Podcast
Questions and Answers
Urine examination is used to detect ______ in female patients.
Urine examination is used to detect ______ in female patients.
eggs
Enterobius vermicularis is also known as ______.
Enterobius vermicularis is also known as ______.
Pinworm
Flubendazole is an oral medication used to treat ______.
Flubendazole is an oral medication used to treat ______.
Nematodes
To prevent autoinfection and reinfection, treatment of all ______ members is necessary.
To prevent autoinfection and reinfection, treatment of all ______ members is necessary.
Ancylostoma duodenale is also known as ______ hook worm.
Ancylostoma duodenale is also known as ______ hook worm.
The third stage of the hook worm lifecycle is the ______ larva.
The third stage of the hook worm lifecycle is the ______ larva.
The adult hook worm attaches to the ______ of man.
The adult hook worm attaches to the ______ of man.
The hook worm can cause ______ due to sucking of blood and bleeding at the site of attachment.
The hook worm can cause ______ due to sucking of blood and bleeding at the site of attachment.
Mass treatment and hand washing before meals and after defecation are methods of ______ and control.
Mass treatment and hand washing before meals and after defecation are methods of ______ and control.
The female hook worm lays approximately ______ eggs.
The female hook worm lays approximately ______ eggs.
Flashcards
Nematodes
Nematodes
Cylindrical, elongated, smooth, and unsegmented worms with a complete digestive system.
Nematode classification
Nematode classification
The primary location of the nematode, either in the intestine or in tissues.
Ascariasis
Ascariasis
The disease caused by Ascaris lumbricoides, a giant intestinal roundworm.
Infective stage
Infective stage
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Diagnostic stage
Diagnostic stage
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Pulmonary phase of Ascariasis
Pulmonary phase of Ascariasis
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Intestinal phase of Ascariasis
Intestinal phase of Ascariasis
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Ancylostoma duodenale
Ancylostoma duodenale
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Enterobius vermicularis
Enterobius vermicularis
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Autoinfection
Autoinfection
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Study Notes
Nematodes
- Cylindrical, elongated, smooth, and unsegmented body with a complete digestive system
- Body is tapered to a pointed posterior end and a rounded anterior end
- No circulatory or respiratory systems
- All are unisexual, with females usually larger than males
Classification of Nematodes
- Classified into two main categories according to their primary location:
- Intestinal nematodes
- Tissue nematodes
Ascaris lumbricoides (Giant Intestinal Roundworm)
- Disease: Ascariasis
- Habitat: Small intestine of man
- Definite host (DH): Man
- Infective stage (IS): Embryonated egg (ingestion)
- Diagnostic stage (DS): Worm or egg
- Worm reaches up to 35 cm in length, the largest nematode of humans
- Worldwide distribution, with highest prevalence in tropical and subtropical regions, and areas with inadequate sanitation
Pathogenesis and Clinical Picture of Ascaris lumbricoides
- Pulmonary phase:
- Larval migration through lungs causes Loeffler's syndrome
- Characterized by fever, asthmatic cough, dyspnea, wheezes, and blood-tinged sputum
- Intestinal phase:
- Light infection: Asymptomatic
- Heavy infection: Nausea, vomiting, diarrhea, colic, and weight loss
- Allergic reaction: Bronchial asthma and urticaria
Complications of Ascaris lumbricoides
- Intestinal obstruction due to worm mass
- Adult worms have the tendency of wandering habit if irritated by fever, drugs, or anesthetics
- Wandering single worm can cause:
- Migration up and down to be expelled from mouth or anus
- Passage through intestinal orifices (e.g., bile duct, pancreatic duct, appendix)
- Perforation of the alimentary canal, leading to peritonitis
Diagnosis of Ascaris lumbricoides
- Clinical diagnosis: Non-specific symptoms
- Laboratory diagnosis:
- Stool examination for egg (fertilized and unfertilized)
- Sputum examination: In pulmonary phase for larvae
- Blood examination: Eosinophilia
Treatment of Ascaris lumbricoides
- Albendazole (Bendax) or mebendazole (Vermox)
Prevention and Control of Ascaris lumbricoides
- Treatment of infected population
- Environmental sanitation (clean water supply and safe sewage disposal)
- Health education (hand washing before meals and washing raw vegetables)
- Avoid using human excreta as fertilizers before exposure to sunlight or raising temperature to 51°C
- Fly control
Enterobius vermicularis (Pinworm)
- Disease: Enterobiasis
- Habitat: Large intestine
- Definite host (DH): Man
- Infective stage (IS): Larvated egg (ingestion)
- Diagnostic stage (DS): Worm in feces or egg on perianal folds
- Adult female: 8-10 mm in length, adult male: 1-5 mm in length
Egg Description of Enterobius vermicularis
- Size: 50-60 um x 20-32 um
- Shape: Elongate-oval and slightly flattened on one side (D-shaped)
- Shell: Thick double-walled shell
- Color: Colorless
- Content: Mature larva
Mode of Infection of Enterobius vermicularis
- Ingestion or inhalation of larvated egg
- Autoinfection (external) occurs when the host scratches the perianal area and transfers the eggs from the fingers to the mouth
- Retroinfection (internal autoinfection)
- Transmission between hosts (heteroinfection) occurs when another human handles or touches contaminated items
Pathogenesis and Clinical Picture of Enterobius vermicularis
- Irritation and pruritis of anus, especially at night
- Nervous irritability, restlessness, and insomnia
- Intestinal pain (inflammation of intestinal mucosa)
- Appendicitis (worms present in the appendix)
- In female patients: the worm may reach the urether, urinary bladder, vagina, and cause urethritis, nocturnal enuresis, and vaginitis
Diagnosis of Enterobius vermicularis
- Clinical diagnosis: Children with pruritis anus
- Laboratory diagnosis:
- Recovery of adult worm: Crawling from anus at night or in stool
- Recovery of egg (D-shaped) by:
- Stool examination (5% of cases)
- Swabbing of perianal area (in early morning before defecation)
- Urine examination (for female patients, eggs)
Treatment of Enterobius vermicularis
- Oral: Flubendazole (Fluvermal) or mebendazole (Vermox)
- Topical: 1% white precipitate mercury ointment at night on the anus region to kill the females and relieve itching and avoid secondary bacterial infection
Prevention and Control of Enterobius vermicularis
- Mass treatment
- Hand washing before meals and after defecation
- Finger nails should be kept short
- Underwear, nightwear, and bed linen must be changed and boiled
- Unwashed clothes should be exposed to sunlight to destroy eggs
- Toilet seats must be washed with disinfectants
Ancylostoma duodenale (Old World Hookworm) and Necator americanus (New World Hookworm)
- Disease: Ancylostomiasis
- Habitat: Small intestine of man
- Definite host (DH): Man
- Infective stage (IS): 3rd stage filariform larva L3 (skin penetration)
- Diagnostic stage (DS): Egg (female lays 30,000 eggs)
Adult Worm of Ancylostoma duodenale
- Size: Male 10 mm, female 15 mm
- Head slightly bent in relation to the rest of the body (hook-like)
- Buccal capsule contains teeth
Pathogenesis and Clinical Picture of Ancylostoma duodenale
- Skin invasion: Itchy papule, edema, and erythema (ground itch)
- Pulmonary migration: Loeffler's syndrome
- Intestinal attachment: Nausea, vomiting, diarrhea, epigastric pain, and bloody stool (due to laceration of intestinal mucosa)
- Polyphagia, puffy face, swollen feet, and general edema (due to malabsorption of protein and hypoproteinemia)
- Mental and physical growth retardation in children due to anemia
- Hookworm anemia: Due to sucking of blood by the worm and bleeding at the site of attachment
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Description
This quiz covers the characteristics of nematodes, also known as roundworms or thread worms, including their physical features and biological systems. Part of the Pharm D program.