Birds, Bird Parasites, Deer Ticks, and the Spread of Lyme Disease

There are lots of bird parasites that can climb off dead birds and empty nests onto human skin. Bird parasites can spread diseases like Lyme disease in new locations.

I've been thinking about the dark side of bird watching - birds and disease, and the risk of suffering a nasty illness carried by a bird. See my recent blog entries, Migrating Birds Spread Diseases, and Mosquito Control When Birds Bring West Nile Virus.

I can remember putting my hand into a recently vacated bird's nest as a child, and noticing a host of little bird mites crawling around on my hand and up my arm. I wasn't too impressed, but I brushed them off and went on my way. My mother firmly cautioned me not to interfere with bird's nests or pick up dead birds. At the time, I thought it was the "bugs" you could see that were the problem. Now I know it's the "bugs" you can't see - the ones that can make you sick - that you need to worry about.

Birds have lots of little parasites living beneath their immaculate feathers. Most of these bird parasites prefer birds: they may climb onto human skin, especially if they find themselves marooned in the nest, or if the host bird has died, but they generally don't stay. Before long, they wander off in search of a more suitable host. Some parasites are on the bird accidentally, just as bird parasites get on humans accidentally, and these ones will jump ship at the first opportunity.

That's how Lyme disease spreads with migrating birds: deer ticks climb onto birds for a blood meal and get a free ticket to the bird's next destination. The ticks don't prefer the bird, and they don't want to stay, so they soon drop off and settle in in a new location. They bring their own parasites with them. Watch for my upcoming article on birds and Lyme disease to learn more about a bird's role in the spread of Lyme.

Meanwhile, don't panic about birds and disease! The risk is small and a few common sense precautions will make it negligible. Don't handle dead birds or recently vacated nests with bare hands. Wear insect repellent when mosquitoes, ticks, and other biting pests are about, and pay attention to public health advisories and recommendations in your area.