[NOTES] EXTRAINTESTINAL NEMATODES (2nd Year BS Medical Technology) PDF

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CLINICAL PARASITOLOGYModule2 – Extraintestinal NematodesTranscribed by PORPION References: Powerpoint and video discussionTABLE OF CONTENTSExtraintestinal Nematodes Trichinella spiralis Filarial Worms ✓ Lymphatic Filarial Worms ✓ Subcutaneous Tissue Filarial Worms ✓ Body Cavity Tissue Filarial Worms...

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CLINICAL PARASITOLOGY Module2.2 – Extraintestinal Nematodes Transcribed by PORPION References: Powerpoint and video discussion TABLE OF CONTENTS Extraintestinal Nematodes Trichinella spiralis Filarial Worms

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Lymphatic Filarial Worms ✓ Subcutaneous Tissue Filarial Worms ✓ Body Cavity Tissue Filarial Worms ✓ Laboratory Diagnosis for Filarial Worms ✓ Periodicity ✓ Treatment for Filarial Worms ✓ Other Filarial Worms Summary of Extraintestinal Nematodes

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• Has conical papillae • Die after copulation Female • With club-shaped uterus • Viviparous o This means they have NO EGG STAGE • May live up to 30 days • Can lay 1500 larva in its lifetime

Larva ✓ ✓

Coiled larva Encysted in the nurse cell of striated muscles (skeletal muscles) • Nurse cells are cells that provide food for neighboring cells • Only nurse cells are capable of supporting T. spiralis

EXTRAINTESTINAL NEMATODES Nematodes whose habitats are outside the intestine (could be in the muscles, eyes, meninges, subcutaneous tissue, lymphatics etc.) Pathology (Trichinellosis) Trichinella spiralis NOTE: Refer to Powerpoint for the life cycle Common Name Final Host

Host/Intermediate

Habitat

Diagnostic Stage Infective Stage Mode of Transmission

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Muscle worm Trichina worm Pigs Rat Man (Dead-end host – because no one consumes humans) ✓ Adult: Small instestine ✓ Larva: Skeletal muscle (nurse cells) Encysted larva Encysted larva Ingestion of encysted larva

History ✓ Tiedemann (1822) • First described trichinellosis ✓ James Paget and Richard Owen • First to demonstrate T. spiralis on cadavers ✓ Dickson Despommier • Called T. spiralis the LARGEST INTRACELLULAR PARASITE • Discovered that the larva resides in the nurse cells of skeletal muscles Known Trichinella spp. T. spiralis T. brivoti

T. nativa

T. murrelli T. nelson T. papuea T. pseudospiralis Adult ✓ Male

Most common to infect man ✓ 2nd most common ✓ Widely distributed in Asia, Europe, Northern and Western Africa Infects wild carnivores in frigid zones of Asia, North America, and North Eastern Europe

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Also known as ‘great imitator’ • Because it can mimic other diseases • Symptoms are general (diarrhea, fever etc.) Due to adult • Diarrhea and abdominal pain Due to larva • Eosinophilia o T. spiralis is the nematode that gives/produces the highest number of eosinophils • Muscle pain at the site of encystation, edema o Eyelid edema

Laboratory Diagnosis for Trichinella spiralis ✓ Muscle biopsy • ‘Muscle tissue sample’ • Most common diagnosis ✓ Immunotest • Tests that involve antigenantibody reactions • Bentonite Flocculation Test o Detects T. spiralis antibody in serum • Intradermal Bachmann Test o Injects T. spiralis extract intradermally in blood to detect if antibodies are present in the blood o Swelling, redness, and itching at the area of the injection indicates the presence of the antibodies (the patient has or had T. spiralis) • Beck’s Xenodiagnosis o Involves animal (the test animal are albino rats) o The rats are fed muscle samples that are suspected to be infected with T. spiralis larva (the rats will be observed for symptoms -> wait for symptoms -> collect muscle sample from rats and perform muscle biopsy to for larva in the animals’ muscles) Treatment ✓

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• Antiparasitic agent Prednisone • Alleviates inflammation and swelling

FILARIAL WORMS NOTE: Refer to Powerpoint for the life cycle Final host Intermediate host Diagnostic stage Infective stage

Mode of transmission

Man Arthropod vectors Microfilaria (larval stage of filarial worms) ✓ Intermediate host: Microfilaria ✓ Final host: Filariform larva Vector-borne

Brugia timori ✓ Can cause timorian filariasis ✓ Occurs in the Indonesian archipelago, specifically the Timor-Flores islands Vector Microfilaria

Mosquitos (Anopheles spp.) ✓ Sheathed ✓ Tail with two separate nuclei

Habitat HABITAT Lymphatics Subcutaneous tissue Body cavity

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PARASITE Wuchereria bancrofti Brugia malayi Loa loa Onchocerva volvulus Mansonella ozzardi Mansonella perstans

LYMPHATIC FILARIAL WORMS Can cause lymphatic filariasis (one of the most debilitating disease in tropical countries) 2nd most common cause of permanent and long-term disabilities (next to psychiatric illness)

Wuchereria bancrofti ✓ Most prevalent specie (most common specie in the Philippines) ✓ Most commonly identified specie of filarial worms that infect man Common name Vector Microfilaria

Bancroft’s filarial worm Mosquitos (Aedes, Anopheles, Culex) ✓ Sheathed ✓ No nuclei in tail

Pathology (Lymphatic Filariasis) ✓

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Due to microfilaria • Tropic pulmonary eosinophilia (TPE) o Occurs in patients in areas in an endemic o Characterized by asthma attacks and enlarged spleens Increased eosinophil count High IgE antibody level Due to adult • Acute dermatolymphanioadenitis (ADLA) o Most common manifestation o Inflammation of lymph nodes and cellulitis which leads to swelling of extremities • Acute filarial lymphangitis (AFL) o Inflammation of lymphatic vessels progresses distally along the lymph vessels producing palpable cords • Lymphedema o Most chronic manifestation o Can lead to elephantiasis • Elephantiasis o Enlargement and hardening of lymph and extremities due to tissue swelling • Genito-urinary lesion o Hydrocele (swelling of scrotum) Most common chronic manifestation of W. bancrofti W. bancrofti Bancroftian filariasis Lower elephantiasis

Brugia malayi Common name Vector Microfilaria

Malayan filarial worm ✓ Mosquitos (Anopheles, Mansonia) ✓ Sheathed ✓ Tail with two separate nuclei

B. malayi Malayan filariasis Upper elephantiasis

SUBCUTANEOUS TISSUE FILARIAL WORMS Loa loa Common Eye worm name Vector Flies (Chrysops spp.: tabanid fly, deer fly, mango fly) ✓ Sheathed Microfilaria ✓ Nuclei continues up to tail tip

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NOTE: Loa loa literally means ‘worm worm’ Onchocerva volvulus Common name

Vector Microfilaria

Mansonella perstans Old name was Dipetalonema perstans Common name Vector

Covoluted worm, blinding worm, river blindness worm, gale filarienne) Flies (Simulium spp.: blackfly) ✓ Unsheathed ✓ No nuclei in the tail

Microfilaria

Perstans filaria Biting midges/gnats (Culicoides spp.) ✓ Unsheathed ✓ Nuclei continues up to tail tip

LABORATORY DIAGNOSIS FOR FILARIAL WORMS Specimen ✓ ✓

NOTE: The blackfly flies near rivers, hence the name river blindness fly Pathology ✓ Loa loa • Calabar swelling/fugitive swelling ✓ Onchocerca volvulus • River blindness • 2nd most common cause of blindness (1st is caused by bacteria Chlamydia trachomatis) • Leading cause of blindness in endemic areas (Africa, Central America, and Northern South America)

BODY CAVITY TISSUE FILARIAL WORMS They are non-pathogenic parasites Mansonella ozzardi Common name Vector Microfilaria

New world filaria Biting midges/gnats (Culicoides spp.) ✓ Unsheathed ✓ No nuclei in the tail

Blood Skin nips • Should be little to no blood contamination in order to prevent sample contamination especially if there are multiple infections

Techniques and Methods ✓ Wet smears • Demonstration of live microfilaria from blood sample ✓ Giemsa-stained blood smears • Method of choice • Demonstrates structure of filarial worms specifically microfilaria ✓ Lymph node biopsy • For lymphatic filariasis ✓ Ultrasound • Detects cause of hydrocele ✓ Diethylcarbamazine provocative test • Treatment of choice for filarial worms • Since filarial worms reside in different habitats, so in order to stimulate the filarial worms to reveal themselves, diethylcarbamazine is used (3mg/Kg body weight) o The diethylcarbamazine stimulates the filarial worms to migrate to the blood vessels, wherein they can be sampled via blood collection ✓ Immunochromatography • Antigen detection technique o Circulating filarial antigen (CFA) A test kit embedded with filarial worm antibodies which includes a reaction bar and a sample well. The reaction bar has indications for C (control) and T (test). When positive blood is dropped in the well, the antibodies in the test kit will react to the worms (antigens), then a colored bar will appear in the reaction bar. A colored bar should appear in the C section of the bar to indicate that the test is working properly. ✓ Concentration method • Knott’s technique o Used if there is no number of microfilaria o Isolates microfilaria o Process: 1mL blood + 2% formalin or HAC (to hemolyze the RBCs for better visualization of microfilaria) -> centrifuge -> smear the sediment on a slide -> stain slide with Giemsa > Microfilaria worms will be observable • Membrane filtration o Uses swincy filter (filters microfilaria)

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PERIODICITY OF FILARIAL WORMS Filarial worms exhibit periodicity PERIODICITY – an event where a parasite is present in the bloodstream only during a certain period Knowing the periodicity helps the medical technologist in collecting samples at the best time

FILARIAL WORM W. bancrofti B. malayi

Blood Blood

L. loa O. volvulus M. ozzardi M. perstans

Blood Skin snips Blood Blood

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SPECIMEN

PERIODICITY Nocturnal Subperiodic but more on nocturnal Diurnal Nonperiodic Nonperiodic Nonperiodic

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NOCTURNAL – they occur at night; best time to collect blood sample is at midnight SUBPERIODIC – have no specific time; can appear in the morning or at night DIURNAL – they occur at daytime NONPERIODIC – collection of sample doesn’t matter

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TREATMENT FOR FILARIAL WORMS Diethylcarbamazine Ivermectin

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Habitat Diagnostic stage Infective stage Mode of transmission Pathology

Common name

Definitive host Intermediate host Habitat Mode of transmission Pathology

Guinea worm, medina worm, dragon worm, fiery serpent Man Crustaceans (Copepods, cyclops) Adult subcutaneous tissue Ingestion of infected copepods Dracunculiasis or Guinea worm disease

Mollusks/snails: Pila luzonica (Kuhol) and Brotia asperata (Suso) CNS Adult worm (Female) Larva Ingestion of infected copepods Larva migrates to the brain and spinal cord causing eosinophilic meningoencephalitis

Dirofilaria immitis Common name Natural host Pathology

Dog heartworm Dog Produce solitary, peripheral nodules in the lungs (coin lesions)

Anisakis spp. Common in Japan Common name Definitive host

Intermediate hosts (3)

OTHER FILARIAL WORMS Dracunculus medinensis ✓ Longest nematode of man (can reach 1m in length) ✓ Trivia: it is the serpent seen in the medical symbol

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Intermediate host

Infective stage Mode of transmission Pathology

Herring’s worm ✓ Whales ✓ Dolphins ✓ Man (dead-end host) 1st host – copepods 2nd host – small fishes 3rd host – large fishes (salmon) Larva Ingestion of raw fish with infective larva Abdominal pain and granuloma caused by migrating larva in intestinal wall

NOTE: Summary of extraintestinal nematodes is in the next page

Treatment • Immersion of affected body part in water o Stimulate worm exclusion • Wound cleaning • Worm extraction o Be careful not to sever it (it can’t be extracted further if severed) • Topical antibiotics • Aspirin/Ibuprofen prescription o Pain reliever and anti-inflammatory drugs

Angiostrongylus cantonensis ✓ New name is Parastrongylus cantonensis ✓ Adult females have a barbe’s pole appearance (red and white stripes)

Common name Natural/final host

Rat lungworm Rats (Rattus rattus var. rattus and Rattus norvegicus)

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SUMMARY OF EXTRAINTESTINAL NEMATODES

FILARIAL WORM

MICROFILARIA HABITAT

W. bancrofti Lymphatics B. malayi

L. loa Subcutaneous tissues O. volvulus M. perstans Body cavities M. ozzardi

VECTOR/S

Mosquito (Aedes spp., Anopheles spp.)

SHEATH

NUCLEI

SPECIMEN

PERIODICITY

Sheathed

Absent in tail

Blood

Nocturnal

Sheathed

2 separate nuclei in tail

Blood

Subperiodic but more on nocturnal

Fly (Chrysops spp.): tabanid fly, mango fly

Sheathed

Continues up to tail tip

Blood

Diurnal

Blackfly (Simulium spp.)

Unsheathed

Absent in tail

Skin snips

Nonperiodic

Unsheathed

Continues up to tail tip

Blood

Nonperiodic

Unsheathed

Absent in tail

Blood

Nonperiodic

Biting midges/gnats (Culcoides spp.)

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