Detection of a gypsy-like sequence in the genome of the cat flea Ctenocephalides felis (Bouché 1835).

The gypsy virus of Drosophila melanogaster is the first identified retrovirus of insects. Its infectious properties have been reported, and it is able to cause diverse mutations of the phenotype in the fruit fly. As a typical endogenous retrovirus, it is transmitted vertically as part of the host genome, but horizontal transmission has also been shown for the D. melanogaster gypsy virus. Using polymerase chain reaction with degenerate primers designed from the gypsy element of Drosophila subobscura, a gypsy-like sequence was amplified from the genome of the cat flea Ctenocephalides felis in a pool of laboratory and field strains. High identities with other gypsy-like sequences of Drosophila spp. can be detected. In contrast to some of these gypsy sequences, the 410-bp fragment of C. felis possesses two deletions, which are localised in the env gene region. Because of these deletions and the lack of virus particles in C. felis, the criteria for host infectivity are not fulfilled. Nevertheless, the general detection of a gypsy-like sequence in C. felis and the capability of the ectoparasite to act as transmitter of viral diseases can be of importance for the cat flea's position in the epidemiology of diseases, which are accompanied by a higher rate of mutation.