filariasis by dr.t.v.rao md

8/20/2019 Filariasis by Dr.T.V.Rao MD

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FilariasisDr.T.V.Rao MD


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WHAT IS

Filariasis•Filariasis (or philariasis) is a parasiticdisease caused by an infection with

roundworms of the Filarioidea type. These are spread by blood-feedingblack ies and mosquitoes. Thisdisease belongs to the group of

diseases called helminthiasis.•Eight known larial nematodes usehumans as their deniti!e hosts.


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Epidemiology-

International•"#$ million in %$ countries•

" billion at risk•&$' - ucherariaancrofti

•*emainder + rugia ,alayi


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Parasites• hite slender roundworms• Three types uchereriabancrofti rugia malayi rugiatimori

• /i!e for 0-1 years produce

millions of o2spring•lock the lymphaticsystem•3etwork of channels andlymph nodes that helpmaintain uid le!els in thebody

•lockage leads to edema(collection of uid in tissues)


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Mosquitos are Vectorsand spread the

Inection•4 mosquito is the intermediatehost and carrier. The most

common !ectors5carriers are•in 4frica 4nopheles species•in the 4mericas 6ule7

quinquefasciatus•in the 8acic and in 4sia,ansonia and 4edes species.


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Millions are Inected

!ith "lariasis•9ne hundred and twenty million people inat least %$ nations of the world ha!elymphatic lariasis 9ne billion people are

at risk of getting infected. 3inety percentof these infections are caused byuchereria bancrofti and most of theremainder by rugia malayi. For .

bancrofti humans are the e7clusi!e hostand e!en though certain strains of .malayi can also infect some felines andmonkeys.


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Wucheraria

#ancroti• 8rimary causati!e agent of lymphaticlariasis

• 9!ert bancroftian lariasis ""0 millioncases worldwide (:0.0 million ;ndia :$million sub-il)


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12/62Micro"laria o Mansonella ozzardi.


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%haracters o the Adult

Parasites•4n 4dult femaleuchereriabancrofti is about%$+"$$ mm longand $.#:+$.?$mm in diameterwhereas a male isabout :$ mm longand $." mm indiameter.


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Ho! the )ar*a Appear

•4 microlaria is about #:$+?$$@m (micrometers) long and 1.0+"$

@m thick. ;t is sheathed and hasnocturnal periodicity e7cept the


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Ho! the )ar*a

Appear• The nuclearcolumn (the cellsthat constitute itsbody) is looselypacked. The cellscan be seenindi!idually undera microscope anddo not e7tend tothe tip of the tail.


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Filarial )ar*ae


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Impact o Filariasis

•with the disease can su2er fromlymphedema and elephantiasis and inmen swelling of the scrotum called

hydrocele. /ymphatic lariasis is aleading cause of permanent disabilityworldwide. 6ommunities frequently shunand reAect women and men disguredby the disease. 42ected peoplefrequently are unable to work becauseof their disability and this harms theirfamilies and their communities.


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)ie %ycle(•;nfecti!e lar!ae aretransmitted by infected biting

mosquitoes during a bloodmeal. The lar!ae migrate tolymphatic !essels and lymph

nodes where they de!elopinto microlariae-producingadults.


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)ie %ycle(• The adults dwell inlymphatic !essels and

lymph nodes where theycan li!e for se!eral years.

The female worms producemicrolariae whichcirculate in the blood


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Micro"lariae• The microlariae infect bitingmosquitoes. ;nside the mosquito themicrolariae de!elop in " to # weeksinto infecti!e lariform (third-stage)lar!ae. Buring a subsequent bloodmeal by the mosquito the lar!aeinfect the human host. They migrate tothe lymphatic !essels and lymphnodes of the human host where theyde!elop into adults.


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)ie cycle o Brugia that also

applies to Wuchereria #y %+%


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Multiplication and

)ie %ycle•4dult female worms producemicrolariae. Feeding !ectormosquitoes ingest microlariae fromthe bloodstream. ;n the mosquito themicrolariae mature to infecti!elar!ae which migrate to the

mosquitoCs mouth-parts enter a newhost !ia the !ectorCs puncture woundmigrate to the lymphatics matureand mate.


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Why %linical

Maniestations•Bisease manifestations aredue to lymphatic dysfunction

resulting from the presence ofli!ing and dead worms lymphthrombi inammation and

immune reactions to wormsand worm products.


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Pathogenesis and

Pathology •6omple7 interplay of thepathogenic potential of the

parasite the immune response ofthe host and e7ternal(CcomplicatingC) bacterial andfungal infections.

•,ost recogni>able + Denitaldamage ( =ydroceles ) and/ymphoedema5elephantiasis


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Clinical features.There are chronic, acute and

asymptomatic presentations oflymphatic larial disease, as well

as some syndromes associated with

these infections. Among chronicmanifestations, h ydrele, even

though found only with W.

bancrofti infections not in Brugia infections is the most commonclinical manifestation of lymphatic

lariasis.


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Bisease ,anifestations

•4lthough the parasite damagesthe lymph system most infected

people ha!e no symptoms andwill ne!er de!elop clinicalsymptoms. These people do notknow they ha!e lymphatic

lariasis unless tested. 4 smallpercentage of persons will de!eloplymphedema.


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+isease

Maniestations• This is caused by uid collectionbecause of improper functioning

of the lymph system resulting inswelling. This mostly a2ects thelegs but can also occur in thearms breasts and genitalia. ,ostpeople de!elop these symptomsyears after being infected.


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What is elephantiasischaracteri,ed #y

• Thickening and hardening of theskin

•6orrect.• ) ;ncreased body si>e due tomasses of worms all o!er the

body especially in the nose• 6) Eosinophilia heart failureand breathing diculty


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What causes

elephantiasis•4) Becrease of blood ow dueto worms inside blood !essels

• ) lockage of lymph uiddue to worms inside lymph!essels• 6) ,asses of microlaria inskin tissue


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Tropical pulmonaryeosinophilia .TPE/

• Bistinct syndrome in some indi!iduals

• 8aro7ysmal cough and whee>ing

•

eight loss low grade fe!erpronounced blood eosinophilia

• Total serum ;gE and antilarial 4btitres raised

• *esponds well to treatment but in itsabsence progressi!e pulmonarydamage


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SymptomsFe!erGidney damage


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Social Impact o

+isease


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Clinical features.There are chronic, acute and

asymptomatic presentations oflymphatic larial disease, as well

as some syndromes associated with

these infections. Among chronicmanifestations, h ydrele, even

though found only with W.

bancrofti infections not in Brugia infections is the most commonclinical manifestation of lymphatic

lariasis.


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Pathogenesis

•,en can de!elop hydrocele or swelling of thescrotum due to infection with one of theparasites that causes /F specically .bancrofti.

•Filarial infection can also cause tropicalpulmonary eosinophilia syndrome althoughthis syndrome is typically found in personsli!ing with the disease in 4sia. ing. The eosinophilia is oftenaccompanied by high le!els of ;gE(;mmunoglobulin E) and antilarial antibodies.


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•=istologically - dilatation and

proliferation of lymphaticendothelium H abnormallymphatic function•

Cnon-inammatory pathwayC•Iinammatory pathwayI - adenitisand retrograde lymphangitis•bacterial and fungalsuperinfections


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6linical Features•Chronic manifestations: =ydrocoele (mostcommon ) elephantiasis 6hyluria

• Acute manifestations: 4cute inammatoryepisodes CB/4C(dermatolymphangioadenitis)

Clarial fe!erC tropical pulmonaryeosinophilia acute inammatory reaction• Asymptomatic Presentations•Other Syndromes: arthritis (typically

monoarticular) endomyocardial brosistenosyno!itis thrombophlebitisglomerulonephritis lateral popliteal ner!epalsy and others.


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While lymphedema can develop in theabsence of overt inammatoryreactions and in the early stages beassociated with microlaremia, the

development of elephantiasis (eitherof the limbs or the genitals) is mostoften associated with a history ofrecurrent inammation. The early

pitting edema gives rise to a stronger


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Diagnosis.ntil very recently, diagnosinglymphatic lariasis had been

e!tremely di"icult, since parasites

had to be detected microscopicallyin the blood, and in most parts ofthe world, the parasites have a

nocturnal periodicity that restrictstheir appearance in the blood toonly the hours around midnight.


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+iagnosisJntil recently !ery dicultto diagnose3octurnal periodicity Theworms can only be detected in

the blood of those infectedaround the hour of midnight.

3ew specic card testBetects parasites using onlynger prick blood tests any

time of day.Jltrasound can identifyrapidly mo!ing adult worms.


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BiagnosisJntil recently diagnosisdepended on the direct

demonstration of the parasite Antigen detection: 6irculatinglarial antigen (6F4) - CgoldstandardC for diagnosing

Wuchereria bancrofti infections.6linical Biagnosis


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S l


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Serology

•


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Treatment.Communities where

lariasis is endemic. Theprimary goal of treating thea"ected community is to

eliminate microlariae


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Management •Treating the infection: BE6 (K mg5kgper day) for "# days in bancroftianlariasis and for K days in brugianlariasis repeated at "-K monthlyinter!als if necessary

•;!ermectin

•4lbenda>ole

•


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Treatment andManagement o

Elephantiasis8re!ention,osquito nets insect repellents

Loodoo healing techniques

Ele!ate and e7ercise a2ected body part


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Management andTreatment o )ymphatic

Filariasis•6urrently Jsed• 4ntilarial drugs (BE6 and i!ermectin)are useful against lar!al o2spring

• Testing• Bo7ycycline

• Tested on a Tan>anian !illage.

• Found to almost completely eliminate adultworms ": months after treatment.

•


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8re!ention

•y decreasing contact betweenhumans and !ectors or bydecreasing the amount of infection

the !ector can acquire•Population: through reducing thenumbers of mosquito !ectors

•#-drug treatment regimens(selecting among albenda>ole andeither i!ermectin ordiethylcarbama>ine MBE6N)


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Ho! to pre*ent the Filarialinection

•Individuals: personalrepellents bednets or

insecticide-impregnatedmaterials.•8rophylactic regimen ofBE6 (K mg5kg per day 7 #days each month)

Ho! can I pre*ent


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Ho! can I pre*entinection

•=ow can ; pre!ent infectionO

•4!oiding mosquito bites is the best form ofpre!ention. The mosquitoes that carry the

microscopic worms usually bite betweenthe hours of dusk and dawn. ;f you li!e in ortra!el to an area with lymphatic lariasis

•


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Treating theindividual.

•$oth albenda%ole and &' havebeen shown to be e"ective in

illing the adult*stage larialparasites. +t is clear that thisantiparasite treatment can resultin improvement of patients

elephantiasis and hydrocele(especially in the early stages ofdisease)

WHO's Strategy toWHO's Strategy to


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WHO s Strategy to WHO s Strategy toliminate !ym"haticliminate !ym"hatic

#ilariasis#ilariasis

•The strategy of the World -ealthrgani%ation (W-) of the /lobal0rogramme to 'liminate1ymphatic 2ilariasis has 3 aims4 a)to stop the spread of infection(interrupt transmission), and

secondly b) to alleviate thesu"ering of a"ected individuals.


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Mass Treatments orPre*ention

•To interrupt transmission, districts in whichlymphatic lariasis is endemic must beidentied, and then community*wide (5masstreatment5) programs implemented to treatthe entire at ris population. +n mostcountries, the program will be based on once* yearly administration of single doses of 3drugs given together4 albenda%ole plus either

diethylcarbama%ine (&') or ivermectin, thelatter in areas where either onchocerciasis,loiasis or another may also be endemic.

i


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%ommunity

Treatments•To alleviate the su"ering caused by thedisease, it will be necessary to implementcommunity education programmes to

raise awareness in a"ected patients.This would promote the benets ofintensive local hygiene and the possibleimprovement, both in the damage that hasalready occurred, and in preventing thedebilitating and painful, acute episodes ofinammation.

International communities


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International communitieshelp or elimination o

+isease•The pledge in 6778 by/la!co9mith:line to collaborate withthe W- in its elimination e"orts

included the donation of numerousresources, but especially albenda%olefree of charge, for as long asnecessary. This donation, coupled

with the recent decision by ;erc toe!pand its wellnown ;ecti%an


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conomic and Socialconomic and Social$m"act.$m"act.


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• Program %reated and+esigned #y +r'T'V'0ao M+

or Medical and Paramedicalstudents on glo#al Educationon %ommunica#le diseases

• Email• doctort!raoPgmail.com

filariasis by dr.t.v.rao md

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