Exam 1 Flashcards
1
Q
What is the goal of surveillance?
A
to detect a pathogen/disease obtain an estimate of pathogen/disease prevalence in a population
2
Q
Pathogen prevalence
A
estimate of proportion of individuals in a population that are infected with a pathogen
3
Q
T/F: infection equals disease
A
false
4
Q
How do we know baseline prevalence in the absence of disease?
A
- Previous surveillance studies (longitudinal) with the target host species and pathogen
- Pathogen challenge experiments in the lab
5
Q
What is the difference between prevalence and incidence?
A
Prevalence: the proportion infected (or diseased) at some time point
Incidence: the rate of new infections (or occurrence of disease) over an interval
6
Q
What is a limitation of prevalence?
A
only gets a snapshot at one point in time
7
Q
What does incidence track?
A
it tracks individual through time
8
Q
What are some types of detection bias?
A
vegetation, water depth, seasonality, sample frequency
9
Q
What are the uses of surveillance?
A
Occurrence and distribution
Evidence of emergence: pathogen or disease that is increasing in distribution, prevalence/incidence, or host range
Evidence of hotspots
Identification of mechanisms of emergence
10
Q
What are some disease intervention strategies?
A
interrupt host-pathogen cycle, reduce stressors
11
Q
What is the difference between novel pathogen vs. endemic pathogen?
A
A “novel pathogen” refers to a new, previously unknown infectious agent that has recently emerged in a population. (new)
An “endemic pathogen” is a pathogen that is consistently present within a specific geographic region, maintaining a relatively stable level of infection over time (well-established).
12
Q
Resistance, tolerance, susceptibility, and competence all do what?
A
facilitate host tolerance
13
Q
Resistance
A
ability to limit pathogen loads once infected
14
Q
Tolerance
A
ability to limit or survive pathogen effects once infected
15
Q
Susceptibility
A
whether a host becomes infected once exposed
16
Q
Competence
A
ability of an organism to generate new infections in other hosts
17
Q
Competent hosts are ___ of infections.
A
tolerant
18
Q
R0 = ?
A
invasion potential
19
Q
R0 >1 means what?
A
the greater than 1, the greater the rate of infection
20
Q
Random sampling
A
all individuals or surveillance locations have an equal probability of being sampled
21
Q
What info is needed to estimate a sample size?
A
Assumed pathogen prevalence level (APPL)
Estimated host population size
Confidence in detection (95%)
22
Q
One health
A
environmental health, animal health, and human health are all severely integrated
23
Q
Zoonoses
A
an infectious disease that transmits from animals to human and vice versa
24
Q
Zoonosis
A
animal to human
25
Reverse zoonosis
human to animal
26
Types of zoonoses
bacterial, viral, parasitic, fungal, protozoal
27
Vector
living organism that transmits an infectious agent from an infected animal to a human or another animal
28
How can we prevent zoonotic diseases?
by managing contact with wildlife (e.g. wildlife trade, land use)
29
What does EID stand for?
emerging infectious disease
30
Reportable Dz
diseases ID locally, reported to state health departments
31
Notifiable Dz
120 diseases ID by CDC, CDC notifies regions/nation of outbreaks and potential public health threats
32
Endemic vs. epidemic vs. pandemic
endemic: consistently present but limited to a particular region
epidemic: disease cases in a specific geographical area
pandemic: virus covers a wide area, affecting several countries and populations
33
Spillover
an event in which a species specific pathogen establishes infection in a novel, susceptible host
34
Spillback
when a pathogen is transmitted from a novel host back into an origin host
35
How does climate change relate to wildlife disease and spread?
Temperature stress --> disease susceptibility --> spread of disease
36
Ecosystem services
any positive benefit that wildlife or ecosystems provide to people whether by direct or indirect means
e.g. earthworms
37
Dracunculus Medinesis
often found in freshwater fish and frogs, affects humans and dogs. It has to be removed by slowly twirling the worm on a stick.
38
Lung worm
parasitic nematode worms that reside in the lungs of various vertebrate animals, including mammals, birds, and reptiles. First seen in musk ox.
39
Winter tick
seen a lot in moose, climate-change and warmer temperatures have an effect. Warm temperatures don’t allow for ticks to die off due to lack of frost. Causes hair loss and weight loss. Affects calves and therefore affecting the overall population
40
Histomonas meleagridis
poultry disease that affects turkeys, chickens, and game birds such as partridges, pheasants, and quail. has caused mass turkey loss nationwide.
41
Disease
a condition that impairs normal function
42
How is disease measured?
in terms of impariment of function rather than by death of individual
43
Factors that may cause disease are either ___ or ___.
intrinsic (e.g. inherited defect)
extrinisic (e.g. virus, contaminant)
44
Infection vs. disease
infection is the pathogen
disease is the response to the pathogen
45
Pathology
absence from normal
46
Pathogen
organism that is capable of causing disease (viruses, bacteria, fungi, parasites)
47
T/F: Not all pathogens cause disease all of the time.
true
48
What are the two things that impact disease?
Human driven impact
Nature driven impact
49
What are some costs of disease?
Cost to population from loss of individuals
Cost of loss of biodiversity
Cost to animal: increase energy needs
50
What are the best methods to monitor for pathogens/disease?
Recognize that animal health, plant health environment health, and human health are all interconnected
Multiple disciplines/expertise/skills
Include stakeholders (property owners, community, etc.)
Generally measuring frequency
51
What do we sample for(5)?
Antibodies: looking for past/recent exposure
Antigen: looking for the pathogen
Toxin/chemical: measuring concentration (chronic vs. recent exposure)
Type of disease: new, re-emerging, emerging
Patterns of disease (enzootic, epizootic): number of cases that occur over a time period relative to the number of cases that would be expected or that would “normally” occur during that period
52
Enzootic
occurs regularly and is predictable, to be expected at a certain rate in a population/area
53
Epizootic
occurs at a time or place where it is not expected or at a rate that is greater than expected based on past experience
54
What is La Crosse virus?
viral disease that causes brain swelling/damage
most poeple are asymptomatic, but symptoms include fever, headache, chills
primary vectors: container mosquitoes
#1 virus that causes brain swelling/damage in U.S. children
55
Longhorned tick
pathogenetic
develops in 1 year
3-host tick
first found in eastern Asia
56
What are the factors that lead to the resurgence of vector-borne diseases (6)?
Insecticides and drug resistance
Changes in landscape ecology
Demographic and societal changes
Genetic changes in pathogen and vectors
Decreased funding in prophylactic programs
Changes in health policy
57
What are some ways to manage vector-borne diseases (5)? And how?
Target the vector: natural, chemical, genetics, behavior
Target the hosts: remove, provide treatment
Target the pathogen: vaccines, medicines
Targe the habitat: reduce developmental sites, refuge
Target the vulnerable
58
Arthropods are ____.
ectotherms
59
What are some factors that affect disease cycles?
Physical factors: rainfall, humidity, temperature, sunshine, wind speed/direction, topography, soils, hydrography
Social factors: population distribution/density, standard of living, housing, diet, clothing, sanitation, income, religious customs
Biological factors: plants, animals, parasitoids, prevalent diseases, immunity
60
What are the impacts of arthropods?
Direct damage: biting, blood loss, myiasis, toxins, disturbance
Indirect damage: pathogen transmission, weaking, psychoses
Peripheral: quarantine, restrictions, misdiagnosis/treatment
61
Arthropod
exoskeleton, lots of legs (e.g. ticks, spiders)
62
Vector-borne disease
when a vector transmits a pathogen and then elicits a response (e.g. West-Nile, malaria, the plague)
63
What is the difference between a reservoir and a vector?
reservoir: where virus amplifies
vector: moves and amplifies host
64
Chronic Wasting Disease characterstics
Affects cervids (deer, elk, reindeer)
Is caused by infection of the animals with CWD prion
Prion can be transmitted through direct animal-to-animal contact (Salivea), through contaminated environment (carcass, feces, urine >> soil, water)
Symptoms: weight loss, lack of coordination, lack of fear of people
Fatal to affected animals. There is no treatment or vaccine available.
Currently tested using ELISA and immunohistochemistry (IHC)
If positive, you see color.
IHC uses brain and lymphoid tissue.
65
What are some ways we test for SARS-CoV-2 in animals?
Molecular tests (nuclear acid detection): Diagnosis active infections. Amplify genetic component of virus. Measure the amplified genetic component (RNA)
Antibody tests (serology): Detect immune response to exposure
66
Rabies characteristics
Pathogen: Rabies lyssavirus (negative-sense, single-stranded RNA)
Symptoms: headache, fever, uncontrolled excitement, and hydrophobia, (late stage) lethargy, coma
Host: humans, cats, dogs, racoons, skunks, bats, foxes
Treatment (human): wound care, human rabies immune globulin, rabies vaccine
Diagnosis:
Animal: detection of virus form the affection brain is the most common diagnostic test for rabies in animals. Human: history of animal bite, skin biopsy for detection of rabies virus antigen (dFA)
67
What does A,B,C,D stand for in terms of diagnostics?
A: true positive, B: false positive, C: false negative, D: true negative
67
What are some problems of detection tests?
Antibody may not be produced in early stage of infection
Antibody level may be remained after infection is cleared
Microorganisms similar to the pathogen may cause cross-reactive antibodies
Vaccination cause antibody production and confounds test results
All these factors can cause false positive/negative test results and lower diagnostic sensitivity and specificity.
68
Antigen specific T-cell is ___ if exposed/infected.
present
69
How do you calculate sensitivty?
A/(A+C) * 100
70
How do you calculate specificity?
D/(B+D) * 100
71
What are the two types of neutralizaiton tests?
toxin: Toxin mixes with cell. The cell will be damaged by toxin. If you add sample that contains antibodies, it neutralizes the toxin and the cell will be undamaged.
virus: red blood cells + antiviral antibodies from serum + viruses ---> viruses neutralized
72
Indirect immunofluorescence assay (IFA)
Indirectly tests presence of antibody using fluorescently-tagged antibody
If sample contains pathogen, you see fluorescent
73
Direct immunofluorescence (DFA, dFA)
Directly tests presence of antigen using fluorescently-tagged antibody
If sample contains pathogen, you see fluorescent
74
Enzyme-linked immunosorbent assay (ELISA)
Enzyme: horseradish (HRP), alkaline phosphate (ALP), etc.
HRP and AP mediate chemical reactions, resulting in development of color
The color of the solution will be read by spectrophotometry
If antibody is present, you see color. If absent, you see no color!
75
What are the pathways of the complement system?
Classical pathway
Lectin pathway
Alternative pathway
76
What is the result of the complement system?
cell lysis: process of breaking down the cell membrane through physical, chemical, or enzymatic methods, allowing the release of intracellular components such as proteins, nucleic acids, and small molecules.
77
What are the 2 categories of adaptive immune response?
Cellular immune
response
Humoral immune response
78
What are the 3 targets of immunological diagnostic methods?
pathogens with PAMPs and antigens
antigen specific antibody-mediated immunity
cytokine production
79
What are the first lines of defense once pathogen invades?
Enzymatic: lysozyme in tears and other secretions dissolves cell walls
Physical: skin is a physical barrier
Chemical: stomach acidity (pH2) inhibits microbial growth
Microbial: normal flora compete with pathogens
80
What is another line of defense if pathogen invades past the first line of defense (2)?
innate immune responses
adapative immune responses
81
