Health Care Missions SG3 Parasites

T/F Parasites rarely travel alone

True

Is prevention or treatment more effective?

Prevention

Nemathelminthes =

Roundworms

Platyhelminthes =

Flatworms

Roundworms are...

Elongated, cylindrical worms

Why do roundworms have hooks or teeth?

Attachment or penetration

What are roundworms resistant to?

Digestive enzymes

What do roundworms thrive on?

Carbohydrates

Is Ascaris Lumbricoides a roundworm or hookworm?

Round worm

Where is ascaris lumbricoides found?

Asia, Africa, Latin America

How much of the population is infected with ascarid lumbricoides?

1--%

What is the largest intestinal worm?

Ascaris Lumbricoides

How long is the ascaris lumbricoides?

Female 20-35
Male 15-30

What is the pulmonary phase of ascaris lumbricoides?

Hypersensitivity reaction, asthman

What is the intestinal phase of ascaris lumbricoides?

Colic, Obstruction

How do you treat ascaris lumbricoides?

Vermox 100 mg BID x 3 days
(Do not give to pregnant women or children under 2 years old)

In children under two years old how do you treat ascaris lumbricoides?

Antiminth

How long do ascaris lumbricoides eggs remain viable?

Years

Can ascaris lumbricoides eggs survive heat and direct sunlight?

No

How many people are infected with hookworm?

More than 700 million

How was hookworm introduced to USA?

Probably existed among egyptians - Introduced via west african slave trade

What does hook thrive in?

Sandy loose soil

How does someone get hookworm?

Barefeet

What does hookworm cause?

Anemia

How much blood does a hookworm remove per day?

0.25 ml

How do you treat hookworm?

• Vermox 100 mg BID x 3 days

• Iron replacement

How can one find source of iron in diet?

• Legume

• Nuts

• Dried Fruits

• Green leafy vegetable

• Fish

• Poultry

• Lean Meat

How does one prevent hookworm?

• Wear shoes

• Use latrines

• Eliminate use of night soil

Whipworm are…

Roundworms

Where is whipworm?

Worldwide distribution

What does whipworm exist with?

Ascaric and hookworm

What does whipworm thrive in?

Warm, moist soil

How big is a whipworm?

5 cm

How does one get whipworm?

Ingested, goes into digestive tract

Where does bleeding occur with whipworm?

Attachment site in colon

Is whipworm symptomatic or asymptomatic?

Asymptomatic

What is the risk of whipworm in children?

Chronic mucoid, bloody diarrhea, anemia, delayed growth, rectal prolapse

How do you treat whipworm?

• Vermox 100 mg BID x3 days

• Eat only cooked food

• Wash vegetables in disinfected water

Pinworms are…

Roundworms

______ is the most common intestinal parasite in developed world?

Pinworms

How big are pinworms?

1 cm

How are pinworms transmitted?

• Fecal-oral

• Inhalation of eggs

What is the lie cycle of pinworms?

4-6 weeks

Describe the life cycle of pinworms

• Eggs ingested orally

• Hatch in duodenum migrate to ileum

• Mature female migrates to anus to lay eggs

• Eggs viable up to two weeks

How do you diagnose pinworms?

• Perianal itching

• Visible observation

• "Tape Test"

How do you treat pinworms?

• Vermox 100 mg X1

  • Treat ALL household occupants

  • Avoid in pregnancy and children younger than 2 years

How to prevent pinworms?

• Handwashing after defecation

• Cover food

Wuchereria bancrofti are…

Roundworm - filiaria

What is the most widely distributed human filarial parasite?

Wuchereria bancrofti

Where is wuchereria bancrofti endemic?

Tropics

How is wuchereria bancrofti transmitted?

Mosquito

How many different species proven vectors of wuchereria bancrofti?

48

Where do wuchereria bancrofti live?

Blood in lymphatics

How large are wuchereria bancrofti?

8-10 cm

What is asymptomatic filariasis (wuchereria bancrofti)?

• Children exposed at early age

• Enlarge lymp nodes

• Adult worms die in time

• No residual microfilariae

What is inflammatory filiariasis?

• Allergic phenomenon

• Sensitive to both living and dead worms

• Recurrent attacks:
  1. Fever
  2. Headache
  3. Vomiting

• Inflammed lymphatics of legs and genitalia

• Abscesses in nodes

What is obstructive filariasis (elephantiasis?)

• Not acute

• Fibrous tissue inflamed by filariae obstruct lymph channels

Is elephantiasis common or uncommon?

Uncommon in persons < 30 y/o

How do you treat wuchereria bancrofti?

Hetrazan

How does hetrazan work?

Kills adult female worms or permanently sterilizes them

What are side effects of hetrazan?

• Headaches

• Nausea

• Fever

What is privation of wuchereria bancrofti?

• Control mosquitoes

• Bednets

• Protective clothing

Onchocerca volvulus are…

Filarial worms

What is onchocerciasis?

River blindness

Where is river blindness?

• Equatorial regions

• Africa, Central America

How large are onchocerca volvulus?

Female: 40-60 cm
Male: 3-6 cm

How long is Onchocerca volvulus lifespan?

18 years

What is the vector of onchocrca volvulus?

Simulian Black Fly

What does onchocerca volvulus do to the skin?

• Pruritus

• Premature wrinkling

• Onchocercomata

What is onchoceromata?

Subcutaneous nodules containing adult worm

What does onchocerca do to the eyes?

• Reaction to microfilariae

• Conjunctivitis

• Photophobia

• Corneal Scarring

What is the treatment onchocerca volvulus?

• Surgicall remove nodules of close to eyes

• Hetrazan

• Control vectors

• No drug beneficial for prophylaxis

What do flatworms look like?

Flat and ribbon shaped

What is the flatworms head called?

Scolex

Where does the scolex attach?

Bowel wall

What is the flatworm body called?

Prolottids

What is the proglottis composed of?

Segments

What is the proglottid?

Repository for eggs

What does the proglottid do?

Detach and rupture

What are the tapeworm hosts?

• Taenia Saginata

• Teania Solium

What is the taenia saginata?

Beef tape worm

What is the lifespan of taenia saginata?

Up to 25 years

What is the size of the taenia saginata?

4-12 meters

What is the taenia solum?

Pork

What is the size of the taenia solum?

2-8 meters

How do you treat taenia?

Niclosamide 500 mg (take 4 tablets)

What does niclosamide do?

Kills proglottids but not eggs

Two hours after you take niclosamide what do you do?

Take cathartic to eliminate eggs

How do you know you have had a successful treatment of taenia?

Passed scloex

How do you prevent taenia?

• Eliminate night soil

• Throughly cooked meat

What are protozoas?

Unicellular

What does intestinal protozoas do?

Form cysts capable of surviving adverse environmrnyal conditions

What are the types of protozoas?

• Ameba

• Blood/Tissue protozoa

What is Entomoeba hystolytica?

Ameba

How big are Entomoeba histolytic?

Microscopic

What does Entomoeba hystolytica do?

Form infective cysts

What does the pathgenicity depend on?

• Resistance of host

• Virulence of the strain

• Status of intestinal tract

How his Entomoeba hystolytica transmitted?

Cysts ingested from food/water contaminated with fecal matter

Where does ameba emerge from with Entomoeba hystolytica?

Cyst in ileum

How long is Entomoeba hystolytica incubation period?

7-21 days