a. the infectious process 03-07

7/28/2019 A. the Infectious Process 03-07

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The Infectious Process

1. Inflammation

( Latin, inflammare, to set on fire) is part of the

complex biological response of vascular tissues toharmful stimuli, such as pathogens, damaged cells,or irritants.

-is a protective attempt by the organism to remove

the injurious stimuli and to initiate the healingprocess.


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Inflammation can be classified as either acuteor chronic.

Acute inflammationis the initial response of

the body to harmful stimuli and is achieved by theincreased movement of plasma and leukocytes(especially granulocytes) from the blood into theinjured tissues.


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Prolonged inflammation, known aschronic inflammation, leads to aprogressive shift in the type of cells

present at the site of inflammation and ischaracterized by simultaneousdestruction and healing of the tissue

from the inflammatory process.


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Epidemiology and terminologies of

communicable diseasesEpidemiology is the study of thedistribution and determinants of health-

related states or events (includingdisease), and the application of this studyto the control of diseases and other health

problems.----- is the backbone of disease prevention.


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Word is derived from Greek word:opi: upon

demos: people

- refers to what descends upon peopleand was originally restricted to studythose which are characterize sudden

occurrence of an abnormal number ofcases.


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Carrier : person who carries an organism withoutapparent signs and symptoms; one who is able totransmit an infection to others

Centers for Disease Control and Prevention (CDC):federal agency responsible for monitoring endemic

and epidemic disease, for recommending strategies todecrease disease incidence, and developingguidelines to reduce risk to patients and health careworkers.

Colonization : microorganisms present in or on a hostinterference or interaction and interaction andwithout eliciting symptoms in the host.


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Host : person who provides living conditions to

support a microorganisms. Normal flora : persistent non pathogenic organisms

colonizing a host.

Virulence: the degree of pathogenicity


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Infection - implies that organismcapable of causing disease ispresent and multiplying within the

body. Body respond to some way todefend itself against invader eventhough the evidence of their

response may not be visible.


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Infectious Diseaseis the state inwhich the infected host displays a decline inwellness due to the infection.

- When the host interacts immunologicallywith an organism but remains symptomfree, the definition of infectious disease hasnot been met.


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Forces of

Infection

Human

Body

Resistance

Infecting Forces made up of

many components1. Type of infecting organisms

2. Its quantity

3. Virulence

4. Capacity for multiplication

5. invasion


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Four ways Germs Causes

Disease

1. Local Inflammation

Cardinal Signs: by the Roman physician Celsus

roughly 2000 years ago. The four distinct symptonsa. Heat Calor

b. Redness rubor

c. Swelling tumor

d. Pain dolor

e. Loss of function (by Galen)


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2. Surface Cell formation

ex: common colds-germsdestruction of the cell surface lining URT

- The clotting mechanism in the blood is activated.,

immune cells (mostly phagocytic) move to the site in

response to chemicals. The first cells, neutrophils,accumulate within 30-60mins. If it persists longer, 5-

6 hours later macrophages and lymphocytes will

infiltrate the area.


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3. Production of Toxins

example: Diphteria and Tetanus

- Toxins via blood stream causes paralysis

and poisoning of nervous system.

Poliomyelitis does not produce toxins but

the virus itself enters the bloodstream

and invades the cells of the nervoussystem and destroys them.


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4. Bloodstream Invasion

Example: Abscess in the lungs or Ulcer in Peyerspatches of small intestines in TY.

- Enter the bloodand multiply

General Infection (systemic) The virulence or strength of invading microorganisms

has spread through the blood stream and has

migrated to the other systems of the body as the

immune system of the body is unable to contain the

infection. This infection is now termed as Sepsis.


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Three Ways the body reacts to

infection1. Cellular Response body pours out blood

cells and fluids containing various substance

to attack the germs.Example: Boil in the skin, if occur inside the

body occur in form of abscess.

- Ulcer in Typhoid or Bacillary dysentery, ulcer inthe intestinal wall break down and cause

severe hemorrhage or peritonitis


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2. Vascular Response germs or toxins

stimulate blood vessels to swell or dilate

Example: Small pox rash

Scarlet fever rashes

Meningococcal septicemia vascular response

occurs inside the body. Bleeding in the adrenal

gland causes death to the patient.


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3. Antibody Response

antibodies formed in the body reactsonly with the stimulus that produced

it. Outcome depends on theinteraction.


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Diagnosing Infections

Two ways the doctor can diagnose

Infection

1. By symptoms presented by the patient2. By tests to detect the germs: Special tests

a. Swab of the nose, throat or the skin, sample urine,sputum, feces or blood or other fluids

b. Blood for antibodies


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Diagnostic Assessment

WBC count:

Indicator for ongoing infection. Increased levels meaninfection, ,while decreased levels may mean

immunosuppression.Normal: Total count : 4,500 11,000/cu mmNeutrophils: 45% - 73%Eosinophils: 0% - 4%

Basophils: 0% - 1%Lymphocytes: 20% - 40%Monocytes: 2% - 8%


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Erythrocyte sedimentation rate (ESR):

laboratory test that measures the rate of settlingRBCs; elevation is indicative of inflammation; alsocalled the sed. rate. Increasedin tissue destruction,whether inflammatory or degenerative; duringmenstruation and pregnancy and in acute febrile

diseases.Westergren method:

Males under 50 yr:


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Culture of suspected infectious site:

A specimen is drawn from a suspected infectious siteto identify the specific etiological agent present. This

may be the defining test for possible medical andpharmacological treatment for a client.


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STAGES OF INFECTION

1. INCUBATION STAGE ( SILENT STAGE)

the pathogens has gained entry to the

host and starts replicating.


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2. PRODROMAL STAGEpathogens begin invade tissues.( itchy, runny nose, dry eyes, etc.)

3. PEAK (CLINICAL STAGE)

the disease reaches its highest

point of development. (severe aches,chills, vomiting, etc.)


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4. RECOVERY STAGE/ CONVALESCENCE

symptoms have all but completely

vanished; pathogen has been

eliminated.

- tissue damage is repair and the

patient regains strength.


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Chain or Six Links of Infection


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Chain or Six Links of Infection

I. Causative Organism/Agents-the types of microorganisms that causeinfections.

Types of Infecting Organisms1. Animal parasites

a. protozoa-single celled parasiticorganisms with flexible membranesthat live in the soil and obtainnourishment from dead or decayingorganic material.


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- infect human through fecal-oral

contamination or the ingestion offood or water contaminated with

cyst or spores.

Example: Entamoeba Histolytica

b. metozoa


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2. Bacteria

a.bacillus rod shaped , hard to kill,spores

b. cocci - spherical

Classified according to their stainingproperties

1. grams method

2. Acid fast staining


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Bacteria respond to stains in one of three ways

1. Gram positive bacteria stain purple2. Gram negative bacteria lose purple stain-

when exposed to alcohol but stain red withsecond dye.

3. Acid fast bacteria keep purple stain when anacid is applied.


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Growth depends on oxygen, nutrition, light,temperature and humidity.

1.Aerobic bacteria such as those found on the skin,need oxygen to live.

2. Anaerobic bacteria bacteria in GIT live withoutoxygen.


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3. Viruses organisms smaller than bacteria

that depend on host cells to live andreproduce.

Example: epstein barr, HEPA, HIV,

influenza, rubella, rubeola.

4. rickettsiae --- typhus fever and rocky

mountain spotted fever.


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5. Plant Parasites -fungi

epidormophytesis( ahletes foot) and

coccidiooidomycosis

6. Helminths wormlike parasitic animals:

roundworm, flatworm, tapeworm- disease transmission occurs through

skin penetration of larvae or

ingestion of helminths eggs.


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II. The Reservoir of Infection

Group of reservoir1. Human Reservoir: Subdivided

a. Frank cases obviously ill with

the disease-the more severe cases are less dangerous tothe community than the mild ones.


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b. Subclinical Infections (missed cases, abortioncases, walking cases)

Example: walking typhoid, measles risk ofspread to the community is far greater than inthe case of a seriously ill.

c. Carrier not aware because does not giverise to any symptoms and there is no way ofrecognizing it other than bacteriologicalmethods


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Classified according to criteria:

1. Convalescent carriers following recovery fromdisease.

2. Chronic or permanent carriers harbor theorganisms for a long period of time usually theduration of life.

3. Transient carrier- who without a recognizedattack of the disease, harbors the organisms fora short period of time.


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2. Animal reservoirs principal: domestic animaland rodents

3. Other reservoirs

: Fungi and molds-independent growth in and around the soilwhen they spread to man.


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III. Portal or Mode of Exit from the

Reservoir1. The respiratory tract most common and most

dangerous channel of escape..

Speaking, sneezing , expectoration,exhalation

2. Intestinal tract principal exit is feces usuallynot pathogenic

dysentery, cholera, and other Intestinaldiseases- pathogenic.


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3. Urinary Tract- urine less frequent carrypathogens.

4. Open Lesions- abscess develops and ruptures onthe surface-ready means of escape- patient enterinto a communicable stage.

5. Mechanical Escape external force is brought

into play to liberate the infecting agents from thetissue.

-biting or sucking- biologic

- hypodermic syringe or transfusion


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Example: malaria, hepatitis and syphilis

- eating infected flesh- mechanicalmethod- parasitic worms.

Duration of escape- varies greatly, limited to a fewdays or extend in many years.

- measles is highly communicable yet its periodof infectiousness is short, whereas leprosy has alow infection potential but can be communicatedover many years


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IV.Mode or Route of Transmission1. Direct contact- from one person to anotherwithout intervention of intermediate objects

- fairly intimate association of persons though notnecessarily actual physical contact.

- occurs thru touching, biting, kissing, sexualcontact or droplet spray into the eyes or onmucous membranes while sneezing, coughing,

spitting, singing or talking


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-Droplet spread is usually limited to 3 feet or less.

Illnesses spread by direct transmission may

include: Influenza

Impetigo

Scabies Conjunctivitis

Pediculosis

Herpes

C. difficile and all sexually transmitteddisease


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Indirect contact-without close relatioship betweenreservoir and new host.

Factors Essentials for transmission:

a. organisms capable of survival for a period of timeoutside the body

b. vehicleClassification of vehicles

1. Animate vehicles- are vectors : insects that bridgesthe gap from reservoir to victim

Example: malaria- anopheles mosquito


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2. Inanimate vehicles- all non living objects that

may contaminate and transfer infection.Substances serve as vehicles for transmission

of infection: water, milk, other foods, air,fomites(articles as clothes, bedlinen, books, toys,

doorknobs and money), soil (hookworm eggsand larvae)


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AIRBORNE TRANSMISSION- is different fromdroplet transmission because the particles floating in

the air are much smaller, remain suspended in the airfor a long tme and may travel long distances.

- can be inhaled or deposited on the mucousmembrane of a susceptible host.

- example: measles, chicken pox,

tuberculosis


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V. Portal of Entry- correspond to theavenues of escape.

1. Respiratory tract- breathing of fine dropletsexhaled by infected persons.

2. Gastrointestinal tract- via oral

3. Direct Infection of membranes like indiphtheria or gonorrheal involvement

4. Percutaneous infection- via skin

ex.: rabies,insect borne disease-skin,


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VI. Susceptible host for infection tooccur, host must be susceptible ( notpossessing immunity to a particularpathogen).

- a person who is immunosuppressed hasmuch greater susceptibility to infection than ahealthy person.


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Different Kinds of Infections1. Nosocomial infection acquired inside thehospital while admitted or being admitted.

2. Community acquired infection disease acquiredin the community. If on admission to a hospital or

health-care agency a patient already has an infection3. Iatrogenic infection Infection caused by medical

factors, predominantly medications. ( side effects ofcorticosteroid therapy is immunosuppression)


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Nosocomial infection

( hospital-acquired infection, HAI)

- An infection whose development is favored by ahospital environment, such as one acquired by apatient during a hospital visit or one developingamong hospital staff. Such infections include fungaland bacterial infections and are aggravated by thereduced resistance of individual patients.


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Nosocomial infections are commonly transmitted when

hospital officials become complacent and personnel donot practice hygiene regularly.

Increased use of outpatient treatment means that peoplewho are hospitalized are more ill and have more

weakened immune system than may have been true in thepast.

Medical procedures bypass the bodys natural protectivebarriers. Since the medical staff move from patient topatient, the stafff themselves serve as a means forspreading pathogens. Essentially, the staff act as vectors.


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Main routes of transmissions

1. Contact transmission

direct contact transmission

indirect contact transmission

2. Droplet transmission

3. Airborne transmission4. Common vehicle transmission

5. Vector borne transmission


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Risk factors

Factors predisposing a patient to infection can broadly

be divided into three areas: People in hospitals are usually already in a poor state

of health, impairing their defense against bacteria.

Invasive devices

A patients treatment itself can leave them vulnerableto infection.


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What is Infection Control:

All of the practices used to prevent the spread ofmicroorganisms that could cause disease in aperson.

Infection control practices help to protect clientsand healthcare providers from disease byreducing and/or eliminating sources of infection.


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Prevention

Hospitals have sanitation protocols regarding uniforms,

equipment sterilization, washing, and other preventivemeasures. Thorough handwashing and/or alcohol rubsby all medical personnel before and after each patientcontact is one of the most effective ways to combat

nosocomial infections. More careful use ofantimicrobial agents, such as antibiotics, is alsoconsidered vital.


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Sterilization

Isolation

Handwashing and gloving

Surface sanitation


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Infection Control in theHospital


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What is IsolationAre Measures designed to prevent the

spread of infections or potentially infectiousmicroorganism to healthy personal, clientsand visitors.

Isolation Precaution

1.) Standard/Universal Precaution

2.) Transmission Based Precautions


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Universal precautions (UP)

Are techniques to be used with all clients to decreasethe risk of transmitting unidentified pathogens.

UP obstruct the spread of blood borne pathogensthose microorganisms carried in blood and bodyfluids that are capable of infecting other persons.


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Isolation Precaution in Hospitals1. Standard (universal precautions)

Used in the care of allhospitalized personsregardless of their diagnosis or

possible infection status.

Use appropriate barrierprecautions for the task

performed and the potentialfor exposure to infectiousmaterials


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Standard

Precaution


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Types of Personal protective equipment( PPE) Used in

healthcareSettings

Gloves protect hands

Gowns/aprons protect skin and/or clothing


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Cont.>>>

Masks and respirators protect mouth/nose

Respirators protect respiratory tract from airborneinfectious agents


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Cont.>>>

Goggles protect eyes

Face shields protect face,

mouth, nose, and eyes

El f S d d


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Elements of Standard

Precautions1. Handhygiene2. Gloving

3. Mask, eye protection, face shield(droplet,conjunctival)

4. Gowns

5. Environmental control

6. Patient placement7. Transport


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2. Transmission Based Precaution

Are used in addition to SP for clients with

known or suspected infections that arespread by airborne, droplet or contact.

are designed to supplement standardprecautions in patients/ residents withdocumented or suspectedinfection/colonization of highly

transmissible or epidemiologicallyimportant pathogens.


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A. Airborne transmission

spreading of droplet nuclei that

may suspend in the air for longer

periods of time.Needs negative pressure room &

respiratory protection

The three categories of Transmission-Based

Precautions include:


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Examples of Diseases: varicella (chicken pox),tuberculosis, measles.

Special Factors:

Private room with special ventilation; door

must be kept closed.

The patient/resident should stay in his or herroom except for essential reasons; a special

mask should be worn when out of the room.


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Respirators are worn by the personnel if the patient/resident has or is suspected of having an airborne

illness. In general, students are not usually fitted forrespirators.

Rspirators are worn for chicken pox or measles only ifthe employee entering has had not the diseasse or has

not been immunized.

Gloves: worn when in contact with a respiratorysecretioons.


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Patient/resident care items such as blood pressurecuffs, etc. should be dedicated and disinfected or

discarded after the patient/resident is discharged. Patient/resident should be taught to cover their nose

and mouth with a tissue when coughing and sneezingand to discard tissues in a bag.


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B. Contact Precautions Gown and gloves forcontact with patient or environment of care (e.g.,

medical equipment, environmental surfaces).

Contact Precaution are designed to reduce the risk oftransmission of microorganisms by direct or indirectcontact.

Direct contact transmissions involves

the physical transfer of

microorganisms to a susceptible hostfrom an infected or colonized person.


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indirect contact transmission involves

contact of a susceptible host with acontaminated intermediate object.

Examples of Diseases: gastrointestinal infections (including diarrhea of unknown origin), wound and

skin infections ( e.g. impetigo ) and colonization witha multidrug- resistant bacteria ( e.g. methicillin-resistant staphylococcus aureus ( MRSA).


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Special factors:

private room or rooms with a patient / resident whohas a similar diagnosis.

Patient/ resident should stay in room except formedically necesarry procedures or therapies.

Gloves for any any contact with patient/ resident ortouching anything in the room.

C D l t P ti


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are designed to reduce the risk of droplettransmissions of infectious agents. Infectiousdroplets are released when the infected personsneezes or coughs and the large droplet spray mayspread as far as three feet.

Examples of Diseases: Influenza, meninggococcal

meningitis, mumps, rubella, diptheria, pneumonicplague, pertussis and infections caused bymultidrug resistant Streptococcus pneumonia.

C. Droplet Precautions

Surgical masks within 3 feet of

patient.*

S i l F t


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Special Factors: Private room or rooms with a patient/resident who

has a similar diagnosis. Patient/resident should stay in their room except

for medically necessary procedures; a mask shouldbe worn when out of therequired room.

A regular/surgical mask should be used for anypotential exposure within three feet of thepatient/resident.

Gloves and gowns are required when deliveringpatient/resident care in droplet precautions.

Patient /resident care items such as blood pressure cuff,etc. should be dedicated to the patient/resident.


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Patient/resident should be taught to cover their noseand mouth with a tissue when coughing or sneezing

and to discard tissues into a bag.

I f i l i h


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Infection control in the

communitySanitation techniques (eg. Water

purification, disposal of sewage and other

potentially infectious materials)Regulated health practices (eg. The

handling, storage, packaging, and

preparation of food by institutions) Immunization programs.


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THANK YOU

a. the infectious process 03-07

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