Tissue Nematodes
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Tissue Nematodes II BPT Dr Ekta Chourasia Microbiology
Classification – Tissue Nematodes Lymphatic
Wuchereria bancrofti Brugia malayi Brugia timori
Subcutaneo us
Loa loa (african eye worm) Onchocerca volvulus (blinding filaria) Dracunculus medinensis (thread worm)
Conjunctiva
Loa loa
08/04/09
Dr Ekta, Microbiology
Wuchereria bancrofti (Filarial worm) Definitive host
Man
Intermediate host
Female Culex, Aedes or Anopheles mosquito
Infective form
Third stage larva
Mode of transmission
Inoculation – bite of mosquito
Site of localization
Lymphatics / lymph nodes of man
08/04/09
Dr Ekta, Microbiology
Life cycle
08/04/09
Dr Ekta, Microbiology
Clinical features
Infection - Wuchereriasis/ Lymphatic filarisis/ Bancroftian filariasis
Pathogenic states are produced only by adult worm (living/ dead) – classical filariasis Occult filariasis – lesions produced by microfilaria
Clinical states in classical filariasis can be classified as:
08/04/09
Asymptomatic ( in endemic areas) Inflammatory – lymphadenitis, lymphangitis, fever, lymphoedema Obstructive – elephantiasis, lymphangiovarix, chyluria, hydrocele Tropical pulmonary eosinophilia Dr Ekta, Microbiology
Obstructive stage Lymphatic
obstruction – occurs with the death of worms
Causes
of obstruction –
Blocking
of lumen by dead worms Excessive proliferation & thickening of walls of lymphatic vessels Fibrosis of lymphatic vessels 08/04/09
Dr Ekta, Microbiology
Consequences of Lymphatic Obstruction Elephantiasis
of organs like leg, scrotum, penis, vagina, breast, arm etc – fibrotic thickening of skin & subcutaneous tissue
Lymphangiovarix
lymphatics.
– dilatation of afferent
Rupture
of Lymphangiovarix into urinary tract – chyluria
Hydrocele 08/04/09
Dr Ekta, Microbiology
Lymphatic filariasis
08/04/09
Dr Ekta, Microbiology
chyluria
08/04/09
Dr Ekta, Microbiology
Classical v/s Occult filariasis Classical filariasis
Occult filariasis
Cause
Developing worms & adults
Microfilariae
Basic lesions
Acute inflammation followed An eosinophilic granuloma by an epitheloid granuloma (hypersensitivity reaction) surrounding the adult worm & a fibrous scar
Organs involved
Lymphatic system
Lymphatic system, lungs, liver & spleen
Microfilaria
Present in Blood
Present in affected tissues not in blood
Therapeutic response
No response to any drug
Responds to microfilaricidal drug, DEC.
08/04/09
Dr Ekta, Microbiology
Laboratory diagnosis
Specimen - blood collected at night, preferably capillary blood from ear lobes, chylous urine, hydrocele fluid, exudate from lymphangiovarix
Microscopic examination – wet mount or stained with giemsa: sheathed microfilaria with no nuclei at tail tip
08/04/09
Dr Ekta, Microbiology
Laboratory diagnosis
Concentration techniques – for capillary blood, venous blood (Knott’s technique)
DEC provocation test – 100 mg of DEC orally, examine peripheral blood smear after 30 to 45 minutes
Serology – using non specific Ags 1. 2. 3.
08/04/09
Passive hemagglutination test Fluoresecent ab test ELISA Dr Ekta, Microbiology
Treatment
Prevention
DEC (Diethylcarbamazine) – microfilaricidal: 6mg/ kg/day for 2-3 weeks Elevation of the affected limbs, use of elastic bandages & local foot care – reduces symptoms of lymphatic obstruction Surgical treatment of hydrocele
08/04/09
Dr Ekta, Microbiology
Destruction of mosquitoes
Protection against mosquito bites
Treatment of carriers
Brugia sps
Two species infect humans : B.malayi & B.timori
Causes lymphatic filariasis
Transmitted by Mansonia & Anopheles species of mosquitoes
Life cycle, pathogenesis, clinical features, diagnosis & treatment – similar to W. bancrofti, with a following differences
08/04/09
Children commonly affected Rapid development of signs & symptoms Elephantiasis affect lower extremities Chyluria & hydrocele rare
Dr Ekta, Microbiology
Onchocerca volvulus (Blinding filaria – 2nd most common cause of infectious blindness)
Definitive host
Man
Intermediate host
Black flies (simulium)
Infective form
Larva
Mode of transmission
Inoculation
Site of localization
Subcutaneous tissue, dermis & eye
08/04/09
Dr Ekta, Microbiology
Clinical features
Incubation period - 10 to 12 months
Eosinophilia and urticaria.
Nodular and erythematous lesions (Onchocercomata) in the skin and subcutaneous tissue
Photophobia, lacrimation, keratitis and blindness – due to trapping of microfilaria in the cornea, choroid, iris and anterior chambers.
08/04/09
Dr Ekta, Microbiology
08/04/09
Dr Ekta, Microbiology
Diagnosis & Treatment
Nodular biopsy – adult worm
Skin snip – unsheathed microfilaria with no nuclei
Treatment – Ivermectin, surgical removal, DEC in non ocular onchocercosis
08/04/09
Dr Ekta, Microbiology
08/04/09
Dr Ekta, Microbiology
Loa loa
(African eye worm)
Definitive host
Man
Intermediate host
Chrysops (deer fly)
Infective form
Larva
Mode of transmission
Inoculation
Site of localization
Subcutaneous & deep connective tissue
08/04/09
Dr Ekta, Microbiology
Clinical features Subcutaneous
swelling – Calabar or fugitive swelling, measuring 5 to 10 cm, marked by erythema and angioedema, usually in the extremities
Migrating
worm in subconjunctival tissue
08/04/09
Dr Ekta, Microbiology
Diagnosis & Treatment •
Peripheral blood smear - Sheathed microfilaria with nuclei upto rounded tail tip
•
Isolation of worms from the conjunctiva or subcutaneous biopsy
•
Treatment - Ivermectin, surgical removal, DEC (effective against adult & microfilaria)
08/04/09
Dr Ekta, Microbiology
Dracunculus medinensis
(Guinea Worm)
Adult worms
Male 2 to 4 cm Female 70 –120 cms, viviparous
Definitive host
Human
Intermediate host
Cyclops
Infective form
Larva inside Cyclops
Mode of transmission
Ingestion of water contaminated with cyclops
Site of localization
Subcutaneous tissue
08/04/09
Dr Ekta, Microbiology
08/04/09
Dr Ekta, Microbiology
Clinical Features
Disease – Dracunculosis
Clinical features develop an year after infection following the migration of worm to the subcutaneous tissue of the leg
Blister formation – rupture of blister when in contact with water ulceration – release of larvae by adult female worm
Secondary bacterial infection of ulcer
08/04/09
Dr Ekta, Microbiology
Diagnosis & Treatment
Detection of adult worm – when it appears at the surface of skin
Detection of larva – in milky fluid released by worm on exposure to water
Radiology – calcified worm in deeper tissues
Treatment – 1.
2.
3. 08/04/09
Thiabendazole/ Metronodazole – symptomatic relief, easy removal of worm Gradual extraction of worm by winding of a few cms on a matchstick per day, over 3 to 4 weeks Surgical excision Dr Ekta, Microbiology
Prevention
Provision of safe water supply
Education to discourage people from entering water source
Filtering water through a double folded cloth
Boiling water before drinking
Discouraging the use of step wells
08/04/09
Dr Ekta, Microbiology
Classification – Tissue Nematodes Lymphatic
Wuchereria bancrofti Brugia malayi Brugia timori
Subcutaneo us
Loa loa (african eye worm) Onchocerca volvulus (blinding filaria) Dracunculus medinensis (thread worm)
Conjunctiva
Loa loa
08/04/09
Dr Ekta, Microbiology
Wuchereria bancrofti (Filarial worm) Definitive host
Man
Intermediate host
Female Culex, Aedes or Anopheles mosquito
Infective form
Third stage larva
Mode of transmission
Inoculation – bite of mosquito
Site of localization
Lymphatics / lymph nodes of man
08/04/09
Dr Ekta, Microbiology
Life cycle
08/04/09
Dr Ekta, Microbiology
Clinical features
Infection - Wuchereriasis/ Lymphatic filarisis/ Bancroftian filariasis
Pathogenic states are produced only by adult worm (living/ dead) – classical filariasis Occult filariasis – lesions produced by microfilaria
Clinical states in classical filariasis can be classified as:
08/04/09
Asymptomatic ( in endemic areas) Inflammatory – lymphadenitis, lymphangitis, fever, lymphoedema Obstructive – elephantiasis, lymphangiovarix, chyluria, hydrocele Tropical pulmonary eosinophilia Dr Ekta, Microbiology
Obstructive stage Lymphatic
obstruction – occurs with the death of worms
Causes
of obstruction –
Blocking
of lumen by dead worms Excessive proliferation & thickening of walls of lymphatic vessels Fibrosis of lymphatic vessels 08/04/09
Dr Ekta, Microbiology
Consequences of Lymphatic Obstruction Elephantiasis
of organs like leg, scrotum, penis, vagina, breast, arm etc – fibrotic thickening of skin & subcutaneous tissue
Lymphangiovarix
lymphatics.
– dilatation of afferent
Rupture
of Lymphangiovarix into urinary tract – chyluria
Hydrocele 08/04/09
Dr Ekta, Microbiology
Lymphatic filariasis
08/04/09
Dr Ekta, Microbiology
chyluria
08/04/09
Dr Ekta, Microbiology
Classical v/s Occult filariasis Classical filariasis
Occult filariasis
Cause
Developing worms & adults
Microfilariae
Basic lesions
Acute inflammation followed An eosinophilic granuloma by an epitheloid granuloma (hypersensitivity reaction) surrounding the adult worm & a fibrous scar
Organs involved
Lymphatic system
Lymphatic system, lungs, liver & spleen
Microfilaria
Present in Blood
Present in affected tissues not in blood
Therapeutic response
No response to any drug
Responds to microfilaricidal drug, DEC.
08/04/09
Dr Ekta, Microbiology
Laboratory diagnosis
Specimen - blood collected at night, preferably capillary blood from ear lobes, chylous urine, hydrocele fluid, exudate from lymphangiovarix
Microscopic examination – wet mount or stained with giemsa: sheathed microfilaria with no nuclei at tail tip
08/04/09
Dr Ekta, Microbiology
Laboratory diagnosis
Concentration techniques – for capillary blood, venous blood (Knott’s technique)
DEC provocation test – 100 mg of DEC orally, examine peripheral blood smear after 30 to 45 minutes
Serology – using non specific Ags 1. 2. 3.
08/04/09
Passive hemagglutination test Fluoresecent ab test ELISA Dr Ekta, Microbiology
Treatment
Prevention
DEC (Diethylcarbamazine) – microfilaricidal: 6mg/ kg/day for 2-3 weeks Elevation of the affected limbs, use of elastic bandages & local foot care – reduces symptoms of lymphatic obstruction Surgical treatment of hydrocele
08/04/09
Dr Ekta, Microbiology
Destruction of mosquitoes
Protection against mosquito bites
Treatment of carriers
Brugia sps
Two species infect humans : B.malayi & B.timori
Causes lymphatic filariasis
Transmitted by Mansonia & Anopheles species of mosquitoes
Life cycle, pathogenesis, clinical features, diagnosis & treatment – similar to W. bancrofti, with a following differences
08/04/09
Children commonly affected Rapid development of signs & symptoms Elephantiasis affect lower extremities Chyluria & hydrocele rare
Dr Ekta, Microbiology
Onchocerca volvulus (Blinding filaria – 2nd most common cause of infectious blindness)
Definitive host
Man
Intermediate host
Black flies (simulium)
Infective form
Larva
Mode of transmission
Inoculation
Site of localization
Subcutaneous tissue, dermis & eye
08/04/09
Dr Ekta, Microbiology
Clinical features
Incubation period - 10 to 12 months
Eosinophilia and urticaria.
Nodular and erythematous lesions (Onchocercomata) in the skin and subcutaneous tissue
Photophobia, lacrimation, keratitis and blindness – due to trapping of microfilaria in the cornea, choroid, iris and anterior chambers.
08/04/09
Dr Ekta, Microbiology
08/04/09
Dr Ekta, Microbiology
Diagnosis & Treatment
Nodular biopsy – adult worm
Skin snip – unsheathed microfilaria with no nuclei
Treatment – Ivermectin, surgical removal, DEC in non ocular onchocercosis
08/04/09
Dr Ekta, Microbiology
08/04/09
Dr Ekta, Microbiology
Loa loa
(African eye worm)
Definitive host
Man
Intermediate host
Chrysops (deer fly)
Infective form
Larva
Mode of transmission
Inoculation
Site of localization
Subcutaneous & deep connective tissue
08/04/09
Dr Ekta, Microbiology
Clinical features Subcutaneous
swelling – Calabar or fugitive swelling, measuring 5 to 10 cm, marked by erythema and angioedema, usually in the extremities
Migrating
worm in subconjunctival tissue
08/04/09
Dr Ekta, Microbiology
Diagnosis & Treatment •
Peripheral blood smear - Sheathed microfilaria with nuclei upto rounded tail tip
•
Isolation of worms from the conjunctiva or subcutaneous biopsy
•
Treatment - Ivermectin, surgical removal, DEC (effective against adult & microfilaria)
08/04/09
Dr Ekta, Microbiology
Dracunculus medinensis
(Guinea Worm)
Adult worms
Male 2 to 4 cm Female 70 –120 cms, viviparous
Definitive host
Human
Intermediate host
Cyclops
Infective form
Larva inside Cyclops
Mode of transmission
Ingestion of water contaminated with cyclops
Site of localization
Subcutaneous tissue
08/04/09
Dr Ekta, Microbiology
08/04/09
Dr Ekta, Microbiology
Clinical Features
Disease – Dracunculosis
Clinical features develop an year after infection following the migration of worm to the subcutaneous tissue of the leg
Blister formation – rupture of blister when in contact with water ulceration – release of larvae by adult female worm
Secondary bacterial infection of ulcer
08/04/09
Dr Ekta, Microbiology
Diagnosis & Treatment
Detection of adult worm – when it appears at the surface of skin
Detection of larva – in milky fluid released by worm on exposure to water
Radiology – calcified worm in deeper tissues
Treatment – 1.
2.
3. 08/04/09
Thiabendazole/ Metronodazole – symptomatic relief, easy removal of worm Gradual extraction of worm by winding of a few cms on a matchstick per day, over 3 to 4 weeks Surgical excision Dr Ekta, Microbiology
Prevention
Provision of safe water supply
Education to discourage people from entering water source
Filtering water through a double folded cloth
Boiling water before drinking
Discouraging the use of step wells
08/04/09
Dr Ekta, Microbiology
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