Trematodes.docx

7/22/2019 Trematodes.docx

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TREMATODES

General Characteristics

Flattened dorsally, leaf-like, elongated and unsegmented

ovoid, conical or cylindrical depending upon the state of contraction

vary in size from less than 1 mm to several cm covered by non-cellular integument, which maybe covered with

spines or tubercles

Integument: absorption of carbohydrates and may also serve for

secretion of excess metabolites and mucus.

most distinguishing characteristic of adult trematodes: oral suckers:

attachment to the host.

o oral sucker: anterior end

o ventral sucker or acetabulum: larger, blind, located at

ventral surface; posterior to the oral sucker

Digestive system:

o Incomplete

o with mouth

o no anus

o muscular, globular pharynx extends from the mouth in the

oral sucker to a short narrow esophagus

o Below the esophagus, the intestine bifurcates into two

o Intestines:

branched/dendritic

simple

Excretory system:

o diffusely scattered flame cells or solenocytes

o capillaries, collecting tubules, bladder and excretory pore

o The terminal flame cell is a hollow cell with tuft of cilia. Primitive Nervous system:

o two lateral ganglia in the region of pharynx connected by

dorsal commisures.

o From each ganglia arise anterior and posterior longitudinal

nerve trunks connected by numerous commisures.

Hermaphroditic (all trematodes are hermaphroditic except the

BLOOD FLUKES)

LIFECYCLE:

1) adult fluke lays eggs (passed in stool)

2) eggs in watermiracidium (ciliated larva)

3) miracidium ingested by 1st

IH (snail) sporocyst

4) sporocyst redia cercaria (leaves snail) encysts as metacercaria

5) metacercaria: 2nd

IH: water plants, fish, crustacean (crab/crayfish)

6) metacercaria in 2nd

IH is consumed by man

Classification of TrematodesAccording to habitat

Portal vein (Blood Flukes)

Schistosoma japonicum- Oriental blood fluke

Schistosoma haematobium - Vesical blood fluke

Schistosoma mansoni- Mansons blood fluke

Lungs

Paragonimus westermani Oriental lung fluke

Liver and bile passages

Fasciola hepatica Giant or Sheep liver f luke

Clonorchis sinensis Chinese or Oriental liver fluke

Opistorchis felineus Cat liver flukeIntestine

Fasciolopsis buski Giant intestinal fluke

Echinostoma ilocanumGarrisons fluke

Heterophyds

Heterophyes heterophyes Von Siebold fluke

Metagonimus yokogawai

Haplorchis taichu

BLOOD FLUKES:

Schistosoma japonicum

CN: Oriental Blood Fluke

Habitat: superior mesenteric vein of Small Intestines

IS: forked tail cercaria

MOT: skin penetration

Final Hosts: Man

Disease caused:

Oriental schistosomiasis, Intestinal schistosomiasis, Hepatic

schistosomiasis

Schistosomiasis japonica

Katayamas disease


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Schistosoma mansoni

CN: Mansons Blood Fluke

Habitat: mesenteric vein of Large Intestines


MOT: skin penetrationFinal Hosts: Man

Disease caused:

Schistosomiasis mansoni

Rectal/Intestinal schistosomiasis

Schistosomia hematobium

CN: Vesical Blood Fluke

Habitat: portal vein of the urinary bladder


MOT: skin penetration

Final Hosts: Man

Disease caused:

Vesical schistosomiasisBilharziasis

Urinary schistosomiasis

MORPHOLOGY

Schistosoma japonicum adult is provided with smooth tuberculations.

The male have 6 9 testes arranged in rows. The ovary of the female

lies somewhat behind the mid plane of the body and the uterus can

have 50 eggs at one time

Schistosoma mansoni is provided with coarse tuberculations. Male has

6 8 testes while the ovary of the female is situated in the anterior half

of the body. The uterus is short with 20 40 eggs.

Schistosoma haematobium is provided with fine tuberculations, wherein

the ventral sucker is larger than the oral sucker. The number of testes in

male is 4 5 . The ovary of the female is posteriorly located. The

number of eggs in the uterus is 20 100.

EGGS:

Schistosoma japonicum eggs are ovoidal, non operculated. 70 90

micra by 50 65 micra. A rudimentary or minute lateral spine is present.

Schistosoma mansoni eggs are elongated, non operculated.114 175

micra with transparent shell and a prominent lateral spine

Schistosoma haematobium eggs are elongated, non-operculated, light

yellowish brown and possess a distinct terminal spine

LIFE CYCLE

Eggs miracidia (ciliated larva) sporocyst (1st

IH: snail) redia

cercaria (leaves snail) metacercaria (2nd

IH: fresh water plant, fish,

crustacean)man

PATHOGENESIS

Symptoms associated with schistosomiasis include weakness, diarrhea,

hepatosplenomegaly, and carcinoma of the intestine, liver, uterus and

urinary bladder

Treatment: Praziquantel & Niridazole

Sch is tosoma japon icum and Sch is t osoma manson i

Site of entry: Pruritus and rashes = swimmers itch

Migration of the adolescent in the lungs: pneumonitis (Pulmonaryschistosomiasis.)

Deposition of eggs in the tissues: irritation and formation of ulcersin the mucosa leading to the escape of the eggs into the intestinallumen.

Ulceration in mucosa: diarrhea or dysentery seen in acuteschistosomiasis

Granuloma of affected tissue and organ is also evident:o obstructions to the pulmonary circulationo formation of pseudotubercle in affected organs/tissues

maybe observedo Schistosomiasis japonica depending on the major sites of

eggs deposition maybe hepato-intestinal, hepato-splenicor pulmonary.The clinical course of infection is divided into

three progressive stages: Incubation: corresponding to the period from the cercarial

penetration and schistosomular migration to the time the flukesmature

period of early egg deposition and extrusion

period of tissue proliferation

Schis tosoma hematobium

lives primarily in the pelvic veins:

o eggs are primarily deposited in the vessical plexus =


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lesions in the urinary bladder, genitalia (seminal

vesicle, vulva, cervix and vaginal walls)

Uric acid and oxalate crystals, phospate deposits,

eggs, blood clots, mucus and pus maybe present

in urine

** most characteristic symptom is hematuria (blood in the urine) mucosal surfaces become inflamed = painful micturation/urination

and a constant urinary residual. Pain in the suprapubic region and

weakness may occur.

LUNG FLUKE:

Paragonimus westermani

CN: Oriental Lung FlukeHabitat: lungs1

stIH: snail =Antemelania asperata (formerly Brotia asperata),

Antemelania dactylus2

ndIH: crab = Sundathelpusa philippina (formerly Parathelpusa

grapsoides)Infective Stage: encysted metacercaria within 2

ndIH

MOT: ingestion of metacercaria in 2nd

IHFinal Hosts: ManDisease caused:

ParagonimiasisPulmonary distosomiasisEndemic hemoptysis

Morphology

Adult worm:

reddish-brown

7 12 mm length, 46 mm in width and 3.5 5 mm in thickness

cuticle is spinous

oral and ventral suckers are of equal size

intestinal ceca are simple

two testes are deeply lobed, situated opposite each other

ovary has 6 unbranched lobes and is anterior to the testes

shape of adult:

When Active - Spoon-shaped, with one end contracted and theother elongated

When preserved - Oval, flattened, coffee bean shapedPersist in humans for as long as 20 years or more.

Animal reservoir hosts of this parasite include: dogs, cats, field rats andother rodents.

LIFE CYCLE

cercaria leaves snail in about 13 weeks and penetrate 2nd

IH:freshwater crab or crayfish = Sundathelphusa philippina (formerlyParathelphusa grapsoides)

** cercaria penetrates through the soft parts of the body of the craband encysts as metacercaria in the gills, legs, body muscles or theviscera

** definitive host acquires the infection by ingestion of raw orinsufficiently cooked infected crabs

upon ingestion: excysted metacercaria pass through the duodenalwall into the abdominal cavity

adolescent worms: burrows through diaphragm, enter thepleural cavity and in 20 days reach the lungs and become adult in 5 6 weeks

in prolonged migration: adolescent worms mayo remain for long period in the peritoneumo enter and leave the livero lodged in organs (rare cases)

Pathogenesis : PARAGONIMIASIS

Lungs:

o parasite causes development of a fibrous tissue capsule

o FIBROUS TISSUE CAPSULE: (within this cyst) = blood

tinged, purulent material containing eggs

o

Early Infection: dry cough

o Later part: bloodstained, rusty brown sputum (most

pronounced on rising in the morning)

o Pulmonary pain and hemoptysis occurs

o ** Along with these symptoms, the patient may experience

fever, sweating, chest pains, cough = MIMICS symptoms

of PTB


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o ** hard to distinguish from pulmonary tuberculosis,

pneumonia and bronchitis

Cyst formation:

o **localize in the abdominal wall, abdominal cavity,

mesenteric lymph nodes, omentum, pericardium, and

myocardium and in intestinal wall

o abdominal pain, rigidity and tenderness

In the brain:

Jacksonian epilepsy

Visual disturbances

Worms situated in the subcutaneous tissue cause creeping tumor

Identification of eggs in:

Sputum

Bronchial washingFeces

Treatment:Praziquantel, Emetine hydrochloride &Bithionol

LIVER FLUKES:

Fasciola hepatica

CN: Sheeps Liver Fluke, Giant Liver Fluke

Habitat: liver, bile ducts

1st

IH: snail = Lymnae philippinensis, Lymnae swinhoe and Lymnae

truncatula

2nd

IH: aquatic plants

Infective Stage: forked tail cercaria


IH: aquatic vegatation

Final Hosts: Man

Disease caused:

Sheep Liver Rot

Fascioliasis

Morphology

largest fluke infecting man

Adult:

large, flat, leaf-like

20 50 mm in length and 6 12 mm in width

anterior end: conical projection (cephalic cone) and a characteristic

shouldered appearance is also observed **which serve as

distinguishing features

posterior end: broadly pointed

o two relatively small suckerso intestinal ceca are highly branched or dendritic.

o two deeply branched or dendritic testes

o single dendritic ovary

Related species: Fasc iola gigant ica

which commonly infects cattle, water buffaloes and carabaos, is

larger, more lanceolate than F. hepatica.


shorter cephalic cone, less developed shoulders, a larger ventral

sucker and the intestinal ceca is more branched.

EGGS

large, ovoid, operculated, yellowish brown

well rounded posterior end

characteristically hen-egg shaped

140 180 by 80 100 microns and is unsegmented at oviposition

LIFECYCLE

eggs are passed out in the feces and mature in water

miracidium is formed within 9 15 days.

miracidium escapes through the operculum and invade the 1st

intermediate host: snails =

o Lymnae philippinensis

o Lymnae swinhoe

o Lymnae truncatula

Inside the snail intermediate host:o sporocyst one or two generations of rediae cercaria.

Cercaria: emerge from the snail and attach by way of their oral

sucker on the surface of 2ng IH: aquatic vegetation(watercress)

where they develop into metacercaria.

o Ipomea obscura or kangkong

o Ipomea reptans or morning glory

Definitive Host:

o metacercaria excyst in the duodenum, liberating the

juvenile flukes penetrate intestinal wall peritoneal


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cavity viscera liver capsule burrows through the

liver parenchyma bile ducts where it matures in 3 4

months

o The adult worm survives for as long as 11 years in

definitive host.

This parasite infects herbivorous mammals like sheep, cattle,deer and rabbits while man serve as occasional host. The

adult worm inhabits the biliary passages in the liver.

On the other hand the first intermediate host ofFasc iola

gigant icais Lymnae rub ig inosa.

Pathogenesis: Fascioliasis

Latent or chronic phase

period when the parasite has already settled in the bile

ducts

Clinical manifestations:

adult causes obstruction of bile ducts

inflammation on the epithelium of the bile duct

stimulating pipestem fibrosis

Pharyngeal Fascioliasis or Halzoun:

result from ingestion of raw sheep liver or goat liver

containing the adult parasite

attachment of the worm in the pharyngeal mucosa

may result to asphyxiation (suffocation).

Diagnosis: Fascioliasis

recovery of the eggs in the patients stool

Fasciola eggs maybe present in stool of individual who has earlier

consumed infected animal liver (False fascioliasis)

ruled out by keeping the patient on a liver f ree diet for three to 7

days before another stool examination is done. Immunodiagnostic tests:

o CFT, precipitin test, immunoelectrophoresis, counter

immunoelectrophoresis

o FAST (Falcon Assay Screening Test)-EIA alone or in

combination with EITB can detect F. hepatica excretory-

secretory antigens in serum

o EIA with somatic antigen or excretory-secretory antigens

from F. gigantica orF. hepatica (especially excretory-

secretory products), yield high sensitivity, including

detection of reactive IgM in acute fascioliasis and

confirmation by enzyme-linked immunoelectrotransfer blot

(EITB).

Treatment: Bithionol

LIVER FLUKES:

Clonorchis sinensisCN: Chinese Liver Fluke, Oriental Liver Fluke

Habitat: bile ducts; gall bladder, pancreatic duct (heavy infection)

** NOT FOUND IN DUODENUM because it can only survive

the presence of digestive juices for only a few hours

1st

IH: snail = Parafossarulus manchoricus

2nd

IH: = Ctenopharyngodon idellus (f ish), Caridina nilotica gracilipes

(shrimp)

Infective Stage: metacercaria in 2nd

IH

Diagnostic Stage: egg/ova in stool


IH:

Final Hosts: Man, dogs, cats, pigs, ducks (rare occasion)

** a parasite of fish-eating mammalsDisease caused:

Clonorchiasis

1stIH:Parafossarulus manchoricus snails that live in fish culture ponds,

lakes, swamps, and sluggish parts of the river or small streams

2ndIH:Ctenopharyngodon idellus= aka Grass Carp: herbivorous freshwater

fish

Caridina nilotica gracilipes= aka Freshwater shrimp

Adult:

flat, elongated, aspinous, and transparent gray

tapering anteriorly and somewhat rounded posteriorly

8 25 mm in length and 1.5 5 mm in width.

ventral sucker is smaller than the oral sucker.

intestinal ceca: long, simple extending to the posterior end

two deeply branched testes in tandem formation are

situated in the posterior part of the body

single ovary is relatively small with three lobes and located

anterior to the testes

The entire life cycle can be completed in three months. The life span of the

adult is 15 20 years.

LIFE CYCLE:


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free-swimming cercaria dies within 24 48 hours unless ingested

by freshwater fish (2nd

IH): Ctenopharyngodon idellus, Caridina

nilotica gracilipes

Inside 2nd

IH:

o metacercaria encyst chiefly in the muscles and

subcutaneous tissues, less often on the scales, fins andgills of fish.

Infected fish is eaten by the mammalian definitive host:

o metacercaria excyst in the duodenum

o In the human duodenum:

outer wall is dissolved by t rypsin

inner layer is ruptured by the activity of the

metacercaria

freed larva migrates to:

common bile duct

distal biliary ducts: maturation in a

month

Pathogenesis: Clonorchiasis

Eggs are associated with formation of gallstones

Diet affects chronic infections:

o Increased intake of dimethylnitrosamines (in fermented

fish) usually leads to cholangiocarcinoma (neoplasia of the

liver)

Symptoms:

o fatigue, weakness, weight loss, abdominal distress and

altered appetite

o fever, enlargement and tenderness of the liver and

eosinophilia (acute infection)o anemia, liver enlargement, slight jaundice, edema and

diarrhea (heavy infection)

Diagnosis:

o Identification of characteristic eggs in the feces

o Immunodiagnostic test and liver scan

Treatment: Praziquantel

LIVER FLUKES:

Opistorchis felineus

CN: Cat Liver Fluke

Habitat: biliary passages

1st

IH: snail = Bythinia leachi

2nd

IH fish: = Idus melanotus, Tinca tinca, and Cyprinus carpio, Barbus

barbus


IHDiagnostic Stage: egg/ova in stool


IH

Final Hosts: Man

Disease caused:

Opistorchiasis felineus

Adult:

reddish yellow

Lancet shaped

712 mm in length and 1.5 3 mm in width

intestinal ceca is simple

two testes are lobate and arranged obliquely in tandem (in

pairs)

oral sucker is smaller than the ventral sucker

single ovary is lobed

A closely related species infecting man: Opistorchis viverrini= differentiated

from Opistorchis felineus:- ovary and testes are nearer to each other, both of

which are more deeply lobulated - testes are obliquely arranged

EGGS

yellowish-brown, ovoid and is smaller than Clonorchis sinensis ova

With operculum that sits on the thickened rim and a minute

aboperculum is also present

o LIFE CYCLE: Same as Clonorchis sinensis differs only in

the specific species as intermediate hostso Pathogenesis: Opistochiasis felineus

clinical involvement depends largely on worm burden and the

duration of the infection.

Moderate infections: (about 100-1000 worms)

o enlargement of the liver, passive congestion of the spleen,

with icterus and local eosinophilia in the wall of the bile

ducts

In heavier infections:


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o Worms found in the pancreas and the gall bladder and the

patient suffers from digestive disturbances

o Bile stones maybe formed around the parasite eggs

Opistorchis has been linked to carcinoma of the bile ducts and the

liver

Diagnosis: identification of egg/ova in the stoolTreatment: Praziquantel

INTESTINAL FLUKES:

Fasciolopsis buski

CN: Giant Intestinal Fluke

Habitat: duodenum and jejunum

1st

IH: snail = Segmentina trochoideus orHippeutis umbilicalis

2nd

IH aquatic plants: = Trapa bicornis (water caltrop), Eliocharis

tuberosa (water chestnut), Ipomea aquatica (water morning glory) and

Nymphae lotus (lotus)


IH


MOT: ingestion of metacercaria in 2nd IHFinal Hosts: Man

Disease caused:

Fasciolopsiasis

Morphology

20 70 mm in length, 8 20 mm in width

elongated and oval in shape

oral sucker is about one- fourth the size of the nearby ventral

sucker.

This fluke resembles Fasciola hepatica:

o Differentiation:

No cephalic cone

shoulder and the intestinal ceca are simple but

wavy and unbranched

testes are highly dendritic in tandem formation

single ovary is branched

EGGS

yellowish ellipsoidal

thin-shelled, rounded at both ends and operculated

80 85 micra

The adult inhabits the small intestine particularly the duodenum and the

jejunum. It is either attached to the intestinal mucosa by the ventral

sucker or lies buried in the mucous secretions. Each adult produces an

average of 16,000 eggs per day.

LIFECYCLE:

Each adult produces an average of 16,000 eggs per day. egg is undeveloped when passed in the feces

In water: eggs miracidium (3 7 weeks)

Miracidium penetrate the 1st

IH (snail): Segmentina trochoideus

orHippeutis umbilicalis

In the snail intermediate host:

o Miracidium sporocyst rediae 1 rediae 2

cercaria

Cercaria will leave the body of the 1st

intermediate host (4 7

weeks) encyst on the surfaces of the 2nd

IH (aquatic plants):

Trapa bicornis (water caltrop), Eliocharis tuberosa (water

chestnut), Ipomea aquatica (water morning glory) and

Nymphae lotus (lotus)

Metacercaria in 2nd

IH are ingested by man

metacercaria excyst in the duodenum and attach themselves

to the intestinal wall and becomes an adult worm in about three

months.

Pathogenesis: Fasciolopsiasis

Pathology maybe due to the following:

Traumatic

inflammation and ulceration at the site of attachment

increase mucus secretion and minimal bleeding

Epigastric pain, nausea and diarrhea may occur especially in

the morning.Obstructive

In heavy infections: edema and partial intestinal obstruction

due to the large size of the worm

Toxic

Intoxication occurs: absorption of the worms excess

metabolites and excretory by-products which become

systematic upon absorption

generalized toxic and allergic symptoms

profound intoxication may result in death


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Treatment: Praziquantel,

Niclosamide,Tetrachloroethylene,Hexylresorcinol,Dichlorophen

INTESTINAL FLUKES:

Echinostoma spp.

Echinostoma:

medium sizedadult worms: unique due to the presence of collar of spines

around the oral sucker

Many species have been reported in man and are differentiated on

the basis of number of spines and number of lobes in testes

In the Philippines:

Echinostoma ilocanum

Echinostoma malayanum

Echinostoma ilocanum

CN: Garrisons Fluke

Habitat: small intestines

1st

IH: snail = Gyraulus convexiusculus orHippeutis umbilicalis

(IN THE PHILIPPINES)2

ndIH snail = Pila luzonica or kuhol and Vivipara angularis or susong

pampang


IH



IH

Final Hosts: Man

Disease caused:

Human Echinostomiasis

Echinostoma malayanum

Habitat: small intestines

1st IH: snail = unkown (IN THE PHILIPPINES)

2nd

IH snail = Lymnae cumingiana or birabid (formerly Bullastra

cumingiana), Radix quadrasiand Physastra hungerfordiana


IH



IH

Final Hosts: Man

Disease caused:

Human Echinostomiasis

Morphology: Echinostoma ilocanum

reddish gray

2.5 6.5 mm in length, 1 1.5 mm in width

anterior end: horseshoe-shaped collar of spines (Collarette of

spines) = circumoral disk surrounded with 49 51 spines in

two rows

oral sucker found at center of this disk Testes: bilobed, in tandem formation

Ovary: globular, anterior to the testes

Morphology:Echinostoma malayanum


Elongated, bluntly rounded ends

43 45 collar of spines

multilobulated testes (6 9 lobes) in tandem formation

ovary is small, rounded or oval

Echinostom a i locanumova:

86116 micra by 5869 micra straw-colored, operculated ovoidal and with

characteristic germ ball

Echinostom a malayanumova:

Larger than Echinostoma ilocanum

120 130 micra by 80 90 micra

operculated with characteristic germ ball

LIFECYCLE:

immature eggs are passed out with the feces

ova mature within 6 15 days miracidium enters the 1st

IH:

forEchinostoma ilocanum: Gyraulus convexiusculus or

Hippeutis umbilicalis

forEchinostoma malayanum: unknownInside the snail intermediate host: miracidium redia 1 redia 2

cercaria

Cercaria escape from the snail 42 50 days to infect the 2nd

IH:

also a snail:

Echinostoma ilocanum:

Pila luzonica orkuhol

Vivipara angularis orsusong pampang

Echinostoma malayanum:

Lymnae cumingiana


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Radix quadrasi

Physastra hungerfordiana

cercariametacercaria

man ingests metacercaria by eating infected snail

metacercaria excyst in the duodenum and the adult fluke attaches itself

to the intestinal wallPathogenesis: Echinostomiasis

little damage to the intestinal mucosa: inflammation at the site of

attachment

In heavy infections:

diarrhea, bloody diarrhea

abdominal pain

General intoxication: absorption of the metabolites of the worms

Diagnosis: identification of eggs/ova in stool

Treatment: Praziquantel & Hexylresorcinol

INTESTINAL FLUKES:

Heterophyds

Family Heterophydiae:

Heterophyes heterophyes


Haplorchis taichu

Adult Heterophyds:

elongated, oval or pyriform in shape

the smallest yet the deadliest: less than 2 mm in length

HABITAT: Small Intestines

Morphology:

Heterophyes heterophyes

CN: Von Siebolds Fluke

Adult:

Grayish

smallest fluke of man: 1.3 by 0.5 mm

oral sucker is very small

ventral sucker is large, situated in the anterior middle-third of the

body

conspicuous genital sucker (gonotyle) found in the lateral

posterior border of the ventral sucker

two testes: ovoid, side by side in the posterior fifth of the body

ovary: subglobuse, anterior to the testes

Morphology:


Adult:

1.4 by 0.6 mm.

large ventral sucker is situated to the right of the midline two oval testes: unequal in size, arranged obliquely side by side

and situated in the posterior third of the body

ovary: globuse, situated at the junction of the middle and lower third

of the body

Morphology:

Haplorchis taichu

Adult:

large ventral sucker

a globuse ovary

only one testis

EGGS

light yellow brown

ovoidal, operculated

smallest trematode egg: 20 30 by 15 17 micra

Shell:

o slight shoulder at the rim of the operculum

o knob at the posterior pole maybe occasionally observed

fully developed miracidium already present within the egg when it is

deposited by the adult worm

LIFECYCLE:

eggs are passed out into the environment with the feces

Eggs ingested by 1st

IH: fresh water snail

o The first intermediate host of the species of Heterophydsare:

H. heteophyes:

Pironella conica

Cerithidia cingula

M. yokogawai :

Semisulcospira, Thiara and Hua

H. taichu

Melania juncea, Thiara riquetti


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Inside the 1st

IH: eggs sporocyst one or two generations of

rediae cercaria

Cercaria, that emerge from the snails and penetrate 2nd

IH: a

suitable fish species

The second intermediate hosts are:

H. heterophyes: Mugil, Salmo, Acanthogobius M. yokogawai : Plecoglossus, Salmo, Richarsonium,

Odontobutis

H. taichu:

Ambassis burensis (langaray)

Amphacathus jacus (samaral)

Anabas testidineus (martiniko)

Arius manilensis (kanduli)

Claris batrachus (hito)

Gerris kapas (malakapas)

o Glossogonius giurus (bia)

o

Hemiramphus georgii (cansusuit or bugning)o Ophiocephalus striatus (dalag)

o Pelates quarilineatus (babansi)

o Therapon plumbeus (ayungin)

Metacercaria:

o encyst on or under the scales, in muscles, fins tails or gills

of the second intermediate host

o Man ingests metacercaria:

raw or insufficiently cooked infected fish is

ingested by the definitive host

metacercaria escapes from the cyst adult

worm (1week) and attaches itself to the intestinal

wall Pathogenesis:inflammation at the site of attachment causing

damage to the intestinal mucosa = mucoid diarrhea

colicky pain: severe abdominal pain caused by spasm, obstruction

or distention of any hollow viscera (ex. Intestines)

adult worm:

may burrow deep into the intestinal wall = become trapped

and eventually die

eggs of the degenerating worms:

blood stream and lymphatics: carried to the different parts

of the body

heart muscles: cardiac failure resembling that of cardiac

beri-beri

brain: fatal cerebral hemorrhage

spinal cord: loss of motor and sensory functions at thelevels where the lesions are located

Diagnosis: identification of eggs/ova in stool

Treatment: Praziquantel & Tetrachloroethylene

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Trematodes.docx