Published Date: 2002-12-03 23:50:00
Subject: PRO/AH> Trichinellosis - Russia (Siberia) (04)
Archive Number: 20021203.5954
TRICHINELLOSIS RUSSIA (SIBERIA) (04)
A ProMED-mail post
ProMED-mail, a program of the
International Society for Infectious Diseases
Date: Mon, 02 Dec 2002
From: Allen Clarkson <firstname.lastname@example.org>
Regarding the comment in the previous posting in this thread (see reference
below), "It may be helpful to know that freezing meat at minus 15 degrees C
effectively kills the parasite [easy to do in Siberia! - Mod.JW]":
Trichinella transmitted in very cold climates is not killed by the same low
temperature exposure that kills this parasite transmitted in moderate
climates. Since posts on ProMED-mail are considered authoritative by many,
a correction should be made. The fact that the moderator accepted the
comment makes this all the more important.
Allen B Clarkson, Jr PhD
Department of Medical and Molecular Parasitology
New York University School of Medicine
New York, NY 10010
Date: 2 Dec 2002
From: Dr Edoardo Pozio <email@example.com> [edited]
Concerning the trichinellosis outbreak in Siberia [associated with] the
consumption of bear meat and the comment of Dr JT Zerwekh, it is very
important to know that freezing game meat of carnivores (for example, brown
bear, polar bear, arctic fox, red fox, wolf, raccoon dog, lynx, walrus) at
-15 degrees C does not kill larvae of _Trichinella nativa_ present in these
animals. Larvae of this _Trichinella_ species in muscle tissue survive to
freezing at -18 degrees C up to 5 years! In arctic and subarctic regions of
Europe, Asia, and North America, the only choice to kill larvae of
Trichinella present in muscles of carnivorous mammals is by heating at +60
degrees C or at higher temperatures with a time related to the thickness of
Furthermore, it is important to keep in mind that muscle larvae of
_Trichinella britovi_ (a species present in carnivore mammals and sometimes
in wild boars and domestic pigs of temperate regions of Europe and Asia)
also survive to freezing for a long period of time.
The following references can be useful to study in depth this subject:
1. Gamble HR, et al. Vet Parasitol 2000; 93: 393-408.
2. Dick TA, Pozio E. Trichinella spp. and trichinellosis. In: WM Samuel, MJ
Pybus, Kocan AA (editors). Parasitic diseases of wild mammals, 2nd edition.
Ames: Iowa State University Press, 2001: 380-96.
3. Pozio E. Vet Parasitol 2000: 93: 241-62.
4. Pozio E. Vet Parasitol 2001; 98: 133-48.
Dr Edoardo Pozio
President of the International Commission on Trichinellosis
Laboratory of Parasitology
Istituto Superiore di Sanita
Tel.+39 06 4990 2304
Fax +39 06 4938 7065
[We thank Dr Pozio for his authoritative statement. The paper by CM Kapel
and colleagues (J Parasitol 1999; 85(1): 144-7) referred to in a previous
posting describes survival of _Trichinella nativa_ for at least 4 months at
18 C in meat from a carnivore host, and survival for shorter periods of
_T. nativa_ at 30 C is well known. As only _Trichinella nativa_ and not
_Trichinella spiralis_ has been described from Siberia, freezing the meat
at 15 C or other temperatures in normal household freezers will not
inactivate trichinella in Siberia. - Mod.EP]