Helminths Flashcards Preview

Microbiology II > Helminths > Flashcards

Flashcards in Helminths Deck (31)
Loading flashcards...
1
Q

Helminths (metazoa)

A

Greek word meaning worm

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

2
Q

Classification for Helminths

A
  1. Nemathehelminthes (Nematodes) elongated , cylindrical (round body)
  2. Platyhelminthes — thin segmented body ( Flat worm)
    A. Custoda— tape worm (ribbon like)
    B. Trematoda— flukes
3
Q

Who are the major targets for Helminths

A

Young malnourished children

4
Q

Transmission for helminths

A
  1. Recalls contaminated soil, food and water

2. By the vector (bite of insect)

5
Q

Nematode general characteristics ( round worm)

A
  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
6
Q

Enterobius vermicularis (pinworm, seatworm)

A

1 type of round worm in the USA

  • humans are the only host
  • infection is self limited
7
Q

Describe how pinworm infects humans

A

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

8
Q

Life cycle of the pinworm

A

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

9
Q

Symptoms of pinworms

A
  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)
10
Q

Treatment for pinworms

A

Mebendazole,
Warm water enema
Whole family should be treated

11
Q

Trichuiris trichiura ( whipworm)

A

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

12
Q

Life cycle of whipworm

A

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

13
Q

Pathology and symptoms of the whipworm ( light infestation)

A

Asymptomatic , sometime slightly painful, self recovery

14
Q

Pathology and symptoms for whipworm ( heavy infestation)

A

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

15
Q

Treatment for whipworm

A

mebendazole

16
Q

Where is the whipworm most prevalent

A

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

17
Q

Ascaris Lumbricoides

A

large intestinal round warm

considered the largest round worm (300mm)

18
Q

Where is Acaris Lumbricoide most prevalent

A

most prevalent in the work

most common in the USA

19
Q

What happens when infected with Ascaris Lumbricoides

A

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

20
Q

What stages occur in humans

A

both larval and adult stages occur

21
Q

Life cycle of Ascaris Lumbricoides in humans

A
  • 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
22
Q

Pathology and Symptoms of Ascaris Lumbricoides

A
  • 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

23
Q

Where is Ascaris Lumbricoides prevalent & the treatment

A

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

can leave double infection with T. trichina

Treatment: Mebendazole

24
Q

Trichnella spiralis

Trichina worm

A

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
25
Q

What are the 5 phases of the Trichinella spirals life cycle

A
  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 ,
26
Q

Strongyloides stercolis (thread worm) characteristics

A
  • 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
27
Q

Which hemilnths have only one adult form

A

Strongyloides stercolis

28
Q

Anisakidae marina characteristics

Herring Worm

A

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
29
Q

Life Cycle of the Herring worms

A
  • females eggs into lumen of intestine
  • ## eggs are passed out into the ocean where smaller fish
30
Q

Where is the Herring worm

A

where row fish is common food

31
Q

Symptoms and pathology of herring worm

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