NEMATODES II Flashcards
Causative Agent of Capillaria?
Capillaria hepatica and Capillaria philippinensis
What are the synonyms of Capillaria?
Synonyms
Intestinal capillariasis
Capillariasis philippinensis
Wasting disease
Pudoc mystery disease
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
Capillaria
What is the life cycle of Capillaria?
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)
___________ is currently considered a parasite of fish eating birds, which seem to be the natural definitive host
Capillaria philippinesis
CAPILLARIA:
____________ as intermediate host and
____________ as the usual definitive host
Small fresh or brackish water fish** fish eating birds**
Raw fresh-water fish_____________ are found in endemic areas of Capillaria are
“BIRUT”,”BAGSANG”, “BAGSIC”
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
jejunum
** one to two months **
Laboratory Diagnosis for Capillaria
Definitive diagnosis is finding the characteristic ova in the ________
stool
capillaria
peanut shaped with flattened bipolar plugs and a striated egg shell.
Capillaria egg
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
Capillaria
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
Capillaria
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
borborygmi and vague abdominal pain
Wh are the differential diagnosis of Capillaria?
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
Treatment for Capillaria DOC:
________200 MG BIDx20-30 days
MEBENDAZOL
NOTE: Alternative: Albendazole 400 mg ODx10 days
Causative agent of Strongyloidis
Strongyloides stercoralis
What are the synonyms for Strongyloides?
Synonyms
Strongyloidosis
Strongulosis
Strongyliasis
Cochin China diarrhea
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
Strongyloides stercoralis
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:
Strongyloides life cycle
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) .
** 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 .
Filariform larvae
______________
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.
Autoinfection:
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)
Autoinfection
_______________- rhabditiform larvae in the feces molts twice > filariform larvae> skin penetration
Direct homogenic cycle (parasitic cycle)
______________ rhabditiform larvae molts four times > adult males and females > embryonated eggs > rhabditiform larvae hatch > filariform larvae
Indirect heterogenic cycle (free-living)-
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.
eosinophilia
Escherichia coli septicemia
Strongyloides
In the Intestines
____________– mucosal congestion and excessive mucus secretion, hemorrhages, tiny mucosal ulcerations. Parasites are found only in intestinal crypts
Catarrhal enteritis
______________- 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.
Edematous enteritis
_____________– 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
Ulcerative enteritis
Clinical characteristics STRONGYLOIDES
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
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
larvae (rhabditiform and occasionally filariform)
Baermann funnel technique
** disseminated strongyloidiasis**
Treatment for Strongyloides
First line:_________________ in single dose 200mcg/kg for 1 to 2 days
Alternative: Albendazole 400mg BID x 7days
IVERMECTIN
What are the causative agents for TOXOCARIASIS?
Causative Agents
Larvae of Toxocara canis (dog roundworm) and less frequently of T. cati (cat roundworm)
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. **
accidental hosts.
Unembryonated eggs
larval encystment in tissues
Puppies
The two main clinical presentations of toxocariasis are __________________Diagnosis is usually made by serology or the finding of larvae in biopsy or autopsy specimens.
are visceral larva migrans and ocular larva migrans.
Laboratory diagnosis
_________(e.g. EIA) confirm clinical diagnosis of visceral larva migrans, ocular larva migrans, and convert toxocariasis
Antibody detection tests
What is the treatment for Toxocariasis?
Treatment
For Visceral Toxocariasis:
ALBENDAZOLE 400mg BIDx5days
MEBENDAZOLE 100-200mg BIDx5days
Also called HUMAN PINWORM
Humans are considered to be the only hosts
Enterobius
What is the causative agent of Enterobius?
Enterobius vermicularis
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
cecum. Appendix, and adjacent portions of the ascending colon
Clinical Presentation
Frequently asymptomatic
Nocturnal perianal pruritus
Vulvovaginitis
Pelvic or peritoneal granulomas
Anorexia, Irritability, Abdominal pain
Enterobius
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
“Scotch test”, cellulose-tape slide test
Anal swabs or “Swube tubes”
Synonym
Caused by Anisakis simplex: **Herringworm disesae, **
ANISAKIASIS
______________
Caused by Pseudoterranova decipiens: Codworm disease, Sealworm disease
Whaleworm disease
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.
Anisakiasis
Life cycle
Adult stages of Anisakis simplex or Pseudoterranova decipiens reside in the_____________where they are embedded in the mucosa, in clusters.
stomach of marine mammals,
What is the lifecycle of Anisakiasis?
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.
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
ANiSAKIASIS
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
vomitus and stoo
lEndoscopy procedure
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
Anisakiasis
_____________ is a constant finding in anisakiasis
Blood within the stool
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
endoscopy
- ___________ - 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
Entamoeba histolytica
- ______________– 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
Amebic liver abscess
- 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
cystic form
- 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
trophozoites (invasive form)
•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.
