Angiostrongylus cantonensis infection

CASES/YEAR
20 (US); 1,000 (Global)
CATEGORY
Tissue Nematodes
AGENT TYPE
Helminths
OTHER NAMES
Eosinophilic meningitis;
ACUITY
Subacute/Chronic
INCUBATION
2-14 days; 2-8 weeks
INITIAL SYMPTOMS
Headache, neck stiffness, paresthesias, and low grade fever or no fever; [CCDM, p. 10]
PRECAUTIONS
Not transmitted from person to person. [CCDM, p. 11]
COMMENTS
The life cycle of this tissue nematode worm includes rats, slugs, and land snails. Fish, prawns, and land crabs that eat slugs or snails may transmit infection. After infecting humans, it may penetrate into the eye and cerebral spinal fluid (CSF). Eosinophilia may be absent or quite high. About 5% of patients have temporary facial paralysis. Patients have a history of eating raw slugs or snails (intermediate hosts). Rats are reservoirs. [CCDM, p. 10-12] If >10% eosinophils in the CSF, then A. cantonensis is the likely cause. Patients have eaten raw snails or slugs, animals such as freshwater crabs or shrimp that eat snails or slugs, or vegetables contaminated with the slime of snails or slugs. Contaminated water is another potential source. Fever may be absent. The disease is usually self-limited and without sequelae. [Guerrant, p. 774-6] In an outbreak in Jamaica, headache was the most frequent symptom, followed by neck pain and fatigue (80%), and paresthesias (75%). [PPID, p. 1118] A. cantonensis (rat lungworm) is the most common infectious cause of eosinophilic meningitis. Complications include paralysis, blindness, and death. To prevent, don't eat undercooked snails, slugs, or other possible hosts and don't eat raw lettuce unless thoroughly cleaned. [CDC Travel, p. 171] Uncommon symptoms are fever, cranial neuropathy, seizures, and lethargy. [Harrison ID, p. 1129]
DIAGNOSTIC
Worms have rarely been found by microscopic exam of the CSF. Blood eosinophilia is not always present, but CSF usually shows pleocytosis with >10% eosinophils; [CCDM]
SCOPE
SE Asia, Pacific Is. (Guam, American Samoa, Hawaii); cases in Ivory Coast, Cuba, Reunion, and Louisiana; [ID, p. 2375] Mainly in Southeast Asia & South Pacific; Also in Caribbean, Brazil, and Louisiana; [Cecil, p. 2135]
SIGNS & SYMPTOMS
  • >fatigue, weakness
  • >fever
  • >myalgia
  • G abdominal pain
  • G nausea, vomiting
  • H eosinophilia
  • N headache
  • N lethargy
  • N muscle weakness
  • N paresthesia
  • N seizure
  • N stiff neck
  • S rash (exanthem)
  • *blindness
  • *cranial neuropathy
  • *encephalitis
  • *meningitis
  • *paralysis
  • *stupor, coma
ANTIMICROBIC

Yes

VACCINE

No

ENTRY
Ingestion
SOURCE
Animal Tissue, Eating Contaminated Food, Eating Infected or Toxin-Containing Fish, Eating Contaminated Mollusks or Crustacean, Eating Contaminated Produce, Waterborne (Ingesting, Inhaling, or Swimming)
RESERVOIR
Fish and Shellfish, Rodents, Wild Animals
RISK FACTORS
  • Eat undercooked meat or fish
  • Ingest infectious agents in food/water
  • Travel to endemic area
TREATMENT
"The larvae die spontaneously and supportive care usually suffices . . ." [CDC Travel]
REFERENCES FOR CASES/YEAR
1. (US) Guesstimate: 20 cases/year;
2. (Global) The rat lung worm is endemic in rats in Asia, the Pacific Islands, Australia, India, Africa, the Caribbean, Louisiana, and Florida; [Cohen] Outbreaks in the South Pacific, Southeast Asia, and Taiwan; More recently reported in Jamaica, Cuba, Egypt, Hawaii, China, Brazil, and Ecuador with Caesar salad the source in one outbreak; [PPID, p. 3240] "Outbreaks of human angiostrongyliasis have involved a few to hundreds of persons; over 2,800 cases have been reported in the literature from approximately 30 countries." [CDC website] Guesstimate: 1000 cases/year;