chain of infection + epid of noncommunicable and communicable diseases Flashcards
a person with inapparent infection who is capable of transmitting the pathogen to others
carrier
never experience symptoms despite being infected
asymptomatic or passive or healthy carrier
can transmit the agent during the incubation period before clinical illness begins
incubatory carriers
have recovered from their illness but remain capable of transmitting to others
Convalescent carriers
continue to harbor a pathogen such as hepa b virus or salmonella typhi for months or even years after their initial infection
chronic carriers
Science concerned with various factors and conditions that influence the occurrence and distribution of health, disease, defect, disability and death among groups of individuals.
Epidemiology
Indicator of how long a population is expected
to live on average (number of years the average person lives)
Life expectancy
Reveals the true health of a population (quality of life)
Healthy Life Expectancy (HALE)
The four main Non-communicable diseases:
- Cardiovascular diseases
- Cancers
- Diabetes
- Chronic lung diseases
Is an illness due to a specific infectious (biological) agent or its
toxic products that is transmitted to a susceptible host by
direct or indirect contact, through a vehicle or vector, or as an
airborne infection.
Communicable disease
A process that begins when an agent leaves its reservoir or host
through a portal of exit, and is transported by some mode of
transmission, then enters through an appropriate portal of entry
to infect a susceptible host.
Chain of infection
The period from exposure to infection to the onset of symptoms
or signs of infectious disease.
Incubation period
The length of incubation period depends on:
- The portal of entry
- The rate of growth of the organism in the host
- The dosage of the infectious agent
- The host resistance
The time during which an infectious agent may be transmitted directly or indirectly from an infected person to a susceptible person or animal.
Period of communicability
The ability of an agent to invade and multiply (produce infection) in a susceptible host.
Infectivity
The proportion of exposed susceptible persons who
become infected.
Secondary attack rate
Secondary attack rate =
Number of secondary cases / number of susceptibles x 100
Is the ability of the organisms to produce specific clinical
reaction after infection
Pathogenicity
It refers to the proportion of infected persons who develop
clinical disease.
Pathogenicity
Ratio of clinical to sub-clinical case =
Clinical cases / sublinical cases
It refers to the ability of organisms to produce severe pathological reaction.
Virulence
It is the proportion of persons with clinical disease who become
severely ill or die (mortality).
Virulence
Case fatality rate =
Total number of deaths from a disease / total number of cases of that disease x 100
Ability of an organism to produce an immune response that
provides protection against re-infection with the same or
similar agent.
Immunogenicity
Person that comes to the attention of public health authorities.
Index case
Person who acquires the disease from an exposure.
Primary case
Person who acquires the disease from an exposure to the primary case.
Secondary case
Relies on mechanisms tha exist before infection
Innate (Non-adaptive)
Relies on mechanisms that adapt after infection
Acquired (Adaptive)
