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Necator americanus 美洲鉤蟲
Ancylostoma duodenale 十二指腸鉤蟲
Ancylostoma caninum 犬鉤蟲
Ancylostoma braziliense 巴西鉤蟲
Ancylostoma ceylanicum 鍚蘭鉤蟲
Ancylostoma malayanium 馬來亞鉤蟲
Hookworms 鉤蟲Distribution between 45oN and 30oSApproximately 9 billion people infected
Over 20 million showed clinical manifestations
Middle EastMediterranean countriesNorth ChinaAfricaSouth-East AsiaSouth AmericaPacific Islands
A. duodenale 十二指腸鉤蟲
Far EastSouth AsiaPacific IslandsTropical AfricaCentral and South America
N. americanus 美洲鉤蟲
Between 45oN and 30oS
A. duodenale 十二指腸鉤蟲
腹齒附齒
次腹齒刀
N. americanus 美洲鉤蟲
腹齒板
雄美洲鉤蟲 9~11 x 0.4 mm
雌美洲鉤蟲 7~9 x 0.3 mm
Anus
Bursa
Posterior end of N. americanus
交尾囊
Copulatory bursa 交尾囊
Spicules 交尾刺
postero-latero ray後側枝 medio-lateral
ray 內側枝
externo-lateralray
ventral ray腹面枝
dorsal ray背面枝
externo-dorsalray 外背側枝
Transmission
Active penetration of skin by infective filariform larvae (L3)Ingesting of infective larvae in A. duodenaleTransmammary transmission of larvae in A. duodenale
infective filariform larvae (L3)
Filariform larva (L3) 絲狀幼蟲
Lungs
Circulation
Penetrates skin
Egg in faeces
2nd stagelarva (L2) in soil
Rhabditiform larvahatches (L1) 桿狀幼蟲
SwallowedPharynx
EXTERNAL ENVIRONMENT
Diagnosticstage診斷期
Infectivestage感染期
Attached tosmall intestine
4~6 wks
2~3 wks
1 wk
3 days MAN
Trachea
Pentration of skin by F- form larvae (L3)Clinical Pathology
Skin reaction (uritcaria 蕁痲疹 )at the site of larval pentrationStinging sensation followed by irration, erythea,oedema and papulovesicular eruption
Gound itch
A. braziliense and A. caninum wandering through the cutaneous layer (cutaneous larva migrans) causeintense irritation and iflammaton.Most of the larva die in the skin.
Creeping eruptions 匍行性疹
Migration of F-form larvae (L3)Clinical Pathology
During invasion of the circulation: Usually no ill-effectsDuring migration through the lungs: Pneumonitis (肺炎) with cough (咳嗽), wheeze (哮喘), fever (發燒 ), transient X-ray shadows (Not as severe as Ascaris)
Haemorrhages and leukocytic or eosinophilic infiltrations
In lungs
In respiratory tractCoughing due to irritation of the
bronchial and tracheal mucous membranes
Established intestinal infection by adult wormsClinical Pathology
Epigastric duodenal-type pain, indigestion, loss of appetite or diarrhoea
Adult worms attach to duodenum and jejunum by teeth or cutting plates (mechanical)
Worms move every 4-6 hours (blood leaking)Worrms feed on blood from cut vessels and
mucosal tissue (chronic blood loss)
Hookworm anaemia (HWA)Losses of blood, iron and proteins
Occassionally associated with folate deficiency
Clubbed Fingers & AscitesClinical Pathology
Laboratory Diagnosis
Colourless with a thin shell which appears as a black line aroung the ovumOval in shape, measuring about 65 x 40 µmContains an ovum which usually appears segmentedLarva may be seen inside in some specimen
Direct smear for eggsEgg culture for 1st stage larva (L1)
Embryonated stage Gastrula stage
Advanced stage Early stage
Hookworm Filariform Larva (L3)
Hookworm RhabditiformLarva (L1)