Eosinophilic Enteritis and Mint Juleps
ABSTRACT & COMMENTARY
Synopsis: Twenty-two cases of abdominal angiostrongyliasis in Guatemala were epidemiologically associated with ingestion of raw mint.
Source: Kramer MH, et al. First reported outbreak of abdominal angiostrongyliasis. Clin Infect Dis 1998;26:365-372.
Kramer and colleagues identified 22 patients with abdominal angiostrongyliasis diagnosed in the first eight months of 1995 in Guatemala City. Eighteen of the patients were enrolled in a case control study; their median age was 37 years (range, 9-68 years, and 61% were male). Eleven (61%) had infection confirmed by detection of adult worms in mesenteric blood vessels or of larvae or ova in the intestinal wall, three (16.7%) had probable infection (massive eosinophilia with granulomas of the intestinal wall plus a positive serological test), and four had possible infection (symptomatic intestinal disease with a positive serological test).
The illness consisted of abdominal pain, fever, anorexia, diarrhea and/or constipation, and weight loss. Three-fourths of patients underwent abdominal surgery, and one patient died of postoperative pancreatitis. Ingestion of raw mint was implicated as the likely vehicle of transmission of Angiostrongylus costaricensis. Since slugs are often found on mint plants, 68 of these mollusks were captured on mint farms and examined. No A. costaricensis were detected, and none were found on two planarians taken from mint plants.
COMMENT BY STAN DERESINSKI, MD, FACP
The nematode, A. costaricensis, infects rodents and, in Latin America and the Caribbean, causes abdominal angiostrongyliasis in humans. In one area of southern Brazil, 66% of residents were found to have serological evidence of infection (Graeff-Teixeira C, et al. Trop Med Int Health 1997;2:254-260). Enzootic infection is reported to be present in Texas, but no reported confirmed human cases have been acquired in the United States.
Infection of rodents occurs after their ingestion of mollusks containing infective third-stage larvae or other nutrients contaminated with the mucoid secretions from infected mollusks. Angiostrongylus cantonensis is also transmitted by planaria that feed on dead mollusks, and the same may be true for A. costaricensis. While the means by which humans become infected are unknown, the article reviewed here indicates that ingestion of raw mint contaminated by infected molluscan mucous secretions or, possibly, with infected planaria, was the means of human infection in these cases.
Most identified and reported cases of abdominal angiostrongyliasis in Central America have involved children, who often present with symptoms and signs suggestive of acute appendicitis (Loria-Cortes R, Lobo-Snahuja JF. Am J Trop Med Hyg 1980;29:538-544). This infection may also mimic Crohn's disease. The clinical illness may relapse repeatedly over several months. Most cases are diagnosed by histopathological examination of tissue (most often intestinal) specimens obtained during surgery. No effective treatment is available.
Cases of abdominal angiostrongyliasis have been reported in tourists to Central America. For instance, a 73-year-old Los Angeles woman who spent five months in El Salvador presented with an acute abdomen four weeks after her return and, at laporatomy, was found to have eosinophilic ileitis with perforation (Wu SS, et al. Arch Pathol Lab Med 1997;121:989-991). A similar illness has occurred shortly after a brief visit to Nicaragua (Vazquez JJ, et al. Gastroenterology 1993;105:1544-1549). Ectopic localization of the worm in the liver has been associated with a syndrome resembling visceral larva migrans (Morera P, et al. Am J Trop Med Hyg 1982;31:67-70). The migrating worm may find its way to some strange places. An 8-year-old boy underwent orchiectomy for presumed torsion of the testicle; histopathological examination demonstrated adult A. costaricensis occluding the spermatic arteries (Ruiz PJ, Morera P. Am J Trop Med Hyg 1983;32:1458-1459).
Anisakiasis ("sushi worm" infestation) may cause eosinophilia and intestinal disease mimicking appendicitis. Other infestations causing eosinophilia that may involve the appendix (although their etiologic role in causing abdominal findings are not always clear-cut) are taeniaisis, trichuriasis, and enterobiasis. Infestation with the dog hookworm, Ancylostoma caninum, has caused human-eosinophilic enteritis in Australia (Prociv P, Croese J. Lancet 1990;335:1299-1302). Complications of intestinal schistosomiasis may cause an acute abdomen. Yersinia infection and intestinal tuberculosis may also mimic appendicitis and Crohn's disease but do not usually cause eosinophilia.
Whether the cases described by Kramer et al was truly an outbreak can be disputed, since accurate epidemiological records were not available. The authors' conclusion that these cases deserve being called an outbreak is based on recollections of fewer numbers of cases seen by pathologists in previous years. Nonetheless, they were able to identify a potential vehicle for transmission (i.e., raw mint presumably contaminated by secreted mucous from infected slugs or by infected planaria). This observation strengthens the need for an effective public health approach to prevention of future infections with this nematode. An intensive educational program recommending thorough cooking of potentially contaminated food and thorough cleaning of vegetables and fruit eaten uncooked was associated with a significant decrease in cases of foodborne eosinophilic meningitis, caused by the related A. cantonensis, in New Caledonia (Ash LR. Rev Biol Trop 1976;24:163-174).
Does anyone know the answer raised to the most important question raised by this investigation-is there enough alcohol in a mint julep to kill A. costaricensis?
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