The only captive killer whale in Mexico, "Keiko" a male 12 years old approximately who arrived from an aquarium in Canada, captured in waters of Iceland. This killer whale arrived to Mexico City in February 1985, in December of that same year, a dark gray neoformation was observed with a coli-flower surface similar to papilloma tissue, with a slow growth, in two years its volume did not grow more than 15 Cm², and had no apparent disturbances for the animal. Its location was bilateral in the external surface of the pectoral fins foldings and it did not present any problems for the growth of the Orca.

It has been observed that with the passing of time this papilloma tissue increases its volume seldom. We consider that this is due to immunological depression determined by hematology tests taken regularly and etiology, manifested by inactivity, depression and even aggressive behaviour.

The hematological studies of the Orca Keiko, show interesting variations in the white blood cells in linfocits levels, mainly as indicators of the variations in the immune response of the animal.

New lesions have appeared in sites which involve continuous movement as in the base of the fluke tail.

The etiological agent had not been identified even though several methods and technics were used such as histopathology, and electronic microscopy.

In the year of 1990-1991 new collections were taken from the neoformations of the papilloma, as its diameter and volume have been seen to drastically grow. With histopathology was found tissue and cell organization that allow the identification of this neoformation as a typical basal papilloma, which corresponds to the clinical image. Other studies were done including:

1.  Immunohistochemistry: where it was considered to look for antigens related to papovavirus, nevertheless the results were negative, actually this study continues with other agents.

2.  Electrophoresis: which gave a positive result with the bovine, rabbit and humane papovavirus.

3.  Virus cultivation: with the isolation of two viruses corresponding their characterization with Herpes virus and Papovavirus.

4.  Electronic microscopy: Intra-plasmatic particles suggesting a Papovavirus were observed.

Meanwhile, a collection of neoplastic tissue was done to make a macerade and through this have a typical autovaccine.

In the first application, good results were obtained and in the second inoculation the results were similar but in the third and fourth inoculation the response was contrary to the expected, having an increase in the growth and a reactivation of the lesion.

At present it has been decided to follow two approaches for the treatment to this problem.

1.  Finish the characterization of the isolated viruses, make innocuity tests, reactions of probable potential and if possible a replica of the disease in laboratory animals, to be able to make a specific vaccine with tissue cultivation and apply it so that we can stimulate specific immunity.

2.  With the development of the autovaccine, a new cycle of inoculations has begun. During this congress this cycle and its results will be presented.