Lab Flashcards
The study of disease, but they involve different aspects of disease.
EPIDEMIOLOGY
Studies the factors that determine the frequency, distribution and determinants of diseases in human populations.
Epidemiologist
British physician, designed and conducted an epidemiologic investigation of a cholera outbreak in London.
John Snow
The infectious disease is transmissible from one human to another (person to person).
Communicable disease
A communicable disease that is easily transmitted from one person to another.
Contagious Disease
Example of Contagious Disease
Influenza, can be transmitted through sneezing, talking and coughing (air droplets)
The human acquires from animal sources.
Zoonotic disease (zoonosis)
The number of new cases of that disease in a defined population during a specific time period
Incidence
Expressed as a number of new cases of a particular disease that occurred during a specified time period per a specifically defined population. (usually per 1000, 10,000 or 100,000 population)
Morbidity Rate
proportion of a population who have a specific characteristic
Prevalence
2 Types of Prevalence
Preiod Prevalence
Point Prevalence
The number of cases of the disease existing in a given population during a specific time period
Period Prevalence
The number of cases of the disease existing in a given population at a particular moment in time
Point Prevalance
- Refers to death
* Also, known as death rate
Mortality Rate
The ratio of the number of people who died of a particular disease during a specified time period per a specified population
Mortality Rate
Levels of Disease
Sporadic Disease
Endemic Disease
Epidemic Disease (outbreak)
Pandemic Disease
Occurs only occasionally within the population of a particular geographic area
Sporadic Disease
refers to a disease that occurs infrequently and irregularly
Sporadic Disease
It is always present within the population of a particular geographic area
Endemic Disease
refers to the constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographic area
Endemic Disease
Greater than usual number of cases of disease in particular region usually occurring within a relatively short period of time.
Epidemic Disease (outbreak)
• Refers to an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area
Epidemic Disease (outbreak)
occur when an agent and susceptible hosts are present in adequate numbers, and the agent can be effectively conveyed from a source to the susceptible hosts.
Epidemic Disease (outbreak)
Epidemic may result from:
A recent increase in amount or virulence of the agent,
The recent introduction of the agent into a setting where it has not been before,
An enhanced mode of transmission so that more susceptible persons are exposed,
A change in the susceptibility of the host response to the agent, and/or
Factors that increase host exposure or involve introduction through new portals of entry
A disease that is occurring in epidemic proportion in many countries simultaneously-sometimes worldwide.
Pandemic Disease
• refers to an epidemic that has spread over several countries or continents, usually affecting a large number of people.
Pandemic Disease
Factors occurs in infectious disease
FACTORS PERTAINING TO THE PATHOGEN
FACTORS PERTAINING TO THE HOST
FACTORS PERTAINING TO THE ENVIRONMENT
- Virulence of pathogens
- Way for pathogen to enter the body
- Number of organism that enter the body
Factors pertaining to the pathogen
- Health status
- Nutritional status
- Other factors pertaining to the susceptibility of the host
Factors pertaining to the host
- Physical factors su8ch as geographical location, climate, heat cold humidity and season of the year.
- Availability of appropriate reservoir
- Sanitary and housing condition, adequate waste disposal
- Availability of potable (drinkable) water
Factors pertaining to the environment
6 components of Chain Infection
Infectious Agent Reservoir Portal of exit Mode of transmission Portal of entry Susceptible host
The sources of microorganism that cause infectious disease
Reservoir of Infection
• Any site where the pathogen can multiply or merely survive until it is transferred to a host.
Reservoir of infection
• May be a living host or inanimate objects
Reservoir of infection
Includes human, household pets, farm animals, wild animals, certain insects, and certain arachnids (ticks or mites)
LIVING RESERVOIRS
Most important reservoir of human infectious disease is other human- people with infectious
Human Carrier
A person who is colonized with a particular pathogen.
Carrier
SEVERAL TYPES OF CARRIER
- Passive carrier
- Incubatory carrier
- Convalescent carrier
- Active carrier
• Carry the pathogen without ever having had the disease.
Passive carrier
• A person who is capable of transmitting a pathogen during incubation period of particular infectious disease.
Incubatory carrier
• Harbor and can transmitted a particular pathogen while recovering from an infectious disease
Convalescent carrier
• Have completely recovered from the disease, but continue to harbor the pathogen indefinitely
Active carrier
• Infectious disease that human acquires from animals’ sources called …
zoonotic disease or zoonoses.
• Acquired by direct contact with animal, by inhalation or ingestion of the pathogen or by injection of pathogen by arthropod.
Animal carrier
• Caused by Toxoplasmosis gondii, can be contracted by ingesting oocytes from cat feces that are present in litter boxes or sand boxes as well as ingesting cysts that are present in infected raw or undercooked meats.
Toxoplasmosis
• May cause brain damage or death
Toxoplasmosis
• Serve as reservoir of infections including insects and arachnids
Arthropods
• These arthropods are referred to as …
Vectors
• Inanimate reservoir of infection includes air, soil, dust, food, milk, water and fomites
Nonliving reservoir
• Inanimate objects capable of transmitting disease
Fomites
• Found within health care setting includes patients gown, bedding, towels, eating and drinking utensils and hospital equipment.
Fomites
5 principal MODES OF TRANSMISSION OF PATHOGENS
- AIRBORNE
- DIRECT CONTACT AND INDIRECT CONTACT
- DROPLET
- VEHICULAR
- VECTORS
• Involves contaminated inanimate objects such as foods, water, dust, and fomites.
Vehicular transmission
• Are various types of biting insects and arachnids.
Vectors
Communicable disease –infectious disease that are transmitted from person to person are follows:
- Direct skin to skin contact
- Direct mucous membrane to mucous membrane
- Indirectly by airborne droplets of respiratory secretions.
- Indirectly by contamination of food and water by fecal material
- Indirectly by arthropod vectors
- Indirectly by fomites
- Indirectly by transfusion
• Its mission is to promote technical cooperation for health among nations, carry out programs to control and eradicate diseases and improve the quality of human life.
WHO
- Which assist the states and local health departments in the application of all aspects of epidemiology.
- The overall mission is to promote health and quality of life by preventing and controlling disease, injury, and disability.
Center for disease control and prevention (CDC)
• Pathogenic microorganisms sometimes wind up in the hands of mentally deranged people who want to use them to cause harm to others. And the microbes are biological warfare agents
Biological warfare
• The member of terrorist or radical hate groups might use pathogens to create fear, chaos, illness, and death.
BIOTERRORISM agent
Four pathogens most often use:
- Bacillus anthracis
- Clostridium botulinum
- Smallpox virus (variola major)
- Yersenia pestis
Sources of water contamination
- Rainwater falling over the large areas collects in lakes and rivers that is subjected to contaminate by the soil microorganism and raw fecal material
- Groundwater from wells also can become contaminated
this are E. coli and other lactose fermenting members of family enterobacter and kleibsiella spp.
Coliforms
3 Sewage Treatment
Primary ST
Secondary ST
Tertiary ST
• The sewage disposal plant, large debris is first filtered out called screening. Skimmers remove floating greases and oil and floating debris is shredded or ground
Primary sewage treatment
• Flocculating substance can be added to cause other solids to settle out.
Primary sewage treatment
The material that accumulates at the bottom of the tank.
Primary sludge
Large debris is filtered out called?
Screening
- The liquid called the primary effluent) then undergoes secondary treatment, which includes aeration or trickling filtration.
- The remaining liquid is filtered and disinfected usually chlorination so that the effluent water can be returned to rivers or oceans.
Secondary ST
- Where water in the short supply, the effluent water from the sewage disposal plant is further treated so that it can be returned directly to the drinking water system. This is very expensive process.
- Involves the addition of chemical, filtration, chlorination and distillation.
Tertiary ST
• Any activity designed to study and or improve patient care outcomes in any type of healthcare institution or setting
Healthcare Epidemiology
- ACQUIRED within the hospital or other health care facilities
- Hospital acquired infection
NOSOCOMIAL INFECTION
• Acquired outside healthcare facilities
Community acquired infection
PATHOGENS MOST OFTEN INVOLVED IN NOSOCOMIAL INFECTION:
SEVEN BACTERIA OR GROUPS OF BACTERIA
A. gram positive cocci= caused 34% of Nosocomial infections in US 1) Staphylococcus aureus 2) Coagulase-negative staphylococci 3) Enterococcus spp. B. Gram-negative bacilli 1) Escherichia coli 2) Pseudomonas aeruginosa 3) Enterobacter spp 4) Klebsiella spp.
caused 34% of Nosocomial infections in US
Gram possitive cocci
• Hard to treat as are infections caused by multidrug-resistant
Pseudomonas Infection
MDRTB), vancomycin-resistant enterococcucos spp. • (VRE) and methicillin-resistant • Staphylococcus aureus (MRSA) • Staphylococcus epidermidis (MRSE)
Mycobacterium tuberculosis
MOST COMMON TYPES OF NOSOCOMIAL INFECTIONS
- Urinary tract infection
- Surgical Wound infection (also referred as Postsurgical wound infections
- Lower respiratory tract infection (primary Pneumonia)
- Bloodstream infection (septicemia)
Other nosocomial infection
Gastrointestinal disease caused by Clostridium difficile (referred to as Clostridium difficile-associated disease.)
a common member of the indigenous microflora of the colon where it exists in relatively small numbers.
Clostridium difficile
two types of toxin ng clostridium difficile
- ENTEROTOXIN
2. CYTOTOXIN
• Causes disease known as antibiotic –associated diarrhea (AAD)
ENTEROTOXIN
- Causes a disease known as pseudomembranous colitis (PMC)
* Which section of the lining of the colon slough off, resulting in bloody stools
CYTOTOXIN
• Both AAD and PMC are common in hospitalized patients.
`MOST VULN
CYTOTOXIN
MOST VULNERABLE PATIENTS IN HOSPITAL SETTINGS
- Elderly patient
- Women in labor and delivery
- Premature infants and newborn
- Surgical and burn patients
- Diabetic and cancer patient
- Patient receiving treatment such as steroid, anticancer drug, antihymolytic serum and radiation
- Patient who are paralyzed
- Immunosuppressed patient
MAJOR FACTORS CONTRIBUTING TO NOSOCOMIAL INFECTIONS
- An ever-increasing number of drug-resistant pathogens
- the failure of healthcare personnel to follow infection control guideline
- An increased number of immunocompromised patient
• Support or monitor basic body function contribute greatly to the success of modern medical treatment
MEDICAL DEVICES