Elephants on the pill

Actually more of a vaccine, contraception for elephants is a proposed alternative to killing elephants in order to maintain and control population growth.

Research efforts are ongoing to determine the best approach for delivering contraceptives and what type should be used.  There are many considerations, like not repeatedly disrupting elephant groups, creating situations that are very stressful for the elephants, the safety of people administering the contraceptive and costs associated with treatment.

An abstract from an article published in the Journal of the South African Veterinary Association summarizes a current project:

The goal of programmes to provide contraception for elephants should be to formulate an approach that does not require the relocation or immobilisation of the same individual year after year, which would be long-lasting and cause minimal disruption to social and reproductive behaviour. The programmes should be simple to administer, safe and cost-effective, and must meet the objectives defined by managers in the field. An immunocontraceptive programme was initiated in a small free-roaming population of elephants at the Greater Makalali Private Game Reserve in Limpopo Province in 2000 to determine whether the porcine zona pellucida (pZP) vaccine can successfully control population sizes. Further objectives were to determine implementation costs and efficiency through a multi-faceted approach. We have demonstrated that immunocontraception meets the objectives set by managers in the field. Minimal social disruption was observed over the course of treatment, with the mode of delivery (ground or aerial vaccinations) determining the degree of stress within herds and speed of resumption of normal movement patterns. Aerial vaccinations resulted in the least disturbance, with target herds being approachable within a day. In 2005, implementation costs were R880-R1000/elephant/year, inclusive of darts, vaccine, helicopter and veterinary assistance. Irrespective of the source or method of vaccine delivery, a non-pregnant elephant is rendered infertile from 1st vaccine administration. The sooner immunocontraception is implemented, the sooner population growth rates can be controlled. pZP contraception is a realistic alternative management tool, particularly if used as part of a long-term management strategy. Mass-darting from the air eliminates the need for detailed individual histories of each elephant or for employing a person to monitor elephants. Thus, implementation of immunocontraception in larger populations is feasible and practical.

 This excerpt from an article in the Journal of Development of Biologicals sheds some light on how the contraceptive works

Of the many targets for such vaccines, several sperm-associated antigens have been proposed for antibody-mediated intervention before fertilization but the very abundance of antigen to be neutralized has been a barrier. Zona pellucida antigens associated with the surface of the oocyte have also been targeted and used successfully for control of ‘wild’ elephant populations but worries concerning immunopathologically-mediated tissue damage have been mooted

 This link provides more information on some of the research into the vaccine’s effectiveness.

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