According to infectious disease experts at The Feinberg School of Medicine at Northwestern University, the Chicago Department of Public Health and the Centers for Disease Control and Prevention who wrote the article, 12 individuals who ate in a restaurant in Jamaica contracted meningitis as a result of eating a Caesar salad contaminated with the larvae of Angiostrongylus cantonensis, otherwise known as rat lungworm.
Humans become infected by eating the A. cantonensis larvae in raw or inadequately cooked mollusks, such as snails or slugs. Freshwater prawns, fish, frogs, fish and contaminated fresh produce occasionally have been implicated. When the larvae are ingested by humans, they penetrate the vessels of the intestinal tract and eventually reach the meninges, the membranes that envelop the brain and spinal cord, resulting in infection, neurological complications and sometimes death.
The lead authors on the article were infectious disease specialist Stuart Johnson, M.D., assistant professor of medicine, and Trevor J. Slom, M.D., formerly an instructor, at the Feinberg School.
As reported in the article, onset of meningitis occurred within 35 days of the trip and included the following symptoms: severe headache, neck pain, altered skin sensation or visual disturbance. Nine of the 12 individuals with meningitis had to be hospitalized.
The Caesar salad associated with the illness included romaine lettuce, which reportedly was washed, and canned, salted anchovies but no shellfish or other seafood. The lettuce had been imported from the United States, and no obvious modes of contamination of the lettuce were identified at either the U.S. or Jamaican distributor.
Since this outbreak, A. cantonensis has been identified in both rats and land snails in Jamaica, which supports the hypothesis that the vehicle of this outbreak could have been contaminated in Jamaica. However, it does not exclude the possibility of contamination in the United States, which was the source of the romaine lettuce used in the Caesar salad.
Johnson said that physicians and public health officials should be alert for human cases of A. cantonensis infection throughout the Caribbean and nearby regions, because A. cantonensis has been found in rats in Cuba, Puerto Rico, the Bahamas, the Dominican Republic and Jamaica, as well as in New Orleans.
Johnson also said that the usual advice given to prevent traveler’s diarrhea should also protect against infection with A. cantonensis, particularly, not eating unwashed fresh produce, such as lettuce, and undercooked or raw foods, such as snails and other shellfish.
Other authors on this article were Margaret M. Cortese, M.D., Susan I. Gerber, M.D., Roderick C. Jones, Timothy Holtz, Adriana S. Lopez, Carlos H. Zambrano, M.D., Robert L. Sufit, M.D., and Barbara L. Herwaldt, M.D. Yuwaporn Sakolvaree and Wanpen Chaicumpa, researchers from Mahidol University, Bankok, Thailand, also contributed to the report.
KEYWORDS: Meningitis, Angiostrongylus cantonensis, traveler’s illness, Jamaica
Journal
New England Journal of Medicine