2. Prevalence of Hookworm
• Hookworm affects about 576 million people globally
• Predominates in tropic and subtropic regions
• Disease of developing and under-developed world,
disease of the poorest of the poor
• Most vulnerable:
– Children
– Pregnant women
– Persons without shoes or adequate protective clothing
– Agriculturalists
4. Offending Pathogens
Majority of hookworm infections in humans
caused by
1) Ancylostoma duodenale
(an-cy-CLO-sto-ma doe-AH-den-al)
2) Necator americanus
(ne-KAY-tor am-er-i-CON-us)
5. N. americanus and A. duodenale
• 0.10 mm length, 0.4 mm diameter.
Female > Male
• 9000 eggs/day, eggs have 3-5 yrs
survival
• Buccal capsule set with two
crescent-shaped cutting plates on
ventral side
• Ingests 30 µl blood/day
• 12 mm in length, 0.6 mm in
diameter. Female > Male
• 20,000 eggs/day, eggs have 1 yr
survival
• Buccal capsule set with symmetric
pair of sharp teeth on ventral side.
• Ingests 260 µl blood/day
9. Ancylostoma duodenale
Common name: Old world hookworm
Habitat: Small intestine
Definitive host: Human
Route of infection: Filariform larvae penetrate the skin of human
Infective stage: Third stage larvae ( filariform)
Diagnostic stage: Eggs in Stool
Disease: Hookworm infection, Ancylostomiasis
Geographic Distribution: Southern Europe, North parts of Africa, China,
India, and Japan.
11. Egg
• Shape : oval with an empty space between the shell and content
• Size: 60 x 40 μm
• Shell: thin egg shell
• Color: colorless and transparent
• Content: 4-8 cell unembryonated
• Immature eggs pass in feces (20,000 eggs ⁄ day).
12.
13. Clinical manifestations:
1-Invasion stage:
The skin, at the site of entry of filariform larva
Maculopapular lesions “ ground itch” or “dew itch”
Itching, edema.
2-Migration stage: passage of the larvae in the lung leads to:
Haemorrhages and pneumonia, cough, fever, eosinophilia.
15. 3-Intestinal stage:
1) sucking of blood by the worm (iron-dificiency anaemia ),
• Severe anaemia leads to weakness.
• 0.15-0.26 mL of blood may be withdrawn by a Ancylstoma in 24 hour.
• Approximately 50% of the red blood cells are hemolyzed
2) Bleeding at the site of attachment and after movement to a new sites.
3) Toxic substances .
-intestinal ulcers: flatulence, nausea, vomiting ,diarrhea.
16. Symptoms Associated with Infection
• Skin Infection
– stinging, burning, itching, pruritus, papulovesicular rash -
can last up to 2 wks
• Lung Infection
– pneumonia, cough --rare and mild.
• Ingestion
– throat soreness, hoarseness, nausea, vomiting
• GI Infection
– anemia, bloody stool (from former attachment sites),
abdominal pain
20. Lab Diagnosis
1. Direct Method:
Examination of stool :
A macroscopic examination of stool is necessary
to find out the adult worms.
A microscopical examination of stool may easily
demonstrate the presence of characterestic
hookworm eggs.
21. 2. Study of Duodenal contents:
The material obtained by duonenal intubation
may sometime reveal either eggs or the adult
worms.
Indirect methos:
Examination of blood: Anaemia,eosinophilia.
Occult blood test: positive reaction(charcot-
leyden crystals are found in stool.
22. Treatment
• Albendazole 400 mg orally in a single dose.
Or 200 mg in children 1-2 yrs of age.
• Mebendazole 100mg orally twice a day for 3
days.
• Pyrantal pamoate 11mg/kg to a maximum of 1
gram day for 3 days.
• Topical albendazole are useful for creeping
eruption.
• Iron therapy may be as important as worm
eradication..
23. Prevention and Control
• Sanitary disposal of human faeces
• Wearing of footwear
• Health education
• Treatment of infected individuals
24. THANK YOU
From : Dr. Saurav Poudel.
saurav7utd@hotmail.com (if any query).
