Necator americanus

AMERICAN HOOKWORM

AMERICAN MURDERER

NEW WORLD HOOKWORM

Necator americanus

Synonym

NECATORIASIS

UNCINARIASIS

Necator americanus

Disease

Necator americanus

Historical NotesPredominant human hookworm in the

Philippines

Agent in the production of “laziness” in poor white population in the Southern USA;

“Tropical Anemia” of Puerto Rico and tropical areas in Western hemisphere

Necator americanus

MorphologyAdult Worm

• Attenuated anterior end w/ a buccal capsule

• Ventral and dorsal pair of semilunar cutting plates

• Strongly flexed dorsal ward the anterior end

Necator americanus

MorphologyAdult Worm

• Amphidial (secretes anticoagulant), excretory and esophageal glands for exodigestive function

• Grayish yellow at times reddish

Necator americanus

Morphology

Adult Male Worm

• 7-9mm long

• Long and wide bursa

Necator americanus

Morphology

Adult Male Worm

• Bipartite dorsal ray

• Long, slender and fused (forming delicate barb) copulatory spicules

Necator americanus

Morphology

Adult Female Worm

• 9-11mm long

• Vulva is situated either in middle or somewhat anterior

Necator americanus

Morphology

Eggs

• Resembles those of Ancylostoma duodenale

• Longer and more elongated than A.duodenale

• Daily egg output is 9,000 eggs

Necator americanus

Morphology

Diagnosis

• Subnormal level of hemoglobin with hookworm eggs in the feces (Hookworm disease)

• Egg number estimation (Egg count)

Necator americanus

Morphology

Diagnosis

• Presence of Charcot Leyden crystals in the feces (heavy infection : prepatent period)

• 24 hour fecal specimen preservation at room temp for egg hatching to hookworm larvae

Necator americanus

Morphology

Treatment

• Single dose of Benzimidazole antihelminthic

• Such as Albendazole or Mebendazole

Necator americanus

STORYANG BUTBOT

A. duodenale N. americanusStrong Weak

Larger and thicker Smaller and more slenderStunted Children Growth and Mental

Retardation

(I Have Enough Power)Iron-deficiency anemia,

Hypothermia, Eosinophilia, Protein Malnutrition

Classic Hookworm Disease

6 Ventral Cutting Teeth 4 Ventral Cutting Plate

No Lung Migration Requires Lung MigrationTripartite Dorsal Ray Bipartite Dorsal Ray

Present Spine Absent Spine

Anterior end bends in same direction Anterior end bends in opposite direction