HIV charities in Mozambique are trying to change attitudes to polygamy as part of efforts to stop the disease from spreading.
More than one in eight people across the country have HIV and rates of infection are rising.
Experts believe the tradition of men having many wives is a major factor.
Workers with the charity Estamos are now trying to discourage men and women from engaging in polygamy.
They are also trying to end another tradition which sees widows marrying their brother-in-law when their husband dies.
Americo Miros, a worker with the charity in the north of the country, said their efforts were aimed at stopping HIV from spreading further.
"In this area, we don't feel that we have a major problem with HIV at the moment.
"However, we want to do everything we can to avoid HIV from coming here and spreading to other communities," he said.
"We are trying to change behaviour. Polygamy is very prevalent here so we are trying to talk to the men and get them to change their behaviour of having several wives.
"The other one is a traditional practise that when the husband dies the wife goes with his brother. We are trying to end this practise too."
The charity is also working with young people to discourage them from having sex at a very young age and to teach them about the risks of contracting HIV.
"We want teenagers to stop engaging in sexual activities at a young age," said Americo.
According to the charity, people living in rural areas are aware of the risks of contracting the disease.
There have been many cases of people emigrating to Malawi, where one in seven is infected, and returning home having contracted HIV.
"There is a lot of movement of people going to Malawi and coming back," said Americo.
"HIV is a concern here because people are afraid that others will bring it back from Malawi. So a lot of our work is focused on prevention to prevent that from happening."
Changes under way
According to Americo, the charity is having some success.
"We are changing attitudes slowly. But we have also seen big improvements with more men now using condoms."
In addition, more young people are abstaining from sex. Women are also much more wary of being circumcised.
"Female circumcision is common here," Americo said. "But women are now aware that they can catch HIV by using the same knife."
Americo acknowledged that many people living in rural areas of the country are finding their traditions and normal way of life under threat because of the spread of HIV.
"Life is changing. It is not the same as it used to be before," he said.
This story is featured in the radio programme Health Matters on the BBC World Service.