1. Wuchereria bancrofti 2. Brugia malayi

PREFINAL: THE FILARIAE Flashcards by Chin Lys

blood feeding arthropod vector-borne nematodes

THE FILARIAE

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LYMPHATIC FILARIAE:

Wuchereria bancrofti
Brugia malayi

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SUBCUTANEOUS FILARIAE:

Loa loa
Onchocerca volvulus

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Filariae that causes infection in the
abdomen

SEROUS CAVITY

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Considered one of the most delabilating diseases that is known in the man

LYMPHATIC FILARIAE

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Wuchereria bancrofti common name

Bancroft’s filarial worm

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Wuchereria bancrofti can cause

Bancroftian filariasis

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creamy white, long and have filiform shaped

w. bancrofti adult worm

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 270-290 um
 Small snake-like organism
 Moved along red blood cells
 Enclosed in a hyaline sheath, Sheathed
 Sheath of microfilaria is much longer than the microfilaria itself
 When stained, shows dark staining nuclei (important identifying features) and tail end culminates in a point that is free of nuclei

w. bancrofti MICROFILARIA

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intermediate Hosts of w. bancrofti

Aedes
Anopheles
Culex

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definitive Host of w. bancrofti

human

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mot of wuchereria bancrofti

mosquito bite

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periodicity of wuchereria bancrofti

nocturnal

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diagnostic stage of w. bancrofti

Sheathed microfilariae

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infective stage of w. bancrofti

3rd STAGE LARVAE

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Brugia malayi common name

malayan filarial worm

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Brugia malayi common name

malayan filarial worm

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Brugia malayi can cause

MALAYAN FILARIASIS

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MALE: 13-23 mm in length
 FEMALE: 43-55 mm

b. malayi adult worm

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sheated
When stained, shows 2 distinct nuclei at the end of the tail

b. malayi MICROFILARIA

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INTERMEDIATE HOSTS of b. malayi

Mansonia

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Definitive host of b. malayi

humans

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PERIODICITY of b. malayi

nocturnal and subperiodic

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 Can be acquired during childhood
 May take years to manifest itself
 Can be asymptomatic, acute stage or chronic stage
 Lymphatic localization (important for parasite survival)
 Lymph is less aggressive than bloodbecause there is no platelets, no complement system, no coagulation, no granulocytes and less violent

LYMPHATIC FILARIASIS

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- parasite induced lymphatic dilatation, common feature of patent infection (parasitic org. can be demonstrated in the body) - Lymph node/system dilates

LYMPHANGIECTASIA

Growth of lymphatic vessels due to the inducement of proliferation of lymphatic endothelial cells (because of the antigens introduced by filarial parasites)

LYMPHANGIOGENESIS

LYMPHANGIOGENESIS can lead to

LYMPHEDEMA

swelling of lymph due to increased lymph fluid

LYMPHEDEMA

limbs like elephants

ELEPHANTIASIS

 Most common acute manifestation of LF  Localized pain  Lymphadenitis or lymphangitis

ACUTE DERMATOLYMPHANGIOADENITIS (ADLA)

Most common chronic manifestation of LF  Most common affected: LOWER LIMBS(but upper limb and male genitalia can be affected also)  Progression to ELEPHANTIASI

LYMPHEDEMA

obstructions of the lymphatic in the tunica vaginalis

Formation of HYDROCELE (CHYLOCELE)

accumulation of fluid or hydrocele fluid (clear or straw colored)

HYDROCELE

milky fluid (presence of lymph fluid) - Accumulates in the sac of the testes of the male patients

CHYLOCELE

(common and more severe)

GENITALS – BANCROFTIAN FILIARISIS

(less common and severe)

GROIN - MALAYAN FILIARIASIS

 Immunologic hyper-responsiveness to mature/maturing worms  Typically occurs from foreigners infected by LF from endemic areas

EXPATRIATE SYNDROME

(enlargement of lymph nodes)

LYMPHADENITIS

(inflammation of lymphatic channels)

LYMPHANGITIS

Clinical manifestation is not present and microfilaria is not seen in the blood but microfilaria hides in tissues specifically LUNG TISSUE  Occult form of FILIARIASIS  May progress to CHRONIC PULMONARY FIBROSIS and RESPIRATORY FAILURE if untreated  High titers of IgE (Ig of parasite)

TROPICAL PULMONARY EOSINOPHILIA

Milky – chyle/lymph fluid leakage

URINE

Traditionally accepted procedure for diagnosis

MICROSCOPIC FINDINGS of MICROFILARIA IN THE BLOOD

o Microfilariae in wet/thick blood smears (8pm-4am due to NOCTURNAL) o Knott’s Concentration Method /Nucleopore Filter – for low infections o Chronic Infections may not be demonstrable in the peripheral blood cause by low intensity of infection, dead worms or obstructive lymphatics due to increased no. of parasites

BLOOD

8pm to 4am collection

thick and blood smear for lymphatic filariae

3 mg/kg DEC SINGLE DOSE o Allows collection during daytime o Stimulate the microfilaria to migrate in the peripheral circulation and collect blood through blood smears

DEC/ DIETHYLCARBAMAZINE PROVOCATIVE TEST

o PREFERRED o Antigens from microfilaria o Latent infections (infections that are delayed/natutulog na parasite) o Mainly done using IMMUNOCHROMATOGRAPHIC CARD TEST o ANTIGEN DETECTION STRIP (card) TESTS – RDTs (sensitive and specific)

CIRCULATING FILARIAL ANTIGENS (CFA)

Growth of mosquito inside the laboratory

XENOMONITORING OF MOSQUITOES

Growth of mosquito inside the laboratory

XENOMONITORING OF MOSQUITOES

MICROSCOPIC COMPARISON using

STAINED THICK BLOOD FILMS

MICROSCOPIC COMPARISON using

STAINED THICK BLOOD FILMS

Mean length (um) of w. bancrofti

290

Mean length (um) of b. malayi

222

Cephalic space: breadth of w. bancrofti

1:1

Cephalic space: breadth of b. malayi

2:1

Sheath in Giemsa of w. bancrofti

unstained

Sheath in Giemsa of b. malayi

pink

Nuclei of w. bancrofti

Regularly spaced, separately situated

nuclei of b. malayi

Irregularly spaced, and overlapping

tail of w. bancrofti

Single row of nuclei that does not reach the tail’s end

tail of b. malayi

Single row of nuclei that reaches the tail’s end

terminal nuclei of w. bancrofti

none

terminal nuclei of b. malayi

2 nuclei, which bulge the cuticle, conspicuously placed

Appearance in blood film of w. bancrofti

Smoothly curved

Appearance in blood film of b. malayi

kinky

Innenkorper length (um) of w. bancrofti

Innenkorper length (um) of b. malayi

30.7

TREATMENT of LYMPHATIC FILARIAE

DEC (DIETHYLCARBAMAZINE) - Drug of Choice - 6mg/kg for 12 CONSECUTIVE DAYS - Discover in 1948

Loa loa common name

AFRICAN EYE WORM

Typically white in color and Threadlike appearance

L. loa ADULT WORM

 248-300 um  Sheathed  When stained, shows tail with continuous end of nuclei (1 nuclei)

L. loa MICROFILARIA

DIAGNOSTIC STAGE OF LOA LOA

 MICROFILARIAE IN BLOOD AND TISSUES  ADULT WORMS EXTRACTED

INFECTIVE STAGE OF LOA LOA:

3RD STAGE LARVAE

INTERMEDIATE HOST of l. loa

CHRYSOPS FLY (DAY BITING FLY)

DEFINITIVE HOSTS of loa loa

humans

mot of loa loa

fly bite

PERIODICITY of l. loa

DIURNAL (they can be found during the day)

Transient subcutaneous swellings

LOIASIS  CALABAR/FUGITIVE SWELLINGS

- MICROFILARIAE IN GIEMSA STAINED IN BLOOD (10:15 AM – 2:15 PM)  Extraction of adult worms on body locations  Serologic testing

BLOOD (DIAGNOSIS)

treatment of loa loa

DEC (DIETHYLCARBAMAZINE)  SURGICAL REMOVAL/EXTRACTION

Onchocerca volvulus common name

BLINDING FILARIA

- Thin and wirelike appearance  MALE: 25-50 mm  FEMALE: up to 500 mm

Onchocerca volvulus ADULT WORMS

 150-355 um  Unsheathed (found in tissue only)  When stained, nuclei do not extend to tip of tail

MICROFILARIA

Adult filariae can live to the nodules for approximately____

15 years

LIFE SPAN OF MICROFILARIAE of onchocerca volvulus

2 YEARS

Diagnostic stage of onchocerca volvulus

MICROFILARIAE IN BLOOD AND TISSUES

Infective stage of onchocerca volvulus

3RD STAGE LARVAE

INTERMEDIATE HOSTS of onchocerca volvulus

SIMULIUM (BLACKFLY)

definitive Host of onchocerca volvulus

humans

mot of onchocerca volvulus

fly bite

PERIODICITY OF ONCHOCERCA VOLVULUS

NONPERIODIC (microfilaria circulate in the blood throughout 24 hour period)

 SKIN: loss of elasticity and nodules  RIVER BLINDNESS: lesion formation in the eye

ONCHOCERCIASIS

Uses SLIT LAMP

OPHTHALMOLOGIC EXAM

- MICROFILARIAE IN GIEMSA STAINED TISSUE - Tissue biopsy in the infected area – SPECIMEN OF CHOICE - Obtained with little blood (to avoid contamination sample)

SKIN SNIPS

treatment of onchocerca volvulus

 IVERMECTIN  THERAPY CAN BE LONG BECAUSE OF THE ADULT WORM LIFESPAN (15 YEARS)