1. Intro to Public Health INTENSE

Health

State of complete physical, mental and social well-being and not merely the absence of disease or infirmity.

World Health Organization (WHO)

The directing and coordinating authority for health within the United Nations system.

Public Health

All organized measures to prevent disease, promote health, and prolong life among the population as a whole.

• Sanitation of the environment

• Control of communicable infections

• The education of the individual in principles of personal hygiene

• The organization of medical and nursing services for the early diagnosis and treatment of disease

• Development of the social machinery which will ensure to every individual in the community a standard of living

adequate for the maintenance of health.

Environmental Health

Branch of Public Health that is concerned with all aspects of the natural and built environment that may affect human health.

Those aspects of the human health and disease that are determined by factors in the environment. It also refers to the theory and practice of assessing and controlling factors in the environment that can potentially affect health.

The total relationship of man to his physical, biological, socio-economic and socio-cultural environment as it affects human well-being.

Environmental Sanitation

The science dealing with the prevention and control of diseases by eliminating or controlling the environmental factors which may form links in disease transmission.

The control of all factors in man’s physical environment that have significant effect on man’s physical development, health and survival.

Public Health Engineering

Deals essentially with the control of the environment, with those modifications and protective and preventive measures that have been found desirable or necessary for providing optimum conditions for health and well-being.

Engineering

The profession in which a knowledge of the mathematical and natural sciences gained by study, experience and practice is applied with judgement to develop ways to utilize, economically, the materials and forces of nature for the benefit of mankind.

Disease

A particular abnormal condition that negatively

affects the structure or function of all or part of an

organism, and that is not due to any immediate

external injury.

Any harmful deviation from the normal structural

or functional state of an organism, generally

associated with certain signs and symptoms and

differing in nature from physical injury

A disorder of structure or function in a human,

animal, or plant, especially one that produces

specific signs or symptoms or that affects a

specific location and is not simply a direct result

of physical injury.

Pathology

The study of the essential nature of diseases and

especially of the structural and functional

changes produced by them.

Epidemiology

The study of the distribution of a disease or condition in a population.

Congenital

Present at birth

Acquired

Began at some point during one’s lifetime

Communicable

Can pass from person to person

Contagious

Can easily pass person to person by direct contact

Non-contagious

Not passed from person to person

Degenerative

Due to malfunction of vital body organ over time

Deficiency (Nutritional)

Due to lack of essential nutrients in diet

Allergies

Due to hypersensitivity of the body to certain foreign substances

Cancer

Due to uncontrolled growth of cells/tissue

Mental

Emotional or psychosomatic

Genetic

Caused by one or more genetic mutations

Hereditary

Errors in genetic Code received from parents

Hormonal (Endocrine)

Excess or deficiency of hormone

Immunological

Hyperactive or hypoactive immunity

Neoplastic

Abnormal cell growth

Latrogenic

Caused by medical treatment/procedure

Idiopathic

Unknown cause or source

Acute

Disease in which symptoms develop rapidly and that runs its course quickly

Chronic

Disease with usually mild symptoms that develops slowly and last a long time

Sub-Acute

Disease with time course and symptoms between acute and chronic

Asymptomatic

Disease without symptoms

Latent

Disease that appears a long time after infection

Local Infection

Infection confined to a small region of body

Systematic Infection

Widespread Infection in many systems of the body

Focal Infection

Infection that serves as a source of pathogens for infection at others sites in the body

Primary Infection

Initial infection within a given patient

Secondary Infection

Infections that follow a primary infection, often by opportunistic pathogens

PREPATHOGENESIS PHASE

Phase before a disease infects an individual through interaction of the agent, the host, and the environment factors.

Infectious agent

is a microorganism capable of producing infectious disease under circumstances of host and environment favoring transmission.

Host

is a person or other living organism that can be infected by an infectious agent under natural conditions.

Environment

refers to the ecological conditions that favour the interaction of host and agent e.g. swampy

areas, bushes within households, sanitation etc.

PATHOGENESIS PHASE

When the agent becomes established in the host.

Start of the four periods of infectious disease.

Incubation Period

is the time that elapses between arrival of the pathogen and onset of symptoms

Prodromal Period

is the time during which the patient feels “out of sorts” but is not yet experiencing actual symptoms of the disease.

Period of Illness

is the time during which the patient experiences the typical symptoms associated with that particular disease.

Convalescence Period

is the time during which the patient recovers.

Chain of Infection

The infection process can be described as a chain composed of links which are clasped securely to one another from beginning to end.

Reservoirs of Infection

The habitat in which an infectious agent normally lives, grows and multiplies, or merely survive until it is transferred to a host.

Reservoirs may be living hosts (human and animal reservoirs), and environmental reservoirs (materials and inanimate objects.

Colonization

when bacteria are present in a person's nose, mouth, gut

or other site, but do not cause illness.

Carrier

A person or animal without apparent disease who harbors a specific infectious agent and is capable of transmitting the agent to others.

Passive Carriers

carry the pathogen without ever having the disease

Incubatory carrier

is a person who is capable of transmitting a pathogen during the incubatory period of a particular infectious disease.

Convalescence Carriers

arbor and can transmit a particular pathogen while recovering from an infectious disease.

Active carriers

have completely recovered from the disease but continue to harbor the pathogen indefinitely.

The carrier state may be of short duration (Transient carrier) or long duration (Chronic carrier).

Zoonotic Diseases (Zoonosis)

An infection or an infectious disease of animals transmissible under natural conditions to man.

Epizootic

An epidemic among animals.

Arthropods

Invertebrate (without back bones) animals with joined legs and commonly associated with human infections.

–Examples are mosquitoes, biting flies, lice, fleas, and arachnids.

–When involved in transmission of diseases, these arthropods are called Vectors.

Chikungunya, Dengue, Lyphatic Filariasis, Rift Valley Fever, Yellow Fever, Zika

Aedes Mosquito Disease caused

Lymphatic filariasis, and Malaria

Anopheles Mosquito Disease caused

Japanese Encephalitis, Lymphatic Filariasis, West Nile Fever

Culex Mosquito Disease caused

Schistosomiasis (Bilharziasis)

Aquatic Snails

Onchocerciasis (River Blindness)

Blackflies

Leishmaniasis, and Phlebotomus fever

Sandflies

Chagas disease (American Trypanosoma)

Triatome bugs

Sleeping Sickness (African trypanosoma)

Tsetse flies

Nonliving Reservoir

– Includes air, soil, dust, food milk, water, and fomites.

– Fomites are inanimate objects capable of transmitting pathogens.

– Healthcare: patient’s gowns, bedding, towels, eating and drinking utensils, and hospital equipment.

– Telephones, doorknobs, and computer keyboards can serve as fomites.

Portals of Exit

– Before the infectious agent can attack a new host, it must have a way of escape from the reservoir of infection, like man, animal, plants, soil, etc.

– The most frequent portals of exit in man are:

• Skin through open lesions or with the aid of insects or hypodermic needles.

• Respiratory tract

• Gastrointestinal tract

• Eyes / Ears

Direct Contact Transmission

The immediate transfer of an agent from a reservoir to a susceptible host by direct physical contact

Droplet Transmission

Involves the transfer of pathogens via infectious droplets. Droplets may be generated

by coughing, sneezing, and even talking.

Indirect Transmission

The transmission of an agent carried from a reservoir to a susceptible host by suspended air particles, inanimate objects (vehicles or fomites), or animate intermediaries (vectors).

Airborne Transmission

Involves the dispersal of droplet nuclei, which are residue of evaporated droplets.

Vehicleborne Transmission

Indirectly transmit an infectious agent include food, water, biologic products (blood), and fomites.

Fomites

Inanimate objects that have come in contact with a sick person.

Vector Transmission

Involves the various types of biting insects and arachnids

Mosquitoes, Ticks, Flea, Bloodsucking flies

Biological Vector Example

Housefly, Cockroaches

Mechanical Vector

Portals of Entry

The manner of entry are similar with the mode of exit from the reservoir.

Channels of infection

are means through which the body becomes infected by disease-producing agents. The channels may be the respiratory tract, the digestive tract, exterior surfaces of the body.

Sporadic

implies the occurrence of a few scattered cases of the disease without relationship to other cases

Endemic

is the term applied to a specific disease when it normally prevails in a locality and does not fluctuate markedly from the normal expected incidence in the community

Epidemic

is the incidence of a communicable disease among a number of people to an extent that is recognized statistically as

being well beyond the normal expectancy for the disease in a community in a definite period of time

Pandemic

affects large number of people at the same time and transcends community boundaries

Primary prevention

refers to the measure that may be applied in the prepathogenesis phase of the natural history of

disease

Secondary prevention

this is applied in the early pathogenesis phase period. This consists of early diagnosis and prompt treatment of the disease in order to arrest the disease and prevent its spread to other people.

Tertiary prevention

includes disability limitation and rehabilitation.

Communicable Period

Time during which the infectious agent may be transferred directly or indirectly from an infected person to another person, or from an infected animal to man.

Contact

Any person or animal known to have been in such association with an infected person or animal having the opportunity of acquiring the infection.

Primary Health Care

Application of the principles of health education, nutrition, immunization, water and sanitation, maternal and child care and family planning, control of endemic diseases, treatment of common diseases, and provision of essential drugs.

Contamination

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

Disinfection

The application of microbicidal chemicals to materials (surfaces as well as water), which come into contact with or are ingested by humans and animals, for the purpose of killing pathogenic microorganisms.

Disinfestation

Any physical or chemical process serving to destroy or remove undesired small animal forms, particularly arthropods or rodents, present upon the person or the clothing, in the environment of an individual, or on domestic animal

Mutagen

A chemical capable of producing a heritable change in genetic material; it can cause miscarriage, stillbirth, or birth defect

Pathogenic

The potential for producing disease, if the organism is sufficiently virulent to enter the body and overcome

the defense mechanism of the host.

Personal Hygiene

Those protective measures, primarily within the responsibility of the individual, that promote health

and limit the spread of infectious diseases, chiefly those transmitted by direct contact.

Pollution

The undesirable change in the physical, chemical, or biological characteristics of air, land, and water that

may or will harmfully affect human life or that of other desirable species, industrial processes, living conditions, and cultural assets or that may or will waste or deteriorate raw material resources.

Sanitation

The effective use of measures that create and maintain healthy environmental conditions.

Sanitize

To reduce microorganism level to an acceptable level, usually by the continuous application of heat or

chemicals at suitable concentrations and times.

Sterilization

The process of killing all microorganisms, including spores.

Intact skin and mucous membrane

Dryness, acidity, temperature of skin, perspiration

Digestive enzymes

Peristalsis (push eat foods) and urination

Indigenous microflora

Non-specific First Line of Defense

Cellular and Chemical Response

Fever, Interforans, Inflammation, Chemotaxis, and Phagocytosis

Non-specific Second Line of Defense