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Saint Lawrence belugas

Lesions and contaminants

Virus (herpes)

One adult animal out of 5 suffered from cancer. (Cancer was observed in 27 % of examined adult animals from 1983 to 1998). In the western world, cancer causes 23 % of all deaths in humans, a percentage similar to that found in Saint Lawrence beluga. Such a high percentage had never been observed in any wild animal species, terrestrial or aquatic (with the important exception of fish). To our knowledge, this is the first population of wild mammals that can be compared to humans in this regard.

The rate of cancer in Saint Lawrence beluga is also much higher than that observed in other cetaceans. Only 28 other cases of cancer have been reported in wild and captive cetaceans worldwide. Thus, cancers reported in Saint Lawrence beluga represent about half of all cancers reported in cetaceans worldwide.

Tête de béluga - Lésions de nécrose dues à un virus Herpès

Head of a juvenile beluga with Herpesvirus dermatitis. Areas of necrotizing dermatitis This young female beluga (1-year old) was recovered on September 3, 1984. Large patches of skin were necrotic ( Top picture), due to a Herpesvirus infection. This animal also suffered a peritonitis due to a perforated gastric ulcer, a arasitic pneumonia, a chronic hepatitis, and a bacteriemia (presence of bacteria in blood) with Vibrio cholerae. This was the first Herpesvirus infection reported in a cetacean (J. Comp. Pathol. vol 98 : 287-311. 1988).

Since 1988, morbilliviruses (a group of virus that include the distemper virus of dogs and the Measles virus of humans) have decimated many populations of cetaceans, among which the Atlantic and the Black Sea dolphins. With Drs. C. House (USDA, APHIS, USA) et C. Montpetit (Institut Armand-Frappier), we determined that Saint Lawrence beluga do not possess antibodies against the cetacean morbilliviruses that are currently known. Since Saint Lawrence beluga have no humoral protection against these viruses, they could be severely affected by morbillivirus-induced disease if they come in contact with cetaceans such as pilot whales, which are known to be infected with these viruses.


Peau de béluga - Vue microscopique - Corps d'inclusion Necrotizing dermatitis Juvenile beluga. Microscopically, skin cells are swollen; their cytoplasm is almost colorless because it is filled with water, which does not retain proteins. The nuclei contain masses of red material (arrow) surrounded by a clear halo. This material is made of dense clumps of viral particles.
Abdomen de béluga - Lésions de nécrose dues à un virus Herpès

Herpesvirus dermatitis Abdomen of a juvenile beluga with Herpesvirus dermatitis. Irregular elongated areas of necrotizing dermatitis.



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