SALT LAKE CITY — Mormon women serving missions in countries threatened by mosquito-borne illnesses now can wear dress slacks to cover their legs, on a geographic and seasonal basis.

The First Presidency and Quorum of the Twelve Apostles made the announcement this week in a news release that includes several new policies to protect the health of missionaries of The Church of Jesus Christ of Latter-day Saints in 230 of the faith's 418 missions around the world.

Until now, LDS sister missionaries have worn dresses or skirts exclusively.

"With this announcement," the release says, "sisters serving in these areas are encouraged to wear full-length dress slacks during proselyting activities."

The Zika virus is among the mosquito-borne illnesses driving the new policies. The release also mentioned dengue fever and chikungunya. Today, the CDC announced it is tracking nearly 300 Zika virus cases in American women. The Zika virus can cause stillbirths, microcephaly or other congenital problems.

A list of affected missions is available on mormonnewsroom.org. None are in North America. However, the church also announced it will pay for "permethrin insecticide solution and DEET-containing repellant" for all missionaries worldwide.

"Major governmental agencies concerned with health care and disease prevention have recently issued alerts and precautions about the spread of mosquito-borne viral diseases throughout major areas of the world," said Elder Gregory A. Schwitzer, assistant executive director of the church's Missionary Department and chairman of the Missionary Medical Health Services Division.

In areas of the world where it is not acceptable for women to wear dress slacks, sister missionaries will be able to wear long dresses to cover their legs to protect against mosquito bites.

Examples of the new dress guidelines for these areas may be viewed on the "Missionary Dress and Grooming Guidelines” page of LDS.org.

The church leaders already had recommended that missionaries avoid stagnant and standing water when possible, because that can be breeding grounds for mosquitos.

"We encourage our members," the release added, "in areas where mosquito-borne diseases are prevalent to protect themselves by following the recommendations of local authorities who are knowledgeable about health risks."

The rainy season is beginning in Thailand, where the Ministry of Public Health warned the public to take precautions against dengue fever. In other parts of the world, dengue fever is already in full bloom. For example Colombia has reported 33 percent more cases this year than at this time last year, with nearly 50,000 cases as of April 30.

The chikungunya virus has spread through South America and the Caribbean since 2013, according to Science Daily. The virus is now threatening the southern United States and Southern Europe.

Both dengue fever and chikungunya cause occasional fatalities.

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

SUNGLASSES, HATS: Other new guidelines for LDS missionaries include allowing them to wear simple and conservative sunglasses outdoors. Missionaries are instructed to not wear sunglasses while speaking with others people and to avoid sunglasses with bright-colored rims or mirrored lenses.

Wide-brim hats — with at least 3-inch brims — also are now allowed when necessary for protection from sun. Baseball, cowboy, bucket, newsboy and fedora hats are not acceptable.

Email: twalch@deseretnews.com