A TICK’S LIFE
TICK TWO-YEAR LIFE CYCLE
Borrelia burgdorferi, the spirochete bacterium that causes Lyme disease, can cause illness in many species of animals, including people and dogs as well as horses. A number of B. burgdorferi subspecies cause disease around the world. In North America, the bacterium is typically transmitted by two particular species of ticks: Ixodes scapularis in the Northeast, Mid-Atlantic and Midwestern states, and Ixodes pacificus on the West Coast. Both species share several common names, including deer ticks, bear ticks and blacklegged ticks.
These ticks have a two-year life cycle, during which they pass through three stages: larva, nymph and adult. At each stage, they must take a blood meal to mature to the next and then lay eggs. The larvae usually feed only on small animals such as mice. If a tick larva feeds on a mouse that is infected with B. burgdorferi, it picks up the bacterium and carries it along as it develops into a nymph. Then, as it feeds again as both a nymph and as an adult, it can pass the bacterium on to its next hosts.
Nymphs, which emerge in the spring and summer, may feed on mice, but they can also bite larger animals, including dogs and people. Adult ticks, which emerge in the fall, are found primarily on deer, where after feeding, they mate and the female drops off to lay her eggs in the grass or leaf litter. Adult ticks, however, may also be found biting other large animals, including horses. lents as well: Dogs are inclined to roam in weedy areas and roll in leaf litter where they can pick up ticks, which they could then carry back to your house and barn.
Cats can also be infected with Lyme disease, although naturally occurring cases are rare. If you want to apply tick repellents to your barn cats, choose products made for felines. Some products for dogs are toxic to cats.
• KEEP PASTURES MOWED. Ticks crawl up onto tall grasses and shrubs and wait to climb onto any large animal that brushes by. Keeping pastures and other turnouts mowed to five inches or less will help prevent ticks from getting on your horse.
• #ONTROL THE HOST SPECIES. The white-footed mouse is an important reservoir for B. burgdorferi. Take steps to keep rodent populations around your farm under control. Eliminate old brush piles and mow down weedy areas that give them cover. Keep grains and other feeds in sealed containers, and clean up spills promptly. Barn cats and natural predators such as black snakes and barn owls can help keep down rodent populations.
Keeping deer away from your farm might not be possible, but you can take steps to avoid attracting them in large numbers. For example, if you have fruit trees, keep fallen fruit cleaned up, and choose deer-resistant plants for landscaping. Deer repellents---products that include ammonia compounds as well as natural substances such as blood meal ---may be helpful, but they need to be reapplied regularly.