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THE ROYAL PENTAGON REVIEW SPECIALISTS, INC.2nd Floor, R.G. Casas Bldg. 886 España Blvd.

Cor. G. Tolentino St., Sampaloc ManilaTel. Nos. (02) 309-9582 / (02) 734-6748 / (02) 7346783

COMMUNICABLE DISEASES

Lecturer: Daniel Joseph Espina Berdida, R.M., R.N.

I. Review of Related Terms

A. Communicable Disease – caused by an infectious agent which is acquired from an infected individual and transmitted to a susceptible host either by direct and indirect contact or through direct inoculation into a broken skin or mucous membrane.

The two persons important for a communicable disease to occur are the infected individual and the susceptible host.

Types of Communicable Disease

1. Infectious – disease is NOT easily transmitted from person to person. It requires inoculation, e.g. tetanus, malaria, dengue, filariasis, rabies

Inoculation – entrance of microorganism through mechanical means, e.g. biting, puncturing, laceration, open wound

2. Contagious – easily transmitted from one person to another through droplet, direct, or indirect contact, e.g. tuberculosis, diphtheria, measles, chickenpox, meningococcemia

B. Epidemiology – the science of the patterns of disease, its occurrence, distribution, or spread and the prevention and control among group of individuals as public health; backbone of disease prevention

a. Patterns of Disease Occurrence

1. Sporadic – on-and-off attack of the disease; intermittent or occasional; 20% susceptible host, 80% immune (because occurrence is predictable and therefore, can be prevented)

2. Endemic – constantly present in a certain locality; 50% immune, 50% susceptibleThree endemic in the Philippines: (1) Malaria, (2) Filariasis, & (3) Schistosomiasis (with high prevalence in Regions 5, 8, and 11)

3. Epidemic – number of cases exceeds beyond the normal number of cases for a short period of time; 80% susceptible host, 20% immune

4. Pandemic – worldwide epidemic, e.g. AIDS, SARS, Bird Flu

C. Triad of Disease Causation or the Epidemiologic Triad (by Leavell & Clark) – factors that interact to cause a disease

Three Factors:1. Agent – these are bacteria, viruses, protozoa, and parasites (biological agents)

Characteristics of Agent:Infectivity – ability to enter the human body and to move into tissuesVirulence – strength, potency, or power of the agent to cause a disease

*the shorter the incubation period, the virulent the agent isAntigenicity – ability to stimulate antibody response (specific response)Pathogenicity – ability to cause infection or disease

2. Environment – the medium for survival and multiplication of causative agent3. Host – the area where the agent gets its nourishment

a. Humansi. Carrier – asymptomatic; a person who harbors microorganisms but does not manifest

signs and symptoms; most dangerousii. Sub-clinically ill – manifests mild signs and symptoms; less dangerousiii. Clinically ill – manifests ALL the signs and symptoms; least dangerous

b. Animal – serves as an intermediate host; secondary or transitional; important in the completion of the life cycle or the microorganisms, e.g. oncomelania quadrasi (snail) in schistosomiasis

c. Plants – breeding places of animalsd. Soil, water, air, milke. Fomites – inanimate objects

Alert: All these factors are necessary to cause a disease; an absence of one factor will not cause a disease *** If one factor is absent, it will lead to health or wellness

D. Chain of Infection (ARPEMPS)

Nonspecific response: Calor Rubor Dolor Tumor Functio laesa

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1. Agent – causative agent that releases toxic products that can be found inside or outside the cellType of toxin:

a. Exotoxin – toxic product that can be found outside the cell when the microorganism is still alive

b. Endotoxin – toxic product inside the cell that is released when the cell is already dead; more dangerous

2. Reservoir – source of infection; normal area in the body where the organisms can be found3. Portal of Exit – from the reservoir to the outside environment

a. Respiratory system – sneezing and coughing of respiratory secretions (SMILING is not included)b. GIT / Alimentary tract – vomitus and fecesc. GUT – urine, semen, vaginal dischargesd. Skin – open wounde. Mechanical – bite of an insect or animalf. Blood – broken skin or mucosag. Transplacental – mother to fetush. Exudates or discharges – conjunctival secretions, saliva, pus

4. Mode of Transmission – channel or the medium in which the microorganism is transmittedTypes:

a. Direct Contact – person to person; needs intimate contact; sexual intercourse, droplet (coughing and sneezing), airborne

Droplet – less than three feet; less than 30 minutesAirborne – more than three feet; more than 30 minutes

b. Indirect – needs vehicle-borne or vector-bornei. Vehicle – matters through which organism can be transmitted

e.g. milk, soil, waterii. Vector – through animals e.g. arthropods or mollusks

5. Portal of Entry – corresponds to the portal of exit6. Susceptible Host – prone individuals

E. Stages of Diseases1. Incubation period – period from the first exposure to the causative agent to the appearance of the first

signs and symptoms2. Prodromal period (catarrhal period) – period from the appearance of the first signs and symptoms to the

appearance of pathognomonic sign (classical sign)3. Stage of Illness – manifestation of all signs and symptoms of the disease4. Convalescence – stage of recovery; the signs and symptoms gradually disappearing

F. Immunity – power to resist specific infection or diseasea. Immunization – the process of rendering the individuals immuneb. Antigen – a substance that induces antibody formationc. Antibody – a protein substance in response to antigen stimulation

Types of Immunity1. Natural Immunity – inborn, innate, and inherent

a. Active – exposure to certain disease and formation of memory cellsb. Passive – maternal antibodies received bu the fetus through placenta and infant through

breastmilk2. Artificial - attained through the introduction of antigen – such as vaccine, toxoid, or antibody by

artificial meansa. Active – attained by introduction of antigen

e.g. all EPI vaccine except Hepatitis Bb. Passive – introduction of antibodies e.g. IgA, gammaglobulins, immunoglobulins from serum or

human* Active – “slow to come, slow to go”* Passive – “quick to come, quick to go” ; immediate

G. Prevention and Control of Communicable Diseases

Based on RA 3573 – Law on Reporting Communicable Disease

1. Preventiona. Health Educationb. Environmental Sanitationc. Specific Protection e.g. nutrition, immunization, personal hygiene

2. Control

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a. Notification and prompt interventionb. Isolation and quarantinec. Case finding – looking for the infected individuals

Contact tracing – looking for the exposed individualsd. Epidemiological investigation

3. Outline Plan of Epidemiological Investigation (WHO)1. Establish fact of presence of epidemic

a. Verify the diagnosis – initial stepb. Reportingc. Prevalence of disease (recording of old and new cases)

* Incidence – recording new cases2. Establish time and space relationship of the disease

a. Area of concentration of the disease (space)b. Onset of the first known case (time)

3. Relations to characteristics of the group of communitya. Age, sex, color, occupation

4. Correlation of all data obtained

4. Types of Isolation Isolation – separation of infected individual from healthy one; used in case finding Quarantine – limitation of the freedom of movement of exposed individual or animal; used in

contract tracing

a. Strict isolation – indicated for highly contagious diseases like SARS, meningococcemia, bird flu, anthrax

b. Protective or Reverse Isolation – intended for those with low resistance or immunocompromised e.g. AIDS, burn, cancer, nephritic syndrome, organ transplant

c. Respiratory Isolation – intended for respiratory diseasesd. Enteric Precaution – intended for GIT diseases e.g. typhoid fever, cholera, shigellosise. Wound and Skin Precaution – intended for persons with skin diseases e.g. leprosy,

fungal infection, impetigof. Blood and Body Fluids / Standard / Universal Precaution – first line of precaution;

used when the disease is unknown; usage of gloves, masks, caps, mask, and goggles

5. Disinfection – destruction of pathogenic microorganisms excluding the spores Sterilization – destruction of microorganisms including spores Delousing – killing of lice or louse Fumigation – destruction of microorganisms by the use of gases or fumes

Two general means of killing microorganisms:a. Mechanical – boiling autoclaving, and burningb. Chemical – use of

i. Disinfectant – used in inanimate objects (e.g. chlorox)ii. Antiseptic – used in live human tissues that inhibits the growth of

microorganisms (e.g. hydrogen peroxide, betadine, Normal Saline Solution)* NSS – most effective antiseptic because as isotonic solution, keeps the wound moisten which facilitates cell regeneration* Povidone Iodine (Betadine) – inhibits growth of hair

Two techniques of disinfectiona. Concurrent – ongoing disinfection, the client is still the source of infectionb. Terminal – final disinfection, the patient is no longer the source of infection performed

upon discharge of the client (e.g. fumigation)

6. Asepsis – absence of pathogen or disease-causing microorganisms1. Two types of Asepsis:

a. Medical / Clean technique - in handwashing, hands are held lower than the elbowPurpose:

1. To prevent transfer of pathogens to others2. To reduce the number of microorganisms

b. Surgical / Sterile technique – to render area free from microorganisms. In handwashing, hands are held higher than the elbow

Techniques:

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1. Handwashing – single most effective way of preventing transmission of microorganisms. * The most important factor in handwashing is friction.

2. Gowning3. Masking4. Disinfection5. Placarding - barrier cards; “Unsterile / Unauthorized Persons Keep Out”

II. Classification of Communicable Diseases According to Causative Agents

A. Virala. Measles / Rubeolab. German measles / Rubellac. Chickenpoxd. Poliomyelitise. H-fever (Dengue)f. Rabiesg. Hepatitish. AIDSi. Mumpsj. Influenza

B. Bacteriala. Tuberculosisb. Leprosyc. Diphtheriad. Pertussise. Tetanusf. Cholerag. Typhoid feverh. Pneumoniai. Syphilisj. Gonorrheak. Bubonic plaguel. Botulism

C. Protozoan Parasitesa. Malariab. Amoebiasisc. Trichomoniasis

D. Fungala. Ringwormb. Moniliasis

E. Rickettsiaa. Chlamydia

F. Intestinal Parasitesa. Ascariasisb. Enterobiasisc. Taeniasisd. Capillariasise. Ancyclostosomiasisf. Schistosomiasis

G. External Parasitesa. Pediculosisb. Scabies

EXPANDED PROGRAM ON IMMUNIZATION

Vaccine Content Form Dosage # of Doses Route

BCG Live attenuated bacteria

Freeze dried and reconstituted in special diluent

infant- 0.05mlPreschool-0.1ml

1 ID

DPT DT- weakened toxinP-killed bacteria

Liquid 0.5 ml 3 IM

OPV weakened virus Liquid 2 drops 3 Oral

Hepatitis B Plasma derivative Liquid 0.5 ml 3 IM

Measles Weakened virus Freeze dried and reconstituted in special diluent

0.5 ml 1 Subcutaneous

 Schedule of Vaccines

Vaccine Age at 1st dose Interval between dose Protection

BCG (Bacille of Calmette and Guerin)

At birth or anytime after birth

   TB

DPT (Diphtheria, Pertussis, Tetanus)

6 weeks 4 weeksDiphtheria, Pertussis, and Tetanus

OPV (Oral Polio Vaccine) 6weeks 4weeks Poliomyelitis

Hepa B At birthSchedule: At birth, 6th week,14th week

Hepatitis B

Measles 9 months   Measles

Transcribed by: rbrtrñ07