Nematoda Kingdom: Animalia (unranked): Protostomia - - PowerPoint PPT Presentation

Biological ¡Sciences ¡318-­‑ ¡Parasitology ¡Lab ¡ ¡ ¡

Nematoda ¡

¡

Kingdom: ¡Animalia ¡ ¡ (unranked): ¡Protostomia ¡ ¡ (unranked): ¡Spiralia ¡ ¡ clade: ¡Nematoida ¡ ¡ ¡ ¡ ¡ Phylum: ¡ ¡ ¡ ¡ ¡

Order Class

Trichinella ¡

¡

Trichuris ¡ ¡ ¡ Mermis ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ Strongyloides ¡ Rhabdina ¡ ¡ ¡ Hooksworms ¡ Trichostrongyles ¡ ¡ Ascaris ¡ Anisakis ¡ Enterobius ¡ ¡ Filarial ¡worms ¡ Dracunculus ¡

Characteristics: Nematodes occupy almost every possible niche: As parasites they infect vertebrates, insects, and plants, as free-living organisms they are found in soil, fresh water and sea

• water. They are a highly successful group of organisms, second only to the insects.

Despite their diversity of habitat, the nematodes have a remarkable consistency of

• shape. This consistency of form is brought about by the constraints of their morphology:

1) bilaterally symmetrical animals (non-segmented) 2) Body contains internal cavity (pseudocoelom) 3) Vermiform, long and slender with pointed ends 4) Complete Digestive System 5) Most are dioecious; (Female w. vulva, Males w. cloaca) 6) Develop by molting, shedding cuticle 7) Development: egg, egg fertilization, embryo in egg, larva, 4 molts, adult

Nematodes

J1 J2 J3 J4 Adult Egg M1 M2 M3 M4

Morphology

• tube within a tube
• Body wall: thick cuticle, a hypodermis, layer of longitudinal muscle
• Pseudocoel functions as hydrostatic skeleton- common in invertebrates
• Digestive system is complete- mouth, gut, anus
• Reproduction:

♀ tube subdivided into Ovary, oviduct, uterus, vulva (gential pore) ♂ chitinous spicule, vas deferens joins digestive tract to form cloaca

Nematoda

Nematoda ¡ Enoplea ¡

Order ¡ Trichurida ¡ (Whipworms) ¡

Rhabditea ¡

Order ¡ Ascaradida ¡ Order ¡ Oxyurida ¡ (Pinworms) ¡ Order ¡ Strongylida ¡ (Hookworms) ¡ Order ¡ Spirurida ¡ (Filarial ¡worms) ¡

Learning Objectives

• 1. Know general characteristics
• Know what is special about their cuticle + epidermis
• Know development + morphology
• 2. Order Trichurida
• Know general characteristics for id + anatomy
• 3. Trichuris trichura
• Human whipworm
• Epidemiology, anatomy
• Purpose of thick and thin end
• Visual id males, females, eggs
• Embryonation, infectivity
• 4. Trichinella spiralis
• (adult slide not good)
• Largest intracellular parasite
• Life cycle, tissue + transmission
• Females are viviparous
• What is special about larvae?
• Why are they hard to eradicate?  lots of reservoir hosts
• Visual id male , female, larvae encysted, muscle infected / larvae section
• 5. Order Ascarida
• General characteristics
• 6. Ascaris lumbricoides
• Epidemiology, pathology
• Size
• Life cycle, transmission, bronchial escalator
• Eggs, embryonated or unembryonated, number of eggs (thick outer shell, persistence)
• Cross section: id parts+ sex
• 7. Order Oxyurida
• Know general charactersitics
• 8. Enterobius vermicularis
• Pinworm
• Most common nematode parasite of human
• Life cycle, transmission
• Itchy bum
• Visual id female, male
• 9. Order Strongylida
• 10. Superfamily Ancylostomatoidae
• Hookworms
• General characteristics
• Life cycle

Vocabulary Cuticle Epidermis Dioecious Cloaca Vulva Filiform Stichosome Stichocytes Viviparous Nurse cell Bronchial escalator Spicule Oviparous Caudal bursa Buccal capsule Microfilaria Nocturnal periodicity Filarial worms Pinworms Hookworms Whipworms

• 11. Ancylostoma caninum
• Where?
• Host, mouthparts – buccal capsule, caudal bursa (copulatory bursa)
• Visual id in copula, male, female
• 12. Necator americanus
• Where?
• Visual ID male, female, eggs
• Mouthparts – caudal bursa
• 13. Order Spirurida
• General characteristics
• 14. Superfamily Filarioidae
• Filarial worm
• General characteristics
• 15. Onchocerca volvulus
• Life cycle, pathology
• Vector
• Visual id nodule cross-section containing adults containing microfilariae
• 16. Wuchereria bancrofti
• Life cycle, pathology, disease, transmission
• Visual id mircofilariae