L19: Anthropods General Biology + Mites Flashcards
What is a non-parasitic way for arthropods to cause harm
- they use their venom
What are parasitic arthropods called what are their groups
ectoparasites
two classes: arachnids + insects
Why medically/vertinarilly important
- as parasites inflict direct injury on hosts
- as vectors they transmit pathogenic microbes like vectors, bacteria, helminths
Name 2 types of vectors
- mechanical are passive vehicles of transmission of etiologic agents
- biological function as an active vehicle of transmission of etiologic agents and env for development/reproduction of an etiologic agent
Describe the morphology of arachnids vs insects
Arachnids
two regions:
1. capitilum or head with mouth parts
2. idiosoma or body with 4 leg pars
- wingless
*mites and ticks that feed on host fluids
Insects
three regions
1. head with 2 antennae and mouth parts
2. thoraz with three pairs of legs
3. abdomen
*can be winges important are lice, flease, bugs, flies
Overall, what are structual features of arthopods
overall:
bilateral symettry
jointed lumbs
segmented bodies
the insides:
hard, chitinous exoskeleton for physical and pshysiological protection
hollow body coelom cavity with hemolymph
open circulatory system with dorsal tubular heart
Desrcibe the digestive/nervous/reproductive of arthopods and distinguish types
the guts:
alimentary tract with hematophagoous blood sucking arhtpods and histophagous tissue feeding arthropods
central nervous system with 2 longitudual nerve tracts
reproductive:
separate sexes in adults with complex life cycle
go through the general life cycle of arthropods
involves metamorphosis where it passes through stages to become sexually mature adult => each time it molts
the stage in between are called instars
Complete metamorphosis
egg, larva, pupa, adult life stages has diff appearances and oten vastly diff habits and diets
incomplete metamorphosis
organism hatches from egg and develops though nymphal stages with only gradual stage and no pupa stage
What are mites, life span, why are they parasitic (3 specific 4 general, physc diseases)
they are acari, very small aracnhids that go through incomplete metamorphosis
egg to adult depends on species, temp and humidity, 10 weeks alive
dust mites cause allergies, scabies cause irritation from bites, verrora mites cause agricultural loss by parasiting product
*can also cause dermitites
*transmit pathogens and be intermediate hosts
*invade respiratory passages, ear canals and organs
*phycological conditions like acarophobia and delusory acariosis
What are house dust mites, cause what, how survive/transmit, optimal conditions
dermatophagoides
=> poop is airbone and become part of dust
=>gut has digestive enzymes that go to poop
=>poop + exoskeleton are very allergenic
cause allergic diseases like asthma, hay fever, eczema, dermatisis
*hitchkike on clothes, pillows, matress and feed on organic debris like dead skin
thrive at 50-80% humidity
2 key species of dust mites
✓ Dermatophagoides pteronyssinus – European house dust mite
✓ Dermatophagoides farina – American house dust mite
How to prevent Dermatophagoides
allergin proof matress/pillowcases
washing clothes and drying in hot cycles
vacuuming carpets with HEPA filter
minimise dust accumulating places like clutter
keep humidity levels low
What are scabies mites
sarcoptes scabiei
* worldwide
*mostly hot, tropical, high density areas
*causes scabies
*infects mammals, and transfer human to animal vv, but they have preferred hosts
*transmission happens during transfer of impregnates females from skin to skin, can happen via bedding
*causes mange in dogs
*humans get pruritic rash
What does S. scabiei var. canis do
*causes mange in dogs
*humans get pruritic rash
Life cyle of S. scabiei
*eggs
*larvae
*nymphs
*larger nymps
*adult mites
Clinical Presentation of Scabies
first time can be unsympotmatic for 2 months
*infected asympto are still carriers
rash on fingers, folds of wrist, elbows, knee, male genitals/female breast => serve to itch
if immunocompromised => crusted/norewegian scabes => thick crust but not too much itching => 2º infection
Diagnosis, Treatment and Prevention of Scabies
Diagnosis
see the rash, microscopy of mites from places with tash
Treatment
*topical creams, ivermectin, not all treatments kill eggs so must repeat
*if severe use intense topical and icermectin
Prevention
*avoid contact with infected people, everyone in the infected house must be treated even if asymptomatic
*infected house, bedding washed or disinfected
*if severe everyone’s treatment should be severe
Discuss the relationship between varroa mites and honeybees
varroa destructor mite is a small ectoparasite that attaches to honey bee
, they are major bee pest and cause varroasis
major cause of economic loss throughout the world and treatment
as soon as it hatches it feeds on developing needs => rip integument => feed on fat and hemolymph => leaves wound where other pathogens can infect
Distinguish between male and demal varroa mites
Females:
*feed on adult bees, larvae and pupae and cause disease
*mobile with phoretic stage
*red brown elliptical shape
*bigger => 2-5 months
Males
*do not feed mouth is for sperm transfer to female
*only have reproductive role and never leave
*white and soft bodies, smaller they die after copulation
Explain the spread of vorroa mites in honeybees
- varroa mites are phoretic on adults so they hitch ride and infiltrate hive
- they go to uncapped brood cells next to developing bees
- wait for bees to cap it then they feed and reproduce
- as young bee emerges, more mites also come out and transfer to other broods from the back
- exponential increase colony infestation gets out of control
What damage can vorroa mites cause
sick larvae look dark spots on body if heavily infected
*malnutrion, smaller size
*hard to feed other broods, restless
*fly badly, deformed wings make them crawl, die easily
How are vorroa mites detected and treated
detection:
examine brood visually,have stick screen that trap falling carroa, can use sugar and ethanol jars to trap them
treatment:
pyrethroids, formamidine
biological measure to select for resistant/tolernat honey bees
brood removal, queen caging and colony spiltting
