Helminths

Question 1

Helminths (metazoa)

Answer 1

Greek word meaning worm

Large multicellular animals with specialized tissues and organs similar to their hosts

Question 2

Classification for Helminths

Answer 2

1. Nemathehelminthes (Nematodes) elongated , cylindrical (round body)
2. Platyhelminthes — thin segmented body ( Flat worm)
   A. Custoda— tape worm (ribbon like)
   B. Trematoda— flukes

Question 3

Who are the major targets for Helminths

Answer 3

Young malnourished children

Question 4

Transmission for helminths

Answer 4

1. Recalls contaminated soil, food and water

2. By the vector (bite of insect)

Question 5

Nematode general characteristics ( round worm)

Answer 5

1. Most abundant
2. Majority free living of soil and fresh water
3. Few parasites
4. Distinct male and female
5. Human parasite
6. Intestine round worm
7. tissue round worm

Question 6

Enterobius vermicularis (pinworm, seatworm)

Answer 6

1 type of round worm in the USA

• humans are the only host
• infection is self limited

Question 7

Describe how pinworm infects humans

Answer 7

Freshly dropped eggs have a sticky coating that causes them to lodge beneath fingernails]
Dried eggs can be spread by air current

Question 8

Life cycle of the pinworm

Answer 8

Parasite does NOT attach to the intestine and feed.
Eggs rarely found in fecal samples because3 release is external to intestine
The female pinworm will travel down the hosts pre-anal area to lay the eggs

Question 9

Symptoms of pinworms

Answer 9

1. Hypersensitivity reaction- itching
2. Mild nausea, vomiting and diarrhea
3. Slight irritation to intestinal mucosa
4. Loss of sleep
5. Velva irritation( eggs can spread to this region in girls)

Question 10

Treatment for pinworms

Answer 10

Mebendazole,
Warm water enema
Whole family should be treated

Question 11

Trichuiris trichiura ( whipworm)

Answer 11

Parasite attaches and penetrates into intestinal mucosa of large intestine by their LONG THIN head… the thicker tail hangs out in the lumen

Question 12

Life cycle of whipworm

Answer 12

Entire life cycle requires 90 days … infestation can last for 2 years

Question 13

Pathology and symptoms of the whipworm ( light infestation)

Answer 13

Asymptomatic , sometime slightly painful, self recovery

Question 14

Pathology and symptoms for whipworm ( heavy infestation)

Answer 14

Heavy load of parasites that feeding and anchoring on the intestinal mucosa can damage intestine and cause the symptoms: bloody diarrhea, weight loss, abdominal pain, colitis and rectal prolapse

Question 15

Treatment for whipworm

Answer 15

mebendazole

Question 16

Where is the whipworm most prevalent

Answer 16

in warm climate and poor sanitation ( warm, humid down south)
usually occurs with Ascaris

Question 17

Ascaris Lumbricoides

Answer 17

large intestinal round warm

considered the largest round worm (300mm)

Question 18

Where is Acaris Lumbricoide most prevalent

Answer 18

most prevalent in the work

most common in the USA

Question 19

What happens when infected with Ascaris Lumbricoides

Answer 19

Death can occur
worms are not attached to intestinal mucosa and feed
They can move around and explore different parts of the body

Question 20

What stages occur in humans

Answer 20

both larval and adult stages occur

Question 21

Life cycle of Ascaris Lumbricoides in humans

Answer 21

• Larvae move to small intestine and penetrates the intestinal wall & enter lymphatic and circulatory drainage > gets to heart
• from heart will be pumped through pulmonary arties to the lung
• then can migrate to respiratory tree to the glottis
• worms that enter the throat will be swallowed and returns to the small intestine or coughed up

Question 22

Pathology and Symptoms of Ascaris Lumbricoides

Answer 22

• Pneumonia , cough , low grade fever ( first sign)
• Intestinal obstruction ( bile duct & small intestine)
• Vomitting and abdominal pain due to adult migration
• protein malnutrition in children w/ heavy infection
• Retardation in mental and physical development in young children with malnutrition
• Adult may exit by nose, mouth, or anus ( large creamy worm)

can be deadly

Question 23

Where is Ascaris Lumbricoides prevalent & the treatment

Answer 23

in warm countries with poor sanitation found most in mountains of was, south and west

can leave double infection with T. trichina

Treatment: Mebendazole

Question 24

Trichnella spiralis

Trichina worm

Answer 24

Different than most worms- Larvae infects humans not eggs

• entire life cycle occurs in mammals
• Larvae encysted in muscles (nurse cell)
• Encysted form remains in mammal > transmits when consumed
• undercooked pork is main cause of infection

Question 25

What are the 5 phases of the Trichinella spirals life cycle

Answer 25

1. Intestinal Phase - occurs first week - small intestine edema & inflammation 2. Migration Phase - Lasts one month - Larvae may get into circulation searching for muscle (high fever , blurred vision - on their way they may penetrate lung, heart and lesions - during 4th&8th wk - death may occur 3. Muscular phase - Acute local inflammation with edema, pain of muscle, weakness & fatigue - Larvae get into bundle of muscle & curl up to form cyst 4. Focal Lesion - Periorbotal edema ,

Question 26

Strongyloides stercolis (thread worm) characteristics

Answer 26

- similar to hookworm - eggs are similar to hookworm - larvae have a simple buccal cavity ( mouth cavity ) - is the worm which reproduces in human body - has only one adult form (female) - Parthenogenic - female reproduce by itself

Question 27

Which hemilnths have only one adult form

Answer 27

Strongyloides stercolis

Question 28

Anisakidae marina characteristics | Herring Worm

Answer 28

causes infection gasterio- intestinal tract - human is not principal host - parasite never reaches maturity in human - stomach of birds , fishes and marine mammals ( natural habitat) - Male and female of the parasite occur with marine mammals

Question 29

Life Cycle of the Herring worms

Answer 29

- females eggs into lumen of intestine - eggs are passed out into the ocean where smaller fish -

Question 30

Where is the Herring worm

Answer 30

where row fish is common food

Question 31

Symptoms and pathology of herring worm

Answer 31

- local ulceration at site of attachment, stomach and bowel mucosa - abdominal pain and nausea and vomitting - chronic may mimic GI disorders