nematoda usus.pptx

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