second level ascariasis -...
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Ascariasis
Dr. Gihan Mostafa Tawfeek
Prof. of Medical Parasitology
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Considering Ascaris lumbricoides:
1- Habitat: Small intestine or large intestine2- Female is oviparous or ovo-viviparous.3- There is autoinfection : yes or no4- Life cycle shows migration to lung: yes or no
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• ILOs: by the end of this lecture, you will be able to:
Classify Ascaris lumbricoides according to taxonomic positions and their habitat in the humanhost. Recognize the mode of transmission of ascariasis. Recognize the geographical distribution of parasitic infection and population at risk. Correlate pathogenesis to clinical picture and complications. Request for an appropriate investigation. Give appropriate treatment to a patient with these helminthic infections. Explain what you would do to prevent the spread of these helminthic infections in yourcommunity.
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Taxonomy
Phylum • Nemathelminthes
Class • Nematoda
Small intestinal
Nematodes • Ascaris
lumbricoides
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Small intestinal Nematodes
1- Ascarislumbricoides
2- Hookworms
3-Strongyloides
stercoralis
4- Capillariaphilippinensis
Large Intestinal Nematodes
1-Trichocephalus
trichiurus
2- Enterobiusvermicularis
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Ascaris lumbricoides
•One of Nematodes•(Class: Nematoda)
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Cuticle
Subcuticle
Muscle
Body cavity
Organs
Roundworms
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Extended Modular Program 8
Lecture slides section 1
Taxonomy of Ascaris lumbricoides
Phylum Nemathelminthes
Class Nematoda
Small Intestinal Nematodes
Ascaris lumbricoides
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They live in the small intestine and
cause a disease “ascariasis”
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Infected human
LIFE CYCLE
Egg containing 2nd stage
rhabditiform larva in 3 weeks
Develops in soil
Soil transmitted helminthinfection
Infection by eating
unwashed vegetables
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Larvae molt twice
Eggs hatch in the upper
small intestine liberating
larvae
Pulmonary lesion
Intestinal lesion
Embryonatedegg is
swallowed
LIFE CYCLE
Egg changes to adult in SI
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Extended Modular Program 13
Lecture slides section 1
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Ingestion of embryonated egg
containing 2nd stage
rhabditiform larva through:
1.Unwashed fruits and
vegetables, particularly those
grown in soil fertilized with
sewage
2.The common house fly
3.Hands contaminated by
polluted soil.
4. Pica (eating soil or mud).
Mode of infection and infective stage:
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Epidemiology
• Ascariasis is a world-wide (including Egypt).
• Common particularly in areas:
of bad sanitation.
Where untreated human faeces are used as fertilizers.
• Children are the most likely to become infected because of bad personal hygiene.
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Pathogenesis and clinical picture
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Early in Infection
• larvae migrating in the lung.
Late in infection
• adult worms in the small intestine
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1. Pulmonary symptoms= Loeffler’s sysyndrome
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Larval migration to lung:
1- Transient alveolar infiltration with
eosinophil.
2- Alveolar hemorrhage
Clinical picture: 1- Fever, cough with blood tinged sputum, dyspnea, asthma.2- Symptoms begin 9-12 days after infection.3- Symptoms subside spontaneously within a couple of weeks
Alveolus
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2. Intestinal symptoms
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Pathogenesis
Mechanical irritation to mucosa
Clinical picture:
Abdominal pain,
vomiting and
diarrhea
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Complications
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1- Even if a single worm is
irritated
Migration of worms
Expulsion from mouth
or nose
Obstruction of ducts or
appendix
Obstructive jaundice Acute
pancreatitis
Acute appendiciitis
Penetration of liver
Liver abscess
Perforation of intestine
Peritonitis
Congregation of worms
Intestinal obstruction
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Expulsion from mouth or anus
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D
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Abdominal pain, vomiting and
diarrhea. Complications:
Intestinal obstruction,
appendicitis, liver abscess, peritonitis
and expulsion of worms from mouth,
nose, anus and with stool and
growth retardation.Fever, cough with blood
tinged sputum, dyspnea, asthma
Diagnostic stages in stool
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Management DiagnosisTreatmentPrevention
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DiagnosisLaboratory diagnosis
Stool examination
Egg
1-With stool
2- With vomitus
3-From mouth
4-From nose
Adult
Sputum examination
Larva
Blood picture
Temporary Eosinophilia
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Sputum examination
•May reveal larvae (early in infection)and Charcot-Leyden crystals •(collections of crystalloid are formed from the breakdown of eosinophils).
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Stool examination
•Fertilized egg: 60x 40 microns, oval and contains unsegmented embryo. It may be brownish with outer coarse mamillation.
•Fertilized decorticated egg: may be pale yellow without outer mamillations.
•Unfertilized egg: 90x 60 microns,
•elongated barrel shaped and
•surrounded by incomplete
•mamillated coat. It is dark and
•contains refractile granules
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Early infection (larval migration):Chest radiography shows scattered mottling of the lungs (ground glass appearance) which tend to be migratory and usually clear after several weeks.
Late infection: Radiography of the gastrointestinal tract after barium meal reveals adult worms as cylindrical filling defects.
Imaging techniques
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Treatment
• 1- Owing to the potential migration, infected individuals should be treated:
• Albendazole 400 mg one dose orally is the drug of choice
• 2- Cases with complication should be sent to hospital.
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30Extended Modular Program
How to prevent
ascariasis????
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1. Treatment of patients.
2. Sanitary sewage disposal.
3. Health education regarding washing of
raw vegetables and fruits and washing of
hands before meals.
4. Treatment of human excreta before
usage as a fertilizer by exposure to sun light
or raising the temperature to 51ºC.
5. Fly control.
How to prevent
ascariasis????
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A 3-year-old girl, a daughter of parents with low educational and socio-economic; her father is a farm vet. She came down with her condition in the previous 72 hours with a diffuse abdominal pain, progressive food intolerance, vomiting, and diarrhea associated with the presence of worms in mouth and anus for the last 24 hours as referred by parents. The previous day she was feverish and received unspecified antihelminthic with increased symptoms. Abdominal radiograph showed bowel obstruction data. Due to intestinal obstruction (IO) and the failure of anthelmintic treatment, urgent surgical management was scheduled. An ileum enterotomy was performed and the worms were removed. Hydration and antibiotics were administered for 72 hours, and after restart of peristalsis, albendazole 100 mg twice a day for 3 days. The patient was discharged uneventfully, with a plan to deworm in 6 weeks.
a) What organism is most likely responsible for the patient’s illness?b) How did the patient become infected?c) What could be the precipitating factors of the condition?e) What is the basic data in your diagnosis?
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Extended Modular Program33
1. Ascariasis is a world-wide (including Egypt), particularly in areas of bad sanitation and where untreated human faeces are used as fertilizers.
2. Ascariasis is characterized by pulmonary symptoms (Loeffler’s syndrome) caused by larval migration and intestinal symptoms caused by adult worms.
3. Even a single worm of Ascaris lumbricoides can cause serious trouble if become irritated
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The cause of pulmonary manifestation in ascariasis is:
a.Ascaris Adults.b.Larvae.c. Eggs.d.Egg containing larvae.e.All of the above