Jeffrey D. Allred, Deseret News
A utility truck drives through water near the LDS Houston Texas Temple after Tropical Storm Harvey in Spring, Texas on Thursday, Aug. 31, 2017.

SALT LAKE CITY — The First Presidency of the LDS Church issued a letter Friday calling for help for victims of the deadly storm Harvey, but asking volunteers to wait before traveling to Texas or Louisiana.

The letter asked for prayers for victims, encouraged donations and expressed gratitude for volunteers while asking them to be patient.

Here is the full letter:

"The still-unfolding disaster caused by the torrential rains of Hurricane Harvey has caught the attention of people throughout the United States. Our hearts go out to the thousands who have borne the brunt of this storm, and we are deeply grateful for the acts of unselfish service and the heroic efforts of first responders that have been reported. All who find themselves amid these grave difficulties are in our prayers.

"Many are expressing interest in helping the thousands of people in the stricken communities in Texas and Louisiana. We are grateful for all who wish to assist in this effort. If you want to help, please consider the following:

"1. Donate toward the relief effort. Anyone wishing to provide support for the Church’s effort to aid those in need is encouraged to donate to the Church’s Humanitarian Fund.

"2. Volunteer. Within the next few days or weeks, volunteers to assist in the massive cleanup effort will be needed, but with rescue efforts still underway, that time has not yet arrived. If you wish to participate, please do not call local church leaders in Texas and Louisiana or travel to the affected areas right now. To learn about upcoming volunteer opportunities and receive information about needed assistance and its timing, we invite you to visit the following web page: https://justserve.org/Houston.

"We encourage your continued prayers in behalf of all who are affected by this natural disaster.

"The First Presidency"

Some cleanup efforts were underway Friday in the Houston area, but rescue crews were still going door-to-door looking for stranded or dead residents. Some of the more than 40 deaths caused by the storm are victims who died trying to save others.

Experts said danger lurks in Harvey's floodwaters, called a rancid brew by one researcher, and that cleanup efforts come with their own hazards.

For example, a Texas A&M University team found dangerous levels of E. coli in floodwater in Cypress, Texas, 125 times the amount of E. coli considered safe for swimming and 15 times higher than acceptable levels for wading.

Other pathogens may be in the water, too, such as flesh-eating bacteria, which showed up after Hurricane Katrina. Sewage, pesticides and other toxic chemicals also are contaminating the floodwaters. The Houston Chronicle reported a list of these concerns in a story on public health threats.

"There could be anything," Houston Health Department spokesman Porfirio Lopez said. "We just know it's contaminated."

A concern for cleanup volunteers includes injuries. Post-disaster studies show that most injuries occur in the weeks after an event during cleanup efforts. More than a quarter of all New Orleans' health problems in the first month after Katrina were injuries, Chron.com reported.

The need, however, is immense.

More than 1.75 million Texans evacuated their homes during Harvey, according to Department of Homeland Security Acting Secretary Elaine Duke.

More than 100,000 homes in Texas and Louisiana have been damaged or destroyed, said Tom Bossert, the official leading the White House’s response to the disaster, the New York Times reported.

Texas Gov. Greg Abbott has mobilized 14,000 members of the Texas National Guard, a number expected to grow to 24,000 by late next week, Chron.com reported.