L19: Anthropods General Biology + Mites

Question 1

What is a non-parasitic way for arthropods to cause harm

Answer 1

• they use their venom

Question 2

What are parasitic arthropods called what are their groups

Answer 2

ectoparasites

two classes: arachnids + insects

Question 3

Why medically/vertinarilly important

Answer 3

1. as parasites inflict direct injury on hosts
2. as vectors they transmit pathogenic microbes like vectors, bacteria, helminths

Question 4

Name 2 types of vectors

Answer 4

1. mechanical are passive vehicles of transmission of etiologic agents
2. biological function as an active vehicle of transmission of etiologic agents and env for development/reproduction of an etiologic agent

Question 5

Describe the morphology of arachnids vs insects

Answer 5

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

Question 6

Overall, what are structual features of arthopods

Answer 6

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

Question 7

Desrcibe the digestive/nervous/reproductive of arthopods and distinguish types

Answer 7

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

Question 8

go through the general life cycle of arthropods

Answer 8

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

Question 9

What are mites, life span, why are they parasitic (3 specific 4 general, physc diseases)

Answer 9

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

Question 10

What are house dust mites, cause what, how survive/transmit, optimal conditions

Answer 10

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

Question 11

2 key species of dust mites

Answer 11

✓ Dermatophagoides pteronyssinus – European house dust mite

✓ Dermatophagoides farina – American house dust mite

Question 12

How to prevent Dermatophagoides

Answer 12

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

Question 13

What are scabies mites

Answer 13

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

Question 14

What does S. scabiei var. canis do

Answer 14

*causes mange in dogs
*humans get pruritic rash

Question 15

Life cyle of S. scabiei

Answer 15

*eggs
*larvae
*nymphs
*larger nymps
*adult mites

Question 16

Clinical Presentation of Scabies

Answer 16

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

Question 17

Diagnosis, Treatment and Prevention of Scabies

Answer 17

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

Question 18

Discuss the relationship between varroa mites and honeybees

Answer 18

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

Question 19

Distinguish between male and demal varroa mites

Answer 19

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

Question 20

Explain the spread of vorroa mites in honeybees

Answer 20

1. varroa mites are phoretic on adults so they hitch ride and infiltrate hive
2. they go to uncapped brood cells next to developing bees
3. wait for bees to cap it then they feed and reproduce
4. as young bee emerges, more mites also come out and transfer to other broods from the back
5. exponential increase colony infestation gets out of control

Question 21

What damage can vorroa mites cause

Answer 21

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

Question 22

How are vorroa mites detected and treated

Answer 22

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