Round Worms and Relatives

Transcription

1 Round Worms and Relatives

2 Phylum Rotifera Ciliated crown looks like rotating wheels Shape and color many colors, shapes, some colonial Habitat fresh water, marine, terrestrial, parasitic (can survive dehydration)

3 PHYLUM Nematoda nemato meaning "thread" Roundworms General characteristics Habitat fresh water, soil, marine, parasitic Cylindrical shape Tegument (waxy coating)

4 Body wall Longitudinal muscles 4 cords Spindle that projects into pseudocoel Fluid acts as hydrostatic skeleton to provide leverage

5 Digestive system Mouth, pharynx, intestine, rectum, anus Food rotifers, small worms, plant juices, host tissue

6 Nervous system Ring of nervous tissue around pharynx 2 nerve cords (dorsal and ventral) Some sensory papillae (projections) on head

7 Excretory system One or more large gland cells or canal system (filter waste) Empty out excretory pore

8 Reproductive system most are dioecious Male (usually smaller than female) uses a special copulatory spine to open the females reproductive tracts and inject sperm Sperm are unique in that they lack flagella and move by pseudopodia, like amoebas Female fertilization is internal, eggs stored in uterus until laid

9 We ll Use Ascaris for the Reproduction Example Picture Warning

10 Ascaris intestinal roundworm

11 Ascaris infections

12 A pile of Ascaris worms that came from people living in a small village in the south of India. The worms will mainly came from children.

13 Massive Ascaris infection. The worms are expelled after medical treatment

14 Life Cycle (Ascaris - The Large Roundworm in Humans) Life cycle Egg - swallowed by host hatches Juveniles 4 stages of molting burrow through intestine Organs affected Veins Heart Lungs (trachea) cough/swallow Stomach About two months later intestine (adult worms) Female may lay 200,000 eggs a day, passing out in the host s feces Boys tend to be more heavily affected than females presumably because boys are more likely to eat dirt than girls.

15 Symptoms Nausea, vomiting, intestinal cramping, Wandering worms Emerge from anus, throat, eustachian tubes (ears)

16 Hookworms

17 Hookworm

18 Hookworms Size and shape ~ 9-11mm Body form large plates in mouth to cut intestine of host and suck blood Human symptoms Anemia (lack of RBC s) In children: Mental retardation Stunted growth

19 Hookworms Life cycle Eggs feces, hatch in soil Larvae feed on bacteria Organs affected Blood Lungs (cough and swallow) intestine Prevention Wear shoes

20 Life cycle Burrows into intestine Female produces live young Organs affected Blood vessels Skeletal muscle cyst intestine Prevention Cook pork thoroughly! Trichina worm a pork infesting parasite

21 Pinworms The most common worm infection in the US Common in young children FYI: spread from child to child on clothing, bedding toys then they put their fingers in their mouth

22 Pinworms Life cycle adults live in large intestine Female: migrate to outside the anus (at night) to lay eggs Symptoms Itchiness around anus Restless sleep Irritability Loss of appetite Many affected people have no symptoms

23 Pinworms Prevention Wash hands frequently Keep your child's fingernails trimmed Discourage your child from nail-biting and putting things in his/her mouth Make sure your child wears clean underwear

24 Tropical countries Symptoms Filiarial worms Obstruct lymph vessels FYI quick review on the lymphatic system The lymphatic system is like the blood circulation tubes branch through all parts of the body LIKE the arteries and veins that carry blood EXCEPT that the lymphatic system carries a colorless liquid called 'lymph'. Lymph is a clear fluid that circulates around the body tissues. It contains a high number of WBC s. Plasma leaks out of the capillaries to surround and bathe the body tissues. This then drains into the lymph vessels.

25 Filarial Worms Creates long excessive growth of connective tissue Picture Warning

26 Filarial Worm - Elephantitis

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28 Filarial Worms Prevention Take preventative medications (DEC diethylcarbamazine) when traveling Avoid mosquito bites (mosquitoes serve as vectors) Live somewhere else!!!!

29 Toxacara canis (canine roundworm) Life cycle Worms in feces or soil (can stay there for years) In dog: can travel to eye scar, blind, migrate to liver or spleen Humans can be infected with this worm FYI: They are extremely resistant to adverse environmental conditions once an area is contaminated with eggs (playground, park, back yard) it is difficult to sanitize the area

30 DUSN Diuffuse Unilateral Subacute Neuroretinitis Carried by raccoons, enters through broken skin, eating contaminated food Symptoms attacks retina, ocular migraines Prevention avoid raccoons

31 Guinea Worm Life cycle (~ 1 year) Juveniles in water carried by small crustacean (copeopods) ingested when drinking Reproduce, male dies Female migrates to skin (usually legs, ankles, or feet) produces juveniles Blister forms Juveniles are liberated to the water Symptoms large painful water filled blister, worm under skin Prevention Drink clean water

32 Guinea Worm Pictures

33 Guinea worm

34 Guinea worm fiery serpent

35 Guinea worm