It’s Saturday morning at 8:26, and I see it in the bathroom mirror—a tick embedded in my back. And it’s mighty big. I let out a yell. By 8:28 my husband has responded dutifully, the disgusting creature has been extracted, and promptly dispatched to what we call “the death jar,” a marmalade jar filled with hydrogen peroxide. I was reminded of the first time I had a tick discovered, inside my ear, over lunch in a ’50s diner in Ottawa. That time I didn’t yell, but I forced my husband to yank it out right then and there, between the arrival of the shakes and the burgers.
It’s not just that parasites revolt us. It’s that deer ticks can carry Lyme disease, a particularly insidious and nasty condition that can prove difficult to detect. We are living in an area rife with the creatures. So just what are the chances of getting Lyme disease from a bite? Fortunately, not that high, because not all deer ticks are infected with the Borrelia burgdorferi bacteria and because an infected tick has to be attached, and feeding, for at least 36 hours to transmit the disease. Even with a bite, you have only a 1 to 3 percent chance of actually getting Lyme disease.
According to the Centers for Disease Control (CDC), the number of cases has skyrocketed in recent years, and all since 1975, when mothers in Old Lyme, Conn., began wondering why an elevated number of juvenile rheumatoid arthritis cases existed in three communities.
Since becoming nationally known in 1991, the disease is now considered endemic to the states of Massachusetts, Connecticut, Delaware, Maryland, Minnesota, New Jersey, New York, Pennsylvania, Rhode Island, and Wisconsin. The CDC’s most recent data are for 2003 to 2005 and show that the median age of patients was 41 years, with males accounting for 54 percent of reported cases, and 61 percent of cases occurring among children aged 5 to 14 and adults from 45 to 54. Cases peak in the summer, indicating the transmission by deer ticks during May and June. Patients were most likely to have shown onset in May (7 percent), June (25 percent), July (29 percent), or August (13 percent). Fewer than 8 percent reported onset during December to March.
In 2005, the CDC was reporting approximately 20,000 new cases each year, making Lyme disease the most common vector-borne disease in the U.S. The large increases in numbers indicate more cases plus better detection.
Early signs of Lyme disease include fever, headache, fatigue, muscle or joint pain, and a characteristic “bull’s-eye” skin rash called erythema migrans. Some people have the disease but lack early symptoms. Others have a fever and flu-like symptoms without a rash.
After days or weeks, the bacteria may spread through the body, creating more rashes, pain that moves from joint to joint, and inflammation of the heart or nerves. If not treated, serious problems can develop months later, including swelling and pain in major joints, and mental changes.
The CDC defines a “reportable case of Lyme disease” as used for national reporting as a physician-diagnosed erythema migrans of 5 cm or more in diameter, or at least one “objective late manifestation (i.e., musculoskeletal, cardiovascular, or neurological) with lab evidence of infection with B. burgdorferi in a person with possible exposure to infected ticks.” Although this is the standard normally used, the CDC notes that this definition “is not intended to be used in clinical diagnosis.”
Given the realities of living in Harvard, much of the prevention weighs on residents to be informed and take steps to protect themselves and their families. Everyone knows it’s a good idea to avoid grassy or wooded areas where ticks cling to brush, high grass, or anything else higher up so they can spring onto a passing host. One should also wear light-colored clothing so ticks will be more visible. Favor long-sleeved shirts tucked into pants, and socks with high rubber boots. Apply tick repellents judiciously; the CDC calls for the application of those containing DEET to skin and clothes, and permethrin on clothes. It says that “DEET can be used safely on children and adults but should be applied according to Environmental Protection Agency guidelines to reduce the possibility of toxicity.” Never use on infants, and use with great caution on children, including avoiding application to the face. Follow a ritual of daily self-examination for ticks (get spouses involved, if necessary); remove them with fine-tipped tweezers, and cleanse the area with an antiseptic. Landscape yards and play areas to reduce the living area of rodents, deer, and ticks. This involves removing brush, leaf litter, and wood piles “or creating a buffer zone of wood chips or gravel between forest and lawn or recreational areas.” The CDC lastly calls for avoiding tick-infested areas, a tall order where we live.
For more detailed information on Lyme disease prevention, visit www.cdc.gov/ncidod/dvbid/lyme.
While a Lyme disease vaccine was licensed in 1999, it was withdrawn from the market in 2002, due to what the CDC calls poor sales. No vaccine is now available.
Prompt diagnosis and treatment are necessary to prevent serious, long-term complications. Most cases, say the CDC, can be successfully treated with a few weeks of antibiotics.
One of the great joys of living in a place like Harvard is the ability to have pets that can roam and enjoy the great outdoors. The problem is that outdoor pets can also be infected because they are likely to go exactly where ticks thrive. They can also bring the little hitchhikers back home, where they can jump to indoor pets and people. Ticks bite mice infected with Lyme disease, and then bite deer, people, dogs, or horses, thereby infecting them.
A good vet can test pets for Lyme disease and recommend a preventative. In any case, there is a great likelihood that outdoor pets in Harvard have been exposed to the disease. I can also recommend the benefits of having a yellow lab. They may run amok but ticks are easy to see on them.
If you want to learn more, visit www.cdc.gov/ncidod/diseases/submenus/sub_lyme.htm. The Harvard Board of Health has also added to the town website in recent weeks a link to information on Lyme disease and deer ticks. Included are links to other sources of information, including the Massachusetts Department of Public Health. Go to www.harvard.ma.us.
Because deer tick saliva contains a substance that allows it to evade the host’s immune system as it feeds for up to seven days, scientists are looking at the creatures with a new sense of appreciation. Recently reported in the news is that UMass Amherst researchers have found that a protein in the saliva prevents the HIV-1 virus from attaching to the surface of the T-cells (white blood cells) of the host’s immune system as it feeds. Normally the HIV-1 virus cripples the immune system by targeting the T-cells that form the body’s first line of defense in fighting infection. Researchers believe that the protein may prove to be an effective treatment for autoimmune diseases like asthma and multiple sclerosis caused by an overactive immune system that attacks itself. It may also suppress the immune system to prevent the rejection of transplanted organs.
Results were published in the February 2008 issue of Biochemical and Biophysical Research Communications.