nematodes pt. 1

Question 1

what group do nematodes belong to

Answer 1

helminths
- multicellular organisms that contain internal organ systems

Question 2

nematodes are commonly known as

Answer 2

intestinal roundworms

Question 3

what are the 3 basic morphologic forms

Answer 3

1. eggs
   - produced after fertilization from female worms
   - size and shape depends on the microorganism
2. larvae
3. adult worms
   - adult female worms are usually larger than adult males
   - equipped w a complete digestive and reproductive system

Question 4

What does it mean when life cycle are similar but organism-specific

Answer 4

Organ specific - infection of nematodes can be initiated in several ways

Question 5

Briefly explain the life cycle of nematodes in general

Answer 5

After entering the body, eggs or larvae grow into adult worms.
The adult worms live in the intestines to obtain nutrients and reproduce.
Female worms lay eggs in the intestine, which can be passed out in stool.
Some eggs need warm, moist soil to continue developing for 2-4 weeks.
Once fully developed, these eggs can infect a new host, repeating the cycle.
Some nematodes don’t need a host and can live freely in the environment.

Question 6

Nematodes SOC

Answer 6

Stool - however, it depends on the organism

Question 7

What conditions do nematode eggs need to develop

Answer 7

Warm, moist soil for 2-4 weeks before becoming infectious

Question 8

True or false:
Nematodes cannot live without a host.

Answer 8

False - they can live without a host as they are a free living nematodes that can survive independently in the environment

Question 9

What are the 3 factor that may contribute to the severity of a nematode infection

Answer 9

Number of worms present
- more worms = heavy infection

Length of time the infection persists
- as they are known to last up to 12 months or longer
- there are cases that it will last 10-15 years or more

Overall health of the host
- if the patient is immunocompromised, the higher the possibility of the infection is severe
- moreover secondary infections like bacterial infections affect other organs beside the intestines

Question 10

true or false:
Occurrence of reinfections and autoinfections is possible

Answer 10

True

Question 11

Infective pinworm eggs that migrate back into the host body, develop and reproduce rather than becoming dislodged

Answer 11

Retroinfection

Question 12

Infected individuals reinfected themselves if reinfecting pinworms eggs are digested via hand to mouth contamination

Answer 12

Autoreinfection
- parasite completes its life cycle within the same hotspot in an individual leading to continuous infection without exposure to external source

Question 13

What are the typical symptoms of nematodes

Answer 13

Typical symptoms:
Abdominal pain
Diarrhea
Nausea
Vomiting
Fever
Eosinophilia

May be present:
Skin irritation
Formation of skin blisters
Muscle involvement

Question 14

Phylum and class of nematodes

Answer 14

Phylum: nemathelminthes
Class: nematoda

Question 15

What are the 2 hookworm spp.

Answer 15

Necator americanus
Ancylostoma duodenale

Question 16

Enterobius vermicularis
Common name:
Common associated disease:

Answer 16

Common Name:‬‭ Pinworm, Seatworm‬
‬‭Common Associated Disease:‬‭ Enterobiasis, Pinworm Infection‬

Question 17

Enterobius vermicularis egg morphology

Answer 17

‭ 48-60 μm long, 20-35 μm wide‬
‬‭ Oval, one-side flattened‬ (“D”)
‬‭ Double-layered, thick, colorless‬‭ shell‬
‬‭ May be seen unembryonated,‬
‭ embryonated, or mature

Question 18

Briefly explain the unembryonated, embryonated or mature Enterobius vermicularis egg

Answer 18

Unembryonated:
Unfertilized eggs where it is the initial stage where the eggs lays
No developed larva, non infectious

Embryonated:
Feretilized eggs where
In the process of maturing into an infective stage

Mature:
Fully developed infective larva (infectious)
Can cause infectious once digested
Infective mature embryonated eggs can be infective within 6-8 hours

Question 19

How can the embryonated eggs be infective in E. vermicularis

Answer 19

Can cause infections once digested Infective mature
Can be infective within 6-8 hours

Question 20

Briefly explain the adult worm morphology of Enterobius vermicularis

Answer 20

Male:
2-4 mm log, no more than 0.3 mm wide
Yellowish-white in color and are rarely seen

Female:
7-14 mm long, 0.5 mm wide
Yellowish-white in color equipped with organ system such as digestive tract, intestinal tract and reproductive structure
Tail is pointed that resembles pinhead (distinctive feature of a small)

Question 21

Laboratory diagnosis for Enterobius vermicularis

Answer 21

Cellophane tape preparation
Stool samples
- eggs or adults females may be recovered in stool samples on rare occasions a

Question 22

What is the cellophane tape preparation specimen of choice for the recovery of E. vermicularis

Answer 22

Collected from the perianal region of the person suspected of infection
- mostly seen are eggs
- however adult females may also be present
- multiple sample may be required
- another term: scotch tape method

Question 23

Why do the cellophane tape preparation requires multiple samples

Answer 23

To confirm the presence of a light infection or to determine a patient is free of infection

Question 24

E. vermicularis
Host -
Infective stage -
Diagnostic stage -

Answer 24

Host - only known hosts is human
Infective stage - mature embryonated eggs where
Diagnostic stage - eggs in perianal region

Question 25

Briefly explain the life cycle of E. vermicularis

Answer 25

1. Infection is initiated following the ingestion of the infective eggs. 2.Eggs migrate through the digestive tract into the S.I. where they hatch and release young larvae. 3. Resulting larvae continue to grow and mature= transform into adult worms. 4. It reside on the colon. 5. Following copulation, the gravid female worm migrates outside the body to the perianal region, where she may deposit up to 15,000 eggs. 6. The developing eggs achieve infective status after 4-6 hours. 7. Infective eggs may then become dislodged from the body. Once apart from the host, the eggs may take up residence in a number of locations. 8. Ingestion of these infective eggs initiates a new cycle.

Question 26

mating process where the male and female parasites reproduce sexually.

Answer 26

copulation

Question 27

term used to describe a female parasite that is caring for fully developed eggs or embryos.

Answer 27

gravid

Question 28

How long is the incubation period before the eggs of Enterobius vermicularis become infective?

Answer 28

4-6 hours.

Question 29

how can the infective Enterobius vermicularis eggs become dislodged from the body

Answer 29

due to intense scratching of the anal area afterwards, the eggs may take residence in surfaces like dust, linens and clothing.

Question 30

true or false: the infected eggs of E. vermicularis can become airborne

Answer 30

true [these eggs are light and can be carried by dust or air currents making them easy to inhale or settle on surfaces]

Question 31

how long can the infective eggs of E. vermicularis can survive

Answer 31

for a few days to several weeks under suitable environmental conditions - ideal surroundings consist of moderate temperature accompanied with high humidity.

Question 32

true or false: all Enterobius vermicularis infections are symptomatic

Answer 32

false - many cases are asymptomatic

Question 33

symptom of enterobiasis

Answer 33

most common: Intense itching (Pruritus ani) and inflammation around the anal and/or vaginal areas. other common: Inflammation of the anal/vaginal areas Intestinal irritation Mild nausea or vomiting Irritability and difficulty sleeping less common: Minute ulcers Mild intestinal inflammation Abdominal pain

Question 34

epidemiology of Enterobius vermicularis

Answer 34

found worldwide most common helminth known to cause infection in the US

Question 35

who appears to be at the greatest risk of contracting Enterobius vermicularis

Answer 35

children

Question 36

how is Enterobius vermicularis transmitted

Answer 36

hand-to-mouth contamination

Question 37

treatment and prevention and control for E. vermicularis

Answer 37

TREATMENT albendazole mebendazole pyrantel pamoate PREVENTION AND CONTROL practicing proper personal hygiene - handwashing - applying ointment to an infected perianal area - avoiding scratching the infected area thorough cleaning of all potentially infected environmental surfaces providing treatment to all household members

Question 38

Trichuris trichiura Common Name: Common Associated Disease:

Answer 38

Common Name: Whipworm Common Associated Disease: Trichuriasis, Whipworm Infection

Question 39

morphology of Trichuris trichiura eggs

Answer 39

50-55 μm long, 25 μm wide Barrel-shaped or football-shaped Hyaline polar plug at each end Unicellular, undeveloped embryo Smooth shell that retains a yellow-brown color from its contact with the host bile.

Question 40

morphology of Trichuris trichiura adult worm anterior end vs posterior end

Answer 40

2.5-5 cm long (males usually smaller than females) Anterior end: Colorless and contains slender esophagus Small that resembles a whip handle Posterior end: Pinkish-gray color, consisting of the intestine and reproductive systems Large and resembles whip itself Male possess a prominent curled tail

Question 41

why is the Trichuris trichiura's egg shell yellow-brown in color?

Answer 41

As it has contact with bile in the host, hence the outer covering/ shell is yellow-brown in color.

Question 42

what is the SOC for the recovery of T. trichiura eggs

Answer 42

stool

Question 43

how can adult Trichuris trichiura worms be detected

Answer 43

visible on macroscopic examination of the intestinal mucosa

Question 44

Where can Trichuris trichiura be found in heavy infections

Answer 44

seen in areas of the intestinal tract down to and including the rectum

Question 45

Which laboratory method helps detect Trichuris trichiura eggs in stool samples

Answer 45

The Zinc Sulfate Flotation Method - eggs are prominent in infected samples processed using this method

Question 46

How do Trichuris trichiura eggs appear in treated patients?

Answer 46

may be distorted, showing a variety of unusual shapes

Question 47

life cycle of T. trichiura

Answer 47

1. Ingestion of infective T. trichiura eggs containing larvae = initiates human infection. 2. Larvae emerge from the eggs in the small intestine. 3. Growth and development of the larvae occur as they migrate within the intestinal villi. 4. Larvae return to the intestinal lumen and proceed to the cecum, where they complete their maturation. 5. Resulting adults take up residence in the colon, embedding in the mucosa. 6. Following copulation, the adult female lays her undeveloped eggs which are passed into the outside environment via feces. 7. Approximately 1 month outside the human body, the eggs embryonate, become infective, and are ready to initiate a new cycle.

Question 48

How long do Trichuris trichiura eggs take to become infective

Answer 48

approx 1 month outside the human body

Question 49

Where do Trichuris trichiura eggs develop outside the human body?

Answer 49

in the soil

Question 50

How long can adult Trichuris trichiura worms live in untreated infections?

Answer 50

up to 4-8 years

Question 51

Do all Trichuris trichiura infections cause symptoms

Answer 51

No, mild infections are often asymptomatic

Question 52

What is another name for Trichuris trichiura infection?

Answer 52

Trichuriasis (Whipworm Infection) - heavy infection: 500-5000 worms - symptoms depend on the age of the host

Question 53

what symptoms do children and adult with Trichuris trichiura infection often experience

Answer 53

CHILDREN - Symptoms resembling ulcerative colitis - Chronic dysentery (with as few as 200 worms) - Severe anemia - Possible growth retardation - Increased rectal prolapse and peristalsis ADULT - Symptoms mimicking inflammatory bowel disease - Abdominal tenderness and pain - Weight loss - Weakness - Mucoid or bloody diarrhea

Question 54

third most common helminth

Answer 54

Trichuris trichiura

Question 55

Most common helminth known to cause infection the US.

Answer 55

Enterobius vermicularis

Question 56

Most common intestinal helminth infection in the world.

Answer 56

Ascaris lumbricoides

Question 57

epidemiology of Trichuris trichiura

Answer 57

Found in warm climates where poor sanitation practices are common. - Example using feces as fertilizations for farming.

Question 58

who has the most risk contracting whipworm infections

Answer 58

children as well as those in psychiatric facilities.

Question 59

treatment and prevention and control for Trichuris trichiura

Answer 59

TREATMENT mebendazole albendazole PREVENTION AND CONTROL exercising proper sanitation practices - avoidance of defecating directly into the soil, using feces as fertilizer, and placing potentially infective hands into the mouth thorough treatment of infected persons. educating children and aiding mentally handicapped persons in their personal hygiene and sanitation practices.

Question 60

Ascaris lumbricoides Common name: Common associated disease:

Answer 60

Common name: Large Intestinal Roundworm Common associated disease: Ascariasis, Roundworm Infection

Question 61

morphology of A. lumbricoides unfertilized egg

Answer 61

85-95 μm long, 38-45 μm wide Shape varies Thin shell Unembryonated; amorphous mass of protoplasm Usually corticated

Question 62

morphology of A. lumbricoides fertilized egg

Answer 62

40-75 μm long, 30-50 μm wide More rounded than the unfertilized egg Undeveloped unicellular embryo Thick nitrogen-containing polysaccharide coating called chitin, also known as shell. - Less evident in corticated eggs.

Question 63

morphology of A. lumbricoides adult worm male vs female

Answer 63

Largest known intestinal nematode. Creamy white color with a tint of pink. Fine striations are visible on the cuticle. Male: - Small, reaching up to 30 cm in length. - Slender and possesses a prominent incurved tail. Female: - 22-35 cm in length - Resembles a pencil lead in thickness.

Question 64

Largest known intestinal nematode

Answer 64

A. lumbricoides, adult worm

Question 65

present of heavy albuminous coating: absence of heavy albuminous coating:

Answer 65

Corticated: present of heavy albuminous coating. Decorticated: absence of heavy albuminous coating. *Fertilized egg shell is thin and the insides are amorphous mass of protoplasm (unembryonated)

Question 66

what is the SOC for the recovery of A. lumbricoides eggs

Answer 66

stool

Question 67

Where can adult Ascaris lumbricoides worms be found in severe infections?

Answer 67

Small intestine Gallbladder Liver Appendix may be present in: - stool - vomit - external nares (nostrils)

Question 68

In what types of samples can adult Ascaris lumbricoides worms be recovered?

Answer 68

Stool Vomit External nares (nostrils)

Question 69

What serological test is available for diagnosing Ascaris lumbricoides?

Answer 69

Enzyme-linked immunosorbent assay (ELISA)

Question 70

Do all Ascaris lumbricoides infections cause symptoms?

Answer 70

No patients infected with 5-10 worms often remain asymptomatic.

Question 71

What is another name for Ascaris lumbricoides infection?

Answer 71

Ascariasis (Roundworm Infection) may be infected with only a single worm - can produce tissue damage as it migrates through the host - sec bacterial infection may also occur

Question 72

true or false: a person can be infected with only a single Ascaris lumbricoides worm?

Answer 72

true

Question 73

How does Ascaris lumbricoides cause tissue damage?

Answer 73

By migrating through the host’s body.

Question 74

What can happen if an Ascaris lumbricoides worm perforates the intestine?

Answer 74

A secondary bacterial infection may occur. [perforates the intestine (makes a hole in the intestinal wall)]

Question 75

symptoms when there are many worms of Ascaris lumbricoides

Answer 75

Abdominal pain Vomiting Fever Distention *Mature worms may entangle themselves into a mass that may ultimately obstruct the intestine, appendix, liver, or bile duct

Question 76

How can Ascaris lumbricoides cause intestinal obstruction?

Answer 76

Mature worms may entangle into a mass that blocks the intestine, appendix, liver, or bile duct.

Question 77

it is one of the parasites that can undergo lung migration

Answer 77

A. lumbricoides patients may also experience pulmonary symptoms when the worms migrate through the lungs. - Low-grade fever, cough, eosinophilia, and/or pneumonia. - Asthmatic reactions to the presence of the worms may also occur.

Question 78

How can Ascaris lumbricoides exit the body

Answer 78

discomfort from adult worms exiting the body through the - anus - mouth - nose

Question 79

What nutritional condition can heavily infected children develop in the presence of Ascaris lumbricoides

Answer 79

Protein malnutrition

Question 80

life cycle of Ascaris lumbricoides

Answer 80

1. Infection begins following the ingestion of infected eggs that contain viable larvae. 2. Once inside the small intestine, the larvae emerge from the eggs. 3. Larvae then complete a liver-lung migration by first entering the blood via penetration through the intestinal wall. 4. FIRST STOP IS THE LIVER. From there, the larvae continue via the bloodstream to the SECOND STOP, THE LUNG. 5. Inside the lung, the larvae burrow their way through the capillaries into the alveoli. Migration to the bronchioles then follow. 6. The larvae are transferred through coughing into the pharynx, where they are swallowed and returned to the intestine. 7. Larvae matures which results to adult worms that take up residence in the small intestine. - Adults multiply and a number of the undeveloped eggs (up to 250,000/day) are passed in the feces. 8. Outside environment provides the necessary conditions for the eggs to embryonate. 9. The resulting embryonated eggs are the infective stage for a new host and when consumed by a human host, initiate a new cycle. - Infective stage: mature embryonated eggs

Question 81

How do Ascaris lumbricoides larvae travel from the lungs back to the intestine?

Answer 81

They migrate to the bronchioles. They are coughed up into the pharynx. They are swallowed and return to the intestine.

Question 82

How many undeveloped eggs can an adult Ascaris lumbricoides female lay per day?

Answer 82

Up to 250,000 eggs.

Question 83

Where do Ascaris lumbricoides eggs embryonate?

Answer 83

In the outside environment.

Question 84

What is the infective stage of Ascaris lumbricoides?

Answer 84

Mature embryonated eggs.

Question 85

true or false: Ascaris lumbricoides infective eggs cannot survive in 10% formalin fixative?

Answer 85

false - they can survive

Question 86

epidemiology of Ascaris lumbricoides

Answer 86

most susceptible areas are - warm climates - areas of poor sanitation

Question 87

which population is most at risk of A. lumbricoides

Answer 87

children who place their contaminated hands into their mouths

Question 88

treatment and prevention and control for A. lumbricoides

Answer 88

TREATMENT - albendazole - mebendazole PREVENTION AND CONTROL avoidance of using human feces as fertilizer. exercising proper sanitation personal hygiene practices.