Wuchereria bancrofti and Brugia malayi

Arthropod-borne/vector borne Nematodes

What kind of nematodes are FILARIAL WORMS?

Definitive Host: Man

Intermediate Host: Vector

FILARIAL WORMS

HOSTS:

Definitive Host:

Intermediate Host:

Infective Stage to Man: Filiform
Larva/Third stage larva

Infective Stage to Vector: Microfilaria

Diagnostic stage: Microfilaria

FILARIAL WORMS

INFECTIVE STAGE AND DIAGNOSTIC STAGE

Infective Stage to Man:

Infective Stage to Vector:

Diagnostic stage:

Skin penetration

FILARIAL WORM

MOT:

Wuchereria bancrofti
Brugia malayi
Loa-loa
Onchocerca volvolus

FILARIAL WORMS

Wuchereria bancrofti: Aedes/ Anopheles mosquito/ Culex
Brugia malayi: Mansonia sp. mosquito

VECTOR (specific)

Wuchereria bancrofti:
Brugia malayi:

Wuchereria bancrofti: Lymphatics (lower)
Brugia malayi: Lymphatics (upper)

HABITAT

Wuchereria bancrofti:
Brugia malayi:

Blood (BOTH)

SPECIMEN

Wuchereria bancrofti:
Brugia malayi:

Wuchereria bancrofti: Elephantiasis (lower
Brugia malayi: Elephantiasis (upper)

DISEASE

Wuchereria bancrofti:
Brugia malayi:

Bancrofti's filarial worm

Wuchereria bancrofti

COMMON NAME:

☺Long, creamy white, filiform in shape

MORPHOLOGY of Wuchereria bancrofti

length:
color:
shape:

☺Minute, snakelike organisms
☺270-290 microns by 6-7 microns
☺Enclosed in a hyaline sheath

Wuchereria bancrofti - LARVA OR MICROFILARIA

appearance:

size:

enclosed by:

☺Sheathed microfilaria

Wuchereria bancrofti

sheathed or not?

☺The tail is pointed and FREE of nuclei
☺NOCTURNAL PERIODICITY

unique feature of Wuchereria bancrofti

tail:

periodicity:

Wuchereria bancrofti

Has several curvature and graceful
appearance.

Giemsa

When stained with this, the sheath of
Wuchereria bancrofti does not stain well.

Malayan filarial worm

Brugia malayi

COMMON NAME:

111-230 MICRONS

MICROFILARIA of Brugia malayi

size:

☺Sheathed microfilaria

Brugia malayi

sheathed or not>

tail: PRESENCE OF TWO (2) DISTINCT NUCLEI IN
THE TIP OF THE TAIL.

periodicity: SUBPERIODIC NOCTURNAL PERIODICITY

unique feature of Brugia malayi

tail:

periodicity:

In Giemsa-stained blood films, they appear PINK in color and have angular curvatures with secondary kinks.

Unlike with Wuchereria bancrofti, Giemsa does stain Brugia malayi well.

W. bancrofti is larger

Brugia malayi is smaller

W. bancrofti vs Brugia malayi

what is larger in size ?

W. bancrofti: Curves of body are natural, smooth (GRACEFUL)

Brugia malayi: Curves of body are rigid, the small in larger curve

SHAPE OF THE BODY

W. bancrofti:

Brugia malayi:

W. bancrofti: Shorter

Brugia malayi: Longer

CEPHALIC SPACE

W. bancrofti:

Brugia malayi:

W. bancrofti: Equal sized, clearly defined, countable

Brugia malayi: Unequal sized, coalescing, uncountable

BODY NUCLEI

W. bancrofti:

Brugia malayi:

☺Inflammation, edema, fibrosis
☺Acute fever, lymphadenitis, funiculitis, swelling, redness
☺ELEPHANTIASIS
☺Expatriate syndrome
☺Hives, rashes and blood eosinophilia
☺HYDROCOELE
☺Genital and pedal enlargements are common
☺CHYLURIA

PATHOLOGY -

W. bancrofti:

Exposure to Wolbachia-

PATHOLOGY - W. bancrofti:

inducer of inflammation

(BANCROFTIAN FILARIASIS)

PATHOGENESIS - W. bancrofti

Stage 1 (Chronic lymphedema) - Swelling increases during the day but reversible once the patient lies flat in bed

Stage 2 - swelling is no longer reversible at night

Stage 3 - presence of shallow skin folds, and base of the lesion are seen when leg or foot moves

Stage 4 - knobs are present in affected areas

Stage 5 - with deep skin folds

Stage 6 - bulky lesions are present and leakage of fluid

Stage 7 - patient is unable to perform daily activities

(BANCROFTIAN FILARIASIS)

Stage 1 -

Stage 2 -

Stage 3 -

Stage 4 -

Stage 5 -

Stage 6 -

Stage 7 -

∞Deformity produced in infected cases is not as severe as in bancroftian filariasis

∞There may be enlargement of the epitrochlear, inguinal and axillary lymph nodes

∞Rarely in scrotum

PATHOLOGY - B. malayi

a. Thick blood smear: 2~3 drops of free flowing blood by finger prick method

b. Membrane filtration method: 1~2 ml intravenous blood filtered through 3µm pore size membrane filter

c. DEC provocative test (2mg/Kg): after consuming DEC, mf enters into the peripheral blood in day time within 30~45 minutes

d. Adult: biopsy of the nodes or lymphatic vessels

e. Immunological tests: antibody or circulating filarial antigen (CFA)

f. KNOTT'S TECHNIQUE

DIAGNOSIS

Wuchereria bancrofti and Brugia malayi

Thick blood smear: capillary blood from skin puncture

NOTT'S TECHNIQUE: Venous blood (Venipuncture)

DIAGNOSIS - specime

Thick blood smear:

KNOTT'S TECHNIQUE:

KNOTT'S TECHNIQUE

DIAGNOSIS

This technique involves ISOLATION of microfilariae

GIEMSA

ideal stain for BLOOD parasite.

• Reagent: 1 part of blood + 9 parts of formalin + Acetic Acid

NOTE: RBC will be hemolyzed; what will be left are WBC's and MICROFILARIA

KNOTT'S TECHNIQUE

• Reagent:

1. urban type-
2. rural type-

2 types of Bancroftian filariasis

1. urban type- Aedes poecilus
2. rural type- Anopheles minimus flavirostris

2 types of Bancroftian filariasis

1. urban type-
2. rural type-

> most prevalent in ABACA raising areas - urban type; Aedes poecilus

> towards the mountains and hills - rural type; Anopheles minimus flavirostris

2 types of Bancroftian filariasis

> most prevalent in ABACA raising areas -

> towards the mountains and hills -

45 endemic provinces (e.g. REGION IV)

83 endemic countries

Epidemiology

Wuchureria bancrofti and Brugia malayi

# endemic provinces (PH) -

# endemic countries -

- Most mosquitoes are NIGHT BITERS and usually starts biting as early as 5:00 pm to around 11:00 pm

- With (B. malayi), CAT is an important reservoir host.

TAKE NOTE!

M. bonneae- breed in freshwater swamps

M. uniformis- breed in rice field

EPIDEMIOLOGY: (B. malayi)

M. bonneae-

M. uniformis-

With (B. malayi), cat is an important reservoir host.

TAKE NOTE!

- Diethylcarbamazine citrate, Ivermectin with albendazole

- Relieving the pain (cooling the area, , washing the affected area,

- surgery (for hydrocoele )

- All abaca workers must wear long sleeved shirts and use mosquito repellents on the exposed skin ☺

-Use mosquito nets especially for endemic provinces/ use of insecticides

- Keep the surroundings clean and throw away possible habitat for the vectors.

TREATMENT, PREVENTION AND CONTROL