Parasithic Arthropods: Insecta

Parasitic Arthropods: Insecta

1. Parasitic Arthropods: INSECTA Group 1 Cliff richard emanel Macy gumiran Kimberly padilla Jennyrose padre Maricar tuliao Rovic zipagan

2. Class Insects Insects have: three body sections: head, thorax, abdomen three pairs of legs, all attached to the thorax one pair of antennae one or two pairs of wings The mouthparts of insects are elaborate. There are two different kinds of metamorphosis in insect: simple and complete.

3. Class Insecta have 4 medical important orders: Order Anoplura - lice Order Siphonaptera - fleas Order Hemiptera – bugs Order Diptera - mosquitoes and flies

4. Order Anoplura - lice Body is flattened dorso -ventrally. Lice are wingless insects with short legs. Order Anoplura displays incomplete metamorphosis. Pediculus humanus - Head louse Morphology: adult louse is 2-5 mm in size, male is smaller than female. These are insects that can't jump or fly. Their style of movement relies on 6 legs, each of which ends in a claw which can grasp human hair. The head louse found on humans is specific to people. It can't be contracted from the family dog, cat or any other animal. Mammals and birds can have lice but they are species specific.

5. Pediculus humanus life cycle Female louse lays about 10 eggs daily. Eggs are cemented to hairs or to fibers of clothes. Eggs hatch in about one week. Nymphs feed on blood and passthrough 4 instars. Adult louse emerges in about two weeks.

6. Transmission of Head Lice Host-to-host (direct contact from someone who is infested) By wearing infested clothing (hats, scarves, coats, hair ribbons etc.). By using infested combs, or brushes. By lying on a bed, couch or carpet that has recently been in contact with an infested person.

7. Order Siphonaptera - fleas About 2500 species, most are parasites of mammals only approx. 100 species on birds. Temporary obligate parasites, blood-feeding exclusively as adults.

8. Flea life cycle

9. Important Flea Species Xenopsylla cheopis (Oriental rat flea) - primary urban plague vector. Pulex irritans (human flea) - occasional epidemic plague vector. Ctenocephalides felis , C. canis (cat and dog flea) - primary pest species. Tunga penetrans ( sandflea ( chigoe ). Line of flea bites

10. Order Hemiptera - True Bugs Features Piercing & sucking mouth parts When present, 2 pairs of wings(hind pair reduced) - Incomplete life cycle Immature stages = nymphs Nymphs are mostly small wingless replicas of adults No pupal stage Of lesser medical importance Most are phytophagous orpredators of arthropods Few blood suckers - 2 families

11. Family Cimicidae - bed bugs Identification Small, apricot- coloured &wingless Circular body & flattened extensions of prothorax behind eyes Medical importance Most species are ectoparasitic on rodents, poultry, birds & bats • 3 species parasitic on humans • Cimex lectularius occursworldwide Do not appear to vector anypathogens

12. Family Reduviidae - assassin bugs Identification - Large robust bugs = ambush predators of arthropods - Strong recurved beak for –biting • Inject paralytic toxin to subdue prey • Bite very painful to humans • No species in SA usually bite mammals Medical importance - South American subfamily Triatominae (kissing bugs) • Feed on human & animal • Transmit Chagas ' disease

13. Triatominae - kissing bugs - Live in woodland & forest habitats Triatoma infestans33 - Colonized human dwellings • Live in ceilings, cracks &crevices etc. - Behave like bed bugs & attack humans at night - Spread protozoans which cause Chagas's disease (American trypanosomiasis ) - Most notorious species are Triatoma infestans & Rhodnius prolixus

14. Order Diptera - Flies • The key distinguishing adult structure: two wings. • All Flies are Holometabolous (having a complex metamorphosis- i.e. egg, larvae pupa, and adult). The habitat of the larval stage is basically "aquatic or semi aquatic," and they have adapted to live in very, very "challenging" environments.

15. Diptera - flies as parasites Ectoparasites 1. Adults are free living but blood feeding with the larvae stages aquatic or in moist semi-aquatic habitats. ( Nematocera and Brachycera )

16. 2. Adults ectoparasites (or blood feeding) but larvae develop within female and essentially pupate after emerging from mother ( Glossina , Hippoboscidae ) Endoparasites 3. Adults free living but partially internal (flesh feeding)larvae are internal or Gasterophilus , Cochliomyia hominovorax )parasites of vertebrates ( Oestrus ,

17. Myiasis defined The invasion of organs and tissues of humans or other vertebrate animals with dipterous larvae, which for at least a period feed upon the living or dead tissue or, in the case of intestinal myiasis, on the host's ingested food.

18. Metallic Flies Cochliomyia hominivorax

19. Lucilia spp. Calliphora spp.

20. Musca domestica Housefly is a medium-sized fly, 6- 10 mm in length; the female is generally slightlylarger than the male. Distribution: cosmopolitan. Morphology. Adult fly has a gray color, 4 dark stripes, red eyes. Life cycle. 1. Eggs are laid into masses of decaying organic substances, garbage, refuse or manure. 2. Larvae hatch in 6-24 hours and feed on organic matter. 3. They molt 2 times giving 3larval stages. 4. The third larva pupates inside the larval skin. 5. The adult emerges after a few days . The whole cycle takes about one week.

21. Medical importance of House fly 1. Indirect mechanical transmission ofmicroorganisms (as typhoid, poliomyelitis and bacillary dysentery), eggs of helminthes and cysts of protozoa. 2. Accidental myasis . Control 1. Sanitary disposal of refuses, garbage and manure (breeding media) by dumping, burning or application of insecticides. 2. Control of adult flies by screening or space spraying of insecticides.

22. Mosquitoes - Blood feeding – only females take blood - Males feed on plant sugars Disease transmission Some species of Anopheles transmit: 1. Human malaria 2. Wuchereri bancrofti Some species of Culex transmit 1. Wuchereria bancrofti 2. Encephalitis 3. Rift valley fever

23. Life Cycle of the Mosquito

24. Differences between Anopheles, Culex, and Aedes