43
1

Filariasis Sph

Embed Size (px)

DESCRIPTION

presentation on filariasis

Citation preview

Page 1: Filariasis Sph

1

Page 2: Filariasis Sph

pa

ra-la

b b

y l. wa

fa m

en

aw

i

2

Page 3: Filariasis Sph

3

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Wuchereria bancrofti and Brugia malayi are filarial nematodes

Spread by several species of night - feeding mosquitoes

Causes lymphatic filariasis, also known as ElephantiasisCommonly and incorrectly

referred to as “Elephantitis”

Page 4: Filariasis Sph

4

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Humans are the definitive host for the worms that cause lymphatic filariasis

There are no known reservoirs for W.bancrofti.

B.malayi has been found in macaques, leaf monkeys, cats and civet cats

Page 5: Filariasis Sph

5

pa

ra-la

b b

y l. wa

fa m

en

aw

i

W.bancrofti is transmitted by Culex, Aedes, and Anopheles species

B.malayi is transmitted by Anopheles and Mansonia species.

Anopheles

Aedes

Culex

Mansonia

Page 6: Filariasis Sph

6

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Endemic in 83 countries1.2 billion at riskMore than 120 million people infectedMore than 25 million men suffer from

genital symptomsMore than 15 million people suffer

from lymphoedema or elephantiasis of the leg

Page 7: Filariasis Sph

7

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Adult: White and thread-like. Two rings of small papillae on the head.

Female:5~10cm in lengthMale: 2.5~4cm and a curved tail with

two copulatory spicules.

Page 8: Filariasis Sph

8

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Microfilaria: 177~296 µm in length, a sheath with free endings. Bluntly rounded anteriorly and tapers to a point posteriorly. A nerve ring with no nuclei at anterior 1/5 of the body.

Wuchereria bancrofti Brugia malayi

Page 9: Filariasis Sph

9

pa

ra-la

b b

y l. wa

fa m

en

aw

i

B.malayi microfilariae are slightly smaller than those of W.bancrofti.

Microfilariae are sheathed, and about 200 to 275 µm.

Not much is known about the adult worms, as they are not often recovered

One distinctive feature of B.malayi is that the microfilarial nuclei extends to the tip of the tail

Page 10: Filariasis Sph

10

pa

ra-la

b b

y l. wa

fa m

en

aw

i

W.bancrofti B. malayi

Size 244~296 µm 177~230 µm

Cephalic space Shorter Longer

Nuclei Equal sized Unequal sized

clearly coalescing

countable uncountable

Terminal nucleus No Two

Page 11: Filariasis Sph

11

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Host: Mosqutoes (intermediate host) Human (final host)Location: Lymphatics and lymph

nodesInfective stage: Infective larvaeTransmission stage: MicrofilariaeDiagnostic stage: Microfilariae

Page 12: Filariasis Sph

12

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Life cycle

Page 13: Filariasis Sph

13

pa

ra-la

b b

y l. wa

fa m

en

aw

i

WUCHERERIA LIFE CYCLE

Page 14: Filariasis Sph

14

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Phenomen which the number of microfilariae in peripherial blood is very low density during daytime, but increase from evening to midnight and reach the greatest density at 10p.m to 2 a.m.May be related to cerebral activity and vasoactivity of pulmonary vessels.

Page 15: Filariasis Sph

15

pa

ra-la

b b

y l. wa

fa m

en

aw

i

• Larva deposited by mosquito bite• Travel through dermis to lymphatic vessels• Growth (approx 9 months) to mature worms(20-100mm long)

• Worms live 5-7 years (occasionally up to15 years)

• Mate->Microfilariae (1st stage larva)• Females->release up to 10,000 microfilariae/day into bloodstream

• Microfilarie taken up by mosquito bite• Develop into 2nd and 3rd stage larva over 10-14 days inside mosquito vector

Page 16: Filariasis Sph

16

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Network of vessels that collect fluid that leaks out of the blood into tissues (lymph)

Redirects lymph back into the blood stream

Page 17: Filariasis Sph

pa

ra-la

b b

y l. wa

fa m

en

aw

i

17

• Initially asymptomatic• Symptoms develop with increasing numbers of worms

• Less than 1/3 of infected individuals have acute symptoms

• Clinical Course is 3 phases:• Asymptomatic Microfilaremia• Acute Adenolymphangitis (ADL)• Chronic/Irreversible lymphedema• Superimposed upon repeated episodes of ADL

Page 18: Filariasis Sph

pa

ra-la

b b

y l. wa

fa m

en

aw

i

18

• Presents with sudden onset of fever and painful lymphadenopathy

• Retrograde Lymphangitis• Inflammation spreads distally away from lymph node group

• Immune mediated response to dying worms

• Most common areas: Inguinal nodes and Lower extremities

Page 19: Filariasis Sph

19

pa

ra-la

b b

y l. wa

fa m

en

aw

io Inflammation spontaneously resolve

after 4-7 days but can recur frequently

o Recurrences usually 1-4 times/year with increasing severity of lymphedema

o Secondary bacterial infections in edematous(elephantatic) areas

o Filarial fever (fever w/o lymphangitis)o Tropical Pulmonary Eosinophiliao Hyperresponsiveness to microfilariae

trapped in lungso Nocturnal Wheezing

Page 20: Filariasis Sph

pa

ra-la

b b

y l. wa

fa m

en

aw

i

20

o Lymphedemao Mostly LE and inguinal, but can

affect UE and breasto Initially pitting edema, with gradual

hardening of tissues hyperpigmentation & hyperkeratosis

o GenitaliaHydroceles

Page 21: Filariasis Sph

21

pa

ra-la

b b

y l. wa

fa m

en

aw

i

o Renal involvement o Chylurialymph discharge into

urineo Loss of fat and protein

hypoproteinemia & anemiao Hematuria, proteinuria from ?

immune complex nephritiso Secondary bacterial/fungal infections

Page 22: Filariasis Sph

22

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Elephantiasis: accumulation of lymph in extremeties, fibrosis, and thickening of skin.

Page 23: Filariasis Sph

para-lab by l. wafa menawi 23

Debilitates millions of humans by scarring eyes & causing permanent blindness Affects people along rivers in West

& Central Africa (native) & South America (introduced via slavery)

Caused by Onchocerca volvulus Adult females are up to 500mm

long & males up to 40mm long Adults live up to 14 years Restricted to humans (no known

animal reservoirs) Transmitted by black flies

(Simuliidae) Larvae live in fast-flowing water

Page 24: Filariasis Sph

para-lab by l. wafa menawi 24

Black flies ingest microfilariae from blood Move from gut to flight muscles &

mature into infective larvae (L3) L3 larvae migrate to head & enter

humans via bite wound; mature into adults (2-4 months)

Adults accumulate in subcutaneous nodules (1cm diameter) which don’t cause much damage

Mating in nodules produces microfilariae Live under skin causing rashes &

wrinkles Cause blindness when invade eyes

tissues & die there

Nodules

Damaged eye tissues

Page 25: Filariasis Sph

25

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Page 26: Filariasis Sph

para-lab by l. wafa menawi 26

Early stages of eye damage can be reversed by drug treatment Parasiticide ivermectin is most

popular Transfer of worms affected by

feeding behaviour of flies Waggle mouth parts during biting

to increase wound size & create pool of blood (‘pool feeders’)

Main vector = Simulium damnosum Complex of >40 sibling species in

West & East Africa Not all sibling species transmit

worms Insecticide applications used to

control larvae in rivers

Page 27: Filariasis Sph

para-lab by l. wafa menawi 27

Caused by infection with Loa loa Adult worms move under human skin Observed beneath skin or passing

through conjunctiva of eyes (‘eye worms’)

Worms = 2 races (attack humans or arboreal primates)

Transmitted by horse flies (Tabanidae) in genus Chrysops Day-feeding & forest-dwelling Rare case of Tabanidae = biological

vectors Disease endemic to rain forest regions

of West & Central Africa Generally mild & painless (chronic) with

10-15 year incubation period May cause swellings of skin (Calabar

swelling)

Microfilariae in human blood

Adult in human eye

Page 28: Filariasis Sph

28

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Page 29: Filariasis Sph

29

pa

ra-la

b b

y l. wa

fa m

en

aw

i

The standard method for diagnosing active infection is the identification of microfilariae by microscopic examination

However, microfilariae circulate nocturnally, making blood collection an issue

Page 30: Filariasis Sph

30

pa

ra-la

b b

y l. wa

fa m

en

aw

i

A “card test” for parasite antigens requring only a small amount of blood has been developedDoes not require laboratory

equipmentBlood drawn by finger stick

Urinalysis, CBC and Comprehensive Chemistries

Foot Biopsy: Normal Skin with areas of chronic inflammation

Page 31: Filariasis Sph

31

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Microfilariae are seen in blood smears and are DIAGNOSTIC

Page 32: Filariasis Sph

para-lab by l. wafa menawi 32

BLOOD SMEAR - MICROFILARIA

Note wavy microfilarial worm in the thick part of blood film.

Dark blue structures are nuclei

Tail end tapering (no nuclei)

Sheath covering worm.

Page 33: Filariasis Sph

para-lab by l. wafa menawi 33

BLOOD SMEAR - MICROFILARIA

Note wavy microfilarial worm in the thick part of blood film.

Head end of the worm – rounded (no nuclei)

(Sheath is not clearly seen)

Page 34: Filariasis Sph

para-lab by l. wafa menawi 34

BLOOD SMEAR - MICROFILARIA

Note wavy microfilarial worm in the thick part of blood film.

Dark blue structures are nuclei

Tail end - tapering sheath (no nuclei)

Page 35: Filariasis Sph

para-lab by l. wafa menawi 35

HYDROCELE FLUID – CELL BLOCK. Note wavy

microfilarial worms.

Inflammatory cells – lymphocytes.

Hemorrhagic fluid sediment

Page 36: Filariasis Sph

para-lab by l. wafa menawi 36

HYDROCELE FLUID – CELL BLOCK.

Note wavy microfilarial worms.

Inflammatory cells – lymphocytes.

RBC

Page 37: Filariasis Sph

para-lab by l. wafa menawi 37

HYDROCELE FLUID – CELL BLOCK.

Note wavy microfilarial worms.

Inflammatory cells – lymphocytes.

RBC

Page 38: Filariasis Sph

para-lab by l. wafa menawi 38

HYDROCELE FLUID – CELL BLOCK.

Inflammatory cells – lymphocytes.

RBC

Microfilaria.

Page 39: Filariasis Sph

39

pa

ra-la

b b

y l. wa

fa m

en

aw

i

As with malaria, the most effective method of controlling the spread of W.bancrofti and B.malayi is to avoid mosquito bites

The CDC recommends that anyone in at-risk areas:

Sleep under a bed netWear long sleeves and trousersWear insect repellent on exposed skin, especially at night

Page 40: Filariasis Sph

40

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Covering water-storage containers and improving waste-water and solid-waste treatment systems can help by reducing the amount of standing water in which mosquitoes can lay eggs.

Killing eggs (oviciding) and killing or disrupting larva (larviciding) in bodies of stagnant water can further reduce mosquito populations.

Page 41: Filariasis Sph

41

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Treatment of filariasis involves two components:

Getting rid of the microfilariae in people's blood

Maintaining careful hygiene in infected persons to reduce the incidence and severity of secondary (e.g., bacterial) infections.

Page 42: Filariasis Sph

42

pa

ra-la

b b

y l. wa

fa m

en

aw

i

Anti-filariasis medicines commonly used include: Diethylcarbamazine (DEC)

reduces microfilariae concentrations kills adult worms

Albendazole kills adult worms

Ivermectin kills the microfilariae produced by adult worms

Page 43: Filariasis Sph

43

pa

ra-la

b b

y l. wa

fa m

en

aw

i

The disease is usually treated with single-dose regimens of a combination of two drugs, one targeting microfilariae and one targeting adult worms (i.e.,either diethylcarbamazine and albenadazole, or ivermectin and albendazole

In some areas, DEC laced table salt is used as a prophylactic