Angiostrongylus cantonensis

Question 1

Angiostrongylus cantonensis

Common Name:

Answer 1

Rat Lungworm

Question 2

Angiostrongylus cantonensis

Was described by Chen in 1935 from domestic_____ in_______

Answer 2

rats

Canton, China

Question 3

Angiostrongylus cantonensis

The worm normally lives in the lungs of______ but can cause___________ in man

Answer 3

rats

eosinophilic meningoencephalitis

Question 4

Angiostrongylus cantonensis

Disease: (2)

Answer 4

• Angiostrongyliasis
• Eosinophilic meningoencephalitis

Question 5

Angiostrongylus cantonensis

• 16 to 19 mm x 0.26 mm in diameter

Morphology

• Male:

• pale and filiform
• they have a well-developed__________

Answer 5

caudal bursa (kidney-shaped & single-lobed)

Question 6

Angiostrongylus cantonensis

Morphology

• Female:

• pale and filiform
• 21 to 25 mm x 0.30-0.36 mm in diameter
• has_______ which are round spirally around the intestine (barber’s pole pattern)
• lays________ eggs/day

Answer 6

uterine tubules

15,000

Question 7

Angiostrongylus cantonensis

Eggs

• Have delicate_____

• Measure 46-48 micra x 68 micra

•_________ when oviposited

Answer 7

hyaline shells

Unembryonated

Question 8

Angiostrongylus cantonensis

Life Cycle

• Infective stage –
• Definitive host –
• Incidental host –
• Intermediate host –

Answer 8

3 rd stage larva

rats

humans

snails (Achantina fulica)

Question 9

Angiostrongylus cantonensis

Diagnosis

• Relatively difficult

• Presumptive diagnosis is made by travel history and exposure

(3)

Answer 9

• CSF (10% eosinophilia in proportion to the WBC)

• CT Scan

• ELISA

Question 10

Definitive Host

Answer 10

• Rats

Question 11

Intermediate Host

Answer 11

Snails or slugs

• Achatina fulica (Giant African Snail), Hemiplecta sagittifera, Helicostyla macrostoma, Veginilus plebeius, Veronicella altae

Question 12

Paratenic Host

Answer 12

• Crabs, freshwater shrimps

Question 13

Accidental host

Answer 13

Humans

Question 14

Epidemiology

• First human infection documented by Nomura and Lin in_____ in 1945

• Documented in at least___ countries

Answer 14

Taiwan

30

Question 15

Biology: Adult

• 16-22mm by 0.25-0.35mm
• Posterior end: welldeveloped caudal bursa: kidney-shaped and single lobed

Answer 15

• Male

Question 16

Biology of Adult

• 19-33mm by 0.28-0.50mm

• Uterine tubules wound spirally around the intestine observed through the____ cuticle

• _______pattern

• Blunt posterior end

• Lay 15,000 eggs per day

Answer 16

Female

transparent

Barber’s pole

Question 17

Biology: Ova

• 46-48um by 68-74um

•______ with delicate_____ shells

•_____ when oviposited

Answer 17

Elongated ovoidal eggs; hyaline

Unembryonated

Question 18

Biology: Larva

• Found in lungs of rodents

• Distinct small knob near the tip of the tail

Answer 18

Rhabditiform Larva

Question 19

Biology: Larva

• Two well-developed chinitous rods below the buccal cavity

• Rods have expanded knob-like tips

Answer 19

• Filariform Larva

Question 20

1. Ingestion of snails, slugs
2. Ingestion of paratenic hosts: crabs, freshwater shrimps

Answer 20

Humans

Question 21

Pathogenesis and Clinical Manifestations

• BRAIN: primary site of infection

Answer 21

Eosinophilic meningoencephalitis

Question 22

• Eosinophils on CSF

• Acute, severe, intermittent occipital or bitemporal headache

• Stiffness of neck, paresthesia, vomiting, fever, nausea, blurred vision, diplopia, myalgia, fatigue

• Confusion, incoherence, disorientation, memory lapses, coma

• Intraocular hemorrhage, blindness

Answer 22

Eosinophilic meningoencephalitis

Question 23

Pathogenesis and Clinical Manifestations

eosinophilic inflammation of the mesenteric arterioles of the ileocecal region mimicking appendicitis

Answer 23

• Eosinophilic Enteritis

Question 24

Pathogenesis and Clinical Manifestations

: due to dead worms

Answer 24

Inflammatory Reaction and Local tissue necrosis

Question 25

Diagnosis • Relatively difficult to diagnose since the primary site of infection is the____

Answer 25

brain

Question 26

Presumptive diagnosis

Answer 26

• Travel and exposure history • Clinical symptoms • Medical history • Laboratory findings • Brain imaging • Serological tests

Question 27

Diagnosis • Eosinophilia, elevated eosinophils in CSF similar with other CNS parasitism

Answer 27

Blood Tests

Question 28

Diagnosis • Cerebral edema, hydrocephalus, meningeal lesions

Answer 28

CT Scan

Question 29

Treatment No antihelminthic treatment (2) may be effective

Answer 29

Mebendazole and albendazole

Question 30

Treatment ______of the worm (eyes) Prednisone in severe cases of cranial nerve involvement (2) for headache

Answer 30

Surgical removal Analgesics and lumbar puncture

Question 31

T or F Resolve spontaneously: adult worm cannot survive for a long time inside human body

Answer 31

TRUE

Question 32

Prevention and Control • Awareness and education on proper eating habits and food preparation • Discourage eating raw or poorly cooked ____or unwashed____ • Hand washing after gardening • Use of molluscicides • Metaldehyde or iron phosphate food bait pellets • Copper barriers against snails and slugs

Answer 32

mollusks; vegetables

Question 33

_____are ingested by definitive host.

Answer 33

Third-stage larvae

Question 34

The ______ in rats are found in pulmonary arteries

Answer 34

Adult worms

Question 35

Eggs hatch in the lungs, and ______ are passed in rodent feces

Answer 35

first-stage larvae

Question 36

First-stage larvae shed from definitive host are ingested by______

Answer 36

gastropod intermediate host

Question 37

Larvae reach the_____ stage after two molts in the intermediate host.

Answer 37

infective (third)

Question 38

Larvae migrate to brain (occasionally eyes or lungs) in aberrant human host, and do not reach______

Answer 38

reproductive maturity