NEMATODES II

Question 1

Causative Agent of Capillaria?

Answer 1

Capillaria hepatica and Capillaria philippinensis

Question 2

What are the synonyms of Capillaria?

Answer 2

Synonyms

Intestinal capillariasis
Capillariasis philippinensis
Wasting disease
Pudoc mystery disease

Question 3

o 1963 identified in male patient of PGH form Bacarra, Ilocos Norte diagnoses with malabsorption syndrome

o 1967 assumed epidemic proportions in six provinces in Northern Luzon with over 1,000 new cases and 10% mortality

o Southern Leyte, Thailand, Japan, Korea, Taiwan, Indonesia, Iran, Egypt

o Recently described in Zamboanga del Norte and Compostela Valley

Answer 3

Capillaria

Question 4

What is the life cycle of Capillaria?

Answer 4

Typically, unembryonated eggs are passed in the human stool and
Become embryonated in the external environment
After ingestion by freshwater fish, larvae hatch, penetrate the intestine, and **migrate to the tissues **

Ingestion of raw or undercooked fish results in infection of the human host

The adults of Capillaria philippinensis (males: 2.3 to 3.2 mm; females: 2.5 to 4.3 mm) reside in the human small intestine, where they burrow in the mucosa
The females deposit unembryonated eggs.

Some of these become embryonated in the intestine, and release larvae that can cause autoinfection. This leads to hyperinfection (a massive number of adult worms)

Question 5

___________ is currently considered a parasite of fish eating birds, which seem to be the natural definitive host

Answer 5

Capillaria philippinesis

Question 6

CAPILLARIA:

____________ as intermediate host and

____________ as the usual definitive host

Answer 6

Small fresh or brackish water fish** fish eating birds**

Question 7

Raw fresh-water fish_____________ are found in endemic areas of Capillaria are

Answer 7

“BIRUT”,”BAGSANG”, “BAGSIC”

Question 8

Pathology of Capillaria:

Adult worms are more common usually found partially embedded in the mucosa of the small intestine, primarily the ____________, having developed from larvae _____after ingestion

Do NOT penetrate beyond muscularis mucosae and are probably intraepithelial
Intestinal villibecome flattened and crypts ofLieberkhun atrophy

Cause mild inflammatory response with edema of the basement membrane, distention of mucus glands, infiltration of the lamina propria with plasma cells, lymphocytes, and occasional eosinophil

Answer 8

jejunum

** one to two months **

Question 9

Laboratory Diagnosis for Capillaria

Definitive diagnosis is finding the characteristic ova in the ________

Answer 9

stool

Question 10

Answer 10

capillaria

Question 11

peanut shaped with flattened bipolar plugs and a striated egg shell.

Answer 11

Capillaria egg

Question 12

Intradermal test in epidemiologic studies
Marked hypoproteinemia with low serum albumin

Stools are bulky with an Elevated fecal content and and average daily stool weight of 1200g

Protein loss in the stools maybe 15 times that of controls
Immunoglobulins studies show a normal IgA values but diminished IgM and IgG values

Malabsorption of sugars (xylose) and fats and low serum levels of potassium, sodium, calcium and carotene

Answer 12

Capillaria

Question 13

Clinical characteristics

Most commonly in men ages 20-45 y/o but it occurs in all ages and both sex
Cause a severe protein-losing enteropathy and malabsorption syndrome

I

Answer 13

Capillaria

Question 14

What is the initial symptom in Capillaria include _____________-
Diarrhea develops within 2-6 weeks
Intermittent Diarrhea to persistent diarrhea with passage of five to ten or more watery, voluminous, sprue-like stool per day

Associated weight loss, malaise, anorexia, nausea and vomiting

More advanced condition show **cachexia and weakness with absent or diminished reflexes with absent or diminished reflexes, profound muscle wasting and ** loss of subcutaneous fat, anasarca and dehydration

Weak heart sounds, hypotension and gallop rhythm suggesting a myocardiopathy
Abdomen is distended with severe epigastric pain
Protein-losing enteropaty results in severe hypoproteinemia and peripheral edema
Extreme weight loss, emaciation and death in severely infected individuals

Answer 14

borborygmi and vague abdominal pain

Question 15

Wh are the differential diagnosis of Capillaria?

Answer 15

Differential diagnosis

Tropical and Non-tropical sprue

Lymphangiectasia, amyloidosis, Whipple’s disease, eosinophilic gastroenteritis
Giardiasis

In Giardiasis, changes are most pronounced in the duodenum and proximal Jejunum with the ileum being spared in most patients

Hookworm disease produces small bowelradiographic changes of mucosal edema and malabsorption and usually spares the Ileum

Strongyloidiasis will often show greater distortion of the folds due to edema, Inflammation, and even ulceration of the mucosal surface as well as malabsorption

Question 16

Treatment for Capillaria DOC:

________200 MG BIDx20-30 days

Answer 16

MEBENDAZOL

NOTE: Alternative: Albendazole 400 mg ODx10 days

Question 18

Causative agent of Strongyloidis

Answer 18

Strongyloides stercoralis

Question 19

What are the synonyms for Strongyloides?

Answer 19

Synonyms

Strongyloidosis
Strongulosis
Strongyliasis
Cochin China diarrhea

Question 20

Geographic Distribution

______________ most common in warm, moist region of the tropics, but found worldwide and in all climates
Infection rate is high in some population groups such as recent immigrants, veterans of foreign wars, foreigners, and residents in long term care facilities

In certain subgroups, debilitated children and Immunosuppressed patients

Most coomon in adults but occurs in children as well

Answer 20

Strongyloides stercoralis

Question 21

Life cycle

The_____________- is more complex than that of most nematodes with its alternation between free-living and parasitic cycles, and its potential for autoinfection and multiplication within the host. Two types of cycles exist:

Answer 21

Strongyloides life cycle

Question 22

Free-living cycle:

The rhabditiform larvae passed in the stool (see “Parasitic cycle” below)
can either molt twice and become infective filariform larvae (direct development) or molt four times and become **free living adult males and females
that mate and produce eggs **from which rhabditiform larvae hatch .The latter in turn can either develop
into a new generation of free-living adults (as represented in ), or into infective filariform larvae .
The filariform larvae penetrate the human host skin to initiate the parasitic cycle (see below) .

Question 23

** Parasitic cycle:**

_____________ in contaminated soil penetrate the human skin ,
and are transported to the lungs where they penetrate the alveolar spaces; they are carried through the bronchial tree to the pharynx, are swallowed and then reach the small intestine .
In the small intestine they molt twice and become adult female worms .
The females live threaded in the epithelium of the small intestine and by parthenogenesis produce eggs ,
Which yield rhabditiform larvae. The rhabditiform larvae can either be passed in the stool
(see “Free-living cycle” above), or can cause autoinfection .

Answer 23

Filariform larvae

Question 24

______________

the rhabditiform larvae become infective filariform larvae, which can penetrate either the intestinal mucosa (internal autoinfection) or the skin of the perianal area (external autoinfection); in either case, the filariform larvae may follow the previously described route, being carried successively to the lungs, the bronchial tree, the pharynx, and the small intestine where they mature into adults; or they may disseminate widely in the body. To date, occurrence of autoinfection in humans with helminthic infections is recognized only in Strongyloides stercoralis and** Capillaria philippinensis infections. In the case ofStrongyloides, autoinfection may explain the possibility of persistent infections** for many years in persons who have not been in an endemic area and of hyperinfections in immunodepressed individuals.

Answer 24

Autoinfection:

Question 25

Alternative life cycles of rhabditiform larva

____________-Rhabditiform larva to infective filariform larva in the lumen of the intestine; penetrates the intestinal mucosa (internal autoinfection) or skin of the perianal area (external autoinfection)

Answer 25

Autoinfection

Question 26

_______________- rhabditiform larvae in the feces molts twice > filariform larvae> skin penetration

Answer 26

Direct homogenic cycle (parasitic cycle)

Question 27

______________ rhabditiform larvae molts four times > adult males and females > embryonated eggs > rhabditiform larvae hatch > filariform larvae

Answer 27

Indirect heterogenic cycle (free-living)-

Question 28

Strongyloides

Tissue changes and reactions

In the skin larval invasion produces erythema, edema, and foreign body reaction. Scratching may cause superficial ulcerations
In the blood, __________- is produced. In the late stages, ____________ may be seen
In the lungs, eosinophilic nodules may be forms with foreign body reactions due to larval penetrations or less commonly, adult worm penetrations. Inflammatory changes can occur with development of pneumonitis or bronchopneumonia. Petechial hemorrhagic areas may be present.

Answer 28

eosinophilia

Escherichia coli septicemia

Question 29

Strongyloides

In the Intestines

____________– mucosal congestion and excessive mucus secretion, hemorrhages, tiny mucosal ulcerations. Parasites are found only in intestinal crypts

Answer 29

Catarrhal enteritis

Question 30

______________- thickening of the intestinal wall by submucosal edema, swelling of the folds, and elongation of the villi, followed later by flattening and atrophy of the overlying mucosa,resembling the pattern seen in tropical sprue. Parasites may be present in all layers of the intestinal wall.

Answer 30

Edematous enteritis

Question 31

_____________– thickening of the intestinal wall by edema and fibrosis resulting in a rigid, tube like appearance of the intestine. Longstanding disease can produce irreversible mural fibrosis and a pipestem or “ribbon bowel”. Mucosal atrophy, loss of villi, and ulcers will be seen at this stage. Mucosal and

submucosal inflammation with granuloma formation and eosinophil and infiltrates are present.
Mucosal Hemorrhages and ulcerations in autopsy specimen
Numerous filariform larvae and granulomas were present in the thickened wall of the colon

Answer 31

Ulcerative enteritis

Question 32

Clinical characteristics STRONGYLOIDES

Answer 32

Frequently asymptomatic
GI-abdominal pain, diarrhea

Pulmo-innocuous cough, mild hemoptysis, Loefller’s syndrome, pneumonia, asthma
Derma- focal erythema, edema, urticarial, petechial, eruption is linear around the anus during autoinfection (larva currens)
Disseminated- in immunocompromised patients can present with abdominal pain, distention, shock, pulmonary and neurologic complications and septicemia
Blood eosinophilia- acute and chronic stages but may be absent with dissemination

Question 33

Strongyloides

Laboratory diagnosis

Microscopic ID of_____________in the stool or duodenal fluid
Stool can be examined in wet mounts

Directly
After concentration (formalin ethyl acetate)
After recovery of the larvae by the _____________
After culture of the Harada-Mori filter paper technique
After culture in agar plates

Duodenal fluid examined using Enterotest string or duodenal aspiration
Larvae may be detected in the sputum from patients with _____________
Antibody detection- immunodiagnostic test. E.g. IFA, IHA, EIA

Answer 33

larvae (rhabditiform and occasionally filariform)

Baermann funnel technique

** disseminated strongyloidiasis**

Question 34

Treatment for Strongyloides

First line:_________________ in single dose 200mcg/kg for 1 to 2 days
Alternative: Albendazole 400mg BID x 7days

Answer 34

IVERMECTIN

Question 35

What are the causative agents for TOXOCARIASIS?

Answer 35

Causative Agents

Larvae of Toxocara canis (dog roundworm) and less frequently of T. cati (cat roundworm)

Question 36

Toxocara canis accomplishes its life cycle in dogs, with humans acquiring the infection as _________

__________are shed in the feces of the definitive host .
Eggs embryonate and become infective in the environment .
Following ingestion by dogs ,
the infective eggs hatch and larvae penetrate the gut wall. In younger dogs, the larvae migrate through the lungs, bronchial tree, and esophagus; adult worms develop and oviposit in the small intestine .

In older dogs, patent infections can also occur, but _____________ is more common.

Encysted stages are reactivated in female dogs during late

pregnancy and infect by the transplacental and transmammary routes the puppies ,
in whose small intestine adult worms become established .
_____________ are a major source of environmental egg contamination.

Toxocara canis can also be transmitted through ingestion of paratenic hosts: eggs ingested by small mammals (e.g. rabbits) hatch and larvae penetrate the gut wall and migrate into various tissues where they encyst .
The life cycle is completed when dogs eat these hosts and the larvae develop into egg-laying adult worms in the small intestine. Humans are accidental hosts who become infected by ingesting infective eggs in contaminated soil
or infected paratenic hosts .
After ingestion, the eggs hatch and larvae penetrate the intestinal wall and are carried by the circulation to a wide variety of tissues (liver, heart, lungs, brain, muscle, eyes) .

While the larvae do not undergo any further development in these sites, they **can cause severe local reactions that are the basis of toxocariasis. **

Answer 36

accidental hosts.

Unembryonated eggs

larval encystment in tissues

Puppies

Question 37

The two main clinical presentations of toxocariasis are __________________Diagnosis is usually made by serology or the finding of larvae in biopsy or autopsy specimens.

Answer 37

are visceral larva migrans and ocular larva migrans.

Question 38

Laboratory diagnosis

_________(e.g. EIA) confirm clinical diagnosis of visceral larva migrans, ocular larva migrans, and convert toxocariasis

Answer 38

Antibody detection tests

Question 39

What is the treatment for Toxocariasis?

Answer 39

Treatment

For Visceral Toxocariasis:

ALBENDAZOLE 400mg BIDx5days
MEBENDAZOLE 100-200mg BIDx5days

Question 40

Also called HUMAN PINWORM
Humans are considered to be the only hosts

Answer 40

Enterobius

Question 41

What is the causative agent of Enterobius?

Answer 41

Enterobius vermicularis

Question 42

Enterobius:

Adult worms inhabit the _______________
In gravid females the uteri are tremendously distended, so that the entire body is packed woth eggs; when this happens the female migrates down the colon and out the anus to crawl on the perianal and perineal skin in female patients, at times enters vagina
The time for full development, not known precisely, is reported to be 15-43 days after ingestion of infective stage eggs
No intermediate host is required for subsequent development, and usually eggs are infective within a few hours after they are deposited
Eggs are resistant to disinfectants, and under cool, moist conditions may remain viable up to 13 days

Answer 42

cecum. Appendix, and adjacent portions of the ascending colon

Question 43

Clinical Presentation

Answer 43

Frequently asymptomatic
Nocturnal perianal pruritus
Vulvovaginitis
Pelvic or peritoneal granulomas
Anorexia, Irritability, Abdominal pain

Question 44

Answer 44

Enterobius

Question 45

Laboratory diagnosis for Enterobius

Microscopic ID of eggs collected in the perianal area

____________
__________(a paddle coated with adhesive material)
Eggs can be found in the stool but less frequently and occasionally in the urine or vaginal smears
Adult worms are also diagnostic when found in the perianal area or during ano rectal or vaginal examinations

Answer 45

“Scotch test”, cellulose-tape slide test

Anal swabs or “Swube tubes”

Question 46

Synonym

Caused by Anisakis simplex: **Herringworm disesae, **

Answer 46

ANISAKIASIS

Question 47

______________
Caused by Pseudoterranova decipiens: Codworm disease, Sealworm disease

Answer 47

Whaleworm disease

Question 48

Epidemiology

Europian countries
Asian countries
____________ is most commonly found in areas where eating raw fish is popular, such as Japan.
However, since eating undercooked fish is becoming more common, there have been cases seen in the United States, Europe, South America, and other areas of the world.
Anyone who eats undercooked or raw fish or squid is at risk.

Answer 48

Anisakiasis

Question 49

Life cycle

Adult stages of Anisakis simplex or Pseudoterranova decipiens reside in the_____________where they are embedded in the mucosa, in clusters.

Answer 49

stomach of marine mammals,

Question 50

What is the lifecycle of Anisakiasis?

Answer 50

Unembryonated eggs produced by adult females are passed in the feces of marine mammals .
The eggs become embryonated in water, and first-stage larvae are formed in the eggs.

The larvae molt, becoming second-stage larvae , and after the larvae hatch from the eggs, they become free-swimming .
Larvae released from the eggs are ingested by crustaceans .
The ingested larvae develop into third-stage larvae that are infective to fish and squid

Unembryonated eggs produced by adult females are passed in the feces of marine mammals .
The eggs become embryonated in water, and first-stage larvae are formed in the eggs. The larvae molt, becoming second-stage larvae , and after the larvae hatch from the eggs, they become free-swimming .
Larvae released from the eggs are ingested by crustaceans .
The ingested larvae develop into third-stage larvae that are infective to fish and squid .
The larvae migrate from the intestine to the tissues in the peritoneal cavity and grow up to 3 cm in length. Upon the host’s death, larvae migrate to the muscle tissues, and through predation, the larvae are transferred from fish to fish. Fish and squid maintain third-stage larvae that are infective to humans and marine mammals .
When fish or squid containing third-stage larvae are ingested by marine mammals, the larvae molt twice and develop into adult worms. The adult females produce eggs that are shed by marine mammals .
Humans become infected by eating raw or undercooked infected marine fish .

After ingestion, the anisakid larvae penetrate the gastric and intestinal mucosa, causing the symptoms of anisakiasis.

nd squid .
The larvae migrate from the intestine to the tissues in the peritoneal cavity and grow up to 3 cm in length. Upon the host’s death, larvae migrate to the muscle tissues, and through predation, the larvae are transferred from fish to fish. Fish and squid maintain third-stage larvae that are infective to humans and marine mammals .
When fish or squid containing third-stage larvae are ingested by marine mammals, the larvae molt twice and develop into adult worms. The adult females produce eggs that are shed by marine mammals .
Humans become infected by eating raw or undercooked infected marine fish .

After ingestion, the anisakid larvae penetrate the gastric and intestinal mucosa, causing the symptoms of anisakiasis.

Question 51

Pathology

Human infections are all due to ingestion of larvae
Retrograde migration up to esophagus may cause tingling of the throat, inducing coughing and expectoration
Larvae attach to the mucosa of stomach and small bowel
L3 larva

Answer 51

ANiSAKIASIS

Question 52

Laboratory Diagnosis Anisakiasis

Larva from patient’s_____________ or during endoscopy or surgery
___________ of choice for both intestinal and Gastric anisakiasis
Anisakis= thin white string
Pseudoterranova sp= broader, yellowis brown

Answer 52

vomitus and stoo

lEndoscopy procedure

Question 53

Clinical Characteristics

More common in males (3:1) and in the 20-50 years group
Found where fish is eaten raw (Japanese “sashimi, sushi, sunomono” or Peruvian “ceviche”, insufficiently salted or pickeled (Dutch or German “green herring”) or undercooked (nouvelle cuisine)
Preponderance of gastric anisakiasis in Japan is due to low levels of hydrochloric acid in their stomach and custom of eating raw seafood with alcohol
Gastric symptoms begin 1 to 24hrs after ingesting infected seafood, resembles peptic ulcer or neoplasm with complaints of severe epigastric pain, nausea and vomiting and occasionally diarrhea
Loss of appetite and weight , recurrent epigastric pain
Intestinal symptoms occurs after one or few weeks of incubation
There may be violent colicky abdominal pain, nausea, vomiting, diarrhea, bloating and low fever
Abdominal tenderness is common and is often localized to the right lower quadrant: acute appendicitis is often suspected
Abdominal distention and transient attacks of crampy lower abdominal pain with intermittent slimy diarrhea and weight loss

Answer 53

Anisakiasis

Question 54

_____________ is a constant finding in anisakiasis

Answer 54

Blood within the stool

Question 55

Treatment of Anisakiasis

Removal of the worm by _____________-= both diagnostic and treatment
Surgery for intestinal and extraintestinal infections when intestinal obstruction, peritonitis and appendicitis may occurs

ALBENDAZOLE 400mg BIDx6-21days in cases with presumptive diagnoses

Answer 55

endoscopy

Question 56

• ___________ - a protozoan found worldwide, causing amebiasis
• Humans and perhaps nonhuman primates are the only natural hosts
• Highest prevalence of amebiasis in developing countries where barriers between human feces and food and water supplies are inadequate
• Most cases of amebiasis asymptomatic, but dysentery and invasive extraintestinal disease can occur

Answer 56

Entamoeba histolytica

Question 57

• ______________– most common manifestation of invasive amebiasis
• Other organs may be involved, including pleuropulmonary, cardiac, cerebral, renal, genitourinary, and cutaneous sites
• In developed countries, primarily affects migrants from and travelers to endemic regions, men who have sex with men, and immunosuppressed or institutionalized individuals

Answer 57

Amebic liver abscess

Question 58

• E histolytica transmitted via ingestion of the ____________- (infective stage)
• Cysts viable in the environment for weeks to months, can be found in fecally contaminated soil, fertilizer, or water or on the contaminated hands of food handlers
• Fecal-oral transmission can also occur in the setting of anal sexual practices or direct rectal inoculation through colonic irrigation devices

Answer 58

cystic form

Question 59

• Excystation then occurs in the terminal ileum or colon, resulting in_____________-
• This can penetrate and invade the colonic mucosal barrier, leading to tissue destruction, secretory bloody diarrhea, and colitis resembling inflammatory bowel disease
• This can spread hematogenously via the portal circulation to the liver or even to more distant organs

Answer 59

trophozoites (invasive form)

Question 60

•Ingestion of E histolytica cysts from the environment followed by excystation in the terminal ileum or colon to form highly motile trophozoites
•Upon colonization of the colonic mucosa, the trophozoite may:
–encyst and is then excreted in the feces or
–may invade the intestinal mucosal barrier and gain access to the blood stream and disseminate to the liver, lung, and other sites
•Excreted cysts reach the environment to complete the cycle.