Mosquitoes Flashcards
mosquitoes develop through which life cycle
complete metamorphosis
which stage do mosquitoes become medically important vectors and pests
adult stage
required for larval development
water
can be laid singly or in groups; on or near water; on soil , vegetation or other objects close to water; or on soil that is susceptible to seasonal flooding
eggs
live in water, also known as “wigglers”
can be found in large bodies of water or in very small amounts
larvae
shaped like a comma
live in water and stay on the surface
known as “tumblers”
do not feed
capable of quick, short movements used for escaping
pupae
capable of flight
average flight distance is between 54 yards and 31 miles
many only flying 1-3 miles
both M/F feed on nectar
F only feed on blood, required for egg production
adults
have feathery antennae
males
have hairy antennae
females
Eggs:
laid as a raft, comprised of up to 300 eggs
free floating on water surfaces
Culex mosquito
Habitats:
breed in pools, puddles, ditches, rice fields, water polluted w/ organic debris
found world-wide except extreme northern parts of temp zones
Culex mosquito
Larvae:
have a long siphon “tube” used for respiration and suspend perpendicular from the water’s surface
react to shadows
when disturbed, dive straight down
collect by quickly dipping under the diving larvae
Culex mosquito
Adults:
most often non-descript scales
females tend to rest indoors or in sheltered location before and after feeding and during the day
Culex mosquito
Eggs:
laid individually on damp soil or on the inner, wet walls of artificial containers w/ water, just above the waterline
eggs are very hardy and can survive drying out for up to 8 months
Aedes mosquito
Habitats:
Larvae and pupae are found in marshes and ground pools, some breed in man-made/artificial containers
rest outdoors or indoors before and after feeding
found world-wide
Aedes mosquito
Larvae:
emerge from mosquito eggs, but only after the water level rises to cover the eggs
siphons (tubes) are shorter than Culex
larvae rest perpendicular to water surface
Aedes mosquito
Adults:
many are marked with white & black scales
may fly short or long distances
Aedes mosquito
Eggs:
females lay 50-200 eggs
eggs are laid one at a time and float on the surface of the water
Anopheles mosquito
Habitats:
larvae are found in many different types of habitats such as fresh/salt water marshes, swamps, grassy ditches, rice fields, temporary water collections
Anopheles mosquito
Larvae:
do not have a siphon tube, instead have a paired spiracles for respiration and lay parallel to the water surface to breathe
when disturbed, larvae wiggle across the surface
collect by allowing water to slowly flow into dipper, or skimming the surface
Anopheles mosquito
Adults:
most are dawn/dusk/night feeders
use varied resting areas indoors and outdoors vegetation
Anopheles mosquito
Eggs:
are laid in a sticky compact mass, often arranged as a rosette glued to the undersurface of floating vegetation
Mansonia mosquito
Habitats:
rooted or floating vegetation in permanent water
Mansonia mosquito
Larvae:
use their siphon tubes to pierce submerged aquatic vegetation and breath e
collect by pulling up plants from permanent water
Mansonia mosquito
Pupae:
use paired siphon tubes to pierce aquatic plant to breathe
Mansonia mosquito
Adults:
most are night biters
prefer to rest outdoors
Mansonia mosquito
during the day
diurnal
during the dawn and dusk
crepuscular
at night
nocturnal
feeds indoors
endophagic
feeds outdoors
exophagic
feeds on humans
anthropophagic
feeds on animals
zoophagic
prefers indoors
endophilic
prefers outdoors
exophilic
mosquitoes use which cues for host-seeking
visual and olfactory
acute and chronic disease caused by parasitic protozoa in the genus Plasmodium and transmitted by certain Anopheles species
Malaria
Distribution:
widespread throughout the tropical countries of the world
Malaria
Life cycle:
Two life cycles - primary/secondary
Malaria
occurs in the mosquito and involves transmission between mosquito-human via blood meal
Primary cycle
in humans involves invasion of the liver and RBC
Secondary cycle
only available drug for prevention of malaria relapse
primaquine
hereditary, sex-linked enzyme defect that results in the breakdown of RBC when the person is exposed to the stress of infection
G6PD deficiency
acute febrile illness caused by an arbovirus transmitted by Aedes spp. mosquitoes
Dengue
Distribution:
found throughout much of the tropical world, particularly in Central America, West Africa, South Asia, and many Pacific countries southward into Northeastern Australia
Dengue
Arbovirus transmitted primarily by Aedes spp.
Yellow Fever
Zika Virus
Distribution:
found in tropical and subtropical areas in South America and Africa
Yellow Fever
Vaccine:
available in the US
Yellow Fever
Distribution:
Found in South America, Africa, and Middle Eastern and Asia countries
Zika Virus
can spread from an infected pregnant woman to her fetus
Zika Virus
inflammation of the brain caused by a viral infection transmitted by insects, including mosquitoes, ticks and sandflies
Abroviral encephalitides
Distribution: worldwide
Symptoms: often asymptomatic or present w/ flu-like symptoms
Examples: West Nile virus
Vaccine: one vaccine available in US
Abroviral encephalitides
Direct effects of bites
Dermal: ranging from mild dermatitis to severe hypersensitivity that may cause secondary infections from scratching
Nuisance: causing decrease in morale
overall surveillance should be based on
Populations at Risk (PAR)
conducted to determine the types of vector and pests, their breeding sites and seasonal activities
baseline survey
counts of vectors/pests to help pest management personnel decide when to start/stop control measures
operational survey
specific vector and/or pest targeted for surveillance beyond baseline/operational surveys
includes survey when personnel show symptoms of parasitism by insects, not only disease
specific survey
use which trap to collect eggs
ovitraps
basic tool for larvae surveillance
larval dipper
used for attracting and capturing pregnant females for disease surveillance
gravid traps
traps to survey adult mosquitoes
CDC Light Trap and CO2 traps
used to attract Aedes spp.
BG Sentinel 2
factors taken into consideration when determining which control measure to use
size of control area
protected areas
dwelling
field operations
type of facility
Education
Drain or fill low lying/stagnant water areas
Remove vegetation from streams to allow water to flow faster and to remove potential harborage
Remove debris from housing and work areas that hold water
Cultural control
most environmentally sound, but usually the most expensive to implement and maintain
Bacillus thurengiensis isralensis dunks and mosquito fish are most common means
Biological control
LAST RESORT
larvicides are available to treat identified breeding locations
adulticides are available in many formulations to meet most control needs
give quicker but temporary results
chemical control
