Nematoda. Ascaris lumbricoides The longest intestinal nematoda of human, ( Look like lumbricus ) Male:15-30 cm Female: 25-35 cm.

NematodaNematoda

Ascaris lumbricoides• The longest intestinal nematoda of

human, (Look like lumbricus)

• Male:15-30 cm

• Female: 25-35 cm

Adult worm of A. lumbricoides

Morphology• Covered with cuticle• Digestive system (3 lips in mouth)

• Reproductive system

Ascaris lips

Ascaris - female cross section diagram

Life cycle

200,000 egg/day

2-3 weeks

Liver, heart, lung

1 molting

2 , 3mo

4 molting

2-2.5 months to have oviposition worm

Ascaris

• Fully embryonated eggs are swallowed and L2 hatches in the stomach and penetrate stomach or duodenal mucosa

• Larvae enter blood stream and leave through alveoli into lung

• Larvae molt several times in the lungs L3/L4 move up and get swallowed

• 2-3 months after infection the adult worms start laying eggs (200,000 daily)

• Eggs are shed with the feces and embryonate within 2-3 weeks

Ascaris egg

Fertile egg

unfertile egg

Can survive for 7-8 months in an ambient condition (21-30 oC)

1- albuminoidal layer 2- Thick hyaline layer, 3-thin lipoidal membrane

Unfertile egg

• Longer and narrower

• Thin shell

• Irregular coating of albumin

• Filled with an amorphous mass of protoplasm with refractile granules

Ascaris

• Infection depends on fecal contamination of food, water or soil

• Eggs are sensitive to sun light but otherwise extraordinarily resistant.

• (50 C kills egg in 1 hour, but eggs can survive at -8 to -12 C)

Sign and symptomsAscariasis

• During the lung phase of larval migration:

(4- 14 days after infection)

• Cough (Asthma attacks)

• dyspnea

• hemoptysis

• eosinophilic pneumonitis, edema of lips

• (Loeffler’s syndrome) last for 10-14 days.

Signs and symptoms• Adult worm in intestine: adult worms usually cause no acute symptoms • Vague abdominal pain• Rebound tenderness• Gnashing, Vomiting• Obstruction of intestine (in children)• Migrating adult worms may cause symptomatic

occlusion of the biliary tract or oral expulsion (Biliary ascariasis, cholangitis, Appendicitis, Peritonitis).

• Maltose misdigestion and intolerance

Ascariasis

Fever, anesthetic drugs, other drugs

Ascariasis

Epidemiology

• Highest prevalence in tropical and subtropical regions, and areas with inadequate sanitation

• 1.3 billion people infected worldwide, 500 million in China (18000 tons of Ascaris egg!!)

• One of the most prevalent helminthes in Iran• In Iran 5-6%, in some area up to 49% of people

(children, 5-9 ys) are infected • Contaminated vegetables, but not water, and

soils are the main source of infection.• Ascaris suum can infect human

Ascaris محل سال محقق

0.7 تهران كودكهاي مهد 1371 رخ بهمن

17.8 روستاها- الهيجان 1371 رضائيان

23.68 كنگاور 1373 اشرفي

3.4 كلينيك- كرمانشاه 1369-74 نظري

16.3 روستا- و شهر تنكابن 1375 رضائيان

0.9 مواد- كاركنان كاشانغذايي

1376 والي

2.7 درماني- مراكز زنجان 1376 عطائيان

49 مدارس- همدان 1378 طاهرخاني

Ascariasis in Iran

Ascariasis in Iran1.5 اراك 1378 اسالمي

2.5 شهريار 1379 شهابي

0.4 روستاها- ساري 1380 روحاني

39.6 روستايي- همدان 1380 جم سعيدي

0.18 بهداشتي- مراكز مادران اراك 1380 دوامي

0.7 اشپزخانه- كاركنان اصفهان 1380 كتابي

0.6 شهرري 1380 نائيني

0.3 اسالمشهر 1381 عسگري

39.2 مانده- عقب كودكان همدان 1381 طاهرخاني

1 غذايي- مواد كاركنان ورامين 1382 زاده امين

1.5 ايران 53995 كل از نمونه 1382 سياري

3 كودكها- مهد دامغان 1382 حيدري

Treatment

• Albendazole (adult: 400 mg/kg, children 200 mg/kg; single dose)

• In all nematodes exp strongyloides• (Bind irreversibly to tubulin, blocking microtubule assembly and

inhibiting glucose uptake)

• Mebendazole: 100 mg/day, 2 times; 3 days)• Pyrantel pamoate 11mg/kg (single dose) (no effect

on strongyloides and Trichocephalus)

(Depolarizesthe myoneural junction in worm, paralyzing them in a spastic condition)

Prevention and control

Entrobius vermicularis

• Pin worm, Oxyurus

• Worldwide distribution

• Humans are considered to be the only hosts of E. vermicularis

Morphology

• Thread like and white

• Male: 2-5 mm

• Female: 8-15 mm

• Cephalic ale

• Bulb of esophagus

Entrobius vermicularis

Female

Enterobius vermicularis

Life cycle of E. vermicularis

The time interval from ingestion of infective eggs to oviposition by the adult females is about one month.

4- 6 hours

•The life span of the adults is about two months.

Adult worm in caecum, colon or rectum

Transmission

• Autoinfection/ Retroinfection

• Person-to-person transmission can occur through handling of contaminated clothes or bed linens. 

• Through surfaces in the environment that are contaminated with pinworm eggs (e.g., curtains, carpeting). 

• Some small number of eggs may become airborne and

inhaled. 

Transmission

• Autoinfection

• Retroinfection

• Cross infection

• Inhalation

Clinical Features (Entrobiasis, oxyuriasis)

• Enterobiasis is frequently asymptomatic.• The most typical symptom is perianal pruritis,

especially at night.

• Occasionally, invasion of the female genital tract with vulvovaginitis and pelvic or peritoneal granulomas can occur.

• Other symptoms include anorexia, irritability, and abdominal pain (migration to appendice).

• Ectopic infection (liver, csf, eye)

Epidemiology

• infections more frequent in school- or preschool- children and in crowded conditions.

Entrobious vermicularis

محل سال محقق

54.9 رامسر 1378 راستي

4.71 فريدون كنارمازندرو- شهر ان

روستا

1378 رضويون

52 ايرانشهر 1378 داوودي

8.15 مهد گنابادكودك

1380 فاني

Laboratory Diagnosis

• Microscopic identification of eggs collected in the perianal area.

•  This must be done in the morning, by pressing transparent adhesive tape ("Scotch tape test", cellulose-tape slide test) on the perianal skin and then examining the tape placed on a slide (Graham Method).

• Anal swab• Nail finger (in 1/3 of infected children)

Eggs

Uterus of each female worm contain about 15000 eggs

Eggs

Treatment

• Albendazole (adult: 400 mg/kg, children 200 mg/kg; single dose)

• Pyrantel pamoate: 11mg/kg (single dose)

Trichuris trichiura (Trichocephalus, Whipworm)

•live in the cecum and ascending colon

•3-4 cm

Tail

Head

Trichuris trichiura

Trichuris trichiura

Stichocytes

Trichuris trichiura

Trichuris trichiura

•The adult worms are fixed in cecum and colon, with the anterior portions threaded into the mucosa.

Trichuris trichiura

Female Male

Trichuris trichiura

• On of the most common round worm of humans. 

• Human is the main host (Infection reported from monkey and pigs as well)

• It is estimated that 800 million people are infected worldwide.  Distribution is similar to Ascaris.

• Infections more frequent in areas with tropical weather and poor sanitation practices, and among children. 

Trichuris trichiura

محل سال محقق

0.1 تهران كودكهاي مهد 1371 رخ بهمن

26.8 روستاها- الهيجان 1371 رضائيان

11.26 كنگاور 1373 اشرفي

0.9 كلينيك- كرمانشاه 1369-74 نظري

22.5 روستا- و شهر تنكابن 1375 رضائيان

0.4 درماني- مراكز زنجان 1376 عطائيان

1 مدارس- همدان 1378 طاهرخاني

5.6 رامسر 1378 راستي

1.1 ايرانشهر 1378 داوودي

1 شهريار 1379 شهابي

0.5 - ابتدائي بابل بندپي 1380 قهرمانلو

0.7 اشپزخانه- كاركنان اصفهان 1380 كتابي

0.1 شهرري 1380 نائيني

0.1 اسالمشهر 1381 عسگري

1 مانده- عقب همدان 1381 طاهرخاني

4.8 كودكها- مهد دامغان 1382 حيدري

Trichuriasis in Iran

Life cycle

The females begin to oviposit 60 to 90 days after infection.

3,000 to 20,000 eggs per day

eggs become infective in 15 to 30 days

Larva stay for 3-10 days in intestine and then migrate to cecum

Clinical Features of trichuriasis

• Most frequently asymptomatic.  Heavy infections, especially in small children, can

cause:

1. abdominal pain, (migration to appendice which induce bacterial infection)

2. diarrhea, sometimes bloody or mucoid)

3. Tenesmus

4. rectal prolapse5. Weight loss, weakness, anemia growth retardation.6. Each worm waste 5 µl of blood each day, lifespan 4-6 ys

7. Disease is similar to IBS

Trichuris trichiura

Diagnosis

Concentration (flotation with zinc sulphate) is a useful method for diagnosis)

Treatment

• Albendazole (drug of choice; adult: 400 mg/kg, children 200 mg/kg; single dose)

• Mebendazole: 100 mg/day, 2 times; 3 days) or 500 mg single dose