3. PH CONTROL OF COMMUNICABLE DISEASES PART 1 Maam Love

Epidemiology

Is the study of FACTORS that determine the frequency,

distribution, and determinants of diseases in human

populations, and ways to prevent, control, or eradicate diseases in populations.

Pathology

Is the study of the STRUCTURAL AND FUNCTIONAL MANIFESTATIONS OF DISEASE and involves diagnosing of diseases in individuals.

It is the study of the ESSENTIAL NATURE OF DISEASES and especially of the structural and functional changes produced by them

Infectious Disease

is a disease that is CAUSED BY A PATHOGENIC

MICROORGANISMS, such as bacteria, viruses, parasites or fungi.

Communicable Disease

An infectious disease that is TRANSMISSIBLE FROM ONE PERSON TO ANOTHER.

Contagious Disease

A communicable disease that is EASILY TRANSMITTED

FROM ONE PERSON TO ANOTHER

Zoonotic Disease/Zoonoses

Infectious disease that human ACQUIRES FROM ANIMAL souces

Sporadic Diseases

Disease that OCCURS ONLY OCCASIONALLY (sporadically) within the population of a particular geographic area.

In USA, sporadic diseases includes botulism, cholera, gas gangrene, plague, tetanus and typhoid fever.

In the Philippines, sporadic diseases includes Pellegra, Elephantiasis and Myelitis

Endemic Diseases

Disease that are ALWAYS PRESENT within the population of a particular geographic area.

The number of cases may fluctuate over time, but the disease never dies out completely.

Endemic diseases in USA includes TB, STDs such as gonorrhea and syphilis, common colds, influenza, chickenpox and mumps.

In the Philippines, this includes Chronic Diarrhea, Typhoid and

Epidemic Diseases

Diseases that OCCUR IN A GREATER THAN USUAL NUMBER OF CASES IN A PARTICULAR REGION, and usually occur within a relatively short period of time.

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 different period of time.

In the Philippines, this includes Dengue Fever, German Measles, and Cholera. Recently Measles (2019) and Leptospirosis (2018) were also considered as an epidemic disease in some areas in the Philippines

Pandemic Diseases

Disease that is OCCURRING IN EPIDEMIC PROPORTIONS IN MANY COUNTRIES SIMULTANEOUSLY– sometimes worldwide

Affects large number of people at the same time and TRANSCENDS COMMUNITY BOUNDARIES

Agent/Infectious Agent

Microorganisms capable of producing infectious disease under circumstances of host and environment favoring transmission

Infectious pathogens vary in size and biological makeup from protein particles (prions) and ultramicroscopic viruses to multicellular tapeworms many meters long.

Host

A person or other living organisms that can be infected by

an infectious agent under natural conditions

Environment

Refers to the ecological conditions that favor the

interaction of host and agent

Chain of Infection

AGENT/PATHOGENS

Disease – causing Microorganisms

Viruses and Prions

Acellular (Infectious Particles)

Bacteria, Archaea, Algae, Protozoa, Fungi

Cellular (Microorganism)

INDIGENOUS MICROFLORA

Microbes that lives

on and in the human

body

OPPORTUNISTIC PATHOGEN

Do not cause disease

under ordinary conditions,

but have potential to cause

disease should the

opportunity present itself

DECOMPOSER OR SAPROPHYTES

Involved in the

decomposition of

dead organisms and

the waste products

of living organisms

Microbiology

The study of microbes

Bacteriology

The study of structure, functions

and activities of Bacteria

Phycology

The study of Algae

Protozoology

The study of Protozoa and their activities

Mycology

The study of Fungi

Virology

The study of Viruses and their effects on living cells of all type

Archaea or Cyanobacteria

First microbes on Earth

Bacteria and Protozoa

The First microbes to be observed by humans

Anton van Leeuwenhoek

Father or Microbiology; Father of Bacteriology; Father of Protozoology; First to see live bacteria and protozoa

VIRUSES

Acellular microbes that are smaller than bacteria; Obligate intracellular parasites; Referred to as Infectious particles rather than microbes

They are not composed of cells.

Viruses

Many human diseases are caused by

VIRIONS

Complete virus particles that are very small and simple in structures

BACTERIOPHAGES

Viruses that infects bacteria. They are obligate intracellular pathogens, in that they must enter a bacterial cell to replicate.

Icosahedron

Bacteriophages: Almost spherical in shape, w/ 20

triangular facets; the smallest are about 25nm

Filamentous

Bacteriophages: Long Tube formed by capsid proteins

assembled into a helical structure; they can be up to about 900nm long

Complex

Bacteriophages: Icosahedral heads attached to helical tails; may also possess base plates and tail fibers

VIRULENT BACTERIOPHAGES

Always cause lytic cycle which ends with the destruction (lysis) of the bacteria cell

STEPS IN THE MULTIPLICATION OF BACTERIOPHAGES

ANIMAL VIRUS

Viruses that collectively infect humans and animals

ONCOGENIC VIRUS

Viruses that cause cancer

MIMI VIRUS

An extremely large double – stranded DNA virus that has been recovered from amoeba. It mimics the bacteria

Viroids

are infectious RNA molecules that cause variety of plant diseases.

Prions

are infectious molecules that cause variety of animal and human disease

BACTERIA

These are prokaryotic microscopic single celled organisms.

binary fission

Bacteria reproduce by

cocci (coccus)

ROUND OR SPHERICAL in shape.

diplococci

pairs of cocci

streptococci

chains of cocci

staphylococci

clusters of cocci

bacilli (bacillus)

RECTANGULAR OR ROD shaped. May be short or long, thick or thin, and pointed or w/ curved or blunt ends

diplobacilli

pairs of bacilli

streptobacilli

chains of bacilli

coccobacilli

short and resembling elongated cocci (Ex. Listeria

monocytogenes and Haemophilus influenzae)

spirilla

CURVED and SPIRAL in shape

Pleomorphic

Bacteria that exist in a variety of shapes

Pleomorphism

The ability to exist in a variety of shapes.

Mycoplasma

bacteria that do not have cell wall and are resistant to

antibiotics that inhibit cell wall synthesis

Blue to Purple

Color at the end of the Gram staining procedure Gram positive

Pink to Red

Color at the end of the Gram staining procedure Gram negative

Thick Layers

Peptidoglycan in cell walls Gram positive

Thin Layer

Peptidoglycan in cell walls Gram negative

Obligate Aerobes

Require oxygen to grow and multiply

Obligate Anaerobes

An anaerobes that can only grow in an anaerobic environment

Microaerophiles

Require reduced oxygen concentration

Aerotolerant Anaerobes

Does not require oxygen, grows better in the absence of oxygen but can survive in atmospheres containing molecular oxygen

Facultative Anaerobes

Capable of surviving in either the

presence or absence of oxygen

Acidophiles

Extremely acidic

Alkaliphiles

Extremely alkaline

Thermophiles

Extremely hot

Extremely cold

Psychrophiles

Halophiles

Extremely salty

Piezophiles

Extremely high pressure

PROTOZOA

Single– celled free living microorganisms

TROPHOZOITE

The motile, feeding, dividing stage in a protozoan’s life cycle

CYST

The nonmotile, dormant, survival stage

Cilia

CILIATES

Pseuudopodia (false feet)

AMEBAE (AMEBAS)

SPOROZOA

Generally nonmotile except for certain sex cells

PARASITES

Organism that lived on or in other living organisms, at whose expense they gain some advantage

ECTOPARASITES

Parasites that live outside the host’s body

ENDOPARASITES

Parasites that live inside the host’s body

FACULTATIVE PARASITES

Can be parasitic but are also capable of free living existence

OBLIGATE PARASITES

To survive, they must be parasites (needs a host)

PARASITOLOGY

The study of parasites. It can be divided into the study of parasitic

protozoa, helminths and arthropods

HELMINTHS

Means parasitic worms.

endoparasites

helminths that infect humans are always

ROUNDWORMS

Nematodes

TAPEWORMS

Cestodes

FLUKES

Trematodes

FUNGI

Eukaryotic, non photosynthetic microorganism. That can be either saprophytic or parasitic. It includes yeast, moulds and mushrooms.

Hyphae

Fungi that grows as filaments

Mycelium

A mass of intertwined fungi

YEASTS

Microscopic, single – celled organisms that usually reproduce by budding

Examples are Candida albicans, Candida neoformans

MOULDS

Microscopic, multicellular organisms

FLESHY FUNGI

Mushrooms, toadstool and bracket of fungi, collectively.

These are fungi that are not microorganisms

LIVING RESERVOIRS

Includes humans, household pets, farm animals, wild animals, certain insects and certain arachnids (ticks and mites)

HUMAN AS RESERVOIR/HUMAN CARRIER

The most important reservoirs of human infectious diseases

CARRIER

A person who is colonized with a particular pathogen, but the pathogen is not currently causing disease in that person

CARRIER

A person without apparent disease who harbors a specific infectious agent and is capable of transmitting the agent to other

PASSIVE CARRIER

Carry the pathogen without ever having had the disease