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8/7/2019 Ancylostoma powerpt

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Ancylostoma Duodenale andNecator Americanus

By Marquetta Valdez


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Some Facts.

Hookworms infect an estimated 1 billionpeople worldwide, mostly in tropical andsub-tropical climates

A. duodenale and N. americanus are thetwo hookworms that infect humans

A. duodenale is found in southern Europe,northern Africa, India, China, the MiddleEast, and the Americas

N. americanus can be found in thesoutheastern U.S. and Australia


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Life Cycle and Reproduction

Eggs are passed in the feces and hatch intorhabditiform larvae in about 48 hours in thefeces or in the soil

A. duodenale N. americanus

Eggs are generally 57-76 m by 35-47

m and areoval shaped

with a thin shell


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Rhabditiform Larvae (wet mount)


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Life cycle continued

Juveniles feed on feces for about 3 daysthen molt into 2nd stage juveniles

They molt again 5-10 days later intofilariform larvae. Can survive 3-4 weeksoutside host.


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Life Cycle

Worms molt again two more times toreach maturity

A. duodenale adult males measure 8-11mm

with females being 10-13mm

N. americanus adult males measure 7-9mmand females measure 9-11mm

Adult worms copulate and eggs appear in

the feces in about 6 weeks (females canproduce sever thousand eggs in one day)

Cycle starts over again and adults live 1-2years


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Life Cycle


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Transmission

Filariform juveniles wait in soil orfeces and wave back and forth to

increase chances of finding a host Filariforms then penetrate the skin

(usually hands or feet)

Children, elderly people and peoplewhowork about contaminated soilare at high risk


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Pathogenic Effects

Asymptomatic until worms have alreadystarted multiplying

Symptoms include: Irritation of skin at site of penetration

Iron-deficiency anemia Abdominal pain Diarrhea Loss of appetite Weight loss

Tiredness Difficulty breathing Cardiomegaly Irregular heartbeat Extreme cases include stunted growth and

mental retardation


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Diagnosis

Stool samples showing eggs oractual worms

Watching for symptoms


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Control and Treatment

Scientist are trying to develop avaccine

In some countries, infections arenttreated because they are socommon

Drugs of choice are Albendazole,

Mebendazole, and Pyrantel Pamoate


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Prevention

Wear shoes

Monitor the disposal of humans

feces


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Works Cited

"Hookworm Image Library." Division ofParasitic Diseases. Center for DiseaseControl. 29 Sept. 2006

. "Hookworm Infection Fact Sheet."

Parasitic Disease Infection. Center forDisease Control. 3 Oct. 2006.

"Hookworm." Parasites and Health.Center for Disease Control. 29 Sept. 2006.

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