Hookworms(钩虫) Two major species of hookworms ancylostoma ouden e wae can infect human Necator americanus (美洲板口线虫) Ancylostoma duodenale (十二指肠钩口线虫) 2mm Peter Darben
Hookworms (钩虫) Two major species of hookworms can infect human Necator americanus (美洲板口线虫) Ancylostoma duodenale (十二指肠钩口线虫)
General Introduction . Human intestinal nematode of smaller size inhabit the small intestine . o World-wide distribution about 900 million infections in the world ,o A duodenale is prevalent in Southern Europe, North Africa, Northern Asia(North China), and the more pathogenic one .o N americanus is the predominant species in the Western hemisphere and equatorial Africa(South China gs Many areas are endemic for both species o'o Heaw infection may evoke anemia known as Yellow Laziness
General Introduction ❖ Human intestinal nematode of smaller size, inhabit the small intestine ❖ World-wide distribution, about 900 million infections in the world ❖ A. duodenale is prevalent in Southern Europe, North Africa, Northern Asia (North China), and the more pathogenic one ❖ N. americanus is the predominant species in the Western hemisphere and equatorial Africa (South China) ❖ Many areas are endemic for both species ❖ Heavy infection may evoke anemia known as "Yellow Laziness
Morphology: Adults Ancylostoma duodenale Ancylostoma duodenale ☆ Female is10-13mmin length by 0.6 mm in diameter s Males are 8-11 mm by 0.4 mm 令 Posterior end has an umbrella-shaped bursa with riblike rays .o Two pairs of curved teeth on the ventral wall of its buccal capsule 2mm Peter Darben
Morphology: Adults Ancylostoma duodenale ❖ Female is 10-13 mm in length by 0.6 mm in diameter ❖ Males are 8-11 mm by 0.4 mm ❖ Posterior end has an umbrella-shaped bursa with riblike rays ❖ Two pairs of curved teeth on the ventral wall of its buccal capsule
Morphology: Adults Necator americanus eridanus Female Females are 9-11 mm in length by 0. 4 mm in diameter 冷 Males are7-9mmby0.3 mm Smaller than A, duodenale .o A pair of semilunar cutting plates on the ventral wall of the buccal capsule 1mm
Morphology: Adults Necator americanus ❖ Females are 9-11 mm in length by 0.4 mm in diameter ❖ Males are 7-9 mm by 0.3 mm ❖ Smaller than A. duodenale ❖ A pair of semilunar cutting plates on the ventral wall of the buccal capsule
Buccal capsule And vlostoma duodenale Ancylostoma duodenale Necator americanus
Buccal capsule Ancylostoma duodenale Necator americanus
Morphology: Egg oval or can-shaped with a thin, hyaline shell, measured 60-75 by 36-40 um
Morphology: Egg oval or can-shaped with a thin, hyaline shell, measured 60-75 by 36-40 µ m
Life cycle Filariform larva penetrates skin CDC sE+问+PE⊙LE Filariform Larva http://www.dpd.cdcgov/dpdx Rhabditiform larva atches Adults in small intestine 邀: Diagnostic Stage Eggs in feces
Life cycle
Life cycle No intermediate host is necessary Larva takes a free living mode The filariform larva is the infective stage Infection routes: skin penetration(mainly): orally swallow: maternal-child Residing in human upper small intestine: duodenum, jeJunum Blood-Lung migration: skin --- lymphatic system right side of the heart ---lung - respiratory tree coughed up and swallowed ---small intestine
Life cycle • No intermediate host is necessary • Larva takes a free living mode • The filariform larva is the infective stage • Infection routes: skin penetration(mainly); orally swallow; maternal-child • Residing in human upper small intestine: duodenum, jejunum • Blood-Lung migration: skin --- lymphatic system --- right side of the heart --- lung --- respiratory tree --- coughed up and swallowed --- small intestine
Pathogenesis 1. Hookworm larvae dermatitis Penetration of the skin by the filariform larvae may be asymptomatic in previously uninfected individuals However, those experiencing repeated infections develop itching, known as ground itch"or"dew itch
Pathogenesis 1. Hookworm larvae dermatitis: Penetration of the skin by the filariform larvae may be asymptomatic in previously uninfected individuals. However, those experiencing repeated infections develop itching, known as "ground itch" or "dew itch
Pathogenesis 2. Migration of pre-adult cause temporary pulmonary inflammation In heavily infected individuals (i.e, 500-1000 worms), there can be symptoms of pneumonia during the migratory phase in the developmental cycle of these worms
Pathogenesis 2. Migration of pre-adult cause temporary pulmonary inflammation: In heavily infected individuals (i.e., 500-1000 worms), there can be symptoms of pneumonia during the migratory phase in the developmental cycle of these worms