Islam has won a growing number of followers in this impoverished country, especially after the catastrophe two years ago that killed some 300,000 people and left millions more homeless. A capital where church attendance is so prevalent that the streets echo with Christian hymns on Sundays now has at least five mosques, a Muslim parliament member and a nightly local television program devoted to Islam.
The disaster drew in aid groups from around the world, including Islamic Relief USA, which built 200 shelters and a secondary school with 20 classrooms.
"After the earthquake we had a lot of people join," said Robert Dupuy, an imam or Islamic spiritual leader in the capital. "We were organized. We had space in the mosques to receive people and food to feed them."
Derosier said she was drawn to the religion's preaching of self-discipline, emphasis on education and attention to cleanliness. The constant washing, she said, helps her and other Muslims avoid cholera, the waterborne illness that health officials say has sickened nearly 600,000 people and killed more than 7,500 others since surfacing after the quake.
"This is a victory for me," the 43-year-old woman said about her post-quake conversion. The former Protestant spoke in the tent-filled courtyard of her home, her face framed by a clean, black head scarf. "It's a victory that I received peace and found guidance."
In part, the Muslim community's growth can be attributed to the return of expatriates who adopted the faith in the U.S., said Kishner Billy, owner of the island's Telemax TV station and host of the nightly program "Haiti Islam."
Billy and some others believe that Islam's Haitian past goes back before the country's independence in 1804, and that a Jamaican slave and Voodoo priest named Boukman who led the slave revolt that ousted French colonizers was actually a Muslim.
"Islam is coming back to Haiti to stay," said Billy, who says he converted from Christianity 20 years ago. "Future generations, my sons and daughters, will speak about Islam."
There are no firm statistics on the number of Muslims in Haiti, just as there are no reliable figures for many things in the country, including Port-au-Prince's exact population.
A 2009 study by the Pew Research Center on the world's Muslim population estimated that Haiti had about 2,000 devotees. Islamic leaders in the country insist the figure is much higher and growing.
Islam is hardly unknown in the Caribbean; countries such as Trinidad & Tobago, Suriname and Guyana have significant Muslim populations. Many of those nations have strong roots in countries such as India and Indonesia where Islam is widespread.
The ancestors of Haitians, by contrast, were brought largely from non-Muslim areas of Africa. Haiti's French colonial rulers also imported their Christian beliefs.
The recent growth of Islam, as well as other new religions, shows Haiti is modernizing and becoming more pluralistic, said Patrick Bellegarde-Smith, a professor of Africology at the University of Wisconsin-Milwaukee.
"Inroads made by Islam (and by extension, by Mormonism and Rastafarianism) tell me that Haiti is very much a product of this century, subject to all winds, ill-winds and otherwise, that blow over the Caribbean nation-states," Bellegarde-Smith wrote in an email.
Rosedany Bazille, a 39-year-old teacher who converted several months after the earthquake, said she had felt rudderless before embracing the religion and was looking for a way forward.
"Islam can put people on the right path and show them who's God," she said.
Some Haitian Muslims belong to the Nation of Islam, a U.S.-based branch of the religion that preaches black self-determination. Some local members converted while serving time in U.S. prisons before being deported back to Haiti. The group's leader, Louis Farrakhan, visited the country for the first time last year.
The decision to convert has made some targets of discrimination.
The Haitian government doesn't recognize Islam as an official religion, nor does it honor Muslim marriages. Wearing the skullcaps or flowing head scarves typical of the religion can draw stares and finger-pointing. Derosier said her neighbors gossip that she's evil.
Voodoo, a blend of West African religions created by slaves during the colonial period, has long been a popular faith in the country, with elements followed even by some of the 85 percent of the population who claim Christian beliefs. Voodoo was once so commonly embraced that the notorious dictator Francois "Papa Doc" Duvalier used it to terrify and control the masses.
Most Christian Haitians identify themselves as Roman Catholics. A priest, the Rev. Jean-Bertrand Aristide, was elected president in 1990 by opposing the hereditary dictatorship that continued with Francois' son, Jean-Claude "Baby Doc" Duvalier.
With so much still wrong in Haiti, the need for Islam couldn't be greater, said Billy. Two months ago, he launched his live talk show to educate his compatriots about his adopted faith.
"Haiti has gone astray. It can't produce anything," said Billy. "Right now Haitians just want a visa to go the United States, to Canada. They don't want to stay in Haiti."
With a tapestry of Mecca and praying crowds as a backdrop to his TV show one recent evening, Billy and his co-host Ruben Caries invited watchers to send questions about Islam via text messages.
Billy's BlackBerry buzzed with missives, including this one in Creole: "M vle vini Muslim" — "I want to be a Muslim."