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Professor Richard Fayrer-Hosken
"It's safe and reversible"
 real 28k

Ian Whyte, senior scientist, Kruger National Park
"It's just like a little flu shot"
 real 28k

Wednesday, 13 September, 2000, 18:07 GMT 19:07 UK
Wild elephants given novel contraceptive
Elephant BBC
Large herds cause problems for humans and other wildlife
A novel contraceptive has been tested successfully on elephants in South Africa's famous Kruger National Park.

Researchers believe the new approach will help rangers control numbers where elephant populations are on the increase after the ivory ban.

Very large herds can cause major disruption, trampling crops and damaging the vegetation on which other wildlife depend.

Effective contraceptive control would remove the need to cull elephants, a practice that is both distressing and politically difficult.

Pig's eggs

Professor Richard Fayrer-Hosken, at the University of Georgia in Athens, US, and colleagues have developed an immuno-contraceptive vaccine which works in a very different way to the more familiar hormone contraceptives.

Instead stopping ovulation, the vaccine makes the elephant's immune system produce antibodies that prevent fertilisation from taking place.

The antibodies target the clear, protein coat that surrounds all mammalian eggs called the zona pellucida. This interferes with the sperm's ability to penetrate an egg, making it very difficult for the animal to conceive.

The vaccine was derived from pig's eggs, whose zona pellucida is very similar to that found in elephants.

Elephants were tracked down by helicopter, checked to see they were not already pregnant and fitted with radio collars to monitor their movements.

Elephant first

Some of the animals were injected with the contraceptive; some were given a placebo. Boosters were administered by dart after just a few weeks.

The researchers then checked their subjects 10 months later. In one trial, only two out of the 10 test elephants fell pregnant. Whereas, 16 of the 18 controls had conceived.

The scientists, who report their work in the journal Nature, have shown the vaccine to be reversible. The elephants are also free of the antisocial behaviour sometimes seen in herds when females are given hormonal contraceptive implants.

Immuno-contraceptive vaccines have been used before with mice, rabbits and larger animals such as horses, but this is the first research to show that they will work with wild elephants.

'Expensive choice'

But some observers have questioned just how practical it would be to use such a vaccine in the field.

Steve Osofsky, an elephant expert at the World Wildlife Fund, said the approach was promising but would probably be expensive and limited to smaller parks or refuges because it was time-consuming to administer.

And he said some African nations would actually prefer to allow hunters to kill excess elephants for food and ivory, or for trophies on special big game hunting safaris.

"For them, culling is seen as an income generator, whereas contraception would need to be paid for,'' Steve Osofsky said. "Where you have wildlife seen as a commodity, contraception would not be something they would choose.''

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