COMMUNICABLE DISEASE Flashcards
transmitted from one host to another
Communicable disease
easily transmitted
Contagious disease
are readily transferred from one infected person to a susceptible and uninfected person and maybe caused by
microorganisms.
Communicable diseases
occasional cases
Sporadic
constantly present
Endemic
outbreaks
Epidemic
worldwide outbreaks
Pandemic
number of infected people during a particular time period (i.e. year)
Incidence
number of diseased people at any given time
Prevalence
measurable changes
Signs
patient complaint
Symptoms:
study of disease
Pathology
cause of disease
Etiology
disease process
Pathogenesis:
colonization by microbe
Infection
illness
Disease
organism with potential to cause disease
Pathogen
pathogen is growing in or on host
Infection
degree or intensity of pathogenicity
Virulence
ability of pathogen to spread to other
tissues in body
Invasiveness
ability of pathogen to establish infection
Infectivity
ability of pathogen to secrete toxins
Toxigenicity
infection in which pathogen grows massively in the body, being found in blood and throughout organs.
Usually leads to death
Septicemia
Developed in late 1800’s , provide basic logical proof that
disease is caused by a microbe
Koch’s Postulates
Compete for living space and nutrients with
pathogens
* Ex. Lactobacillus acidophilus
Normal Microbiota/Flora
- Organisms that cause disease when they enter different environment
– Staphylococcus aureus enters break in skin
– Escherichia coli enters peritoneal cavity from burst appendix
– Clostridium difficile colonizes intestines when normal flora have been killed by antibiotics
Opportunistic Pathogens
the most common infection causing microorganisms
Bacteria
consist primarily of nucleic acid and therefore must enter living cells in order to produce infection.
Viruses
includes yeast and mold.
Fungi
CHAIN OF INFECTION
- Etiologic agent (Microorganism)
2.Resevoir (source) - Portal of exit from reservoir
- Mode of transmission
- Portal of entry to the susceptible host
- Susceptible host
The extent to which any microorganisms is capable of producing an infectious process depends on the number of microorganisms (pathogenicity), the ability of the microorganisms to enter the body, the susceptibility of the host, and and the ability of microorganism to live in the host’s body.
Etiologic Agent
There are many sources of Microorganisms. Common sources are the other humans, the client’s own microorganisms, plants, animals, or the general environment. People are the most common source of infection for others and for
themselves.
Reservoir
source of organisms
– Humans
– Animals (zoonoses)
– Environment
Reservoir
Before an infection can establish itself in a host,
the microorganism must leave the reservoir.
Portal of exit from the Reservoir
involves immediate and direct transfer of microorganisms from person to Person through touching, biting, kissing, or sexual intercourse. Droplet spread is also a form of direct transmission but can occur only if the source and the host are within 3 feet of each other.
Direct transmission
may either vehicle- borne or vector borne.
Indirect transmission
any substance that serves as an intermediate means to transport and introducing infectious agent into susceptible
host through a suitable portal of entry.
Vehicle
is an animal or flying or crawling insects that serves as an intermediate means of transporting the infectious agents.
Vector
Spread of Disease
- contact
– direct
– indirect (fomite) - droplet
- vehicle
- vector
Before a person can became infected, microorganisms must enter the body. The skin is a barrier to infectious agents; however, any break in the skin can readily serve as portal of
entry.
Portal of entry to the susceptible host
Portals of Entry
- Skin
- Gastrointestinal Tract
- Respiratory
- Urogenital
- Via Placenta
- Parenteral (injection, bite)
Attachment
- Fimbriae
- Glycocalyx
- Hooks
- Suction discs
- Viral spike
is any person who is at risk for infection.
susceptible host
is a person “at increased risk”, an individual who for one or more reasons is more likely than others to acquire an infection. Impairment of the body’s natural defenses and a number of other factors can affect susceptibility to infection.
compromised host
Disease cycle maybe broken down by these
factors:
- Increasing host resistance
- Destruction of the source and the reservoir
- Destruction of the agent in the environment
- Avoidance of exposure
prophylaxis such as antibiotics, antiviral drugs.
Treatment
hygiene, disinfectants, sterilization, antiseptics and vaccination.
Prevention
can be applied safely to the body. e.g on skin, ethanol and isopropanol.
Antiseptic
cannot be used on the body directly but are used to clear work surfaces, crockery, cutlery, instruments etc.
Disinfectants
Removal of any living organisms from a non-living
object or material. E.g water, operating theatre
gowns.
Sterilisation
pasteurising milk , tinned food.
Heat
autoclave where steam under pressure is fed
into a sealed chamber.
Steam
Longer wave lengths have no effect shorter wavelength such as UV light results in death.
Radiation
Is the process of introducing vaccine into the Body to produce antibodies that will protect our body against a specific infectious agent.
IMMUNIZATION
Immunization against communicable disease
- For infants
- Following exposure
- For all persons in endemic areas
- For person subject to unusual risk
- For known cases
Vaccine available for routine immunization
- DPT (Diphtheria, pertusis and tetanus) vaccine.
- OPV (Oral Polio Vaccine)
- MMR ( Measles,Mumps,Rubella ) vaccine
- Hib(H. influenza type B) Polysaccharide vaccine\
- Hepatitis B vaccine
- BCG ( Bacillus of Calmette and Guerin)
- CDT (Cholera, Dysentery, Typhoid)
An early start with what? reduces the chance of severe pertussis.
DPT (Diphtheria, pertusis and tetanus) vaccine.
caused by Corynebacterum diphteriae
Diptheria`
caused by Bordetella pertussis
Pertussis
caused by Clostrodium tetani
Tetanus
the extent of protection against polio is increased the earlier the OPV is given.
OPV (Oral Polio Vaccine)
caused by Polio virus
Poliomyelitis
caused by Measles virus
Measles
caused by Mumps virus
Mumps
caused by Rubella virus
German measles
caused by Haemophilus influenza
Meningitis
an early start of hepatitis B reduces the chance of being protects and becoming cancer.
Hepatitis B vaccine
given at the earliest possible protect against the possibility of infection from other family members.
BCG ( Bacillus of Calmette and Guerin)
caused by Mycobacterium tuberculosis
Tuberculosis
caused by Vibrio cholera
Cholera
caused by Shigella dysenteriae
Dysentery
caused by Salmonella typhi
Typhoid
Administration of drugs to prevent occurrence of infection.
* E.g Penicillin for gonorrhea, chloroquine for malaria, INH for tuberculosis
CHEMOPROPHYLAXIS
Placing mechanical barriers between the sources of agent and host such as use of mosquito nets, masks or gloves.
MECHANICAL PROPHYLAXIS
