A famous herd of wild ponies is being stalked by a deadly disease. Human friends have stepped in.

RainDancer, seen here at an auction, was only 6 months old when she died from the disease.

(CNN)Shadow befriended an older stallion named Rainbow Warrior who had been alone for a long time. Essie became a mother again in 2018. And then there's RainDancer, short for Kachina's Shenandoah Raindancer. At 6 months old, she was all legs and as cute as a button.

In just a couple of months' time, those three females and four other ponies were euthanized after a fungus-like disease produced ghastly lesions and other problems that proved too difficult to defeat. The last were put down near the end of December.
The losses have wounded a community fascinated and inspired by the famous wild Chincoteague ponies, which have grazed on a Virginia barrier island for centuries. No one's sure how they got there: Legend and a famous children's book suggest they survived shipwrecks; others say settlers loosed them on Assateague Island to feed.
      The Chincoteague Volunteer Fire Company, which manages the herd, brought in veterinarians to combat the disease, sometimes called "swamp cancer."
        Supporters are pinning their long-term hopes on a prevention vaccine under development, along with enhanced treatment for ponies in the grips of the infection.
          Shadow, right, with Rainbow Warrior. Shadow was euthanized in the last days of 2018.
          "The real secret is catching it early," said Darcy Cole, a photographer who spends 300 days a year studying the creatures. She spotted a few of the ill ponies and notified caregivers.
          While observers say the herd of about 150 wild ponies appears now to be healthy, there is concern of a re-emergence of the infection next summer, when warmer temperatures return.
          "Outside of saving lives and properties these ponies are our No. 1 priority, said Denise Bowden, spokeswoman for the fire company. "We are animal lovers, too."
          The herd is a huge tourist draw and likenesses of them are ubiquitous on Chincoteague Island; sports teams for the high school are called the Ponies.
          The animals roam Chincoteague National Wildlife Refuge on Assateague Island, just across the channel from Chincoteague Island.
          Amanda Geci, an Alabama resident who owns a Chincoteague pony, keeps a searchable pedigree database. She remembers seeing Essie, then a baby, during a visit.
          The losses of the seven ponies and a few others in previous years are heartbreaking.
          "You become friends," Geci said.

          'By then, it is too late'

          According to reports, sores on a few ponies' legs were first noticed a couple of years ago.
          Veterinarians determined they were suffering from pythiosis, a disease that traditionally has been associated with Latin America and Gulf states in the United States.
          The organism typically grows on dead or dying grass and plants and is present near water, said Dr. Richard Hansen, a researcher whose Oklahoma company is doing work on a vaccine and enhanced immunotherapy to combat the infection.
          Zoospores are attracted to a ponies' hair or cuts. "It's attracted to a wound, maybe even a tiny one."
          From there, the disease can create lesions and it compromises the animal's immune system.
          Local veterinarians assisted the fire company in treating the infected animals. Pony supporters said doctors and fire company volunteers did all they could -- using a variety of treatments, including immunotherapy -- to save the animals.
          Dr. George Marble of Eastern Shore Animal Hospital said he tried an antifungal treatment, and for a while it seemed the ponies were improving. But the pythiosis "came back with a vengeance," he said.
          Wild ponies stand at the water's edge last month on Chincoteague National Wildlife Refuge.
          "I think the efforts need to be in prevention," said Dr. Allison Dotzel, a large-animal veterinarian. "It is a notoriously difficult disease to treat."
          Hansen's company at some point will seek approval from the US Department of Agriculture to experimentally use a product "to quell this outbreak."
          Making a rapid diagnosis is crucial for the animal's survival, experts say. But that can be a challenge.
          "I might see one today and they may go into the woods," Bowden said. "You may not see them for two weeks. By then, it is too late."

          Ponies are on the top of the chain on this island

          Every July, wild ponies swim across a channel from Assateague to Chincoteague, where foals are sold.
          You may recognize Chincoteague ponies from the famous five-minute swim they make every July.
          About 35,000 visitors see the entire herd (minus newborns and pregnant mares) paddle the channel that separates the islands. Many more tourists come during the year to see the horses, shop or stay in motels on Chincoteague Island.