Exam 4 Nematodes Flashcards
Explain how nematodes differ anatomically in comparison to cestodes
Cestodes have no digestive tract are acelomate and have no body cavity.
Nematodes are coelmate, have a false body cavity and digestive tract
Some nematodes are ovoviviparous and parthenogenetic- explain?
- unfertilized eggs inside the female hatch inside her and are brown alive
- female can produce eggs that can develop without fertilization- haploid eggs
What external morphological characters distinguish male vs female nematodes
Female is usually larger than the male
What worm species may be associated with intestinal blockage under certain conditions?
Ascaris lumbricoides can cause intestinal blockage
How is Necator distinguished from Ancylostoma?
The mouth parts
Ancylostoma has vampire like teeth
Necator has a smoother opening with plate like discs
What ecological conditions are detrimental to hookworm larvae?
Optimal soil conditions are required
What is an auto infection? What nematodes species can lead to an auto infection?
Reinfect host without leaving the body
Strongyloidiasis stercoralis
What are some ways that trichnosis can be prevented?
Cool meat to safe temperatures
Clean meat grinders after each use
Do not allow pigs or wild animals to eat undercooked meat, scraps or carcasses
Explain how the nematode body cavity functions as a hydrostatic skeleton?
H
What is a stichosome and what nematode is this characteristic to?
Long glandular esophagus
Trichuris trichiura
What species of nematode is an intercellular parasite? Explain
H
By what pathway is the kidney worm passed to the definitive host?
Eating undercooked paratenic hosts
Explain the difference between homogonic vs. heterogenous life cycle in Strongyloides?
Homo- parasite
Hetero- free living in the soil, both male and female can alter to parasitic of soil conditions are not adequate
How is Trichinella spiralis passed to pig hosts?
By scavenging
How is strongyloidiasis diagnosed in humans?
Blood test
How do humans get infected with hookworm disease? Explain the route of infection in humans or how the worm completes its life cycle in humans?
H
How are male and female Ascaris worms distinguished?
N
Explain how humans acquire an infection of ascariasis? How does the work complete its life cycle in humans?
B
Explain the difference between cutaneous larval migrans and visceral larval migrans? What parasite species are implicated in both?
H
How is it young puppies may be heavily infected with Toxocara canis without ever having eaten any intermediate hosts?
The worms can transverse across the placental barrier and the puppies will be born infected
How is it that raccoons get infected with the parasite Bayliascaris?
B
What is the pathway that humans get infected with pinworm? Why is the infection so potentially contagious?
H
What bacteria is often associated with filarial worm infections
H
How are filarial worms transmitted to the definitive hosts?
H
What characters identify the larval stage of Wuchereria bancrofti?
H
Explain the effects of Bancroftian filariasis in humans?
H
What is meant by periodicity and subperiodicity in Wuchereria infections?
Periodicity- comes out at night
Sub- comes out in the day
What are the effects of onchocerciasis in humans? How is the infection acquired?
Onchocerciasis or River Blindness
Hanging groin
The Black fly vector bites you and the L3 larvae that are in the mouthparts of the fly gain access to the body through the bite
Why is the mode of feeding in the vector of onchocerciasis so important in the parasite being able to complete its life cycle
H
What is the distribution of Onchocerca volvulus?
Mainly central Africa
What was the strategy of the World Health Organization in its Onchocerciasis control efforts?
Aerial larval sprays targeting the black fly larva
Ivermectin to infected individuals
Was ended because of cost
Explain the life cycle of Dirofilaria in the definitive host?
- Mosquito takes a blood meal infected with the microfilaria
- Microfilaria penetrate the mosquitos midgut and and migrate to m tubules
- L1 larvae
- L3 Larvae
- migrate to mosquitos proboscis
- mosquito takes a blood meal and the parasite enters the blood stream through the bite
- adults in pulmonary arteries
Explain how humans acquire an infection of dracunculiasis?
Contaminated drinking water
What is spirocercosis in dogs and what is the cause?
Esophageal cancer
Spirocerca lupi will form nodules in the dogs esophagus and they will eventually become cancerous
By what methods are the following parasites or diseases diagnosed in humans:
Enterobius vermicularis
Pinworm
Scotch tape method
By what methods are the following parasites or diseases diagnosed in humans:
Ascaris lumbricoides
Fecal smear
Eggs are in the fecal matter
By what methods are the following parasites or diseases diagnosed in humans:
Trichnosis
Biopsy of body
What parasitic infliction causes rectal prolapses in children?
Trichuris trichiura
