By Janelle Miles, National Medical Correspondent

BRISBANE, May 15 AAP - An Australian researcher is preparing to put his hand into his own pocket to help fund human trials into whether intravaginal lemon juice protects women from sexually-transmitted HIV infection.

Melbourne University's Roger Short said he would dip into his own, very limited, pension fund if need be to kick-start the project by the end of the month.

Professor Short, of the university's obstetrics department, has previously shown in the laboratory that lemon juice immobilises sperm and kills the AIDS virus.

But until recently, ethical human trials have remained impossible for fear women might contract HIV if the treatment fails.

Those barriers were overcome when Nigerian sex workers in the city of Jos were found to be already using lime or lemon juice douches as a contraceptive and to prevent sexually-transmitted diseases.

Prof Short said preliminary budget estimates suggested a prospective trial of 400 Nigerian prostitutes would cost $US100,000 ($A131,000).

He recently launched the Mary Magdalene Project to raise money for the trial after US president George W Bush announced limitations on funding for overseas HIV/AIDS initiatives.

Mr Bush said groups seeking US government funding must make a written pledge opposing commercial sex work.

American-based population health and family planning professor, Malcolm Potts, has thrown his support behind the project.

"I think it's a worthwhile project," Prof Potts said in an interview. "I think we should be kind to people who are suffering and vulnerable and try and help them but also, we can probably help ourselves.

"This might be something that western women could use."

Prof Potts, of the University of California at Berkley, said the trial would not involve any experiments using the Nigerian prostitutes.

"What we want to do is observe what these women are already doing," he said.

"We merely want to see whether what they are doing is protecting them or, it's always possible that it might be harming them, in which case we also need to know that."

Prof Potts said his university was studying a group of 25 young university students, not exposed to the AIDS virus and not sexually active, to test the affect of lime juice on the vagina.

He said the women were putting lime juice inside their vaginas twice a day and so far, researchers had detected no evidence of damage.

Anyone wishing to donate to the Mary Magdalene Project can find details on the website, www.aids.net.au.

"We really need to fund this project because it's a breakthrough for Africa," Prof Short said.

He said it would be great if research could come out of Africa instead of always being western research superimposed on Africa.

In sub-Saharan Africa alone, an estimated 28 million people are HIV-positive.

AAP jhm/lma/bwl