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Archive Number 20100518.1627
Published Date 18-MAY-2010
Subject PRO/AH/EDR> Paralytic shellfish poisoning - China: (HK) scallops, alert
PARALYTIC SHELLFISH POISONING - CHINA: (HONG KONG) SCALLOPS, ALERT
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A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>
Date: Mon 17 May 2010
Source: Hong Kong Information Services, Health & Community News [edited]
<http://www.news.gov.hk/en/category/healthandcommunity/100517/html/100517en05004.htm>
The Centre for Health Protection urges people not to eat fresh
scallops until further notice, as 17 people have come down with
paralytic shellfish poisoning since 15 May 2010.
The 6 men and 11 women, aged 17 to 69, from 9 clusters, came down
with facial, oral, tongue and throat numbness, limb weakness,
dizziness, blurred vision, abdominal pain, nausea, vomiting, and
diarrhea after eating scallops at home on 14 and 16 May 2010. The 16
sought treatment at public hospitals, with one admitted to Caritas
Medical Centre. All are stable.
The scallops were bought from markets in Wong Tai Sin, Sham Shui Po,
Kowloon City, and Tuen Mun. The case has been referred to the Food &
Environmental Hygiene Department.
Poisoning can result from eating shellfish contaminated with
phycotoxins produced by free-living micro-algae, upon which the shellfish feed.
--
Communicated by:
HealthMap Alerts via ProMED-mail
<promed@promedmail.org>
[Paralytic shellfish poisoning (PSP) is a significant problem in
several geographic areas, especially on both the east and west coasts
of the United States, but occurs in Asian Pacific waters as well
often associated with algal blooms such as "red tide". Produced by
several closely related species in the genus _Alexandrium_, PSP
toxins (saxitoxin and related compounds) are responsible for
persistent problems due to their accumulation in filter-feeding
shellfish, but they also move through the food chain, affecting
zooplankton, fish larvae, adult fish, crustaceans, and even birds and
marine mammals.
It is important to note that the shellfish affected by the toxins
usually do not appear different. The toxin also has no taste or smell
and is heat stable. Typical vehicles are clams (both hard and soft
shell), oysters, mussels, and cockles. The liver of lobster (the
tomalley) can also contain toxin.
Safe seafoods during toxic algal bloom include scallops (only the
adductor muscle is safe), lobster (only the meat), crab (only the
meat, properly cleaned), and shrimp. The observation in this posting
that scallops were the vehicle of transmission strongly suggests that
more than the adductor muscle was ingested or that the entire scallop
was cooked, allowing the toxin to contaminate the cooking water and the muscle.
Within minutes to 10 hours of eating shellfish contaminated with PSP
toxin, the lips will feel numb and tingling. The amount of toxin
consumed will determine the severity and extent of symptom
progression. The tingling can extend to the fingers and toes,
eventually resulting in a loss of use of the arms and legs. Paralysis
can progress to the muscles throughout the trunk of the body,
including the chest and respiration. In severe cases of poisoning,
death can occur in 2 to 25 hours after consumption.
The adductor muscle of scallops is larger and more developed than
that of oysters, because they are active swimmers; scallops are in
fact the only migratory bivalve. A picture of the parts of the
scallop can be found at
<http://www.cfs.gov.hk/english/multimedia/multimedia_pub/images/multimedia_pub_fsf_11/scallop.jpg>.
- Mod.LL]
[Hong Kong can be located on the HealthMap/ProMED-mail interactive
map at <http://healthmap.org/r/01i8>. - Sr.Tech.Ed.MJ]
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