(C) Daily Montanan This story was originally published by Daily Montanan and is unaltered. . . . . . . . . . . How deadly brainworms jump from deer to moose – Daily Montanan [1] ['Christopher Ingraham', 'More From Author', '- September'] Date: 2023-09-23 Minnesota’s moose are dying. Researchers with the Department of Natural Resources and tribal groups estimate that the statewide population numbered around 3,300 this year. While the population has been relatively stable for the past decade, it’s a decline of more than 50% since the mid-2000s. One major factor in that decline? Brainworms. Several years ago scientists discovered a parasite known as Parelaphostrongylus tenuis was responsible for anywhere from 25 to 30% of Minnesota moose deaths. The parasite naturally infects white-tailed deer, and can spread to other hoofed animals like moose when the two species inhabit the same area. But the how of that interspecies transmission has been something of a mystery. Deer and moose tend to avoid each other, and the parasite has very specific and very weird life cycle requirements that must be met for infection to occur. A new study by researchers at South Dakota State University, Michigan State University and the Grand Portage Band of Lake Superior Chippewa sheds some light on how moose are getting infected with the bug. A camera trap project on the Grand Portage Reservation has shown that deer and moose both frequent spots called mineral licks, which are wet areas the animals visit to drink water and eat soil containing various minerals they need to survive. “We’ve known for a long time that brainworm has been one of the biggest factors in the (moose) population decline,” said lead author William Severud, a professor at South Dakota State University, in a statement. “The biggest mystery has always been, how are they catching it?” To understand why these spots are important, you need to know a bit about the brainworm’s unusually complicated (and quite frankly disgusting) lifecycle. Adult worms lay eggs in the brains and spinal cords of infected animals. Those eggs hatch into larvae which travel through the bloodstream into the animal’s lungs, where they’re coughed up, swallowed, and then pass through the digestive system unharmed. Once expelled from the initial host’s body, the larval worms seek out certain types of terrestrial snails that live in the forests and grasslands populated by deer. The worms burrow into the snails’ flesh, and then those infected snails are inadvertently ingested by deer and other animals as they graze (yes, really). Once inside their new host they migrate to the brain tissue to begin the cycle anew. Deer have evolved alongside the worms for long enough that brainworm infections are both common and fairly mild. Previous research, for instance, found worm larvae in two-thirds of deer poop samples collected from the Grand Portage Reservation. Moose, on the other hand, lack those defenses. The deer and their parasites only moved into Minnesota moose territory in the last several centuries. As a result, infections in moose cause severe neurological damage and are often lethal. The camera trap study found that not only do deer, snails and moose frequent the same mineral licks, but they’re all often present at the same time. That establishes a clear chain of transmission that was missing before: the deer poop out the larvae, the larvae enter the snails, and the snails get ingested by the moose. This knowledge may open the door to new efforts to combat moose brainworm infections, centered around these mineral lick sites. The sites could be made inaccessible to moose or deer, for instance, or perhaps there’s a reasonable way to remove the snails from the equation. “Any sort of forest management treatment might decrease the gastropod numbers, and that might lead to a decrease in the number of infected gastropods on the landscape,” Severud said. As they so often say in the sciences, more research is needed. This story was originally produced by the Minnesota Reformer which is part of States Newsroom, a network of news bureaus, including the Daily Montanan, supported by grants and a coalition of donors as a 501c(3) public charity. [END] --- [1] Url: https://dailymontanan.com/2023/09/23/how-deadly-brainworms-jump-from-deer-to-moose/ Published and (C) by Daily Montanan Content appears here under this condition or license: Creative Commons CC BY-NC-ND 4.0. via Magical.Fish Gopher News Feeds: gopher://magical.fish/1/feeds/news/montanan/