RIO DE JANEIRO ~ Brazilian researchers have developed an algae-based microbe-killing gel for women aimed at blocking the sexual transmission of HIV.

The microbicide was 95 percent efficient in the first phase of testing over the last three years, the research’s coordinator, immunologist Luiz Castello Branco, told Folha de Sao Paulo newspaper.

A second round of tests will start in February on mice and live cells from the cervix, said Branco, a researcher at the Oswaldo Cruz Institute in Rio de Janeiro. Human studies would start in 2008.

“We will certainly get to a final product with an efficiency above 50 percent,” he said.

The gel – based on a substance taken from Dictyota pfaffi, a type of algae found on the Brazilian coast — could be put on the market in seven years, he said.

“A woman could use the gel without the husband knowing,” Branco said.

“Right now we will test the product’s safety and the ideal dose,” said Branco, whose team is working with researchers from Fluminense Federal University and Ataulpho de Paiva Foundation.