Biological Sciences 318- Parasitology Lab

Arthropod Vectors

Characteristics:

1) highly successful (⅔ of all known organisms are Arthropods)

2) segmented Eucoelomata with exoskeleton (Arthropod Metamerism)

2) Tagmata/Tagmatization (segments grouped into body regions)

3) Molting, Ecdysis (Ecdysozoa)

4) Hemimetabolous (gradual) / holometabolous (complete)

5) Cephalization (highly developed sensory organs)

6) Open circulatory system (hemolymph / hemocoel)

7) Respiratory system (trachea / book lungs)

8) Malpighian tubules / Coxal glands

9) Involved in virtually every kind of parasitic relationship

• definitive and intermediate hosts for protozoans, flatworms, nematodes, arthropods

• function as vectors (blood-feeding / need for protein for development)

Arthropods

• Class Arachnida:

• Prosoma (Cephalothroax) – Opisthosoma (Abdomen)

• Subclass Acari: Capitulum (head) – Idiosoma

• transmit a large number of disease agents (viruses, rickettsia, apicomplexa,

nemotodes)

• Ticks are pool feeders (once attached to the host, the tick will inject saliva into the wound, which liquidizes the tissues and allows them to suck up the fluid)

• Ticks sense CO2, warmth and movement from animals

• Ticks are divided into two families: Ixodidae (hard ticks) and Argasidae (soft ticks).

• outnumber all other known animals put together (almost 1million species described)

• Head – Thorax – Abdomen

• eyes, antennae, sucking , chewing mouthparts, 2 pairs of wings, 3 pairs of legs

• can vector many diseases (mechanical / biological)

• Blood-feeding (need for protein), Flexibility in development, Response to host presence

+/- low host specificity, can live near or in human dwellings…

Learning Objectives1. Know general characteristics-Know differences between Insecta + Arachnida!!!-What character(s) of some arthropods allows them to be effective vectors?2. Class Insecta-General characteristics + anatomy3. Oder Diptera-Tsetse fly: Glossina -Visual id + know parasite and disease association4. Family Culicidae - Mosquitoes -Parasite and disease association-Life cycle-How can they find their hosts?-Behavioral characteristics that allow them to be effective vectors5. Family Psychodidae – Sand flies-Parasite and disease association-Visual id6. Family Simuliidae – Black flies-Habitat-Visual id-Characteristics that make them good vectors-Parasite and disease association7. Family Tabanidae – Horse flies-Visual id-Parasite and disease association8. Order Hemiptera-Know general characteristics-mouthparts9. Rhodnius prolixus-Lifecycle-What habits allows them to be effective vectors?-Why might these habits affect transmission in lower income areas?-How do they find their host?10. Family Cimicidae - Bed bugs-Why might these insects be good vectors?-Are they vectors?11. Order Siphonaptera – Fleas-Know they are parasites themselves-Life cycle, host, how do they find their host-What makes them good vectors?-Xenopsylla male and female: visual id-Parasite and disease association-Transmission-Plague cycle

12. Order Mallophaga – Lice-Parasites themselves-How do they attach to host?-Life cycle-Chewing vs. sucking lice-Visual id Pedicularis humanus + Phthirus pubis-Parasite and disease associations-Typhus!13. Class Arachnida-Know general characteristics-Know general characteristics of ticks: families, feeding…14. Order Ixodidae - Ticks-Life cycle-1,2,3 – host life cycles-Development-No Rhipicephalus – so know parasite and disease associations etc.15. Ixodes scapularis-Visual id-3 host life cycle-Parasite and disease association16. Dermacentor andersoni-3 host tick-Disease and parasite association-Habits-Hosts