gh TAME DOLPHINS ARE INFECTION CARRIERS

The blood serum of the Black Sea bottle-nosed dolphins inhabiting the Utrish dolphinarium contains antibodies to dangerous infection pathogene – morbilliviruses, brucellas and toxoplasm. Although specialists of the VECTOR State Scientific Center for Virology and Biotechnology, who examined the animals, have not found evident signs of the disease, they do not exclude the possibility that these bottle-nosed dolphins can play an important role in spreading morbillivirus infection, toxicoplasmosis and brucellosis.

Within the last 20 years, morbilliviruses have become the cause for mass diseases with the pinniped and cetacean. These viruses antibodies were found with toothed whales populating various areas of the Atlantic and the Pacific Oceans. Morbilliviruses, the canine distemper virus in particular, can infect multiple mammal species, without causing evident signs of the disease. Brucellosis is a new disease for marine mammals. Brucellas (these are bacteria) were found with different species of seals, sea-swines (Phocaena gen.), dolphins and true otters. The toxoplasmosis causative agent is an animalcular. Toxoplasmosis affects a lot of species of domestic and wild animals. This disease often becomes chronic and causes miscarriages.

The researchers drew blood from caudal fin vessels of 59 Black Sea bottle-nosed dolphins from different dolphinaruims of the Utrish Dolphinarium Limited Liability Company and determined the infection pathogene antibodies levels. Some dolphins were tested 2 to 4 times at the intervals of 1 to 2 years. It was only with 8 animals out of 59 that the researchers never found antibodies to any pathogen within four years of observations. The last test proved that only 18 dolphins had no antibodies. Sixteen bottle-nosed dolphins turned out to have antibodies to two or three pathogens at once.

The Russian researchers have for the first time discovered traces of toxoplasm, brucella and morbilliviruses presence with the captive Black Sea dolphins. While circulating in the bottle-nosed dolphin population, these pathogens can cause acute or chronic form of the disease. Chronic clinical course decreases the dolphins’ immunity, provokes to miscarriages, stillbirth and a high death-rate with both young and adult animals. Besides, toxoplasm and brucellas are also dangerous for people.

Bottle-nosed dolphins have always willingly got into contact with human beings. Even ancient Greeks and Romans had tame dolphins, the fact being mentioned by a lot of writers of antiquity. The mid-sixties of the last century witnessed a real dolphin boom – the animals were caught in dozens, placed in the sea-water pools and used for scientific, military and partly commercial purposes. The researchers, instructors and attending personnel are constantly communicating with their wards. A considerable part of the Utrish dolphinarium takes part in circus performances, therefore the duration and intensity of their contacts with people are particularly high. The risk of dolphins getting infection from human beings and of people being infected by a sick dolphin is also high. This circumstance should certainly be taken into account when working with bottle-nosed dolphins in dolphinariums.

***