Field Parasitology Exam 2

what class is considered a traditional group containing free-living flatworms; marine, freshwater and terrestrial

Class Turbellaria

what class is a Monophyletic group containing most of the parasitic flatworms

Superclass Neodermata

what class has direct life cycles and is primarily ectoparasitic on the gills of fish

Class Monogenea

What class has a subclass digenea, has parasitic flukes and has at least two hosts one is a mollusk?

Class Trematoda

What class has tapewoms?

Class cestoidea

• no body cavity

• body is filled with ______

This describes what kind of organisms?

Acoelomate organisms

• body is filled with parenchyma

What type of symmetry do flatworms have?

bilateral symmetry

The outer covering in parasitic platyhelmihtes is called?

tegument

What type of digestive system do flatworms have?

incomplete digestive system

Flatworms do excretion by __________ (aka _____ cells/ bulbs)

protonephridia (aka flame cells/bulbs)

How could you best describe the nervous system of flatworms?

ladder type arrangement (in most)

most parasitic platyhelminths are __________ aka hermaphroditic

Monoecious

flukes can be defined as:

parasites of all classes of vertebrates

in the subclass Digenea of trematoda sexual reproduction occurs in a ___________ in the definitive host

vertebrate

in the subclass Digenea of trematoda their first intermediate host is almost always a _______

mollusk (snail, clams)

the _________ is the outer covering and is typically _______ in nature

tegument, syncytial

what does the complex muscle system of trematodes allow them to do? the muscle tissue can be described as _______

complex movement and smooth

Trematoda reproduction can be described as ________

monoecious

Life cycles of trematodes include sexual reproduction in vert. host and asexual in molluscan host, asexual reproduction =

polyembryony- multiple embryos from the same zygote (egg)

Life cycles of trematodes include sexual reproduction in vert. host and asexual in molluscan host, sexual reproduction =

sexual reproduction produces the egg

most trematode eggs have an ________ at one end, and it is used for?

operculum, it is used as an escape hatch

what stimulates hatching of the trematodes eggs?

light, osmotic pressure, etc.

What is the difference between the redia and sporocyst stages?

the sporocyst has does NOT have a mouth and the redia does have a mouth

the miracidium stage is typically found where? and has a retractable ______ ________ that penetrates the snail?

the miracidium is typically found in water and has a retractable apical papilla

in the snail the miracidium becomes a ________, which lacks what?

sporocyst, which lacks a mouth and digestive system

the intramolluscan stages often occupy the ______ and ___________ (digestive gland) of snail

gonad and hepatopancreas

who is active, ingest snail tissue (has mouth, pharynx, short gut), can ingest sporocysts

redia

what stage leaves the redia or sporocyst and snail, is free-swimming and short-lived, most have a tail, often must find the next host in the life cycle

cercariae

what types of glands do cercariae have?

• penetration

• mucous production for adhering to host

• cyst production

what stage is this?

• encysted quiescent (resting) stage

• may be in, or on a host on some substrate (vegetation, rocks, etc.)

• Encystment

metacercaria

what stage matures to adult in definitive (vert) host?

adult fluke

what happens in the vertebrate host?

cercaria penetrates definitive host or metacercaria is ingested —> excystation may be triggered by host cues —> migrate to cite of infection (liver, lungs, bladder, circulatory system) —> develop —> sexual maturity (adult)

what stage is an intermediate stage between cercaria and metacercaria?

mesocercaria

different environments = different challenges such as?

osmolarity, temperature, PH

who are facultative anaerobes?

adult flukes

phylum mollusca includes who?

snails, octopuses, squid, clams, scallops, oysters and chitons

mollusks are _________ meaning they have a body cavity

eucoelomate

mollusks body plan are typically all covered with?

covered with a mantle typically secretes the shell

what does gastropoda mean?

stomach foot

who is the largest group of mollusks?

class gastropoda

gastropod shells can either be _____ or ______ because they exhibit chirality

sinistral (opening to the left) or dextral (opening to the right)

there are 2 gastropoda systematics, what are they?

pulmonata and prosbranchia

this describes what gastropoda systematic

• name refers to gills located in body cavity

• contains most freshwater, marine and land snails

• possess shell aperture with calcareous or horny operculum

• mostly dioecious

• includes freshwater viviparidae

Prosobranchia

this describes what gastropoda systematic?

• mostly freshwater and terrestrial

• no gills

• no operculum (mostly)

• monoecious

• freshwater taxa include: planorbidae, lymnaeidae, physidae

Class Bivalvia includes?

Clams, mussels, osyters, scallops

what class of mollusks does this describe:

• no distinct head

• shell divided into halves

• no radula

• some have eyes or sensory tentacles along outer edge

• mantle cavity contains gills for feeding and has exchange

• most are suspension (filter) feeders

• mostly sessile

Class Bivalvia

What lifecycle does this describe?

family Unionidae : freshwater mussels

what phylum has:

• bilateral symmetry

• is pseudocoelomate

• has complete digestive system

• most dioecious with sexual dimorphism

phylum Nematoda

papillae is a ______ receptor that is cephalic and caudal

touch

amphids are a __________ located on the head of nematodes

chemoreceptor

what sensory structure is similar to amphids but is located on the posterior end? (is also a chemoreceptor)

phasmids

what sensory structure is similar to papillae but is located near nerve ring?

Derids

Do nematodes have a complete digestive system?

yes

Most nematodes have what type of excretion?

secretory-excretory (SE)

Nematodes gonads are solid cords of ______- continuous with tubes for what 3 things?

Tissue, continuous with tubes for development, storage and ejection

What type of sexual dimorphism do nematodes exhibit?

females are larger

males often have curled posterior ends and sex structures at cloaca

How do male and female nematodes find each other?

Chemoreception, using pheromones and Thigmotaxis (touch)

Male nematodes reproduction system have accessory structurees called _______, that are used to hold vulva of female open while sperm is inserted

spicule

What are the 3 layers of the nematode egg?

vitelline (outer)

Chitinous (middle)

Lipid (inner)

in nematode dev. the number of cells remains constant through life is called?

Eutely

How many juvenile stage are there in nematodes? what happens between each juvenile stage?

J1-J4

molt cuticle between each

what is hypobiosis?

developmental arrest

Give the common name, order and family of who this description refers to:

• name from curvature of anterior end

• impt path of humans and domestic animals

• male have distinct copulatory bursa

• female has 2 eggs and produce thousands of eggs/day

• buccal capsule- bears cutting plates or teeth

Hookworms

Order: strongylida

Family: ancylostomatidae

How do humans become infected with hookworms?

Upon contacting human skin (usually feet, hands or butt) penetrates and enter blood or lymph circ.

What is the name of the most common hookworms of domestic dogs?

A. caninum

Describe a cutaneous larva migrin (aka creeping eruption)

Occurs when sp. that normally develop in non-human hosts attempt to infect humans

What is the drug of choice for cutaneous larva migrins (creeping eruption)

Topical Thiabendazole

What is the order and family of trichuris trichiura?

Order: Trichurida

Family: Trichuridae

This morphology describes who?

• adults thin except for posterior end

• mouth w/o lips

• small buccal capsule followed by a long esophagus

trichuris trichura

thing tube surrounded by unicellular glands is called?

stichocytes

gland cells + esophagus =

stichosome

do both male and female trichuris trichura have a single gonad?

yes

this is the pathology of who?

• often infection is light and asymptomatic

• heavy infection (>200 worms) may result in: anemia, dysentery, retardation of growth, finger and toe clubbing, retal prolapse, reduced cognitive func.

Trichuris trichura

______ _________ is large round worm of humans

ascaris lumbricoides

A. suum is the large round worms of who?

pigs

_____ ______ is a very common parasite of dogs and an important parasite of humans

toxicara canis

visceral larva migrins can be caused by a number of nematodes but ______ is the most common cause

Toxicara

These are symptoms of?

• juv wonder into deep tissues and organs (nearly any organ may be infected)

• causes a delayed type hypersensitivity reaction (sympt: fever, hepatomegaly, pulmonary probs)

• liver is most common site

• brain and CNS are also commonly infected

visceral larva migrins caused by Toxicara

why are small children most likely to ingest eggs of toxicara canis?

close association with dogs and puppies

How can Toxicara canis be disgnosed?

ELISA

Are there any treatment/ control methods for toxicara canis

No effective control treatment known and control= worming pets and careful handling of feces

_____ is common in domestic and other cats

T. cati

T. cati may cause _____ ______ ______ (sim to T. canis) what is an effective control method?

Visceral larva migrins

covering the sandbox

What is the name of the ascarid parasite of raccoons?

Baylisascaris proyonis

Can humans be infected by Baylisascaris procyonis?

yes, commonly migrates to the brain or eyes

What is the name of the parasite of marine mammals? (use fish as 2nd int. hosts)

Anisakis sp.

How are humans infected by anisakis sp? what does it cause?

humans infected by ingesting juv. in raw, salted, or pickled fish

causes anisakiasis

How can anisakiasis be controlled? and where (in the world) is it most commonly seen?

it can be controlled by freezing fish to kill the juvenile worms

most commonly seen in Japan (100s to 1000s cases per year)

What does the phylum name Acanthocephala mean?

Means thorny-headed worm

is the Phylum Acanthocephala pseudocoelomate?

yes

the _____________ sp can be found in adult turtle intestines

neoechinorhynchus sp

what are the 1st and 2nd intermediate host of the neoechinorhynchus sp?

1st int. host= ostracod

2nd int. = snails or fish