nematoda usus.pptx
TRANSCRIPT
NEMATODA USUS
Parasitology Dept
• Infeksi cacing usus yang ditularkan melalui tanah (soil transmitted helminthiasis)merupakan masalah dunia terutama di negara yang sedang berkembang.
• Diperkirakan 1milyar penduduk dunia menderita infeksi parasit cacing.
• Prevalensi pada anak usia sekolahdasar di Indonesia antara 60%-80%. Paling sering disebabkan oleh Ascaris lumbricoides,Trichuris trichiura dan cacing tambang.
Soil – Transmitted Helminthiasis ( STH )
nematode infections transmitted via soil medium either
1. Ingestion of embryonated eggs
2. Skin penetration by infective larvae refers to these helminths:
Ascaris lumbricoidesTrichuris trichiura
HookwormsStrongyloides stercoralis
Toxocara spp.
Common STH agents
Habitat of STH in host
Large intestine
Small intestine
Trichuris trichiura
A. lumbricoidesHookwormsS. stercoralis
Infections STH associated with:
Poverty and poor condition
Inadequate sanitation and water supplies
Soil quality and climate
Poor personal and environmental hygiene
Poor health awareness
Ascaris lumbricoides
Ascaris lumbricoidesMorphology
AscariasisEtiology: Ascaris lumbricoides ( roundworm )
Habitat : small intestine, especially jejunum and upper ileum
Morphology:
Adult – large, broad, cylindrical, tapers at both ends
- light cream pinkish whitish
- female bigger than male
Male spicule
FemaleVulval opening between anterior and midlle 1/3 body
Ascaris mouth partventral view
3 fine toothed lips
2 ventral lips
1 dorsal lip
covered with sensory papillae
Ascaris lumbricoidesMorphology
Egg consists of three layers (walls): albuminoid (protein), hyaline, and lipoid
Due to the albumin layer: corticated or decorticated eggs
Due to the content: fertilized, unfertilized, or infectious eggs
Eggs resistant to desiccation
Fertilized eggs:Rounded, have a thick shell, with an external mammillated layer that is often stained brown by bile Size: approximately 60 µm in diameter when spherical, and up to 75 µm when ovoid.
Unfertilize:elongated and larger (up to 90 µm in length); their shell is thinner; and their mammillated layer is more variable, either with large protuberance
Morphology:
Ascaris eggs
fertilized unfertilized
mammilated
semi-decorticated
Ascaris lumbricoidesLife Cycle
Adult worms in small intestine, produce eggs which are
excreted with stool
tracheal migration
Lung passage
Eggs cleavage under optimal condition in soil
embryonated eggs
Ingested/swallowed by human
Hatched in the upper part of small intestine
Invade blood vessels
3 weeks
Prepaten Period: 2 months
Ancylostomatidae
Ancylostoma duodenale Morphology
Reddish white worm, form C-like appearance in alcohol 70%
Female measures 10-13 mm in length, male is 8-11 mm with a characteristic copulatory bursa at the tail end
2 pairs of teeth
Necator americanus Morphology
Female is 9-11 mm long and male is 7-9 mm long, copulatory bursa is exist
Form S-like appearance in alcohol 70%
cutting plates (chitin)
Adult Hookworms:
Ancylostoma duodenale- 2 pairs of teeth
Necator americanus- cutting plates (2 ventral + 2 dorsal)
Hookworm eggs
Oval, 65 x 40 um
Colorless, transparent hyaline membrane
Segmented ovum with 4 blastomers
Clear space between egg and ovum
Similar forms between two species
Both polar ends are blunt
Trichiuris trichiura
Trichiuris trichiuraMorphology
Female
- larger
- whip-like
Male- coiled posterior
Anterior end
3/5 body length
Posterior end
2/5 body length
Contain intestine, reproductive organs
Trichuris trichiura eggs
Eggs in fresh feces- barrel shaped- mucus plugs at both ends- unsegmented ovum
Eggs in external environment- similar characteristics- embryonated larva inside
AHS
Enterobius vermicularis(pin worm)
AHS
Distribution
• Worldwide• E. vermicularis is one of the most common
childhood helminth infections in the developed world
• This infection more frequent in family or community and in crowded conditions such as ophanages, hospital, school, etc.
AHS
Morphology
Adult worm• Small and white• Three lips surounding the mouth• Habitat is in the large intestine (caecum and
appendix), sometimes in ascending colon and ileum
AHS
Male• Size 100 µm - 141 µm• The posterior ends strongly curled ventrally and has
papillaFemale• Size 8 mm – 13 mm• Pointed tail end• Vulva opens between the first and second thirds of the
body• When gravid, uterus filled with thousands of eggs (ovipar)
Morphology
AHS
Morphology
Pointed tail end Curled tail end
AHS
Eggs • Size 50 µm - 60 µm x 20 µm - 30 µm• Asymmetrical; elongated oval and flattened on
one side • Transparent eggshell• Contains larvae• Obtained from anal swab
Morphology
AHS
Morphology
Flattened side
AHS
Life Cycle & Transmission
Infective stage:Embryonated eggsDiagnostic stage:Eggs obtained from anal swab
AHS
Life Cycle & Transmission
1. Eggs on perianal folds. Larvae inside the eggs, matur within 4-6 hours at body temperature.
2. Infection occurs by :• Autoinfection : swallowed by hands that
have scratched the perianal area • Retroinfection : the migration of newly
hatched larvae from the anal skin back into the rectum
AHS
• Some small number of eggs may become airborne and inhaled.
• Handling of contaminated surfaces environment (e.g., clothes, bed linen, curtains, carpeting
3. Following ingestion of infective eggs, the larvae hatch in the small intestine and become adult
4. The adults establish themselves in the colon
Life Cycle & Transmission
AHS
5. Time interval from ingestion of infective eggs to oviposition by the adult females is about one month. The life span of the adults is about two months. • Males die soon after copulation• Gravid females migrate nocturnally outside the
anus and oviposit while crawling on the skin of the perianal area . • One worm may deposit 4600-16000 eggs. • Females die soon after oviposition
Life Cycle & Transmission