SALT LAKE CITY (AP) - Female missionaries with The Church of Jesus Christ of Latter-day Saints worldwide now have the option to wear dress slacks, the church announced Thursday.

Members of the Missionary Executive Council said the change takes effect immediately and is primarily motivated by safety concerns. Women in roughly half of the church's 407 missions have previously been wearing dress slacks during the wet seasons to help protect them from mosquito-borne viral diseases.

"There are a lot of vector-borne diseases because of mosquitoes and ticks and fleas," said Sister Bonnie H. Cordon, Young Women general president and Missionary Executive Council member. "This helps the sisters to prevent any of those bites or at least minimizes them."

She said the change will help women who serve in cold climates to stay warm and wearing dress slacks also will make it easier for them to ride bicycles. They can wear slacks year-round if they choose, the church said.

"This is truly optional," Cordon said. "The sisters can wear dresses, they can wear slacks; whatever will help them in their service as they're out amongst the people."

Female missionaries will continue to wear skirts and dresses when attending the temple and during Sunday worship services, mission leadership and zone conferences, and baptismal services.

Elder Dieter F. Uchtdorf, a member of the Quorum of the Twelve Apostles and chairman of the Missionary Executive Council, said adjustments to the missionary dress standards have occurred since 1830 "and will continue to do so in the future."

Mormon missionaries serve as volunteers at their own expense.

Men ages 18 to 25 serve for two years while women ages 19 to 39 serve for 18 months.

Senior missionaries generally serve from six months up to two years.

Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.