Hook wormsHook-like Ancylostoma duodenale Ancy: bent stoma: mouth present in Egypt

Necator americanus Necator: killer not present in Egypt

With a bursa at posterior end

With pointed posterior end

Ancylostomiasis Ancylostoma duodenale Definitive host: Man only Mouth opening (buccal capsule) Habitat: small intestine (jejunum) Cutting mucosa by teeth & plates 4 Teeth 2 lancets 2 Plates Buccal capsule10 mm in length 12 mm in length

Cylindrical worms Adult worms attached to with bursa intestinal mucosa by their buccal capsule

Cylindrical worms with pointed end

Life Cycle of Ancylostoma duodenaleInfected human

Negative geotropism Positive hygrotropism Thermotropism Infective Rhabditiform Geohelminthic infection filariform larva larva 2nd 1st Develops on the ground moult moult

Diagnostic StageEgg in stool

Infective StageFilariform larvePointed tail

S S C C

60X40Oval with rounded poles Thin-shelled

Filariform oesophagus filling anterior of larva

Ensheathed

Translucent Immature ovum with 4-cell stage

700 in length

Development of Ancylostoma duodenale inside the human bodyLarva is swallowed

Pulmonary lesion

3rd moult Venous blood

Skin lesion4th moult Filariform larvajejunum

Adult Ancylostoma

Intestinal lesion

Pathogenesis and Clinical Picture Skin lesion: at the site of entrance of larvaeItching, erythema, vesicles, pustule

(ground itch) Pulmonary lesion: due to passage of larvaethrough the lungs causing:

- asthmatic bronchitis - minute haemorrhage - verminous pneumonitis - eosinophilia Fever, cough, haemoptysis, dyspnea Inflammatory cells

Plain X-ray of the lungs during migration stage

Normal lung

Lung shows scattered mottling Loefflers syndrome

Pathogenesis in small intestineAdult worm attached to mucosa of small intestineFresh areaInflamed tissue Inflammatory cells

Worm secretes anti-coagulant

Each worm sucks about 0.3 cc blood/day

Mucosa of small intestine

The adult Ancylostoma changes its site of attachment to mucosa to move away from inflamed tissue to fresh areas.

Pathogenesis and Clinical Picture Intestinal lesion: due to adults cutting mucosa & feeding on blood. Plates This causes: Haemorrhage, minute ulcers Hypoproteinaemia Hypochromic microcytic anaemia Pallor, fatigue, dyspnea, tachycardia Due to anaemia

Subcutaneous oedema Due to hypoproteinaemia Diarrhoea, nausea, vomiting and melaena Black stoolPhysical & mental retardation & Pica

Diagnosis Stool examination for eggs. Determination of anaemia: Hypochromic microcytic anaemia Testing for occult blood ) ( in stool.

TreatmentAlbendazole Iron supplement protein rich diet.

Epidemiology Ancylostomiasis is prevalent in tropics, subtropics & some temperate zones. Widespread in areas where people defaecate on the ground, dont wear shoes and handle mud.

Suitable temperature, rainfall.

Prevention and ControlSanitary disposal of human excreta.Mass treatment. Health education.

X

Larvicides and disinfection of human excreta used as fertilizers.