Block 4 Part 2 Flashcards
EPIDEMIOLOGY OF VIRUSES-what is it?
THE STUDY OF THE DETERMINANTS, FREQUENCY, DYNAMICS, AND DISTRIBUTION OF VIRAL
DISEASES IN POPULATIONS.
EPIDEMIOLOGY OF VIRUSES-why do we study it?
- TO CHARACTERIZE THE VIRUS, UNDERSTAND THE HOST AND HOST POPULATION, AS
WELL AS THE BEHAVIOR, ENVIRONMENT, AND ECOLOGICAL FACTORS OF VIRUS
TRANSMISSION.
EPIDEMIOLOGY OF VIRUSES: what is the role of epidemiology?
- ID AND CLARIFY THE ROLE OF THE VIRUS IN DISEASES
- UNDERSTAND INTERACTION WITH ENVIRONMENTAL DETERMINANTS OF THE DISEASE
- MODE OF TRANSMISSION
- THE IMPACT ON HEALTH, ECONOMY AND SOCIETY
- ROLE OF INFECTIOUS PATHOGENS (ESPECIALLY CANCER)
- LARGE SCALE ACCINE AND DRUGS
EPIDEMIOLOGY OF VIRUSES
HOW DOES THIS HELP?
- ADVANCES OUR UNDERSTANDING OF THE NATURE OF
DISEASES - ALERT AND DIRECT DISEASE TREATMENT, CONTROL AND
PREVENTION ACTIVITIES - PROVIDE EARLY WARNING SYSTEMS AND TRACKING THE
DISEASE - ASSESS THE ECONOMIC AND SOCIAL IMPACT OF THE
DISEASE - ASSESS THE EFFICACY AND COST OF DISEASE CONTROL
AND PREVENTION
OUTCOME OF DISEASE IN POPULATION
PERCENTAGE OF DEATHS
AMONG CLINICALLY ILL is called?
- CASE FATALITY RATE:
OUTCOME OF DISEASE IN POPULATION
PERCENTAGE ANIMALS IN A
POPULATION THAT DIE FROM A PARTICULAR
DISEASE OVER SPECIFIC PERIOD OF TIME is called?
MORTALITY RATE
OUTCOME OF DISEASE IN POPULATION
PERCENTAGE OF POPULATION
THAT DEVELOP CLINICAL SIGNS TO A VIRUS OVER
A DEFINED PERIOD OF TIME is called?
MORBIDITY RATE:
DURATION AND/OR FREQUENCY OF OCCURRENCE
THE NUMBER OF NEW CASES THAT OCCUR IN A POPULATION OVER A SPECIFIED
PERIOD OF TIME is called?
INCIDENCE
DURATION AND/OR FREQUENCY OF OCCURRENCE
THE NUMBER OF OCCURRENCES OF DISEASE (BOTH NEW AND OLD), INFECTION,
OR RELATED ATTRIBUTES (ANTIBODIES) is called?
PREVALENCE
VIRAL OUTBREAKS
SINGLE/SCATTERED INSTANCES
À RANDOM is called?
SPORADIC
VIRAL OUTBREAKS
constant presence in specific area/population is called?
enzootic
VIRAL OUTBREAKS
more than expected/peak of disease is called
epizootic
VIRAL OUTBREAKS
occurs over several continents or countries is called
panzootic
VIRAL OUTBREAKS
no clinical sign, but shed virus is called
asymptomatic carrier
VIRAL OUTBREAKS
what are the 3 types of asymptomatic carriers?
1-incubatory (acute)
2-convaleschent (chronic)
3-inapparent
VIRAL OUTBREAKS
animals that shed virus during the incubation period of a disease are called?
incubatory (acute) asymptomatic carriers
VIRAL OUTBREAKS
Animals that shed virus during recovery from a disease are called?
convalescent (chronic) asymptomatic carriers
VIRAL OUTBREAKS
carrier state that may exist in an animal with an infedtion that is anapparent throughout it’s course (the worst) is called?
inapparent asymptomatic
carriers
VIRAL OUTBREAKS
spread by direct or indirect contact
contagious disease
VIRAL OUTBREAKS
unknown in a particular country or area (rabies in st kitts)
exotic disease
VIRAL OUTBREAKS
the use of serological data as the basis of investigation
sero-epidemiology
VIRAL OUTBREAKS
The use of molecular biological data as the basis of investigation
molecular epidemiology
rabies has never been reported before in st kitts. suddenly a few cases of canine rabies are reported from st kitts, especially among dogs that accompany incoming rossies. in this context, rabies would ba a ____ disease in st kitts?
exotic
HORIZONTAL TRANSMISSION OF VIRUSES
what is direct contact transmission?
indirect contact transmission?
- DIRECT: BITES/DROPLETS
- INDIRECT: FOMITE/AIR-BORNE
HORIZONTAL TRANSMISSION OF VIRUSES
what is: MECHANICAL (PASSIVE TRANSPORT)/BIOLOGICAL (LIFE CYCLE/MULTIPLICATION)
Vector
HORIZONTAL TRANSMISSION OF VIRUSES
what is: CLASS OF VIRUSES TRANSMITTED TO HUMANS BY ARTHROPOD
ARBOVIRUS
HORIZONTAL TRANSMISSION OF VIRUSES
what is: medical/surgical practice. Can get as a side iffect to drugs, tx, etc. (contaminated drug/instraments)
Iatrogenic
HORIZONTAL TRANSMISSION OF VIRUSES
what is a common vehicle for transmission?
FECAL CONTAMINATION OF FOOD/WATER
HORIZONTAL TRANSMISSION OF VIRUSES
what is NOSOCOMIAL
WHILE IN A VETERINARY HOSPITAL
HORIZONTAL TRANSMISSION OF VIRUSES
I horizontal transmission the most common route of virus transmittal?
yes
HORIZONTAL TRANSMISSION OF VIRUSES
What is: passive transport of the infectious agent on the feet or other body part of the arthropod vector?
mechanical transmission
HORIZONTAL TRANSMISSION OF VIRUSES
what is an infectious agent that undergoes either a necessary part of it’s life cycle or multiplication in the vector before transmission to susuceptible host?
Biological transmission
HORIZONTAL TRANSMISSION OF VIRUSES
what is: virus transmitted from the mother tick through infected eggs to next generation of ticks?
transovarian transmission
HORIZONTAL TRANSMISSION OF VIRUSES
what is: virus transmitted from larva or numph to next stage of development (nymph or adult). but not transmitted vertically (from mother tick to eggs and next generation) ex. tick-borne flaviviruses?
trans-stadial transmission
TRANSMISSION
OF
ARBOVIRUSES
what is arbovirus?
class of viruses transmitted to humans by arthropods
(mosquitos/ticks)
TRANSMISSION
OF
ARBOVIRUSES
what is sllvatic or jungle
-between wild animals/birds and primary vector?
enzootic cycle
TRANSMISSION
OF
ARBOVIRUSES
what is: rural
-between non-wild/domestic and primary or accessory insect vector?
Epizootic cycle
TRANSMISSION
OF
ARBOVIRUSES
what is : between humand and insect vector?
urban cycle
TRANSMISSION
OF
ARBOVIRUSES
Level of virus high enough to infect the vector feeding off it.
Amplifying Host
TRANSMISSION
OF
ARBOVIRUSES
Infectious agent cannot be transmitted and don’t
develop sufficient viremia.
Dead- End Host/ Incidental
what is:INFECTION THAT IS TRANSFERRED FROM DAM TO EMBRYO OR
FETUS OR NEWBORN BEFORE, DURING OR SHORTLY AFTER
PARTURITION (COLOSTRUM, MILK, FECAL CONTAMINATION OF TEATS)
VERTICAL
TRANSMISSION
OF VIRUSES
The physical stability of a virus affects its what?
survival in the environment
Example: viruses that are transmitted by the respiratory route hace a low invironmental stability, whereas those transmitted by the fecal-oral route hace a higher stability.
what is: FORM OF IMMUNITY THAT OCCURS WHEN THE
VACCINATION OF A SIGNIFICANT LARGE PORTION
OF A POPULATION/HERD PROVIDES PROTECTION
FOR INDIVIDUALS WHO HAVE NOT DEVELOPED
IMMUNITY. (LARGE POPULATION WILL PROTECT THE
FEW WHO HAVE NO IMMUNITY)
HERD IMMUNITY
course of a typical infectious disease
what are the 5 stages?
INCUBATION PERIOD
PRODROMAL PERIOD
ACUTE
DECLINE
CONVALESCENT PERIOD
course of a typical infectious disease
FIRST SIGNS/ FEELING OF ILLNESS AFTER INCUBATION PERIOD AND
BEFORE CHARACTERISTIC SYMPTOMS OF DISEASE
which stage?
PRODROMAL PERIOD
course of a typical infectious disease
BODY RETURNS TO PRE-DISEASED STATE AND HEALTH IS RESTORED
which stage?
- CONVALESCENT PERIOD
course of a typical infectious disease
CS SUBSIDE
which stage?
decline
course of a typical infectious disease
INFECTION TO ONSET OF CLINICAL SIGNS
which stage?
INCUBATION PERIOD
course of a typical infectious disease
SEVERE CS AND HEIGHT OF INFECTION
which stage?
Acute
CLASSIFICATIONS OF RISK
GROUPS
MODERATE INDIVIDUAL , LOW COMMUNITY
RISK
example of what group?
GROUP 2
CLASSIFICATIONS OF RISK
GROUPS
HIGH INDIVIDUALITY RISK, LOW COMMUNITY
RISK
example of what group?
GROUP 3
CLASSIFICATIONS OF RISK
GROUPS
HIGH INDIVIDUAL RISK AND HIGH COMMUNITY
RISK
example of what group?
GROUP 4
CLASSIFICATIONS OF RISK
GROUPS
LOW TO NO INDIVIDUAL OR COMMUNITY RISK
example of what group?
GROUP 1
TERMINOLOGY
MAXIMUM CONTAINMENT LABORATORY, THAT HANDLES
DANGEROUS AND EXOTIC PATHOGENS. RISK GROUP 4 (EBOLA)
BSL-4
TERMINOLOGY
BIOLOGICAL SUBSTANCE THAT POSES A THREAT TO HEALTH
BIOHAZARD
TERMINOLOGY
CONTAINMENT PRINCIPLES, TECHNOLOGIES, AND PRACTICE
IMPLEMENTED TO PREVENT UNINTENTIONAL EXPOSURE OR RELEASE.
**Public health
BIOSAFETY
TERMINOLOGY
VERY SMALL DROPLETS OF FLUID THAT SPREAD VIA AIR. VIRUSES
CAN SPREAD IN THE LAB THIS WAY!
AEROSOL
TERMINOLOGY
PROTECTION, ACCOUNTABILITY, AND CONTROL OF
BIOLOGICAL MATERIALS, TO PREVENT UNAUTHORIZED ACCESS, LOSS, THEFT,
ETC.
**More personal health
BIOSECURITY
TIMING OF SAMPLE COLLECTION IS IMPORTANT!
COLLECTED ASAP AFTER ONSET OF
SYMPTOMS, THIS IS WHEN THE MAXIMUM TITER OF THE VIRUS IS
PRESENT. VIRAL RECOVERY IS BEST DURING THE FIRST THREE DAYS
AND GREATLY REDUCED AFTER FIVE DAYS WITH MANY VIRUSES.
why?
FOR VIRUS ISOLATION
TIMING OF SAMPLE COLLECTION IS IMPORTANT!
TWO BLOOD SPECIMENS ARE GENERALLY
COLLECTED, ONE DURING THE **ACUTE PHASE OF ILLNESS **AND THE
SECOND DURING THE CONVALESCENCE PERIOD (TYPICALLY 10-14
DAYS APART).
why?
FOR SEROLOGICAL TESTS
*antibody
TIMING OF SAMPLE COLLECTION IS IMPORTANT!
COLLECT ASAP DURING THE EARLY
PART OF THE ILLNESS
why?
FOR MOLECULAR DIAGNOSTICS
*antigen
TIMING OF SAMPLE COLLECTION IS IMPORTANT!
SWABS IN STERILE VIALS
why?
VIRAL TRANSPORT MEDIUM (VTM):
TIMING OF SAMPLE COLLECTION IS IMPORTANT!
IN ORDER TO PREVENT SPILLAGE, do what?
FOLLOW THE BASIC TRIPLE
PACKAGING SYSTEM
TIMING OF SAMPLE COLLECTION IS IMPORTANT!
IN ORDER TO PREVENT SPILLAGE, do what?
FOLLOW THE BASIC TRIPLE
PACKAGING SYSTEM
! What would be a good time frame to collect samples
for virus isolation:
A. Within 3 days of appearance of clinical signs
B. Within 7 days of appearance of clinical signs
C. Within 14 days of appearance of clinical signs
D. Within a month of appearance of clinical signs
A. Within 3 days of appearance of clinical signs
DIAGNOSIS AND DETECTION
CLINICAL SIGNS, NECROPSY,
HISTOPATHOLOGY
- DIAGNOSIS
DIAGNOSIS AND DETECTION
CELL TISSUE CULTURE/ISOLATION,
INOCULATION OF EGGS, AND ELECTRON MICROSCOPY
- DETECTION
DIAGNOSIS AND DETECTION
USED FOR VIRUSES THAT
CANNOT BE GROWN IN-VITRO
- ELECTRON MICROSCOPY
DIAGNOSIS AND DETECTION
THE METHOD IN TEM IS BASED ON
TRANSMITTED ELECTRONS AND SEEKS TO SEE
INSIDE OR BEYOND THE SURFACE
* PRODUCES IMAGES THAT ARE HIGHER
MAGNIFICATION AND GREATER RESOLUTION
ELECTRON MICROSCOPY: USED FOR VIRUSES THAT
CANNOT BE GROWN IN-VITRO
* TEM
DIAGNOSIS AND DETECTION
THE METHOD IS BASED ON SCATTERED
ELECTRONS AND FOCUSES ON THE SAMPLE’S
SURFACE AND ITS COMPOSITION
* PRODUCES 3-D IMAGES
ELECTRON MICROSCOPY: USED FOR VIRUSES THAT
CANNOT BE GROWN IN-VITRO
* SEM
DIAGNOSIS AND DETECTION
below is an example of what?
Negative-stain electronic microscopy
SEROLOGICAL ASSAYS TERMINOLOGY (antibody)
THE MOST ACCURATE AND BEST
AVAILABLE
GOLD STANDARD TEST
SEROLOGICAL ASSAYS TERMINOLOGY (antibody)
THE PROBABILITY THAT CASES WITH THE
INFECTION WILL HAVE A POSITIVE RESULT
SENSITIVITY
(sensitive=positive)
SEROLOGICAL ASSAYS TERMINOLOGY (antibody)
THE PROBABILITY THAT CASES WITHOUT THE
INFECTION WILL HAVE A NEGATIVE RESULT
- SPECIFICITY
COLLECTION OF SAMPLES
RED TOP: COLLECTS ?
SERUM
COLLECTION OF SAMPLES
PURPLE TOP/EDTA: COLLECTS ?
PLASMA
ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) (serological and molecular)
“direct” molecular is a…
TYPICAL ELISA
ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) (serological and molecular)
this is :
ANTIGEN COATED IN A WELL
ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) (serological and molecular)
this is:
ADD ANTIBODY TAGGED WITH AN ENZYME
ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) (serological and molecular)
this is:
ANTIGEN BINDS TO ENZYME-TAGGED ANTIBODY
ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) (serological and molecular)
this is:
WASH THE EXCESS UNBOUND ANTIBODIES
ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) (serological and molecular)
This is:
ADD SUBSTRATE
ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) (serological and molecular)
this is
ENZYME WILL CHANGE SUBSTRATE COLOR (POSITIVE REACTION)
ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) (serological and molecular)
this is:
LAYMEN TERMS: ADD AN ENZYME TAGGED ANTIBODY TO THE
ANTIGEN, ADD THE SUBSTRATE, THE ENZYME WILL CHANGE COLOR
TYPES OF ELISA
ANTIGENS ARE IMMOBILIZED AND PRIMARY ENZYME-CONJUGATED ANTIBODIES
ARE USED
DIRECT ELISA
*diagnosis unknown antigen
refer back to my cool analysis of balls, soccer players and the sunlol
TYPES OF ELISA
PRIMARY ANTIBODIES NOT LABELLED, BUT DETECTS SECONDARY ENZYME-
CONJUGATED ANTIBODIES THAT RECOGNIZE PRIMARY ANTIBODIES
Indirect ELISA
*diagnosis unknown antibody
TYPES OF ELISA
ANTIGEN MEASURED BOUND BETWEEN A LAYER OF CAPTURE ANTIBODIES
AND A LAYER OF DETECTION ANTIBODIES, THE ANTIBODIES THEN CHOOSE WISELY TO
PREVENT CROSS-REACTIVITY OR COMPETITION OF BINDING SITES.
sandwich ELISA
*diagnosis unknown antigen
DIRECT VS INDIRECT ELISA
ANTIBODY BINDS TO THE
ANTIGEN
*diagnosis unknown antigen
DIRECT
Direct is shorter word than indirect
Antigenis shorter word than antibody
DIRECT VS INDIRECT ELISA
2 ANTIBODIES NEEDED
* PRIMARY IS NOT LABELLED
* SECONDARY ANTIBODY IS
LABELED AND RECOGNIZED THE
PRIMARY
*diagnosis unknown antibody
INDIRECT
Direct is shorter word than indirect
Antigenis shorter word than antibody
DIRECT VS INDIRECT ELISA
is used for detecting
antibodies in a sample in order to
quantify immune responses.
Indirect ELISA
Direct is shorter word than indirect
Antigenis shorter word than antibody
DIRECT VS INDIRECT ELISA
is a
plate-based immunosorbent assay intended for the
detection and quantification of a specific analyte (e.g.
antigens, antibodies, proteins, hormones, peptides, etc.)
from within a complex biological sample.
A direct ELISA (enzyme-linked immunosorbent assay)
Direct is shorter word than indirect
Antigenis shorter word than antibody
- CAPTURE ANTIBODY GRABS THE
ANTIGEN - ENZYME LABELLED ANTIBODY THEN
ATTACHES TO THE ANTIGEN - ANTIBODY-ANTIGEN-ANTIBODY
SANDWICH
SANDWICH ELISA
*I am allergic to sandwiches w tree nuts
onthem
The technique is used for allergy testing. The test
will capture antibodies from blood samples
towards specific foods or other typical allergens.
ELISA can also be used to detect allergen proteins
in food products for quality control
SANDWICH ELISA
this is what?
SANDWICH ELISA
*diagnosis unknown antigen
*antibody antigen antibody
*enzyme labelled
