Filariasis

NematodaSystemic round worms

Filaria-a roundworm

-Adult filaria live in body cavities, lymphatics, and subcutaneous tissues

-embryos (microfilaria) live in blood or dermis

-all require an insect or crustaean vector

-microfilaria (150-350 µ long)

- adults 2 cm – 120 cm (4 – 10 µ wide)

Filaria

1. Onchocerca volvulus - river blindness - black fly

2. Wuchereria bancrofti - lymphatic filariasis - mosquitoBrugia malayi

3. Loa Loa - eye worm - deer fly

4. Dracunculus medinensis - Guinea worm - cyclops

5. Mansonella perstans - midge

6. Mansonella ozzardi - midge

Wuchereria bancrofti and Brugia malayi

lymphatic filariasiselephantiasis

Lymphatic filariasis Wuchereria bancroftiBrugia malayi

Lymphatic filariasisWuchereria bancrofti and Brugia malayi

- vector - mosquito (Culex, Anopheles)

- adult - in lymphatics length 4-10 cm.

-microfiliaria - in blood - 150-350 µ long - 4 – 10 µ wide

Wuchereria Chengmai

OnchocercaLoa

Clinical states of Wuchereria bancrofti1. assymptomatic2. inflammatory - lymphangitis - arms 25%

- legs 11%- epididimitis, funiculitis 42%- ‘filarial fevers’- orchitis- filarial abscess

3. Obstructive - elephantiasis- chyluria- hydrocoele

4. Tropical pulmonary eosinophilia

blood microfilaria

1 – direct examination (thick or thin smear)

2 – Knotts concentration technique

3 – millipore filtration

4 – antigen capture

Loa loa

“eye worm”

Loa loa (eye worm)

Crysops (Loa loa vector)

Calabar swelling

Calabar swelling

Loa loa adult in Calabar swelling x section

Loa loa (the “eye worm”)

Loa loa microfilaria

Onchocerca volvulus

“River blindness”

Simulium damnosum

The “black fly”

Onchocerca nodule

X section of Onchocercal nodule

Skin snips for microfilaria with oculoscleral biopsy forceps

Onchocerca microfilaria from a skin snip

Anterior chamber microfilaria and keratic precipitates

Kingdom Animalia

Subkingdom Protozoa

Phylum Sarcomastigophora

Phylum Apicomplexa

Phylum Ciliophora

Phylum Microspora

Subkingdom Metazoa

Phylum Nematoda

Phylum Platyhelminthes cestodes (tapeworms)

trematodes (flukes)

Taxonomy

Trematodes

“flukes”

Trematodes = flatworms

watercresshuman (liver)Fasciola

freshwater crabs, cray fishhuman (lung)Paragonimus

freshwater fishhuman (liver)Opisthorchis

waterhuman (blood)Schistosoma

Source (cercaria/metacercaria)adult

hermaphroditicliver flukes, lung flukes etc.

two sexesblood flukes

Humanadult ~5-8 yrs)

Schistosoma life cycle

Egg (~21 days in tissue)

SnailRedia/sporocysts (~6 wks)

Miracidium (~10 hrs)

Cercaria ~2 days)

Schistosomiasis (blood flukes)

Schistosoma mansoniSchistosoma hematobiumSchistosoma japonicum

etc.

S. hematobium S. mansoni S. japonicum

swimmingciliated miracidium

Swimming cercaria

Clinical Presentation of schistosomiasis

Intestinal

S. mansoni

S. japonicum

S. intercalatum

S. mekongi

Urinary

S. hematobium

Geographic distribution

Chronic Intestinal Schistosomiasis

portal hypertension with splenomegalyoesophagial variceshypersplenismascitis

pulmonary hypertension

CNS lesions: spine - transverse myelitiscerebral – seizures (S. japonicum)

intestinal polyposis: both sessile and pedunculated

chronic salmonellosis

intestinal granulomatosis: contractures of colon, intusseception

Urinary schistosomiasis

Schistosoma haematobium

Schistosoma near urethra

Schistosoma hematobiumPresentation

hematuria (terminal)urinary frequencypyuriapyelonephritisobstructive uropathycancer of bladder (squamous cell)distant metastases (spinal column)

(pulmonary hypertension)

Laboratorydebris in urineeggs in urine (overnight-millipore)I.V.P. abnormalitiescystoscopyserology

Diagnosis: intestinal schistosomiasis

1. History of freshwater exposure2. Stool for O&P (egg counts and viability)3. Serology-- Elisa and Western Blot4. Antigen capture5. Eosinophilia6. Rectal snips or biopsies7. Liver biopsy8. Ultrasound or CT of abdomen

Treatment of Schistosomiasis

praziquantel

Schistosoma japonicum is a zoonosis