UNIT 2 (part two) Flashcards
are un-segmented, elongated and cylindrical. They have separate sexes with separate appearances. They have a tough protective covering or cuticle.
nematodes
They have a complete digestive tract with both oral and anal openings. They are free living (Majority) or parasites of humans, plants or animals.
nematodes
life cycle of nematodes typically include:
- egg
- larvae
- adult
parasitic nematodes are divided into two, which are:
intestinal nematodes and tissue and blood dwelling nematodes
intestinal nematodes with tissue stage:
- ascaris lumbricoides
- hookworms
- strongyloides stercoralis
intestinal nematodes without tissue stage:
- enterobius vermicularis
- trichuris trichuira
tissue and blood dwelling nematodes:
- filarial worms
- dracunculus medinensis
- trichinella
- larva migrans
These are common roundworms infecting more than 700 million people worldwide.
ascaris lumbricoides
term for ascaris lumbricoides when it causes a disease?
ascariasis
male adult worm of ascaris has end that is?
curved ventrally
female worm has end that is?
straight
mode of infection for ascaris is?
contaminated raw vegetables
ingested eggs of ascaris hatch in which part of the small intestine?
duodenum
Larvae in the lungs may cause inflammation of the lungs (_______ syndrome) - pneumonia-like symptoms.
loeffler’s
diagnosis for ascaris lumbricoides:
- stool by direct saline smear method
- demonstration of adult worms
egg of ascaris is covered by?
albuminous mamillatins
when the outer layer of the egg is absent, it is referred to as?
decorticated eggs
unfertile eggs of ascaris contain mainly a mass of?
refractile granules
is caused by a series of related nematode species (ascarids) that routinely infect dogs and cats throughout the world.
toxocariasis
accidental host of toxocara
humans
The larvae penetrate the intestinal wall and are circulated to various tissues such as:
- liver
- heart
- lungs
- brain
- muscle
- eyes
toxocara’s mode of transmission is through?
transplacental or transmammary route
term used for human infection with certan parasites found in the intestines of dogs and cats
visceral larva migrans (VLM)
compulsive eating even on non-food stuff
pica
treatment of toxocara canis
thiabendazole or DEC (diethylcarbomazine)
two species of hookworm:
- ancylostoma duodenale (ancylostoma braziliense)
- necator americanus
Gravish-white in color. The body is slightly ventrally curved. The anterior end follows the body curvature. The buccal cavity is provided ventrally with pairs of teeth and dorsally with a notched dental plate.
acylostoma duodenale
This species is found in the northern part of the world including China.
Japan, Europe, North Africa and Ethiopia.
acylostoma duodenale
term for shedding of outer layer
molt
mode of infection of acylostoma duodenale
through skin penetration
infective stage of larvae
filariform/L3
male ancylostoma duodenale has what end?
two long spicules
female ancylostoma has what end?
straight
larvae that hatch from eggs are 250-300 um long and approximately 15-20 pm wide. They have a long buccal canal and an inconspicuous genital primordium.
rhabditiform
L1 is
rhabditiform
L3 is
Filariform
measure approximately 8-12 mm long and are bursate, with two spicules that do not fuse at their distal ends.
male
measure approximately 10-15 mm long. Adults of both sexes have a buccal capsule containing sharp teeth.
female
host, oral struct, and geographic distribution of Necator americanus
- humans
- 2 cutting plates
- Africa, India, Asia, China, central America
host, oral struct, and geographic distribution of ancylostoma duodenale
- humans
- 2 pairs teeth
- Europe, Africa, India, China, Asia, patchy distribution in North and South America
host, oral struct, and geographic distribution of ancylostoma ceylancium
- cats, dogs, humans
- 2 pairs teeth
- sri lanka, india, asia, philippines
host, oral struct, and geographic distribution of ancylostoma braziliense
- cats, dogs, humans?
- 2 pairs teeth
- brazil, africa, sri lanka, indonesia, philippines
host, oral struct, and geographic distribution of ancylostoma caninum
- dogs, humans
- 3 pairs teeth
- worldwide
host, oral struct, and geographic distribution of ancylostoma tubaeforme
- cats
- 3 pairs teeth
- worldwide
parasite species of ancylostoma:
- ancylostoma americanus
- ancylostoma duodenale
- ancylostoma ceylancium
- ancylostoma braziliense
- ancylostoma caninum
- ancylostoma tubaeforme
stains used for hookworms
hematoxylin and eosin
so called American hookworm, is found in predominantly the tropics. The anterior end is hooked against the body curvature. The mouth is provided ventrally and dorsally with cutting plate.
nector americanus
measures 8 cm in length. The posterior end is broadened into a membraneous copulatory bursa, which is provided with two long spicules fused distally.
male
measures 10 cm in length. The posterior end is straight
female
when do ancylostoma egg become infective?
third stage, becoming filariform
diagnosis of ancylostoma
Examination of stool by direct saline smear to detect the eggs.
treatment of ancylostoma
mebendazole twice daily for 3 days
larva migrans are:
- cutaneous
- visceral
- intestinal
infects both dogs and cats.
ancylostoma braziliense
infects only dogs
ancylostoma caninum
both braziliense and caninum are common in what climate?
tropics and subtropical regions
treatment of larva migrans
thiabendazole (applied topically) or albendazole
A syndrome caused by the migration of parasitic larvae in the viscera of a host for months or years. It may be caused by transient larval migration in the life cycles of several parasites such as hookworm, Ascaris lumbricoides, T. spiralis, S. strecoralis and other filarial worms.
visceral larva migrans
this is a kind of visceral larva caused by toxocara canis (dog ascarid) and toxocara catis (cat ascarid)
toxocariasis
hookworms mnemonics
Hookworm
A. lumbricoides
T. spiralis
S. stercoralis
clinical features of larva migrans:
- Majority are asymptomatic.
- Eosinophilia
- Cerebral, myocardial and pulmonary involvement may cause death.
diagnosis of larva migrans
identification of larvae tissue
treatment of larva migrans
Thiabendazole: 25 mg/kg twice daily for 5 days.
This is an extremely rare kind of larva migrans
intestinal larva migrans
non-soil transmitted helminths
intestinal larva migrans
________ larvae are usually not found in stool, but may be found there is a delay in processing the stool specimen. If larvae are seen in stool, they must be differentiated from the (L1) larvae of Stronyloides stercoralis.
rhabditiform
