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ENTO 210: EXAM 1
The Five Kingdoms: |
Protists, Monerans, Fungi, Plants, Animals |
Five Subphyla of Arthropods |
Trilobitomorpha, Cheliceriformes,
Crustacea, Myriapoda, Hexapoda |
Origin of Arthropods: |
Cambarian explosion (530 million years ago), |
Total number of arthropods: |
1,048,000 |
Total number of insects |
925,000 |
Why so many species of insects? |
very old group, insects are small, live in a large number of habitats, flight, wing folding, co-evolution with flowering plants
|
Class Crustacea: |
52,000 species described, a lot are consumed by humans,
examples: Daphnia, Isopod, barnacles, Copepod, parasitic isopod, lobster, coconut crab |
Class Chelicerata: |
Subclass Merostoma:
-order Eurypterida (Water scorpions)
-order Xiphosura (Horseshoe crabs)
Subclass Arachnida
-Scorpiones
-Uropygi
-order Amblypygi
-order Araneae (spiders)
-order Opiliones
-order Acari (ticks and mites)
-order Solpugidae
|
Class Pygnogonida |
Sea spiders |
order Eurypterida |
-water scorpions |
order Xiphosura |
-horse shoe crabs |
order Scorpiones: |
scorpions |
order Uropygi: ** |
vinegaroons |
order Amblypygi: |
... |
order Araneae |
Spiders |
order Opiliones |
harvestmen |
order Solpugida |
camel spider |
order Acari |
ticks and mites |
Subphylum Myriapoda |
Class Diplopoda (Millipedes) **
Class Chilopoda (Centipedes) **
Class Pauropoda
Class Symphyla
|
Subphylum Hexapoda |
Class Parainecta
Class Entognatha
Class Insecta |
Class Insecta |
-Apterygota (wingless)
-Pterygota (winged) |
Apterygota |
Silverfish |
Pterygota |
-Paleoptera (Dragonflie, Mayflie)
-Neoptera:
|
Neoptera: |
-Exopterygota: Incomplete Metamorphosis)
-Endopterygota (complete metamorphosis) |
Exopterygota: |
-wings develop externally, juvenile (nymph) and adult look similar
-major orders: biting/sucking lice, true bugs/cicadas, thrips, matins, cockroaches, termites, stick insects, grasshoppers ,earwigs, webspinners, stoneflies
|
Endopterygota: |
-wings develop internally, juvenile (larvae) and adult very different
major orders: butterflies, flies/mosquitoes, lacewings, antlions, dobsonflies, scopionflies, beetles, was/bees/ants, fleas, caddisflies |
Importance of arthropods (roles in ecosystem |
-nutrient recycling of leaf litter, wood, carrion, dung, soil turnover
-plant propagations
-maintenance of plant community structure through phytophagy
-source of food for animals
-maintenance of animal community structure |
Importance of arthropods (other ways): |
food, pollinators of human crops, products, honey, silk, and they are a great subject for biologists |
ways in which arthropods are damaging |
-damage crops directly, transmit plant viruses, destroy products in storage, damage wooded structures |
Gypsy moth |
-brought to the US in 1868, breed hardier silk worm, 450 species of plants are its food, $500 million spent on control
|
human health and disease |
-malaria
-yellow fever
-dengue fever
-sleeping sickness
-visceral leishmaniasis
-river blindness
-chagas
-plague
-west nile |
The arthropod body plan |
-exoskeleton
-evolution of molting
-paired segmented appendages
-segmented body
-open circulatory system
compound eyes |
Exoskeleton |
protective armor, support, prevents water loss
limitations: |
segmentation: |
-tagmosis: fusion of segments to create new functional units
-modern spiders, mesothelae |
Respiration: |
causes size limitation because oxygen can not reach very far into body by passive diffusion |
Gas exchange: |
spiders have poor oxygen supply, oxygen is transported by blood (haemolymph) <-- contains haemocyanin which is an oxygen binding protein |
The haemolymphy transports: |
nutrients, hormones, immune cells/proteins, and waste products |
Alimentary canal |
3 parts:
-Foregut: ingestion, transport, storage (sometimes), mechanical digestion
-Midgut: enzyme production, chemical digestion, absorption
- Hindgut: water re-absorption |
Reproductive organs: Females |
-External: teregum, cercus, ovipositor, gonopore
-Internal: ovarial ligment, ovarioles, OVARY, lateral oviproducy, calyx, common oviduct, spermathacal gland, SPERMATHECAE, ACCESSORY GLAND, genital chamber, vagina |
Reproductive organs: Males |
- External: accessory gland, sperm duct, cercus, anus, penis, ejaculatory duct
- Interal: sperm tubes, TESTIS, sperm duct, ACCESSORY GLANDS, SEMINAL VESICLE, ejaculatory duct, penis |
Sensory Preception: |
-Bristles or Setae:
-Smell:
-Vision |
Mechanoreceptors: |
subgenual organs, johnstons organs, tympanal organ |
Vision: |
-Dermal detection: light sensitive cells or receptors under the cuticle
-Stemmata: visual organ of some insect larvae, similar to ommatidia
-Ocelli: ocellus (damesfly and jumping spider)
-compound eyes
|
Smell: |
antennae, palps |
Bristles or setae: |
touch, chemical perception (taste)
|
Insect wings |
-Indirect flight muscles: no hinge betweenn wings
-Direct flight muscles: hinged between
|
Respiratory System: |
main trachea, and spiracles |
Whats an allergic reaction: |
relatively harmless substance or allergen elicits an out-of-proportion reaction of the immune system |
Types of allergic reactions: |
-local allergic reactions, large local reactions, systemic allergic reactions (anaphylaxis) |
local allergic reactions |
where allergen makes contact with the body: lung, nose, skin
example: house dust allergy, mosquito bite |
large local reactions |
-often peaks 12 hours after exposure, can be strong enough to constrict blood vessels or nerves to extremities, these may last as long as 10 days |
systemic allergic reactions |
-more likely to occur when allergen reaches blood or lymph
-most extreme case: anaphylactic shock <--- dangerously low blood pressure and constriction of bronchia
-often caused by wasp, bee and ant stings
-if you have a systematic reaction you are at risk for anaphylactic shock next time you are stung |
Signs of anaphylaxis: |
-generally: apprehension, uneasiness, weakness
-cutaneous: redness, ithcing, rash, swelling
-gestrointestinal: abdominal cramps, vomiting, diarrhea
-genito-urinary: urinary or fecal incontinence
-respiratory: chest tightness, weezing, trouble breathing
-cardiovascular: dizziness, lightheadedness, low blood pressure
-usually begins with rash or swelling
-in extreme case this can cause death within 10-15 minutes, but 20-30 is more common |
management of allergic reactions: |
local reaction: antihistamines and topical corticosteroids
sever local: antihistamines, systemic steroids, high potency topical steroids, rest and elevation of limb, avoid exercise
-if near eye, throat, or wide spread swelling then seek medical attention
systemic reaction: emergency room, ice pact may delay absorption of venom, ue epinephrine kit |
Common arthropod causes of allergic reactions |
-blood feeding insect bites:
-bites and stings:
-Inhalation of body parts:
-Ingestion of insect parts |
Inhalation of body parts: |
house mites ,cockroaches, mass emergences of caddis flies and mayflies <-- symptoms are inflammation of nose mucous membranes, eczema, hives, asthma |
bites and stings: |
bees, ants, wasps, black widow, brown recluse <--most likely to cause systemic reactions
|
blood feeding insect bites |
flea bite |
ingestion of insect parts |
cockroaches, adult beetles (weevils, meal works), moths, fly larvae
-symptoms: diarrhea, abdomincal pain, peri-anal itch |
Arthropods with venomous bite: |
spiders, centipedes
-bited are for subduing and predigestion of prey |
Centipedes: |
-3,000 speices
-most nocturnal, hide during day, emerge at night
-largest ones (Scolopendra <-- very painful bite, subsides with 6-8 hours, rarely fatal)
-anxiety, vomiting, irregular pulse, dizziness, and headache
-house centipedes eat spiders, bedbugs, termites, cockroaches, silverfish ants and other household arthropods
-originally from mediterranean
-one of the most useful arthropods you can find in your home
-bite is incapable of penetrating human skin
-those that can are no worse than a minor bee sting |
Texas scholopendromorph Centipedes |
-largest and most significant: Giant Redheaded Centipede (up to 9 inches long) |
Spider bites |
-36,000 species, and all but one family are venomous
-only a few dozen produce medically significant bites in humans
-three groups of problematic spiders:
1. Brown recluse
2. Widow Spiders
3. Hobo Spiders |
Recluse Spiders (violin spiders) |
-13 species in the US that can produce necrotic lesions
-three produce most bites:
1. Loxosceles reclusa Brown recluse
2. L. laeta Chilean recluse
3. L. arizonica Arizona Brown Spider
-brown recluse is most problematic
-venom is necrotic, not neurologic
-prefers warm and dry areas (woodpiles, cellars of houses
-almost social animals
-active during nighttime |
How to recognize brown recluse? |
-they have 3 pairs of 2 eyes, with space between them, others have 8 eyes |
how often do brown recluse bite? |
-very docile, bite almost always occur:
1. during sleep
2. inside clothing |
symptoms of a brown recluse bite vary from: |
1. no reaction
2. mild, red wound
3. nerotic lesion
-systemic reactions are very rare |
nerotic lesions from brown recluse |
-produce ulcers 1-25 cm
-necrosis: disorganized breakdown of flesh in some part of the party
-healing can take months
-bite usually painless until 3-8 hours later
-assymetrical lesions are typical of brown recluse
^ many necrotic wounds caused by Stapylococcus an dStreptococcus are reported as brown recluse bites, venom contains same compound as produced by pathogenic bacteria (sphyingomyelinase D)
wounds occur through:
-neutrophil activation- produces reactive oxygen products to destory invading pathogens
-platelet aggregation
-intravascular thrombosis
Symptoms: mild to severe pain, erythema and blister formation
blusih discoloration within 24 hours
-3-4 days --> nectrotic lesions
|
Widow Spiders |
-five species in the US 9not all have the hour glass) brown widow, red widow, northern black widow, western widow, black widow
-there is variation within species
-like protected places (crawl spaces, holes, piles of rocks, bricks or firewood, dense plant growth
-only females bite, males are to small, only immatures overwinterduring cold winters
-fairly reclusive, don't bite unless provoked
-neurological venom, not necrotic
-systemic reactions much more common
-anti-venom is available, but rarely used for mild bites
symptoms:
-many people do not realize they have been bitten
-initially mid burning or stinging sensation
-pain in regional lymph nodes
-increased blood pressure
-profuse sweating and nausea
if envenomization is significant systemic symptoms are:
-weakness, tremor, muscular spasms, chest tightness, rigid abdomen, paralysis, convulsions, stupor, DEATH (less than 1%)
-anti-venom has relatively high risk, patients are monitored and treated, if serious systems develop seek medical help
|
Hobo spiders |
-medical significance is controversial
- number of necrotic bites have gone up in last 30 years in north west |
Sidney Funnel Web Spider |
-Habitat: burrows, rotton logs, tree holes, rock crevices
-as many as 100 may form a colony
-males in search of females may wander into houses (esp. during rainy weather)
-VERY AGGRESSIVE
-can cause death in as little as 15-30 minutes
-however in many cases no venom is injected and no symptoms occur
-if venom is injectes: bite becomes extremely painful, spasms, nausea, vomiting, profuse sweating, mouth numbers and anti venom is administered
-4-6 cm |
Tarantulas |
-in US, they are in family Theraphosidae (hunting spiders)
-none are known to have a bite that is deadly to humans
-new world species have urticating hairs
-barbed hairs are irritating and can cause serious irritation if inhales
-skin rash, eye problems |
Arthropods with venomous sting: |
Hymenoptera: bees, wasps, ants
Scorpions: |
Hymenoptera- Wasps: |
-in all, stinger is modified ovipositor, which may no longer function in oviposition (social insects)
-many wasps have venom: 15,000 species of stinging wasps, 95% problematic |
Social Insect: |
-Colonies are composed of:
Queens- reproduction
Males-reproduction
Workers- sterile females
-Colony is also called a super organism
-function of colony is to grow large enough to produce many males and queens that will est. new colonies
-workers specialize in broodcare, foraging, and defense
-social hymenoptera are most important cause of serious injury
-allergic reactions common
-500-1000 stings may result in death through the effect of venom
-site of bite is typically painful for a few hours and may swell or itch for a few days |
Justin O. Schmidt Pain Index: |
1.0 Sweat Bee: light, ephemeral, almost fruity
1.2 Fire ant: sharp, suden, middy alarming
2.0 Bald faced Hornet: Rich, hearty slightly crunchy
2.0 Honey Bee:
3.0 Red Harvester Ant: bold and unrelenting
3.0 Paper Wasp: Caustic and burning, bitter aftertaste
4.0 Bullet Ant: pure, intense, brilliant pain |
Most Problematic Wasps: |
-Yellow jackets
-Honet Vespa Cabro:
-Paper Wasps
-Honey Bee
-Killer Bees |
Killer Bees or Africanized Honey Bee |
*introduced from africa to brazil in 1956, by Warwick Kerr to cross with European bee to produce a type more adapted to tropical climate
*escaped in 1957, 1990: southern tx, 1993: arizona, 1995: california, 2005: florida
*medical importance: 1000 deaths since introduction, 14 deaths in US since introduction, costa rica in 1986 had 8000 stings
*why so dangerous: venom is about same strength as European Honey Bee, much easier disturbed, may protect large area around nest |
Honey Bee: |
introduces from Europe to produce honey and pollination in agriculture
*most colonies are artificial
*produces colonies and can mobilize workers for defense of colony
*bee stinger is barbed and will stay in victim
*produces pheromone that marks the victim for other workers |
Paper Wasps |
*200 species worldwide
*great affinity for building in and around buildings, encounters with humans are common
*other queens sometimes join colonies and compete for reproductive dominance
*mature colonies are 30-70 adults
*colony is single, open faced cone |
Honest Vespa Cabro |
*introduced in US in 1850
*closely related to Yellow Jackets & similar in biology |
Yellow Jackets |
*26 species
*mature colony size ranges from 500-15000 cells
*colonies are build either suspended in air or underground and in structures |
Ants |
-all bite, only some sting
-two main groups of medically relevant ants:
1. Imported Fire ants
-Red imported fire ant
-black imported fire ant
2. Harvester ants: 26 species in US, sting is very painful and very aggressive |
Fire Ants |
-extremely aggressive, at slightest disturbance large numbers of workers are mobilized
-sting: burning sensation at first and welt 24 hrs pustule develops
-no evidence venom can kill humans (unless allergic)
-hypersensitivity is a problem
-introduces in early half of 20th century
-red fire ant form brazil
-black fire ant from uruguay
-red fire ant has spread aggressively
|
Scorpions |
-2000 species worldwide
-contains neurotoxic venom <-- interferes with transmission of neural impulses
-annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths
-only handful are deadly, the most at risk are children, elderly, infirm
-Deathstalker: most potent venom (north africa, middle east)
-nervous and aggressive, readily available in pet trade
-90 species of scorpions in the US |
Centruroides exilicauda (Arizona Bark Scorpion) |
-america's most dangerous scorpion, mostly to infants and children.
-no deaths reported since 1968 in US
-antivenom is experimental, non FDA approved and only available in Arizona
-Distrubtion USA: Arizona, California, Nevade, New Mexico and UTA, and northwestern MExico
-Treatment: Stay calm, do not move stung body part, seek medical treatment |
Texas Scorpions: |
-only 18 speices and only one Striped Bark Scorpion (Centruroides Vittatus) is in eastern part of the state
-C. Vittatus is an active forager and will climb trees and move into attics. When its warm it will move down into living quarters
-sting of species causes local pain and swelling
-deaths attributed to this species have not been substantiated |
Millipedes |
-vegetarians, feed on dead plant and leave matter
-come produce irritating secretions
-symptoms to exposure: pain, itching, local erythema, edema, blisters, eczema, and occasionally cracked skin
-some non US speices produce Hydrogen cyanide |
Caterpillars |
-150 species are medically relevant
-several species produce irritation (stinging) hairs that release poison when touched
-fatalities are rare
-generally: local reaction, swelling, pain, numbness
-systemic reaction: nausea headache, committing, paralysis, acute renal failure
|
Blister Beetles, Family Meloidae |
-when ingested: abdominal pain, kidney damage, and sometimes death
-in case of hay (alfalfa), infestation may kill horses (50 beetles)
-striped blister beetle
-spanish fly: blister beetle from southern europe: used in aphrodisiac |
Introduction to evolutionary theory |
-Charles Darwin and Herbert Spencer
-Evolution is not really about survival -> reproduction is key concept
-one of the main forces of evolution:
*natrual selection: heritable traits that increase relative reproductive success will become fixed in a population
|
Fitness: |
-the proportion of the individual's genes in the next generation
-of population size is stable, 1 copy of a gene on average contributes one copy to the next generation
-if all individuals contribute equally, all have fitness =1 (means no change in frequency, unless by chance, "genetic drift")
-if some ind. have a gene A that increases the proportion of their offspring with 5% in the next generation, fitness fitness -> 1.05 and Gene A will replace Gene B and will go to fixation
|
r strategists |
r=growth rate
-r strategists optimize growth
- beetles
-high fecundity
-small body size
-early maturity
-short generation time
-ability to disperse offspring widely |
K strategists |
-K= carrying capacity
-K strategists optimize competition in crowded niche
-low fecundity
-lot of investment in each offspring (parental care)
-large body size
-long generation time |
Virulence: |
-the degree of pathogenicity of infectious disease
-high virulence: high mortality, severe illness (example: malaria, yellow fever)
-low virulence: low/no mortality, minor symptoms (example: common cold) |
a pathogen's reproductive success depends crucially on: |
its ability to find a suitable host
-in order for a species of pathogen to survive every sick host needs to infect 1 new host on average
-just 1 new infection/host -> pathogen level in host population does not change
-less then <1 new infection/host -> pathogen goes extinct
- greater than >>1 new infection/host -> epidermic, or highly endemic disease area |
How are virulence and transmission correlated? |
-Depends on transmission mode:
example> common cold, no known fatalities, not bad enough that you stay in bed, so direct transmission between people through hand contact, sneezing -> airborne pathogens and through objects
|
Malaria transmission: |
two hosts |
modes of transmission select for high virulence: |
-water-borne transmission
-sit and wait transmission |
water borne transmission: |
Thypoid fever, cholera, gangerour forms of dysentery
-diarrhea: immoblized patient release pathogens on bed sheets or clothing which will be in contact with the water
|
sit and wait transmission |
some can survive outside of hosts for many days or even years
-example: small pox, Variola major kills 30-35%, 3oo-500 million deaths in the 20th century, eradication of small pox in December 1979, small pox can exist outside of a hose for more than a decade |
Other disease that can remain pathogenic outside host for long time: |
Mycobacterium tuberculosis, Cornynebacterium diptheriae, Bordetella pertussis (whooping cough), Streptococcus pneumoniae, Influenza virus (can exist for more than 10 days)
|
Evolutionary Epidemiology: |
when making decisions about control methods, take long term perspective and focus on reducing transmission of disease (example: development of new drugs) -> This should reduce virulence, or replace pathogenic staring with less pathogenic strains |
Examples of evolution of disease virulence: |
-Syphilis: treatment with Plasmodium knowlesi <- induces fever and kills Treponema palladium, which causes syphillus
*P. knowlesi was transferred directly from patient to patient using a syringe
*after 170 transfers it was as dangerous as neurosyphilis
-Cholera: endemic countries in Asia
*caused by Vibrio cholera and is in large part transmitted through contaminated water supply
*India: 1950's and 1960's purification of water supplies, Vibrio cholera is replaces with milder "El TOr" type of Vibrio cholerae
*Bangladesh: no water purification, dangerous form of Vibrio cholera persists
-Myxoma: virus and rabbits in Austrailia, they spread very rapidly because no predators, highly lethal to rabbits with mortality rates greater then 99%
*virus is transmitted by contact infection
*arthropod vectors; mosquitoes, fleas, mites, ticks
*epidemic occurred for 4 years
*now virus kills 40% of rabbits in Australia, Myxoma virus evolved to be less virulent |
changes in behavior of mosquito by parasite: |
malaria infected mosquitos have less salivary apyrase (a platelet inhibitor)
-mosquitoes spend more time feeding
-probe more often
-more persistent in biting
-feed more often
(compared to uninfected)
|
Adaptation of humans to malaria |
-Sickle cell gene:
*1-20% of all sub-Saharan Africans carry this gene
*In US approx. 1 in 5,000, mostly in people from African decent
*Heterozygotes are almost always asymptomatic: (1 copy) -> resistance against malaria
*Homozygotes have sickle cell anemia: (2 copies) -> very serious disease |
Dynamics of Vector-Borne disease: |
1. Vector competence: ability of a vector to transmit a pathogen (can pathogen grow inside vector)
2. Vectorial Capacity: rate at which future inoculations arise from a currently infective case (c= average number of new infections arising daily from a single infection) |
Vectorial Capactiy =c= |
(ma^2VP^n)/(-logeP)
*m=number of vectors per human
*a=number of human blood meals per mosquito per day
*V= vector competence
*P= daily survival rate
*n= incubation period in vector (extrinsic incubation period)
|
what are most sensitive components of vector capacity: |
*a= number of human blood meals per mosquito per day
*P= daily survival rate |
one more parameter that is relevant: |
r= rate at which people recover from infection (=1/ number of recovery days <- number of days people remain infective) |
Basic Reproduction Number =R= |
(ma^2VP^n)/(-rlnP)
* if R<1: infections decrease eventually pathogen goes extinct
* if R > 1: # of infections increase
* if R=1: # of infections stays same
|
Evolution of blood feeding is thought to have occurred along two main routes: |
1. close association with vertebrates
2. Mophological Pre-adaption for piercing |
Close association with vertebrates |
Arthropods that did not have any pre-adaptation for blood feeding |
Morphological Pre-adaption for Piercing |
Blood feeders are often found in entomophagous groups with piercing mouthparts |
Host Preferences: |
-most blood suckers show preference for a certain host species
-degree of host specialization varies from species to species
-direct relationship between locomotory capabilities and number of different hosts it utilizes |
What type of hosts are favored? |
-Large social herbivores: abundant, easily visible
-Small vertebrates: suffer great blood loss, stronger host defenses
-Less favored: carnivores they are less abundant, solitary |
Ecological determination of host choice: |
- |
memory in host seeking mosquitoes: |
-blood fed mosquitoes return to the same host in higher numbers than expected |
Two types of mouth parts in blood feeding insects: |
1. Piercing and sucking: lice, mosquitoes, bugs, fleas
2. Rip, tear, or cut followed by lapping up or sucking: Tabanids, blackflies, biting flies |
Host searching: |
1. Appetitive searching
2. Activation and orientation
3. Attraction |
Appetitive Searching |
Refers to the phase in which insects have yet to detect a host cue
a. passive (ticks)
b. active (everything else)
-Timing of host seeking is important:
*often delayed for the first few days of adult life <- mouth isn't hard enough for piercing, insects aren't physiologically ready for egg production
*only certain times of the day |
Activation and orientation: |
a. Olfaction: component in all blood seeking insects, CO2 plays a role in almost all species
*insects respond to odor by flying upwind
b. vision: most widely used by diurnal insects in open habitat (black flies)
*shorter distance than olfaction |
Attraction: |
-How does insect make decision to land
1. Vision
2. Smell
3. Heat
(mixture of those three) |
Vertebrate haemostasis: |
bleeding at site of tissue damage is stopped by series of interrelated mechanisms (Vasocontriction, Platelet Aggregation, Coagulation) |
Pharmacology of Blood Feeding Insect Saliva: |
-NO DIGESTIVE ENZYMES!
-almost all species studied produce: Vasodilator, Anti-platelet compound, anti coagulant
-Saliva compounds often also reduce pain, but few have anesthetics |
Managing blood meal: |
-Temporary ectoparasites take large bloodmeals (hosts may be hard to find, feeding is risky, abdomen is very extendible)
- Permanent ectoparasites take small blood meals |
Feeding Strategy: |
1. Only larval forms feed on blood
2. Insects that feed excessively on blood throughout their life
3. Insects in which only adults feed on blood
I. obligatory blood feeders (fleas)
*females always have endosymbionts, blood lacks certain nutrients essential to female production
II. both adults are optional blood feeders and both adults take other meals (stable flies)
III. only female adult feeds on blood, make never does (mosquitoes) |
Autogeny |
ability to lay eggs before blood feeding for first time
-facultative: allows insects to decide between blood feeding or reproduction
-obligatory: if hosts are rare
|
Genus Toxorhynchitinae |
94 species, mainly tropical, some species in US
-adult males and females feed on plat vector -> don't transmit disease
-larvae live mostly in container habitats
-larvae are predaceous on other mosquito larvae may eat 400 larvae)
-vertical when at rest
|
Anophelinae |
-3 genera: Anopheles, Chagasi, Bironella
-473 species described
-all females blood feed
-only Anopheles species transmit disease -> malaria, fliariasis, arboviruses
-most have dark and pale scales
-adults rest at an angle
-adults are crepuscular/nocturnal
-blood feeding is from dusk until dawn
-females lay 40-200 eggs
-eggs cannot resist desiccation
-hatch in 2-3 days (tropics)
-Habitats: salt water marshes, temporary pools, rice fields, grassy ditches, edges of stream, open sunlit pools |
Culicinae: |
-38 genera
-2750 species
-Important Genera: AEDES, CULEX, mansonia, Haemagogus, sabethes
-angle of the body?
-eggs don't have floats |
Culex: |
-eggs are layid in pools, puddles, ditches, borrow pits, rice fields
-Cluex quinquefasciatus: breed in water with high organic content
|
Aedes: |
-Wide distribution
-Breed in: Marshes, ground pools, snow melt pools, many species green in container habitats (tree holes, plant axils)
-eggs can withstand desiccation (for several weeks) |
Aedes Aegypti |
-breeds in water storage pots or jars
-transmits yellow fever
-fromm Africa, brought to new world in 15th or 16th century
-found near or in human habitation |
Mosquito mating |
1. males form arial swarms
* females are seized and mater
*most common in crespecular or nocturnal
2. Males and Females assemble at locations of biological significance (emergence sites, around host)
3. Males approach resting females
*typically bright diurnal species
-femlaes become refractory after mating
-many males produce mating plug |
Malaria: |
-one of worlds most devastating infectious disease
-Africa is worst affected (90% of deaths, 25% child death due to malaria)
major control efforts (1950-70) reduce whorl exposure from 64% to 38%
|
Human Malaria: |
1. Plasmodium falciparum (Dominant in Africa)
2. Plasmodium vivax (80-90% of cases in Asia)
3. Plasmodium ovale (3,4,5 minor importance)
4. Plasmodium malariae
5. Plasmodium knowlesi
Mainly transmitted by 30-40 species of Anopheles mosquitoes
|
Malaria Symptoms: |
Chills, sweats, headache, convalescence, nausea, committing, diarrhea, anemia, muscle, joint and back pain, enlarged spleen, dry cough
serious cases: kidney failure, brain damage, coma, death |
P. falciparum |
-symptoms 9-14 days, most virulent form, 2nd greatest killer of humans in tropics, only one liver, 48 hour fever cycle
-DEATH from cerebral malaria or kidney failure
-primarily Africa |
P. Vivax |
-12 - 18 days
-attacks on 48 hour cycle
-shizont in liver can survive up to 8 years (relapses)
-only infect young red blood cells
-Mostly Asia |
P. malariae |
72 hour cycle
-reaction can occur up to 53 yrs post infection (controversial)
-only infect old RBC's |
P. ovale |
-rarest form in humans
-48 hour cycle
-hypnozoite |
Unstable transmission |
Irregular Seasonal transmission
-Hypoendemic: adults susceptible
|
Stable transmission |
Malaria transmission always present |