The good news is that the fungus that causes athlete's foot and other nasty skin and toenail infections is headed for extinction. The bad news is it could take millions of years. Scientists analyzed samples of Trichophyton rubrum fungus and concluded it may have lost its ability to sexually reproduce as it adapted to grow on humans. "It is commonly thought that if an organism becomes asexual, it is doomed to extinction," said study senior author Dr. Joseph Heitman. He is chair of molecular genetics and microbiology at Duke University School of Medicine in Durham, N.C.

"While that may be true, the time frame we are talking about here is probably hundreds of thousands to millions of years," he added in a university news release.

But this research may help uncover vulnerabilities in the fungus that could result in better medications to fight it, according to authors of the study recently published online in the journal Genetics.

About 25 percent of the world's population have fungal infections, and T. rubrum is often to blame. It is difficult to cure and may be drug-resistant.

People can become infected when walking barefoot around swimming pools, showers or locker rooms, or when sharing personal items such as towels or nail clippers. Athlete's foot, also called tinea pedis, is a fungal infection of the foot. It causes peeling, redness, itching, burning, and sometimes blisters and sores.

Athlete's foot is a very common infection. The fungus grows best in a warm, moist environment such as shoes, socks, swimming pools, locker rooms, and the floors of public showers. It is most common in the summer and in warm, humid climates. It occurs more often in people who wear tight shoes and who use community baths and pools.

Ringworm is a common skin infection otherwise known as tinea. It is caused by a fungus. While there are multiple forms of ringworm, the most common affect the skin on the body (tinea corporis), the scalp (tinea capitis), the feet (tinea pedis, or athlete's foot), or the groin (tinea cruris, or jock itch).

Athlete's foot is caused by a microscopic fungus that lives on dead tissue of the hair, toenails, and outer skin layers. There are at least four kinds of fungus that can cause athlete's foot. The most common of these fungi is trichophyton rubrum.

Signs and symptoms of athlete's foot vary from person to person. However, common symptoms include:

•    Peeling, cracking, and scaling of the feet

•    Redness, blisters, or softening and breaking down of the skin

•    Itching, burning, or both

•    Interdigital: Also called toe web infection, this is the most common kind of athlete's foot. It usually occurs between the two smallest toes. This form of athlete's foot can cause itching, burning, and scaling and the infection can spread to the sole of the foot.

•    Moccasin: A moccasin-type infection of athlete's foot can begin with a minor irritation, dryness, itching, or scaly skin. As it develops, the skin may thicken and crack. This infection can involve the entire sole of the foot and extend onto the sides of the foot.

•    Vesicular: This is the least common kind of athlete's foot. The condition usually begins with a sudden outbreak of fluid-filled blisters under the skin. Most often, the blisters develop on the underside of the foot. However, they also can appear between the toes, on the heel, or on the top of the foot.

HealthDay