Board Member Animal Rights Hawaii (ARH) and Vegetarian Society of Hawaii (VSH)
www.vegsource.com/harris
Feral animals and the Contraceptive Vaccine* (CV)
*Author's note: Vaccination is actually a misnomer since the term originally referred to vaccinia, the virus which generates antibodies against smallpox (variola) when injected cutaneously in humans. A more generic term is immunization.
The Kakaako Clucks 11/04
Currently facing lethal threats in Hawaii are feral cats, chickens, coqui frogs, deer, dogs, goats, pigeons, and pigs. All of these species are in part responsible for their own predicament because they don’t practice birth control. Nor does any other animal species on the planet, since they’re all programmed to go forth and multiply without any thought of the consequences. However nature controls irresponsible reproduction via disease, predation, and starvation, methods that animal rights activists abhor.
Surely there must be more benign ways of controlling pest populations than poison, shoot, and strangle, the methods used by most humans. As example one successful method has been TNR (trap neuter and return) as applied to feral cats.
Web Site
However, neutering programs are costly, labor intensive, and are most practical with urban animal species. An alternate approach is intermittent contraception, but animals and many humans don't do it very well.
Of the contraceptive methods, our own species has 44 of years experience with sterol based contraceptives and while those have a low failure rate of 2%-9% depending on the diligence of the user, they all have side effects. When applied to feral animal populations there is an additional problem. The sterol nucleus can be broken down to carbon dioxide and water by several bacterial species but it can not be digested by animal enzymes, so sterols go up the food chain, if there is one.
Under development for at least twenty years is the contraceptive vaccine (CV), in which various reproductive biochemical pathways are disrupted by exposing the animal to a protein similar but not identical to one of its own reproductive proteins. The antibodies subsequently generated cross-react with the hosts own proteins and reproduction is halted for one or more years. Since proteins are digestible they don’t go up the food chain.
A few of the targeted proteins to date include:
Chorionic gonadotrophin The hormone produced in early pregnancy which keeps the corpus luteum producing progesterone follicle stimulating hormone (FSH).
(LH) and GnRH Gonadotropin releasing hormone. GnRH causes the pituitary gland to make luteinizing hormone
Sperm antigens
Zona Pellucida (ZP) the thin protein membrane surrounding the ovum
There are dozens of other reproductive proteins in addition to the above, some of them potential vaccine bases.
Injectable ZP vaccine has a proven track record and Jay Kirkpatrick, Ph,D. the scientist who demonstrated its effectiveness in controlling wild horse populations on Assateague Island Maryland, in 1996 came to Molokai to investigate its possible use in controlling the axis deer population on Kalaupapa peninsula. He concluded the vaccine would not work effectively in that setting, highlighting a major problem in CV delivery:
While sterol contraceptives can be taken by mouth, contraceptive vaccines cannot since they’re proteins and proteins are digested down to peptides and amino acids at which point they no longer generate antibodies even when absorbed. Because of this, the vaccines have not been delivered in an oral bait. The ZP vaccine is usually injected via dart gun into one animal at a time by people patient enough to track them down or round them up. Possibly at some time in the future a ZP-baited food delivery system will find a way around this problem, but in the meantime the Australians, beset by hordes of ecology-disrupting foxes, mice, and rabbits, have developed an alternative.
Ideally, the Aussie vaccine is spliced into the gene sequence of a mild contagious disease. The target animal population is exposed to the virus or bacterium that carries the vaccine and everybody gets the sniffles for a few days. After that, the favorite outdoor sport resumes but no babies are born. Web Site
Most of the animal abuse problems ARH currently faces could either be solved or greatly ameliorated if this humane and effective CV birth control were to become technologically feasible, so we present the following URLs as examples of what is currently in the works. Keeping abreast of this technology and its political pros and cons should be a priority for those concerned with putting an end, once and for all, to animal suffering.
My letter: Alternatives to Eradication
published in: Environment Hawaii(1999)
Web Site
The Humane Society of the United States (HSUS)is one of the few agencies working primarily to reduce animal suffering by means of the CV as opposed to cutting economic losses, the goal of many others.
The HSUS believes that immunocontraception may offer a humane, nonlethal solution to conflicts between people and wildlife in urban and suburban areas as well as a solution to local problems of animal overabundance. HSUS here documents the PZP vaccine working in deer, horses, tule elk, water buffalo and elephants.
Other URLs:
Attenuated Myxoma virus transfer in Australian rabbits. Web Site
Because the modified virus will cause only a mild infection that will not debilitate or kill, it should spread easily through animals and make them infertile.
And: Web Site
Attenuated Myxoma virus transfer in Australian rabbits. History via ABC TV 2003 Web Site
Note: the wild myxoma virus is highly lethal to rabbits and would not do as a CV vector. The object is to prevent the future suffering of individuals not yet conceived, not to cause the suffering of those already here.
Australia vs fox, rabbit and the introduced house mouse. CSIRO is Australia's Commonwealth Scientific and Industrial Research Organisation. Web Site
The concern is that the sterilizing viruses might escape from Australia and decimate mammal populations worldwide. Various fox species ranging across Africa, Europe, Asia and North America could be vulnerable to any infectious virus used to sterilize feral foxes in Australia, reinforcing the need for species specificity in any transmissible virus. The same is true of rabbits. In the Americas, wildlife scientists fear that a recombinant myxoma virus, although non lethal, could still sterilize Sylvilagus rabbits some North American Sylvilagus species are already rare.
Bureau of Land Management 1996 document on Pryor Mountain Wild Horse Herd contraception.
Web Site
Contraceptive Effect of Sperm Agglutinating Monoclonal Antibodies in Rabbits. Acrobat (PDF)
CV by PZP Web Site
But the Humane Society's labor intensive PZP method which costs about $1,000 per doe for the first two years of treatment may keep it from widespread use.
CV by PZP for deer. This is a hunting site opposed to the vaccine. Web Site
From an energetics stand point, dominant bucks would continue to chase subordinate bucks away in order to protect their "territory", thus reducing any stored energy they need to make it through the winter months. Simply put, chances are these bucks will not survive.
This article was originally published in the October Issue of BuckMasters Magazine.
This author might be reassured by the observation that no microbial agent has ever been 100% transmissible and no vaccine has ever been 100% effective. In order to put an end to hunting, the CV would have to surmount both of these historical realities.
CV success in contracepting squirrels (they bite and steal food-nasty buggers!) with a GnRH vaccine in 2002. Reproductive inhibition of over 90%. Web Site
CV success in contracepting wild pigs with a GnRH vaccine. Acrobat (PDF)
CV science. Very good rundown. Acrobat (PDF)
Deer Immunocontraception Program on Fire Island. Web Site
Dog Immunocontraceptive Vaccine: Web Site
Gonadotropin Releasing Hormone (GnRH) Immunocontraception in Mammals Web Site
Overall success 81% reduction in fawns in GnRH group
Luteinising hormone releasing hormone (LHRH. Just in case you didn’t think reproduction was complicated enough)
Web Site
Pet Overpopulation: The Simple Solution. Education, Legislation, Sterilization! Web Site
Porcine Zona Pellucida Vaccine (PZP) Web Site
There are ethical problems with the PZP vaccine since it’s a slaughterhouse byproduct. Although the protein spine of the PZP glycoprotein could be synthesized via recombinant DNA, further work will be required to accurately attach the glyco- fronds to the spine.
Possum immunocontraception in New Zealand Web Site
Potential economic loss from a viable contraceptive virus. Web Site
Both China and France have a high population of domestic rabbits bred for human consumption. In France there is currently a research project under way to produce a vaccine to the myxoma virus to protect their meat industry. It could be potentially devastating if the immunosterilising virus found its way into either country.
This underscores the problem that CV is impeded not only by technological problems but by people exploiting animals for financial gain.
PZP as ideal contraceptive. Can PZP be put in food? Web Site
Research is being done to determine if PZP can be safely delivered in food. The FDA, however, believes that oral contraceptives must be species specific (that is, it must work in only that one species for which it is intended) and to date, this goal presents many scientific challenges and has not been achieved.
Why can't we use PZP vaccine for deer in PA?
The Pennsylvania Game Commission, which controls wildlife in the Commonwealth of Pennsylvania, refuses to allow PZP vaccine to be used.
The PZP vaccine is not commercially available and it is provided at the cost of production which currently runs about $21/dose.
SpayVacTM for Sterilizing Domestic Cats (Felis catus) Didn't work very well. Web Site
Summary from Pennsylvania September 12, 2005 (9:31AM) where white tail deer are a nuisance and a controversy.
Web Site