Intestinal nematodes (PPT lecture) Flashcards
referred to as round worms
Phylum Nematoda
bilaterally symmetrical helminths from the Greek work : ”nemat means thread”
Phylum Nematoda
elongated cylindrical bodies w/ complete digestive tract
Phylum Nematoda
with sensory chemoreceptor
Phasmids
with sensory chemoreceptor
Phylum Nematoda
means only one host
homexenous
means more than one host
heteroxenous
What is the usual cycle of phylum nematoda?
egg stage - larval stage - adult stage
Roundworm Infection can be acquired by means of the following:
- ingestion of fully embryonated ova
- ingestion of encysted larva
- larval skin penetration
- bites of arthropod vectors/skin inoculation
Classification of Roundworms:
According life stages
According to habitat
According to the presence or
absence of caudal chemoreceptor
Classification based on laying eggs or lava:
- Oviparous
- Viviparous
- Ovoviviparous
Under oviparous:
i) eggs with segmented ovum
ii) eggs with unsegmented ovum
iii) eggs with unsegmented ovum with mucus plug at both ends
iv) eggs containing larva
Examples of eggs with segmented ovum:
hookworm, Trichostrongylus species
Examples of egg with unsegmented ovum:
Ascaris species
Eggs with unsegmented ovum with mucus plug at both ends:
Trichuris species
Egg containing larva:
Enterobius species
Female worms directly give birth to larvae; there is no egg stage - filarial worm.
Viviparous
Examples of viviparous
filarial worm, Trichinella species, Dracuncular species
Female worms lay eggs that immediately hatch out
Ovoviviparous
Examples of Ovoviviparous:
Strongyloides species
Parasites that inhabits the small intestine:
Capillaria philippinensis
Ascaris lumbricoides
Strongyloides stercoralis
Hookworms
Parasites that inhabits the large intestine
Trichuris trichiura
Enterobius vermicularis
Parasites that are phasmids:
Ascaris lumbricoides
Strongyloides stercoralis
Hookworms
Enterobius vermicularis
Parasites that are aphasmids:
Trichuris trichiura
Trichinella spiralis
Capillaria philippinensis
Also known as whipworm
Trichuris trichiura
Male of t. trichiura is ____ mm and slightly shorter than female
30-45
Male of t. trichiura has a _______ with a _____ and ______
coiled posterior end
Single spicule
retractile sheath
Female of T. trichiura is _______ mm long and has a _________ posterior end
35-50
bluntly rounded posterior end
female of t. trichiura lays approximately how many eggs
3,000 - 10,000 egg/day
the eggs of t. trichiura measures ______ um long
50-54 long by 23 um
Its egg is lemon shaped w/ plug-like translucent polar
prominences
Trichuris trichiura
Its egg has a yellowish outer & transparent inner shell
Trichuris trichiura
Pathogenesis & clinical manifestations:
- petechial hemorrhages
- the mucosa is hyperemic & edematous
- those w/ more than 20,000
eggs/gm of feces often develop severe diarrhea or dysenteric syndrome - enterorrhagia is common
- rectal prolapse
Trichuris trichiura
Diagnosis of T. trichiura
- DFS
- kato cellophane thick smear
- kato-katz technique (quantitative method)
- acid-ether/formalin-ether
Treatment of T. trichiura
Albendazole and Mebendazole
Prevention and Control for T. trichiura (5)
- treatment of infected individuals
- sanitary disposal of human feces
- washing of hands w/ soap & water
- health education
- thorough washing & scalding of uncooked vegetables
tiny nematode residing in the small intestine
Capillaria philippinensis
Male worm of C. philippinensis is ____ mm and female is ______ mm
male: 1.5 - 3.9 mm
female: 2.3 - 5.3 mm
Its male spicule is 230 - 300 um long, unspined sheath
Capillaria philippinensis
thin filamentous anterior end & a slightly thicker & shorter posterior end
Capillaria philippinensis
peanut-shaped egg w/ flattened bipolar plugs
Capillaria philippinensis
Pathogenesis & clinical manifestations:
borborygmus, abdominal pains, gurgling stomach, diarrhea weight loss, malaise, anorexia, vomiting & edema
Capillaria philippinensis
Diagnosis for Capillaria philippinensis
- finding the characteristic eggs in the feces (DFS)
- doudenal aspiration
Treatment for Capillaria Philippinensis:
- electrolyte replacement & high CHON diet
- mebendazole 200mg/day for 20 days
- albendazole 400 mg once a day for 10 days
Prevention and Control for C. philippinensis (4):
- avoid eating raw fish
- good sanitary practices
- proper waste disposal
- educational programs
whitish in color, 1.5-3.5mm by 0.04-0.06mm
Trichinella spiralis
male is 1.5mm by 0.04 mm has a single testes
Trichinella spiralis
female is 3.5mm by 0.06n mm has a single ovary, oviduct, seminal receptacle, a coiled uterus, vagina & vulva, produce 1,500 larvae or more in her lifetime
Trichinella spiralis
larva 80-120um by 5.6 um at birth reaches 900-1,300um by 35-40um after it enters a muscle fiber it has a spear-like burrowing anterior tip
Trichinella spiralis
Pathogenesis & clinical manifestations:
-severity of symptoms depend on the intensity of infection
- 10 larvae are usually asymptomatic
- 100 or more larvae show symptoms
- 1000/more larvae is severe & even fata
Trichinella spiralis
Phase and stages of infection of T. spiralis
- Enteric phase
- Invasion phase stage
- Convalescent phase
Phase and stages of infection of T. spiralis:
Incubation period and larval migration
Enteric phase
Phase and stages of infection of T. spiralis:
Intestinal invasion stage
Invasion phase stage
Phase and stages of infection of T. spiralis:
Encystment stage
Convalescent phase
Phase and stages of infection of T. spiralis:
diarrhea/constipation, vomiting, abdominal cramps, malaise & nausea
Enteric phase
Phase and stages of infection of T. spiralis:
fever, facial edema, urticaria, pain, swelling and weakness
Invasion phase
Phase and stages of infection of T. spiralis:
fever, weakness, pain & other symptoms
Convalescent phase
Diagnosis for T. spiralis:
- biochemical test
- high counts of peripheral blood eosinophilia
- serology
- muscle biopsy (definitive diagnosis)
Treatment for T. spiralis:
- thiabendazole 2x a day for 7 days
- mebendazole 6 hourly for 10-14 day
Prevention & control of T.spiralis
-meat should be cooked @ 770C
- freezing -150C for 20 days or -300C for 6 days
- meat inspection & keeping pigs in rat-free
pens
- health education
human pinworm
Enterobius vermicularis
causes enterobiasis/oxyuriasis,
characterized by perianal
itching/pruritus ani
Enterobius vermicularis
female adult worm of Enterobius vermicularis is _____ by ______
8-13 mm by 0.4 mm
characteristics of a female adult worm
prominent
esophageal bulb & long
pointed tail
Male Enterobius vermicularis is ____ by ____
male is 2-5mm by 0.1-0.2 mm
characteristics of a male Enterobius vermicularis
curved tail & single
spicule
rhabditiform larva of Enterobius vermicularis is _____ by ______
140-150um by 10um
(Enterobius) asymetrical eggs w/ one
side flattened & the other
side convex ______ by ______
50-60um by
20-30um
(Enterobius) single female lays from
4,672-16,888 eggs/ day
(average: 11,105 eggs)
Pathogenesis & clinical
manifestations of Enterobius vermicularis
- mild catarrhal inflammation of the
intestinal mucosa - irratation of the perianal region
- intense itching
- insomia due to the pruritus
- poor appetite , weight loss,
irritability, grinding of teeth & abdominal pain
Diagnosis of Enterobius vermicularis
graham’s scotch adhesive tape swab
Treatment of Enterobius vermicularis
-albendazole 400mg single dose
- mebendazole 500mg single dose
- pyrantel w/ 2nd dose 2-4 weeks later
Prevention and control of Enterobius vermicularis
- personal hygiene
- proper hand washing
- infected person should sleep alone
large roundworm, normally located in the small intestine.
Ascaris lumbricoides
mature worms is cylindrical with tapering ends.
Ascaris lumbricoides
creamy white to light brown in color.
Ascaris lumbricoides
Female ascaris measures _______ and ______
female measures 20-35 cm long & 3-6mm wide.
smaller male Ascaris lumbricoides measures ________ and _______ and has a _________
male is smaller 12-31 cm long & 2-4 mm wide & has a curved tail
the head has 3 lips with minute teeth or
denticles
Ascaris lumbricoides
it has a thick cuticle.
Ascaris lumbricoides
male has 2 broad spicules.
Ascaris lumbricoides
female vulva opens at the junction of the anterior & the middle thirds of the body
Ascaris lumbricoides
the fertilized egg is brownish, ovoid, 60-70 x 30-50um.
Ascaris Lumbricoides
size of unfertilized egg of Ascaris Lumbricoides
88-94 x 40-44um
What is the distribution of Ascaris Lumbricoides ?
Cosmopolitan
ectopic migration (appendix, bile duct, pancreatic duct).
Ascaris Lumbricoides
Diagnosis of Ascaris Lumbricoides
- detection of ascaris eggs in the feces.
- adult worm are visualized in the intestines by barium
meal examination
Treatment of Ascaris Lumbricoides
-Mebendazole 1 tab 2x/day for 3 days
-Albendazole single dose 400 mg
-Pyrantel pamoate single dose of 10mg/kg body weight
Prevention and Control of Ascaris Lumbricoides
- mass chemotherapy
- environmental sanitation
- improvements in housing
- eating cooked food
- proper hand washing
- good personal hygiene