Australian scientists are raising concerns over the unpredictable nature of a contraceptive vaccine that aims to control populations of wild animals, such as rabbits and foxes.
Writing in the latest issue of the journal, Reproduction, UNSW genetics expert Professor Des Cooper warns that the immuno-contraception method is not fully effective and is manipulating natural reproduction in ways that can't be predicted or controlled.
Professor Cooper also raises concerns that individuals that survive the vaccine may be more likely to carry infectious diseases with the potential to affect other animals.
An immuno-contraceptive vaccine causes an animal's immune system to produce antibodies that act against some essential event or structure in the reproductive process. The antibodies can act against sperm, eggs or reproductive hormones, which prevent either fertilization or the production of sperm and ova.
Proponents of the technique, which was first tested nearly 20 years ago, regard it as more humane than the conventional methods of controlling wildlife populations, such as shooting, trapping, poisoning or viral diseases. It has drawn support from some politicians and animal-welfare agencies.
An expert in mammal reproduction, Professor Cooper, of the UNSW School of Biological, Earth and Environmental Sciences, questions immuno-contraception on three grounds.
"Firstly, immuno-contraceptives are ineffective against substantial minorities of animals, probably for genetic reasons," Professor Cooper says. "If so, the genes responsible for this lack of response will be passed on to offspring. Within a few generations most of the population will be unresponsive to the immunocontraceptive, so its effectiveness as a form of birth control is likely to be short-lived."
Professor Cooper's research reveals that than in 27 out of 32 immunocontraceptive control trials around the world, 10 per cent of animals remained
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Contact: Professor Des Cooper
des.cooper@unsw.edu.au
61-437-677-269
University of New South Wales
11-Feb-2007