the Host: Immunity is a term applied to the condition of refractoriness to further infection in an individual already sick or harboring already the infectious agent due to a previous infection.

Premunition

is the untoward reaction of the body towards certain specific substances (allergen), which stimulates the production of histamine which is responsible for the allergic phenomenon.

Allergy

# T or F The allergic reaction are same among individuals.

F (May not be the same)

This is a condition that is commonly agreed by all to influence the occurrence of most diseases. It further influences the outcome of the disease.

State of Nutrition

the sum total of an organism’s external surrounding conditions and influences that affect life and development.

Environment

Three categories of Environment

* Physical * Biologic * Socio-Economic

what happens when the diseases agent and the biologic environment are the same?

certain biologic factor may become an agent ## Footnote in one instance, and an environmental factor in another. The same applies to inanimate environments.

# EnvornmentalFactors: physical environment Temperature, Altitude, Humidity, Rainfall, and Wind

Climate

# Environmental factors: physical environment These factors affect both the agent and the host of a disease

Climate

If u see this card

read the examples of climates in physical environment

has an effect on the distribution of vectors

Wind ## Footnote Vectors like mosquitoes go with the wind direction and reach places which normally are far out of range of their flying power. Upon reaching such places, the vectors can transmit the disease to the inhabitants of the place (e.g. malaria in some municipalities in Tawitawi)

The Environmental Factors of Disease: Physical environment may either affect the agent of a disease adversely or favorably.

Strong rains

# Adverse or Favor -- Climate After a strong rain, the wash-off is big and all the germs that are swept by this wash-off are taken into dug wells if the latter are in its path, thus contaminating the well.

Adverse

# Adverse or Favor -- Climate the wash-off may empty into rivers and the flow of the river is made faster creating a flushing effect on the river(like the flushing of toilets)

Favor

# Adverse or Favor -- Climate A big wash-off, by increasing the volume of a river, also diminishes the concentration of germs in the river per unit volume, hence less danger to man.

Favor

what does the physical environment controls

life of animals, plants -- these affects food production

If u see this card, use i to damiliarize the good example of the effect of climare

A good example of the effect of climate on disease is with regard to its role in malaria. Temperature affects both the malaria parasite and the vector. At temperatures below 16C, P.vivax and P.malaria will not develop. At extremes of temperature, in order to survive, mosquitoes either hibernate or aestivate. At higher temperatures,the egg-laying cycle is shortened, hence mosquitoes bite more frequently.

is very important for life of mosquitoes.

Humidity

The higher the humidity, the mosquitos better the chances of?

Survival

Below 60% relative humidity, mosquito chances of survival is

very poor

modifies temperature and increases the relative humidity. It is responsible for the extent of the vector breeding surface.

Rainfall

What influences the seasonal transmission of malaria

Together: * Temperature * Humidity

The seasonal incidence of cases on the other hand is governed by ?

Both the: * Season of Transmission * Characteristic of plasmodia strain being transmitted (strain with short incubation period; or strain with protracted incubation period).

The location, the character of the terrain, etc. it also affects the habits of the people and the customs

Geography

In places where there are rivers near the place of human habitation,the rivers may serve as the?

* water supply of the community * Waste Disposal (when drank became so badbad for body)

# T or F In advance localities,the point where water is obtained for drinking purposes and the place where waste are discharged are carefully selected, plus instituting precautions of treatment to the water and to the sewage.

also plays an important part in carrying agents of diseases to points easily accessible to susceptible individuals

geologic structure of the soil

# T or F The agents can't be carried in the soil substrata in the water table, and if there is a well along the direction of the water table, the well may become contaminated.

F (can be carried)

The fertility of the soil governs the

Food habits of the population ## Footnote Certain places are not suitable for rice production, and people plant other kinds that can be used as food.

In Tawi-Tawi,the land is suitable for

Cassava ## Footnote No amount of price enrichment program for these areas can remedy the problem of vitamin deficiency, unless a cassava enriching program is carried out.

The other chief food is

Fish

while suitable for rice in many respects may not be practical because of frequent strong winds which destroy the rice.In such areas,tubers like camote are suitable (Province of Batanes).

Places along typhoon belts

determines the mode of transportation. It also determines the frequency of visits to centrally located health centers and hospitals.

topography of the area

The living environment of man consists of plants, animals, and fellow human beings. These serve as reservoir, sources, and vectors of disease agents

Biologic Environment

Plants and certain animals also serve as sources of

Medicines

The most important biologic environment of man are?

* Man * Arthropod Vectors

# T or F lack knowledge of the bionomics of vectors is important in elucidating the epidemiological behavior of vector-borne diseases.

F (Intimate knowledge)

The presence of other preferred hosts (mosquitoes prefer animals), will influence its

Feeding habits on man

Sydenstricker classified the socioeconomic environment into five | Famillarize niyo nalang to hahaba amputa

1. Factors arising out of social environment aside from the economic status and aside from social stratification due to difference in economic status 2. Factors that are essential concomitants and results of the economic system of the era 3. Factors that are inherent in the nature of specific diseases which are particularly subject to general as well as specific economic and social conditions, i.e., diet in certain nutritional deficiency conditions; environmental conditions in TB; the extent of community sanitation with respect to typhoid and the custom of going barefoot in relation to hookworm infection. 4. Factors arising out of the maladjustments in the production and distribution of curative and preventive services. 5. Factors that essentially are psychological although greatly dependent upon the factors mentioned -- crowd, behavior, fad, fashions, superstitions.

Socioeconomic environment: A well-organized life is very favorable towards taking positive actions in the control of communicable diseases.

Kinds of community life

Health information can easily be effectively disseminated and disease reporting efficient and assistance to local health personnel easily made available in a

well-organized community

Socioeconomic environment: according to such variables as race, ethnic background, language, educational levels, types of occupation, religious affiliation, etc. These play a role in the kind of community life led by the people.

Existence of social stratification

# T or F stratifications limit associations of different classes of people and can limit disease transmission within each other

# Existence of social stratification Different groups will have different?

* Herd immunity * Patterns of Immunity * Disease Susceptibility

Socioeconomic environment: the community regarding family stability, sexual behavior, family size,religious codes, traditions and care ofthe aged and disabled and education may influence the distribution and occurrence of venereal diseases, legitimacy, mental disorders, problems of the aged, and disabled.

Social standards

Factors that are essential concomitants and results of the economic system of the era: Diarrheal diseases occur in places where sanitation is poor, and these localities are almost always inhabited by the lower socio-economic group.

Element of wealth distribution

Factors that are essential concomitants and results of the economic system of the era: is invariably associated with malnutrition, overcrowding, poor housing, and inadequate sanitary facilities which contribute to the spread of communicable diseases or the initiation and perpetuation of chronic ones.

Poor wealth distribution

Factors that are essential concomitants and results of the economic system of the era: This governs the availability of food, funds and the ability to set up and provide medical care facilities

Periods of prosperity, depression and unemployment.

Factors that are essential concomitants and results of the economic system of the era: The philosophy of the community making it a governmental concern to provide medical care facilities, and the degree of advancement of the community in medical science determine the quality and extent of medical service afforded to the citizens.

Available medical services

Components of General Technologies of the Place

* Automation * Industrailization * Advances in transportation and communication * Housing facilities

# General technologies of the place Social enconomic environment: General technologies of the place labor-saving devices, facilities for rehabilitation and training state of Industrialization, etc., are all important environmental factors in disease causation

automation

# General technologies of the place Social enconomic environment: General technologies of the place new products are introduced into the country which can serve as cause of disease.

Industrialization

# General technologies of the place Social enconomic environment: General technologies of the place given us the concept ofthe shrinking world (fast transmission of diseases)

Advances in transportation and communication

Social enconomic environment: General technologies of the place determine the extent of sanitation and eventually the development of slum areas with all its consequences

Housing facilities

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(M) Theory of Disease Causation Flashcards

(226 cards)