HOOKWORM INFESTATION

By: DR.

SAURAV POUDEL 16th

October 2016. 16th October 2016

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

Worldwide Infection

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)

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

Hookworm Egg and Larvae

                      \

Nectar americanus

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.

Ancylostoma hooks

Chitinous teeth plates

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).

Clinical manifestations:

1-Invasion stage: The skin, at the site of entry of filariform larvaMaculopapular 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.

Ground itch or “dew itch”

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of blood by the worm (iron-dificiency anaemia ),• Severe anaemia leads to weakness.• 0.15-0.26 mL of blood may be withdrawn by a Ancylstoma in 24 hour.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.

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

Ancylostoma caninumAncylostoma braziliense

Ancylostoma caninumDog hookworm

Ancylostoma brazilienseCat hookworm

Both cause creeping eruptions

Infection

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.

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.

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..

Prevention and Control

• Sanitary disposal of human faeces• Wearing of footwear• Health education• Treatment of infected individuals

THANK YOUFrom : Dr. Saurav Poudel. saurav7utd@hotmail.com (if any query).