Nematodes

• Trichinella spiralis is also known as

  Pork Worm, Trichina Worm
• Trichinella spiralis


  • Smallest known nematode (male) of humans
• Diseasesof Trichinella spiralis

  • Trichinosis
  • Trichiniasis
  • Trichinellosis
• Scientific Classificationof Trichinella spiralis

  • Kingdom: Animalia
  • Phylum: Nematoda
  • Class Adenophorea
  • Order: Trichurida
  • Family: Trichinellidae
  • Genus: Trichinella
  • Species: T. Spiralis
  • Binomial Name: Trichinella spiralis
• Male Worm of Trichinella spiralis

  • Measures 1.4-1.6mm in length by 40–60 micra in transverse diameter
  • Cloaca is found at the caudal end which is evertible during coitus, guarded by 2 conspicuous conical papillae which clasp the female during copulation
  • Spicule is absent
  • Posterior end of the worm is curved ventrad
• Female Worm of Trichinella spiralis

  • About 3-4 mm long and 60-80 micra in width
  • Vulva open at the anterior fifth of the body
  • Has a single uterus which contains larvae
  • Produce 1500 larvae in its lifetime
  • Lives 30 days
• Encysted Larva of Trichinella spiralis

  • Measure by 100 by 6 micra when extruded by the female worm
  • Provided with a spear-like burrowing tip at its tapering anterior end
  • In the striated muscles, the larva grows to about 0.8-1mm and becomes encrusted along the axis of the muscle fibers
• Life Cycle of Trichinella spiralis

  1. Infective Stage: Encysted Larva – Upon ingestion of contaminated undercooked meat

  2. Definitive Host: Swine, Man (Accidental Host)

  3. Diagnostic Stage: Encysted Larva
• Maturation of Trichinella spiralis is 2 days
• Adult worms begin to mate 5-7 days
• After 3 weeks in the muscle, they will start to coil into individual cysts
• Diagnosis of Trichinella spiralis

  • Muscle Biopsy
  • Bentonite Flocculation Test - Blood test, very sensitive to T. spiralis
• Clinical Diseaseof Trichinella spiralis

  • Destruction of the muscle fiber
  • Eosinophilia
  • May have myocardial involvement
• Prevention and Controlfor Trichinella spiralis

  • Sterilizing garbage containing raw meat scraps
  • Cook meat properly (77 C or 170 F)
  • Storage at -15 C for 20 days or -30 C for 6 days
  • Screening of pigs
• Treatmentfor Trichinella spiralis

  • Thiabendazole
  • Mebendazole
• Diseasesfor Trichuris trichiura

  • Trichuriasis
  • Whipworm infection
• Pathologyof Trichuris trichiura

  • Mild Ulceration
  • Abdominal pain
  • Diarrhea
  • Rectal prolapse
• Male Wormof Trichuris trichiura

  • Measures 3-3.5 cm
  • A single lanceolate spicule protrudes through a refractile penial sheath which has a bulbous termination covered with small, recurved spines
  • Distinguished from the female by its coiled caudal extremity about 360 degrees or more
• Female Wormof Trichuris trichiura

  • Measures 3.5-5.5 cm in length
  • Vulva open at the anterior end, the fleshy portion of the body
  • Has a single uterus and ovary
  • Bluntly rounded at the posterior end
• Ova (infective stage)of Trichuris trichiura

  • Characteristically barrel-shaped with bipolar unstained intralaminar prominences which have the appearance of mucoid plugs
  • Lemon-shaped, Football-shaped
  • Measures 50-54 micra by 22-23 micra
  • In addition to a vitelline membrane, it has a triple shell consisting of: Chorionic layer, Albuminous layer, Bile-stained layer
• Life Cycleof Trichuris trichiura

  1. Infective Stage: Embryonated egg

  2. Definitive Host: Humans

  3. Diagnostic Stage: Egg (unsegmented)

  4. No heart and lung phase

  5. Resides in the Large Intestine

  6. No Intermediate Host needed
• Per gram of feces of a patient with Trichuris trichiura can have 5000 eggs
• Diagnosisfor Trichuris trichiura

  • Direct Fecal Smear
  • Kato-Katz Technique
  • Concentration Tecchnique (Recovery of eggs in the stool specimen)
• Treatmentfor Trichuris trichiura

  • Piperazine Citrate
  • Mebendazole
  • Pyrantel Pamoate
• Capillaria philippinensis was first discovered in the Philippines at PGH

  1963
• Epidemic in Capillariasis in Pudoc, West Tagudin, Ilocos Sur (approximately 1300 person became ill and 90 persons dies from the infection)


  1967
• Diseasesof Capillaria philippinensis

  • Intestinal Capillariasis
  • Capillariasis
• Pathologyfor Capillaria philippinensis

  • Abdominal pain
  • Gurgling of the stomach (borborygmi)
  • Diarrhea
  • Anorexia
  • Loss of weight
  • Vomiting and edema (bipedal)
• Male Wormof Capillaria philippinensis

  • Small, measuring 1.5-3.9 mm in length
  • Characterized by caudal alae and long, non-spiny sheaths (male spicule)
  • Caudal alae – wing-like expansion of the cuticle at the tail ends of the nematodes
• Female Wormof Capillaria philippinensis

  • Measures 2.30-5.3 mm in length
  • Body is divided into 2 almost equal parts: Anterior: Esophagus, Esophageal glands, Posterior: Intestine, Reproductive system with slightly prominent vulva
  • 2 Types of Female Capillaria philippinensis: Atypical Female – Larviparous (responsible for population build-up), Typical Female – Oviparous
  • Both have an esophagus with secretory cells called stichocytes (glandular cells) and the esophageal structure is called stichosome
• Eggsof Capillaria philippinensis

  • Similar to that of the whipworm but are smaller about 42 by 20 micra usually in the single or 2-segmaented stage of development
  • More oval (than T. trichiura) in shape
  • Bipolar mucous plugs that are not protuberant
  • Shell is thick and pitted which appear as striations hence peanut-shaped
• Life Cycleof Capillaria philippinensis

  1. Infective Stage: 3rd stage larva

  2. Intermediate Host: Fishes

  3. Definitive Host: Humans

  4. Diagnostic Stage: Egg, larva, adult in the fecal sample
• Diagnosisof Capillaria philippinensis

  • Demonstration of Characteristic eggs in the feces: Direct Fecal Smear or wet mount, Stool Concentration Methods, Duodenal aspiration
  • Larva and adult stages may also be seen
• Diseasesof Enterobius vermicularis

  • Enterobiasis
  • Oxyuriasis
• Pathologyof Eneterobius vermicularis

  • Perianal itching or pruritus ani
  • Autoinfection
  • Familial disease
• Scientific Classificationof Enterobius vermicularis

  • Kingdom: Animalia
  • Phylum: Nematoda
  • Class: Secernentea
  • Subclass: Spiruria
  • Order: Oxyurida
  • Family: Oxyuridae
  • Genus: Enterobius
  • Species: Enterobius vermicularis, Enterobius anthropopitheci, Enterobius gregorii
• Male Wormsof Enterobius vermicularis

  • Measures 2-5 mm by 0.1-0.2 mm
  • It has a characteristic curved tail with a single spicule and cephalic alae
  • Relatively smaller than the female worm
  • They are rarely seen because they die after copulation
  • Meromyarian musculature
• Female Wormsof Enterobius vermicularis

  • Measures 8-13 mm by 0.4 mm
  • It has a long-pointed tail hence the name, pinworm
  • Uteri of the gravid (pregnant) female are distended with eggs
  • Capable of laying as much as 4672 – 16888 eggs/day
  • Gravid females will deposit eggs at the perianal skin/region of the anus because eggs need oxygen
  • Die after laying eggs
• Ovaof Enterobius vermicularis

  • Asymmetrical (Flattened and Convex)
  • Measure 50-60 micra by 20-30 micra averaging 55 by 36 micra
  • The translucent shell: outer, triple albuminous covering; inner lipoidal membrane
  • Outside the host, eggs become infective in four to six hours (4-6 hours)
  • Resistant to disinfectants but affected by dehydration
  • In moist conditions, they may remain viable for 13 days
• Nematode Somatic Musculature

  • Meromyarian musculature: 2-6 rows of muscle cells present per quadrant
  • Polymyarian musculature: more than 6 rows of muscle cells per quadrant