Exam Two Flashcards
1
Q
Explain what an ectoparasite is and provide an example.
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2
Q
Ectoparasites are organisms that live on or in the superficial layers of the skin of a host but do not enter the body.
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3
Q
Example: Mosquitoes (Order: Diptera) are ectoparasites that feed on the blood of vertebrates and act as vectors of diseases such as malaria and dengue fever.
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4
Q
- Explain vector capacity and vector competence.
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5
Q
Vector Competence: The ability of a vector to become infected
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maintain the infection
6
Q
Vector Capacity: The ability of a vector to transmit an infectious agent
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influenced by extrinsic factors such as host proximity
7
Q
- Explain the factors affecting competence and capability of fleas as vectors of the plague.
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8
Q
Vector Competence Factors (Intrinsic):
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9
Q
Genetics of the ectoparasite
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10
Q
Microbiota of the flea
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11
Q
Anatomy of the flea’s gut
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12
Q
Virulence factors of Yersinia pestis (the plague-causing bacteria).
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13
Q
Vector Capacity Factors (Extrinsic):
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14
Q
Climate (temperature
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rainfall
15
Q
Host population density
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16
Q
Land use patterns
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17
Q
Flea infestation rates on hosts.
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18
Q
- List and explain the morphology and important adaptations of mosquitoes.
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19
Q
Anatomical Adaptations:
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20
Q
Small size (~6 mm long) allows for easy mobility.
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21
Q
Three body segments: head (sensory organs and feeding structures)
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thorax (wings and legs)
22
Q
Mouthparts:
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23
Q
Labrum (food canal)
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24
Q
Labium (tongue-like structure)
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Hypopharynx (salivary duct)
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Behavioral Adaptations:
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Females require blood meals for egg production.
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Maxillary palps and olfactory receptors allow mosquitoes to detect hosts through CO₂ and body odor.
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5. List the three major mosquito species important to humans.
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Aedes spp. – Transmits viral diseases like dengue
chikungunya
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Culex spp. – Vector for West Nile virus and lymphatic filariasis.
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Anopheles spp. – Primary vector of malaria (Plasmodium spp.).
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6. Describe the life cycle and developmental stages of mosquitoes.
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Eggs: 50–400 eggs laid on water surfaces (Anopheles
Culex) or near water (Aedes).
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Larvae: Hatch in 1–2 days
feed on micro-plankton
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Pupae: Non-feeding stage
metamorphosis occurs
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Adults: Males feed on nectar; females require blood for egg production.
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7. Explain the relationship between the Aedes mosquito and the Dengue virus.
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a. What role does the mosquito play?
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Aedes mosquitoes act as vectors by transmitting dengue virus from an infected host to a new host.
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b. What adaptations contribute to the spread of Dengue fever?
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Daytime feeding behavior increases human-mosquito interactions.
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Eggs are resistant to desiccation
allowing survival in dry environments.
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Urban adaptation enables them to thrive in human-dominated environments.
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8. Develop a strategy to reduce the spread of Dengue fever.
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Biological Control: Introduce Wolbachia-infected Aedes mosquitoes to prevent virus transmission.
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Environmental Control: Remove stagnant water where mosquitoes lay eggs.
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Chemical Control: Use insecticides and larvicides selectively to reduce resistance development
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Fleas
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9. Morphology and adaptations of fleas.
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Anatomical Adaptations:
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Wingless
allowing easy movement through host fur.
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Bilaterally flattened
which aids movement between hair shafts.
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Strong exoskeleton makes them resistant to crushing.
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Behavioral Adaptations:
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Jumping ability (7 inches vertically
13 inches horizontally) facilitates host-switching.
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Bristles help them anchor in host fur.
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10. Life cycle of fleas.
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Eggs: Laid in the environment
hatch within 1–2 weeks.
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Larvae: Blind
legless
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Pupae: Can remain dormant for months until stimulated by CO₂ or vibrations.
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Adults: Begin feeding immediately upon finding a host
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Ticks
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13. Key anatomical structures and functions.
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Scutum: Protective shield.
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Hypostome: Feeding tube.
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Haller’s organ: Detects CO₂
temperature
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14. Sensory organs and functions.
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Palp sensilla A: Detects salts and sugars (food location).
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Palp sensilla B: Detects pheromones (mate location).
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17. Tick paralysis and alpha-gal syndrome.
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Tick Paralysis: Caused by neurotoxin in saliva
leading to weakness and potential respiratory failure.
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Alpha-Gal Syndrome: Allergic reaction to mammalian meat after a tick bite due to sugar transfer
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Ticks and the Immune System
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19. Tick saliva proteins and their function.
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Cement Proteins: Anchor the tick in place.
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Anticoagulants: Prevent blood clotting (Ixolaris
TAP).
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Immunomodulators: Suppress immune response (Iris
IRS-2).
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Evasins: Prevent neutrophil recruitment.
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Vector Control
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22. Explain the need for vector control (use epidemiological terms).
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Vector-borne diseases account for 17% of infectious diseases globally.
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Control reduces transmission
incidence
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23. Incidence vs. Prevalence.
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Incidence: New cases over time; measures risk.
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Prevalence: Total cases at a given time; represents disease burden.
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25. Vector control strategies.
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Biological Control: Using Wolbachia bacteria to block pathogen transmission.
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Chemical Control: Insecticides and larvicides.
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Genetic Control: Releasing genetically modified sterile mosquitoes.
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26. Pros and cons of control strategies.
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Biological Control
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Pros: Environmentally friendly
long-term.
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Cons: Expensive
slow implementation.
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Chemical Control
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Pros: Fast-acting.
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Cons: Resistance development
environmental toxicity.
