Johannesburg - KwaZulu-Natal's Hluhluwe-iMfolozi Park has received its first contraceptive vaccine to prevent elephant overpopulation, the Humane Society International (HSI) and Ezemvelo KZN Wildlife said on Monday.The contraceptive programme allows elephant populations to be managed humanely, to slow their growth rates, and to maintain the ecosystem, HSI and Ezemvelo said in a joint statement.Use of the contraceptive at the park began on 4 October."The immuno-contraception vaccine contains agents that, when injected into African elephant cows, causes an immune response that prevents eggs from being fertilised by sperm", it said."The vaccine is delivered remotely by dart gun, making the technique minimally invasive and eliminating the need for anaesthetisation."Immuno-contraception is a non-hormonal form of contraception based on scientific principles of immunisation through vaccination."In total, four populations will receive three years of treatment under an agreement between Ezemvelo, iSimangaliso Wetland Park Authority, and HSI", the statement said.The programme is being funded by Ezemvelo, HSI and the United States Fish and Wildlife Service through the African Elephant Conservation Fund."We are very pleased to work with Ezemvelo in helping control elephant populations in Hluhluwe-iMfolozi Park", said HSI field director Audrey Delsink."We're delighted to see more and more elephant managers count on this technology to control elephant population growth in a proactive, effective and humane manner, and hope it becomes universally adopted."HSI said research conducted over the past 18 years demonstrated that immuno-contraception was a safe and effective way to control the elephant population."It has no effect on behaviour."