IB1091019 Mosquitoes and yellow fever
March 5, 2010, pp. 219-230
1. List two anatomical features that characterize all mosquitoes:
a. Six-part proboscis
b. Scales on the veins and posterior margins of wings
To what family do mosquitoes belong? Culicidae
2. Which of the following feed(s) on blood?
Female mosquitoes
Wrigglers
Male mosquitoes
Tumblers
3. How are Toxorhynchites larvae unlike most mosquito larvae? They are predaceous, feeding on
other mosquitoe larvae. Adults don’t feed.
What is unusual about the habitat of Wyeomyia mosquitoes? They live in pitcher plants
4. How do female mosquitoes find their hosts? Antennae of females respond to pulsed CO2,
lactic acid, and volatile compounds in feet.
5. The mosquito proboscis is a complex affair, with six mouthparts fused in various ways to form
two channels. What fluids move through these channels and which direction do they flow?
Blood is sucked up through the food channel. Anti-coagulants/anaesthetizing agents are injected
through the salivary channel.
6. Species in the genus Aedes are principal vectors of yellow fever.
7. Why is the floodwater mosquito Aedes sollicitans known as the “convict” mosquito and why
is Aedes albopictus called the Asian tiger mosquito? Their bodies are striped
8. Yellow fever is caused by a
a. bacterium
b. rickettsia
c. virus
d. nematode
To what family does this pathogen belong? Flaviviridae
Name two other members of this family—West Nile virus, St. Louis encephalitis, hemorrhagic
fever, dengue virus
What is an arbovirus? Arthropod born virus
9. What must a virus do to get transmitted by a mosquito?
a. Get through the midgut
b. Move into the hemolymph
glands and channel.
c. Move into the salivary
10. Why is the disease known as yellow fever or yellow jack? Causes jaundice or a yellowing of
the skin
Who is the principal vector? Aedes aegypti
What are the symptoms? Dizziness, headache, fever, nausea, vomiting, jaundice
11. Match the man with his contribution:
a. Walter Reed 4
1. First suspected yellow fever transmission by mosquito
b. Carlos Finlay 1
2. Cleaned up Havana and controlled yellow fever epidemic
c. William Crawford Gorgas 2
d. Benjamin Rush 3
3. Philadelphia physician who prescribed “purges” and
bloodletting to cure yellow fever
4. Headed US Army medical team that investigated causes of
yellow fever transmission
12. What standard medical practice began with the Reed Commission? Informed consent
13. True or False: Once you get yellow fever, you can never catch it again.
14. What was it that Max Theiler of Rockefeller Institute produced in 1936-7? Yellow fever
vaccine
15. Provide information to correct this statement: Yellow fever epidemics are no longer a major
health concern anywhere in the world. CDC still issues vaccine advisories for yellow fever when
travelling abroad.
16. Name two other diseases vectored by Aedes species.
a. Dengue fever
b. Hemorrhagic fever
What Aedes-borne disease was reported in Florida in 2007? Chikungunyma
17. Chikungunyma is caused by a:
a. bacterium b. virus
c. nematode
d. fungus
18. Aedes albopictus was introduced into the U.S. from Japan; how did it most likely get here?
Tires
19. List two reasons that it is unlikely that mosquitoes are vectors of AIDS. Blood volume
ingested is low, virus titers in blood is low, virus doesn’t persist in mosquitoes, transmission
from one human to another depends on an interrupted blood meal (doesn’t happen often).
20. What is the transmission cycle for LaCrosse virus? La Crosse virus transmitted by
Ochlerotatus triseriatus mosquitoes.
An adult female mosquito is able to transmit virus to humans and to squirrels and chipmunks
with her first blood meal. Squirrels and chipmunks become viremic and amplify the cycle when
fed upon by infected Ochlerotatus mosquitoes.
Humans, mostly children, develop encephalitis and do not transmit the virus (dead-end hosts).
21. What mosquitoes have been implicated in the transmission of West Nile Virus? Culex
pipien
22. West Nile virus is typically transmitted between mosquitoes and birds but many other kinds
of animals can amplify the virus, including horses and humans
23. “Ornithophilic” means bird-loving
24. What are the symptoms of West Nile fever? Fever, stiff neck, disorientation, mental
confusion, muscle weakness, paralysis, coma
25. True or false:
a. The vast majority of individuals infected with West Nile virus develop serious symptoms.
False
b. Only the elderly and the very young are at risk of dying from West Nile virus infection. False
c. Because of successful screening techniques, there are no cases of West Nile virus acquired
through blood transfusion. False
26. When was the Aedes aeqypti genome sequenced? 2008
How has A. aegypti been genetically modified to help control the spread of dengue?
They have been modified so that they have so signal to stop feeding. They keep feeding and
then they are unable to fly.