Prof. Kabkaew Sukontason Dept. Parasitology, Fac. Medicine

Gnathostoma spinigerum

Filarial worms

Objective

Gnathostoma spinigerum

Filarial worms

- Wuchereria bancrofti - Brugia malayi

- Morphology

- Life cycle & Route of infection

- Clinical manifestation

- Treatment - Prevention

Gnathostoma: Round worm (nematode)

Family : Gnathostomatidae

Thailand: 5 species

G. spinigerum

G. hispidum

G. doloresi

G. malaysiae

G. vietnamicum

พยาธิตัวจี๊ด ~23 species

M

F

spicule (for mating)

- stout body

- head bulb

- 8-11 rows of cephalic spines help worm lodge in host’s tissue

- Female: 1.3-5.5 cm

- Male: 1.6-4 cm (+ 2 spicules)

Morphology of adult

head bulb

cephalic spines

Life Cycle: complex

eL3

aL3

accidental or paratenic host

L2

DH: dog, cat, tiger

wild mammals Habitat: stomach (tumor)

2nd IH: freshwater fish

1st IH: cyclops

PH

PH

PH

PH

PH: fish, amphibians,

reptiles, birds, etc

egg

- oval shape - a polar plug at one end

L2

eL3

When newly hatched, ensheathed L2 were ingested

by cyclop.

Moult to EL3 in the body cavity of cyclop.

eL3 in Cyclops

~0.5 mm

Morphology of L3 - early L3 (0.5 mm) - advanced L3 (3-4 mm)

- head bulb

- 4 rows of cephalic spines

- Incomplete reproductive organs

eL3 aL3

Tumor in stomach wall

become adult after 4-6 mo.

DH: stomach --> peritoneal cavity --> liver --> stomach (tumor)

Human (accidental host): have adult (rare), but cannot return to stomach (+tumor)

Route of infection

Ingestion of raw, undercooked animals (+ L3): 2nd IH, PH..Somfak, Pla-ra (Thailand: eel, snake-headed fish, undercooked chicken)

Skin penetration: during food preparation

Congenital transmission: 3d, 7 d, 1 mo

Swallowing water (+ infected Cyclops)

Wound: use of fresh dead animal (Jpn, China)

(Fresh-water fish foodborne zoonoses)

Fermented fish: ส้มฟัก ปลาร้า

Human: accidental host

- aL3

- immature adult

- mature adult (rare)

Pathology

depend on organ during migration: mechanical injury of organ, tissue produce enz, substances (hemolysin, hyaloronidase, protease)

cause…inflammation, local edema, eosinophil

Clinical manifestation

Human gnathostomiasis

1. Cutaneous gnathostomiasis

intermittent migratory swelling (1 mo. after infection), ~ 1 cm/hr

migrate near body surface may cause creeping eruption inflammatory foci itching

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2. Visceral gnathostomiasis (less common: deep migrate, depend on organ)

CNS: -May present as “myeloencephalitis” or “meningitis”

-Studies in 24 patients with CNS: most common =

“radiculomyelitis” or “radiculomyelitis associated with

encephalitis and subarachnoid hemorrhage”

- may sudden onset of extremely severe radicular pain/

headache paralysis of extremities and/or

cranial nerves

- lung: respiratory symptoms

- eye: pain, visual impairment,

in anterior chamber

- ear, nose, throat: facial swelling

- urogenital

- gastrointestinal tract

- appendix

- etc…..

facial swelling eye swelling

visceral gnathostomiasis: eye

Diagnosis

- definite: parasite identification - parasite migrate out from skin

- dissect out from tissue biopsy (no. nucleus in intestinal cell to identify species)

- clinical manifestation: migratory swelling

1-10 weeks later

- history of ingestion: raw, undercooked animals

- supported by skin test, serology test

G. spinigerum 3-7 nucleus in 1 intestinal cell

Treatment

surgical removal of worm

symptomatic & anti-inflammatory Rx drug: albendazole

- to cure

- to stimulate migration of worm to dermis

-

- ivermectin

Prevention

avoid raw, inadequately cooked animals

prevent larval penetration via skin

avoid drinking water (may +L3)

…boiling water 5 min kill L3...

Filarial worms

Filarial species

- Wuchereria brancrofti

- Brugia malayi

- Loa loa

- Onchocerca volvulus

- Mansonella spp.

- Dirofilaria spp.

Brancroftian filariasis

Malayan filariasis

Habitat: vertebrate host

- lymphatic vessel

- tissue

- body cavity

Disease: Filariasis (Elephantiasis)

Morphology of adult

- long, slender (20-500 mm)

- swollen head, blunt round ends

- white, smooth cuticle - male is shorter than female

M F

Life cycle: complex Definitive host Vertebrate (mammal)

Intermediate host

Invertebrate (blood-sucking insects)

Infective stage

3rd larva

Habitat Adult: lymphatic vessel, tissue, body cavity Microfilaria: blood, tissue

Adult: in tissue produce microfilaria in blood, skin

L1 L2

L3: infective stage

at proboscis

L3

L4

Ad

L3 (infective stage) from proboscis of mosquito

Microfilaria: embryo - thin, long (170-360 mm)

- Bluntly round head, pointed tail - Sheath or no sheath

head

tail

sheath

Morphology of microfilaria

Wuchereria bancrofti Brugia malayi

- long, graceful shape - short, kinking shape

- Giemsa stain: pale sheath - pink sheath

- disperse nuclei - overlapping nuclei

- Short cephalic space (1/1) - long cephalic space (2/1) - No caudal nuclei - 2 caudal nuclei

Wuchereria bancrofti Brugia malayi

Cephalic space

- Short (L/W: 1/1) - long (L/W: 2/1)

Wuchereria bancrofti Brugia malayi

Nuclei

disperse overlap

Wuchereria bancrofti Brugia malayi

caudal nuclei

no 2

Periodic occurrence Continuous occurrence

Microfilarial periodicity

1. Nocturnally periodic

2. Diurnally periodic

1. Nonperiodic

2. Nocturally subperiodic

3. Diurnally subperiodic

In Thailand

W. brancrofti B. malayi

Endemic area

North, west South

Mosquito vector

- Culex

quinquefasciatus

- Anopheles spp.

- Aedes spp.

- Mansonia (Ma. dives)

- Mansonia spp.

- Coquillettidia crassipes

Kanchanaburi

Mae Hong Son

Tak

Narathiwat

Ranong

Ratchaburi

Endemic areas in Thailand

Wuchereria bancrofti (north & west)

Brugia malayi (south)

Mosquito vector

W. Bancrofti B. malayi

Mansonia

www.jameswhiteants.com.my

Clinical manifestation Phase W. brancrofti B.

malayi

1. Asymptomatic

2. Inflammatory (acute) - Lymphadenitis (ต่อมน ้าเหลืองอกัเสบ) - Lymphangitis (หลอดน ้าเหลืองอักเสบ) - Orthitis (อัณฑะอักเสบ) - Epididymitis (ท่อเก็บอสุจิอักเสบ) - Elephantoid fever

3. Obstructive (elephantiasis)

- groin region, arms,

leg - hydrocele (ถุงอัณฑะบวมน ้า)

- chyluria

- leg

Pathogenesis

Adult worm (3-10 cm) & lymphatic vessel

Lymphatic endothelium: hyperplasia

Cell infiltration: lymphocyte, eosinophil, histocyte, epitheroid cell,

giant cell & fibroblasts

Fibrosis & lymph blockage

Elephantiasis

skin in the affected area develops a thickened and may become darkened

do not appear until years after infection

Wuchereria brancrofti Brugia malayi

www.oddee.com

www.europeanmedical.info

Diagnosis

I. Clinical diagnosis

- history

- symptom

II. Demonstration of microfilaria - thick blood film

- Knott’s concentration technique

- Millipore filtration

III. Ultrasound (Ultrasonography)

- living adult in lymphatic system

IV. Advanced technique

- ELISA, PCR

Treatment

I. Mass treatment (microfilaria >0.6%)

- once-yearly

- single dose

- 2 drug treatment (removing microfilariae from the blood)

- albendazole (400 mg) + diethylcarbamazine citrate (DEC) (6 mg/kg)

- albendazole (400 mg) + ivermectin (200 mg/kg)

active community-level surveillance

II. Selective treatment (microfilaria < 0.6%)

- DEC (6 mg/kg: 12 days)

III. Supportive treatment (disability person)

- rehabitation

- surgery

Prevention

- Personal protection (avoid mosquito bite)

- Control of mosquito vector

- Mass treatment

Laboratory