Parasitology

• Ascaris lumbricoides is a giant roundworm and the most common human intestinal nematode

  
• Ascaris lumbricoides causes pathology through tissue reaction to invading larvae, intestinal irritation to the adult, and other complications due to heavy infection and extraintestinal migration
• Adult Ascaris lumbricoides:

  • Males: 10-31 cm
  • Females: 22-35 cm (200,000 eggs/day)
  • Large whitish to pinkish worms with smooth striated cuticles residing in the small intestines
• Ascaris lumbricoides eggs:

  • Infertile eggs are longer and narrower than fertile eggs
  • Infective stage: fully embryonated egg
• Ascaris lumbricoides life cycle:

  • Infective Stage: embryonated eggs
  • Mode of Transmission: mouth
  • Hepato-tracheal migration: 14 days
  • Adult development: 9 to 11 weeks
  • Life span: 1 year
  • Embryonated eggs can survive in the soil for a few months to 2 years
• Ascaris lumbricoides causes Ascariasis with symptoms like lung infiltration, asthmatic attacks, and edema of the lips
• Treatment for Ascaris lumbricoides: Single dose of Albendazole (400mg) / Mebendazole (500 mg) / Pyrantel pamoate (10mg/kg, max 1g); Ivermectin (200 μg/kg)
• Prevention and Control for Ascaris lumbricoides: WASHED (water, sanitation, hygiene education, deworming)
• Hookworms like Necator americanus and Ancylostoma duodenale are small, cylindrical, fusiform, grayish-white nematodes

  
• Hookworm eggs have bluntly rounded eggs with a single thin hyaline shell and a two- to eight-cell stage of division
• Hookworm life cycle:

  • Infective Stage: filariform larva
  • Mode of Transmission: skin
  • Diseases caused: Ground Itch or Dew Itch, Bronchitis
• Diagnosis for Hookworm infections: DFS (heavy infection), Kato thick or Kato-katz method, concentration techniques, culture
• Mode of transmission of Ascaris?
• Ascaris lumbricoides are soil-transmitted helminths
• The adult female ascarid can grow up to 35 cm long and produce over 200,000 eggs per day.
• Larvae penetrate the intestinal wall and migrate through the liver and lungs via the bloodstream.
• Adult worms live in the small intestine and feed on host's nutrients.
• Heavy infestations can cause malnutrition, anemia, and growth retardation.
• Humans serve as definitive hosts for Ascaris lumbricoides.
• Female adult of Ascaris lumbricoides are 22-35 cm in size.
• Ascaris lumbricoides are large whitish to pinkish worms with smooth striated cuticles.
• Eggs of Ascaris lumbricoides are longer and narrower than fertile eggs.
• Adult development of Ascaris lumbricoides lasts for 9 to 11 weeks.
• Embryonated eggs can survive in soil for few months to 2 years.
• Male Ascaris are 10-31 cm in length.
• Some of the diseases Ascaris brought are: lung infiltration, asthmatic attacks, and edema of lips.

  Majority are asymptomatic
• Treatment for Ascaris lumbricoides are: Albendazole, Mebendazole l, Pyrantel pamoate, and Ivermectin.
• Adult male Trichuris trichiura are 30-45 mm in size, while female are 35-50 mm, and lays 3,000 to 10,000 eggs per day.
• Embryonated eggs development of T. trichiura are 2-3 weeks long.
• There are no heart-lung migration in Trichuris trichiura
• Trichuriasis is the disease caused by Trichuris trichiura.
• Chronic dysentery and rectal prolapse are also some disease caused by Trichuris trichiura.
• The symptoms of Trichuriasis are: anemia, poor appetite, wasting, and stunting.
• The diagnosis for Trichuriasis are: DFS, FECT, FLOTAC, and Kato-katz.
• The treatment for Trichuriasis are Mebendazole 100 mg.
• Hookworms are blood-sucking nematodes that attack to the mucosa of small intestine.
• Necator americanus are small, cylindrical, fusiform, grayish-white nematodes.
• N. americanus adult females are 9-11 mm by 0.35 mm.

  Males are 5-9 mm by 0.30 mm
• Necator americanus has buccal capsule - ventral pair of semilunar cutting plates
• Ancylostoma duodenale has buccal capsule - 2 pairs of curved ventral teeth