Introduction to Arthropods, Helminths, and Protozoa. Flashcards
Name the classes of Arthropoda and their parasitic orders.
Class: Insecta - Orders: Diptera (flies), Phthiraptera (lice), Siphonaptera (fleas), Others (hemiptera).
Class: Arachnida - Order: Acari (ticks and mites).
Other Classes: (e.g. Crustacean).
Name the general characteristics of insects.
- 3 pairs of legs.
- A body divided into head, distinct thorax, and abdomen.
- A single pair of antennae.
Name the general characteristics of Arachnids (ticks and mites).
- 4 pairs of legs in the nymphal and adult stages; 3 pairs in the larvae stage.
- A body divided into cephalo-thorax and abdomen.
- Have palps instead of antennae.
Name the general characteristics of ticks.
- 2 families of ticks are: Ixodidae (hard ticks) and Argasidae (soft ticks).
- The ixodidae have rigid chitinous scutums, which covers the entire dorsal surface of the adult male.
- Argasidae lack a scutum and the mouthparts cannot be viewed from the dorsal surface.
Name the three classes of helminths we are concerned about.
- Nematodes (roundworms).
- Cestodes (tapeworms) (flatworms).
- Trematodes (flukes) (flatworms).
Name the general characteristics of roundworms (Nematodes).
- May be free living OR parasitic.
- Usually unsegmented, elongated and cylindrical in shape.
- An alimentary canal is present.
- Sexes are usually separate and the females are generally longer than males.
- ONLY males have bursas, but there are also non-bursate orders.
Name the general characteristics of Cestodes (tapeworms).
- Elongate flat body without a body cavity or alimentary canal.
- A scolex (head) with 4 suckers (holdfasts) with or without hooks.
- Have a rostellum (crown) at the apex.
- The strobila (body) includes the head, neck and proglottids (segments).
- Each proglottid is genitally independent (hermaphrodites).
- Types of larval stages (metacestodes) include: cysticercus, strobilocercus, cysticercoid, coenurus and hydatid cyst.
What are the 2 orders of Cestoda that are of greatest interest to the veterinary field? What are their general characteristics?
1) Cyclophyllidea
- most require one IH.
- Organs of attachment associated with scolex and suckers.
- Eggs with oncospheres.
2) Psuedophyllidea
- Use copepods during intermediate stage.
- Associated with aquatic food chains.
- Most require 2 IHs (first with crustacean).
- oncospheres have motile cilia.
- Organs of attachment associated with scolex and bothria.
Name the general characteristics of Trematodes (flukes).
- Dorso-ventrally flattened, often leaf-like.
- Oral and ventral suckers for attachment.
- Usually genitally independent, hermaphroditic (but some can cross-fertilize as well).
Name the general characteristics of Protozoa.
- Unicellular, eukaryotic animals.
- Locomotion is accomplished by psuedopodia, flagella, gliding movements, or cilia.
Where does the life cycle of a louse occur?
The entire life cycle occurs on the host animal.
Where does the life cycle of a flea occur?
- The egg, larval and pupal stages are in the environment.
- The adult flea can be on or off the host.
How many hosts can a tick use? Where are the eggs laid?
- The tick can use 1, 2, or 3 hosts, depending on the genus and species.
- Eggs are laid in the environment.
What is the major difference between the mite life cycle and the tick life cycle?
The life cycle of the mite is very similar to the tick, but normally all stages (including eggs) of the mite are on the host.
Generally, what are the life cycle stages in the Nematode?
An egg, 4 larval stages, a 5th larval stage/immature adult, and an adult stage.
