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Letter
Human Angiostrongylus cantonensis,
Jamaica
Cecelia A. Waugh,*
Shira Shafir,† Matthew Wise,† Ralph D. Robinson,* Mark L. Eberhard,† and
John F. Lindo*
*University of West Indies, Kingston, Jamaica; and †Centers for Disease
Control and Prevention, Atlanta, Georgia, USA
Suggested
citation for this article
To the Editor: Angiostrongylus cantonensis is the most
common cause of eosinophilic meningoencephalitis worldwide (1).
The parasite's presence has been well documented in Jamaica in rats (definitive
host) and a variety of mollusks (intermediate hosts); infections occur
in humans sporadically on the island. However, the mode of transmission
of infections to humans in Jamaica, where raw or undercooked mollusks
are not usually eaten, is not well understood (2).
An outbreak of A. cantonensis occurred among American medical
students vacationing in Jamaica in 2000. An epidemiologic investigation
identified the probable source of infection (Caesar salad), but no biologic
contaminant was determined (2). During a field investigation
of A. cantonensis, we spoke with local farmers and vendors to identify
possible routes of food contamination. While our observations were preliminary
and anecdotal in nature, our findings provide valuable insight into local
transmission and control of this parasite.
Humans can become infected by eating the intermediate hosts, slugs and
snails, of A. cantonensis. Freshwater shrimp serve as paratenic
hosts and reservoirs of infection for humans, both naturally and experimentally
(3,4). Most reports of Jamaican eating practices indicate
that terrestrial snails and slugs are not eaten and that shrimp and other
meats are always eaten well cooked (5). However, during
interviews with a farmer near Mavis Bank, a rural area outside of Kingston,
and fishermen at the Coronation Market, Jamaica's largest fresh produce
market, we discovered that freshwater and saltwater shrimp, as well as
mussels (paratenic hosts), are occasionally eaten raw. Freshwater shrimp
or mussels are eaten, particularly by men, directly from rivers and streams,
and freshwater and saltwater bait shrimp are eaten by fishermen.
In Jamaica, molluscicides are routinely applied to growing vegetables
such as cabbage, lettuce, and bok choy to keep snails and slugs away,
although this practice is not effective. Snails and slugs withdrew from
produce after the molluscicide was applied to surrounding vegetation,
but returned after several days. We purchased a lettuce head that had
been reportedly treated with molluscicides at the Coronation Market and
found a small slug inside. The role of produce in transmitting A. cantonensis
is still unclear; humans may become infected by inadvertently consuming
small slugs or other infected hosts or by consuming produce directly contaminated
with larvae. Infections in slugs have not been found in previous studies
conducted on the island (2). Regardless, the use of molluscicides
to limit human infection from produce is an ineffective strategy.
At the Coronation Market, vendors repeatedly used a bucket of water to
rinse vegetables before displaying them. This practice could transmit
A. cantonensis in 2 ways. First, if free larvae are deposited on
vegetables in either the slime or feces of mollusks, cross contamination
can occur. Second, dead or decaying intermediate hosts may release larvae
into water (6). If infected mollusks were rinsed from
vegetables into the buckets, the water could become contaminated with
larvae. While cross-contamination by common wash buckets has not been
implicated in an outbreak of a parasitic infection, it has been linked
to outbreaks of other infectious agents (7,8).
Vendors at venues such as Coronation Market primarily buy produce to
sell. These vendors typically purchase their produce from intermediaries
who purchase and transport it from farms in outlying areas. As a consequence,
many vendors are unsure of the farm or region from which their produce
came. This practice makes it difficult, if not impossible, for health
officials and researchers to isolate and link etiologic agents with particular
produce items or regions and complicates the investigation of any foodborne
infection.
A. cantonensis is an important parasitic agent in Jamaica for
which a definitive route of infection is often not found. We found that
potential paratenic hosts are occasionally eaten raw. Because of the high
prevalence of A. cantonensis infection in mollusks in certain parts
of Jamaica, consumption of raw, infected shrimp may be a source of sporadic
angiostrongyliasis on the island. Control of A. cantonensis is
complicated because of the apparent ineffectiveness of molluscicides,
the potential for cross-contamination of produce at markets, and the difficulty
of tracking produce and other products to their source.
References
- Kliks MM, Palumbo NE. Eosinophilic
meningitis beyond the Pacific Basin: the global dispersal of a peridomestic
zoonosis caused by Angiostrongylus cantonensis, the nematode
lungworm of rats. Soc Sci Med. 1992;34:199–212.
- Lindo JF, Waugh C, Hall J, Cunningham-Myrie C, Ashley D, Eberhard
ML, et al. Enzootic
Angiostrongylus cantonensis in rats and snails after an outbreak
of human eosinophilic meningitis, Jamaica. Emerg Infect Dis. 2002;8:324–6.
- Alto W. Human
infections with Angiostrongylus cantonensis. Pac Health Dialog.
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- Wallace GD, Rosen L. Studies
on eosinophilic meningitis. 2. Experimental infection of shrimp and
crabs with Angiostrongylus cantonesnsis. Am J Epidemiol.
1966;84:120–31.
- Lindo JF, Escoffery CT, Reid B, Codrington G, Cunningham-Myrie C,
Eberhard ML. Fatal
autochthonous eosinophilic meningitis in a Jamaican child caused by
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- Cross JH. Angiostrongylosis. In: Palmer SR, Soulsby EJL, Simpson DIY,
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- Centers for Disease Control and Prevention. Hepatitis
A outbreak associated with green onions at a restaurant—Monaca, Pennsylvania,
2003. MMWR Morb Mortal Wkly Rep. 2003;52:1155–7.
- Wachtel MR, Charkowski AO. Cross-contamination
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Suggested citation
for this article:
Waugh CA, Shafir S,
Wise M, Robinson RD, Eberhard ML, Lindo JF. Human Angiostrongylus cantonensis,
Jamaica [letter]. Emerg Infect Dis [serial on the Internet]. 2005 Dec
[date cited]. Available from http://www.cdc.gov/ncidod/EID/vol11no12/05-0217.htm
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