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PARASITES BIOLOGY MOT HOST PATHOGENESIS DIAGNOSIS & TREATMENT GEOGRAPICAL DIS. &EPIDEMIOLOGYBlood flukes Schistosoma japonicum-separate sexes -parasitic in vascular system -female is cylindrical, longer than male and caried in its gynaecophoric canal -several testes are located behin...

Description

Parasitology: Trematodes Infections PARASITES Blood flukes Schistosoma japonicum

BIOLOGY

-separate sexes -parasitic in vascular system -female is cylindrical, longer than male and caried in its gynaecophoric canal -several testes are located behind the acetabulum

MOT

Penetration of the skin by cercariae

HOST

IH: Oncomelania hupensis quadrasi DH: Human

Eggs: ovoid, round, or pearshaped, and is pale yellow: rudimentary lateral spine: has a thin shell onto which residual tissue or red cells may be adherent

Schistosoma haematobium

Egg:

Same as S. japonicum

IH: Bulinus snail DH: Human

Schistosoma mansoni

Egg:

Same as S. japonicum

IH: Biomphalaria snail DH: Human

PATHOGENESIS

DIAGNOSIS & TREATMENT

-Symptoms of schistosomiasis are not caused by the worms themselves but by the body’s reaction to the eggs -swimmer’s itch -Acute schistosomiasis (Katayama fever) - systemic symptoms/signs including fever, cough, abdominal pain, diarrhea, hepatosplenomegaly, and eosinophilia. -aberrant migration of maturing schistosomula occlude the circulation of brain and spinal cord precipitating seizure, paresthesias, transient ischemic attack, and strokes. - Chronic schistosomiasis include granulomatous reactions to egg deposited in the liver and other organs -pulmonary hypertension

Microscopic examinations – most specific MIFC – only for moderate and heavy infection Kato-katz – most suitable for eggs quantification Rectal snips and imprints Immunodiagnostic • intradermal test • indirect hemagglutination • COPT • ELISA

causes urinary schistosomiasis, schistosomal hematuria, vesical schistosomiasis, or urinary bilharziasis

Specific •

- skin rash after cercarial penetration - flukes acquire host antigen protecting them from host immune response - eggs penetrate through the intestinal wall and are excreted in the feces often with blood and mucus - host reaction to eggs leads to the formation of granulomata, ulceration, and thickening of the bowel wall - a proportion of the eggs reach the liver through the portal vein - reaction to the eggs causes thickening of the portal vessels known as claypi pe-stem fibrosis - hepatomegaly with fibrosis - splenomegaly - portal hypertension - ascites - ova can be deposited in the spinal cord, lungs, and other organs of the body Salmonella infections can become chronic and prolonged

GEOGRAPICAL DIS. & EPIDEMIOLOGY Asia only: China, Indonesia, the Philippines and Thailand In PH, endemic in 12 regions covering 28 provinces, 190 municipalities, 15 cities, and 2,222 barangays.

TREATMENT - Praziquantrel 40-50 mg/kg - Single dose 25 mg/kg - Two doses 20 mg/kg - Three doses

Finding the eggs or occasionally the hatched miracidia in the urine • occasionally, eggs can be found in feces • detecting eggs in rectal biopsy or bladder mucosal biopsy Non-specific • hematuria • proteinuria • cells, especially eosinophils can often be found in the urine • bacteriuria may accompany urinary schistosomiasis • finding S. mansoni ova in faeces • occasionally may also be found in the urine following fecal contamination TREATMENT same as S. japonicum

Tropical and subtropical. Africa, Iran, Iraq, Saudi Arabia, Yemen, Syria, India, Mauritus, Malagasy Republic, Zanzibar

Parts of Africa, Middle East, South America (Brazil), West India

Parasitology: Trematodes Infections S. intercalatum - similar to S. mansoni in terms of life cycle, pathology and clinical feature - IH: Bulinus snail -Africa S. mekongi - similar to S. japonicum in terms of life cycle, pathology, and clinical features - IH: Lithoglyphopsis aperta -SEA

Lung flukes Paragonimus westermani (Oriental Lung Fluke)

-Reddish brown resembling a coffee bean/plum egg -Rounded anteriorly, slightly tapered posteriorly -Tegument covered with singlespaced spines -Rust brown subterminal oral suckers TESTES (2) -Deeply lobed -Situated opposite to each other -Midway between ventral sucker & -posterior border of the body OVARY -Located anterior to the testes& posterior to the ventral sucker -Has 6 long unbranched lobes

Ingestion of crustacean containing metacercariae

1st IH: Snails -Antemalania asperata -Antemalania dactylus (Brotia asperata) 2nd IH: Snails – Sundathel pusaphilippina /crustacean/mountain crab/crayfish

PULMONARY PARAGONIMIASIS LUNGS: granulomatous reaction – fibrotic cyst containing (blood-tinged purulent material, adult worms & eggs) • Chronic cough & hemoptysis • Chest pain, dyspnea, low-grade fever, fatigue & myalgia ECTOPIC PARAGONIMIASIS • Aberrant worms lodge & mature different ectopic locations • Can be cutaneous or cerebral Cutaneous paragonimiasis • Slow-moving, nodular lesion in the subcutaneous tissue on the abdomen or chest Cerebral paragonimiasis • Most serious complication • Migration from pleural cavity to cranial cavity • Headache, meningismus, seizures, hemiparesis, blurring of vision, diplopia, homonymous hemianopsia and aphasia

Metacercaria -Round measuring 318 – 457 µm Egg (thickshelled) 80 – 118 µm by 48 – 60 µm -Flattened but prominent operculum with shoulders -Thickened abopercular portion -Undeveloped miracidium surrounded by a thin smooth shell

Intestinal Flukes Fasciolopsis buski (Largest intestinal fluke of humans & pigs)

-Elongated, oval in shape -Compare to F. hepatica and F. gigantica, it does not have cephalic cone

Ingestion of encysted metacercariae from aquatic plants

1st IH: Snails – Segmentina/ Hippeutis 2nd IH: Water caltrop (Trapa bicornis) Water chestnut (Eliocharis tuberosa), Water morning glory (Ipomea obscura)

FASCIOLOPIASIS • TOXIC (absorption of worm metabolites): edema of the face, abdominal wall & lower limbs – INTOXICATION = death of the host • TRAUMATIC: Inflammation & ulceration at site of worm attachment – mucus secretion & minimal bleeding, gland abscesses • OBSTRUCTIVE: Intestinal obstruction

Microscopy -Detection of eggs in sputum, stool, aspirated material from abscesses or pleural effusions -Sputum examination • Best sensitivity for microscopic diagnosis: sputum concentration with 3% NaOH 3x on different days Chest radiographs • Lung parenchyma lesions: nodular, cavitating • Pleural effusions

-Focal distribution -Local patterns of consumption of inadequately cooked crustaceans/paratenic host -Unhygienic food prep -Prevalence rates vary among endemic provinces in the PH

Peripheral blood count • Eosinophilia • Elevated IgE levels Immunological/serological methods • Complement fixation (CF) test • Intradermal test • Double diffusion in agarose gel • Immunoelectrophoresis • Immunoblotting – 99% sensitive • ELISA – 96 to 99% sensitive TREATMENT Praziquantel as the drug of choice • 25 mg/kg 3 times a day for 2 to 3 days • Not recommended during pregnancy & lactation 2. Triclabendazole 3. Bithionol • 15 to 25 mg/kg twice daily on alternative days, for 10 to 15 days

-Detection of parasite eggs -Resembles Fasciola eggs TREATMENT -Praziquantel -3 doses of 25 mg/kg over 1 day

-Endemic in SEA, China, Korea, India -Fasciolopiasis in Filipinos acquired abroad

Parasitology: Trematodes Infections -20 to 75 mm in length & 8 to 20 mm in width -Testes are dendritic, arranged in tandem -Branch ovary lies to the right of the midline -Fine vitelline follicles situated throughout lateral margin

Nymphaea lotus (lotus) DH: Humans

OVUM -Oblong, large, operculated containing undeveloped miracidum -Indistinguishable from eggs of F. hepatica & F. gigantica -130 to 140 µm by 80 to 85 µm

Enchinostoma ilocanum

Artyfechinostomum malayanum

Heterophyid Flukes -Heterophyes heterophyes

-Haplorchis taichui

Size: 2.5 – 6.6 mm long, 1 – 1.35 mm wide Posterior end: Tapered with 49 – 51collar spines Testes: 2 deeply bilobed arranged in tandem Ovary: In front of the anterior testis Eggs: Straw colored, operculated, ovoid 83 – 116um by 58 – 69um Size: 5 – 12 mm long, 2 – 3mm wide Posterior end: round with 43 – 45 collar spines Testes: 2, large with 6-9 lobes arranged in tandem Ovary: small, rounded or oval anterior to testes Eggs: Larger, golden brown color, operculated 120 – 130um by 80-90um -Elongated, oval, pyriform & 2mm in length -Tegument with fine scale-like spines -Testes – variously arranged in the posterior end -Ovary – globular or slightly lobed (submedian/pre-/posttesticular area Eggs:

-Haplorchis yokogawai -Metagonimus yokogawai

Ingestion of metacercariae encysted in snails, the second intermediate hosts of the parasite.

1st IH: -Gyraulus convexiusculus -Hippeutis umbilicalis 2nd IH: -Pila luzonica (kuhol) -Vivipara angularis (susong pampang)

Inflammation at the site of attachment Ulceration, diarrhea (bloody), abdominal pain General intoxication from worm metabolites

Ingestion of metacercariae encysted in snails, the second intermediate hosts of the parasite.

1st IH: Has not yet been identified but is suspected as same as that of E. ilocanum 2nd IH: Lymnaea cumingiana (Bullastra birabid) Ampullarius canaliculatus (Golden Apple snail) 1st IH: Water snails (Melania juncea & Thiara riquetti) 2nd IH: fresh/brackish water fish

Inflammation at the site of attachment Ulceration, diarrhea (bloody), abdominal pain General intoxication from worm metabolites

Detection of eggs in the stool

Inflammation at the site (attached/burrowed) Excessive mucus production & sloughing off of the superficial layers Compostela Valley • Peptic ulcer disease (PUD) & acid peptic disease (APD) • Upper abdominal discomfort/pain, gurgling abdomen, colicky abdominal pain, mucoid diarrhea Africa • Worms burrow deep, trapped and eventually die • Eggs filtered in the lymphatics & blood vessels may be deposited in tissues Findings in the PH

-Rule out APD -Detection of eggs in stool (Kato -thick method than FECT) -Opisthorchid-like eggs -PCR in low-intensity infections

Detection of eggs in the stool TREATMENT: Praziquantel 25 mg/kg per dose over a day

Northern Luzon, Leyte, Samar, provinces of Mindanao

Northern & Central Luzon

TREATMENT: Praziquantel 25 mg/kg per dose over a day

TREATMENT: Praziquantel 25 mg/kg per dose, 3 doses in 1 day

-Worldwide distribution -Adaptation to families belonging to various families -Not specific 2nd IH IH in different habitats (fresh, brackish, salt water) & different climates -Reservoir hosts: dogs, cats, birds Haplorchis taichui in PH -Southern part of the PH (8 provinces of Mindanao)

Parasitology: Trematodes Infections -Light brown, ovoid, operculated, 20-30µm by 1517µm -Fully developed symmetrical miracidium is present -Operculum fits into eggshell smoothly -Does not have an abopercular protruberance

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Observed in the heart & brain of patients died of heart failure & intracerebral hemorrhage Eggs in the spinal cord result in sensory & motor losses

Liver Flukes: Fasciola spp. - Fasciola hepatica - Fasciola gigantica -Clonorchis sinensis -Opisthorchis felineus - Opisthorchis viverrini Fasciola hepatica -temperate liver fluke

Worldwide distribution Great economic importance in livestockraising countries Philippines

ADULT -Large, broad, flat body 1851mm by 4-13mm -Cephalic cone – marked widening at the base of the cone “shoulder” Testes -Highly branched occupying 2nd & 3rd quarters of the body Ovary -Dendritic & situated in front of the anterior testis Uterus -Coiled & short Eggs: -Large, ovoidal, operculated & yellowish to brownish in color -140-180µm by 63-90µm -Containing large unsegmented mass of vitellin cells

Ingestion of metacercariae encysted on edible aquatic plants or by drinking water

1st IH: Amphibious and are usually found living on mud. -Lymnaea trancatula (Europe and north Asia) -L. bulmoides (Austrilia) -Plnorbidae (a snail family) 2nd IH: Ipomea obscura (morning glory or kangkong) Nasturtrium officanale (Watercress) DH: sheep, cattle, humans

FACIOLIASIS -Acute or invasive phase -Chronic or latent phase ACUTE or INVASIVE PHASE • Migration of juvenile parasite from intestine to the liver • Burrows into the liver parenchyma resulting to traumatic & necrotic lesions • Dyspepsia, fever, right upper quadrant abdominal pain Diagnostic significance: high fever, hepatomegaly, marked eosinophilia CHRONIC or LATENT PHASE • Parasite reached the bile ducts • Obstruction & inflammation in biliary epithelium – Fibrosis • Fibrotic bile duct – less bile to be passed out • Atrophy of the liver – cirrhosis • Obstructive jaundice, hemobilia, biliary cirrhosis -Ingestion of raw Fasciola-infected liver -Flukes attach to posterior pharynx – hemorrhagic nasopharyngitis & dysphagia o Halzoun in Lebanon o Marrara in Sudan

-Difficulty because of overlapping symptoms or lack of symptoms -Patient’s history Serological & coprological methods • (ELISA & Western blot) • Rule out diseases with similar symptoms to fascioliasis Parasitological diagnosis -Identification of eggs: stool, duodenal contents, bile -Recovery of adult worms: surgery, after treatment or autopsy -Spurious or false fascioliasis • ingestion of poorly cooked liver from infected animals transiently passing out of eggs in the stool Radiological examinations -Sonography & CT scan • Liver parenchymal lesions migrating through the liver • Presence of parasites in the biliary system Endoscopic retrograde choliangiopancreatography (ERCP) • Biliary obstruction or filling defects TREATMENT :Triclalbendazole Single 10 mg/kg oral dose following food intake Heavy infections: 2 doses of 10mg/kg spaced by 12 hours • Reported drug resistant to Triclalbendazole found in livestock Bithionol

Parasitology: Trematodes Infections -30 to 50 mg/kg on alternate days to complete 10 to 15 doses Peroxidic compounds: Artemisinins & Trioxolanes -Single 200 to 400 mg/kg oral doses

Fasciola gigantica -tropical liver fluke

ADULT -25-75mm by 3-12mm Less developed shoulders & -shorter cephalic cone Ovary -Branches are longer & more numerous

Ingestion of metacercariae encysted on edible aquatic plants or by drinking water

Eggs: 160-190µm by 70-90µm

1st IH: Aquatic snails L. acuminata (Indian subcontinent) L. auricularia (Asia) L. natalensis (Africa) In the PH: L. philippinensis and L. Auricularia rubignosa

Same as F. hepatica

Same as F. hepatica

F. gigantica affecting cattle & water buffaloes -South Cotabato 89.5% prevalence -Transmission linked to eating raw water-grown vegetables harboring F. gigantica metacercariae -Not sufficient to remove encysted metacercariae by washing vegetables with water, vinegar or lemon juice -Use of contaminated kitchen tools

Detection of parasite eggs in the stool -Distinct melon-like ridges on the surface: when stained with potassium permanganate -Cholangiography • Saccular dilations of the intrahepatic bile ducts & rapid ductal tapering toward the periphery “arrowhead sign” • ELISA, EIA & coproovoscopy • PCR TREATMENT: Praziquantel • 25 mg/kg 3x a day for 2 days • 60 mg/kg 3 doses for 1 day • Praziquantel-Albendazole Extract from aspen bark -Salicin on active fractions -Artemisinins & synthetic peroxides – OZ78 single oral dose 300 mg/kg

Distribution of the disease is based on: -Intermediate host -Animal reservoir host -Traditional consumption of improperly cooked fish -Indiscriminate defecation habits

2nd IH: (same as F. hepatica) Ipomea obscura (morning glory or kangkong) Nasturtrium officanale (Watercress) DH: Ruminants are the typical DH, sheep, cattle Liver flukes • Parasites of the bile duct & gallbladder of humans & fish-eating mammals Eggs: • Yellowish brown, ovoid • 26 to 30 µm by 15 to 17 µm • Distinctly convex operculum that fits into the thickened rim of the eggshell & small protuberance at the abopercular end

Clonorchis sinensis

-Leaflike with transparent tegument -10-25mm by 3-5mm -Vitellaria is found in the middle third of the body at the level of the uterus

Ingestion of metacercariae present in raw or undercooked fish -Salted, dried or pickled fresh water fish -Decomposing fish – drinking contaminated water

1st IH: Parafossarulus, Bulinus, Semisulcospira, Alocinma, Thiara, Melanoides 2nd IH: Cyprinidae

CLONORCHIASIS -Local trauma & irritation in the biliary system Phases: 1. Desquamation of epithelial cells 2. Hyperplasia & desquamation of epithelial cells 3. Hyperplasia, desquamation of epithelial cells & adenomatous tissue formation 4. Marked proliferation of the periductal connective tissue with scattered abortive acini of the epithelial cells & fibrosis of the wall of biliary duct CLONORCHIASIS (number of flukes &CM) ≤100 -Asymptomatic, diarrhea & abdominal pain 101 – 1,000 -Fever, diarrhea, loss of appetite, rash, edema, night blindness, swollen abdomen, hepatomegaly

Parasitology: Trematodes Infections Up to 25,000 -Acute pain in right upper quadrant

Tribendimidine/Artemether/Artesunate • Oral dose of 150 mg/kg

CLONORCHIASIS -Chronic stages – liver malfunction • Calculi, acute suppurative cholangitis, recurrent pyogenic cholangitis, cholecystitis, hepatitis, pancreatitis -Hepatocellular carcinoma & cholangiocarcinoma • Classified by the International Agency for Research on Cancer (IARC) as a probable carcinogen

Opisthorchis felineus

8-12mm by 1-3mm -Lobate testes arranged obliquely

Opisthorchis viverrini

-Lobate testes arranged obliquely (positioned close to each other & more deeply lobulated)

Ingestion of metacercariae present in raw or undercooked fish -Salted, dried or pickled fresh water fish -Decomposing fish – drinking contaminated water Ingestion of metacercariae present in raw or undercooked fish -Salted, dried or pickled fresh water fish -Decomposing fish – drinking contaminated water

1st IH: Bithynia 2nd IH: Cyprinidae & Cobitidae

OPISTHORCHIASIS Opisthorchis felineus • Fever & hepatitis-like symptoms • Right upper quadrant abdominal pain, nausea, emesis • Biliary tract obstruction, inflammation, fibrosis, liver abscess formation, pancreatitis, suppurative cholangitis

Same as Clonorchis sinensis

Same as Clonorchis sinensis

1st IH: Bithynia 2nd IH: Cyprinidae & Cobitidae

OPISTHORCHIASIS Opisthorchis viverrini • Flatulence, fatigue, dyspepsia, right upper quadrant abdominal pain, anorexia & mild hepatomegaly • Obstructive jaundice, cirrhosis, cholangitis, acalculous cholecystitis or bile peritonitis • Cholangiocarcinoma – most serious complications

Same as Clonorchis sinensis

Same as Clonorchis sinensis...