Lucy Barnes
Contrary to popular belief, ticks can still be active in cold weather, even when there is snow covering the ground. In January there were approximately 300 new cases of Lyme disease reported to the CDC. Pennsylvania, Maryland and Delaware topped the list, accounting for over 2/3 of the total number of reported cases.
Maine, Michigan, Montana, Vermont and New Hampshire, all known for their winter weather extremes, have reported new cases of Lyme disease this year. Residents of Connecticut, New Jersey, and Virginia also have tested positive for Lyme disease since the New Year arrived.
The United States Department of Agriculture in Beltsville, MD reports ticks carrying Lyme and other tick borne diseases are still active in Maryland in January and February, even when there is a 70% snow cover and air temperatures are below freezing.
Spirochetes, the organisms responsible for causing Lyme disease, have managed to survive for at least 20 million years through extremely harsh conditions. Evidence of their existence has been found fossilized in the intestinal tissue of insects preserved in amber. It is highly unlikely a cold winter will make a noticeable dent in these hardy stealth pathogens.
Outdoor workers, skiers, hunters, and winter enthusiasts should not let down their guard simply because summer is over. Prevention measures, tick checks, proper tick removal and immediate treatment continue to be the best methods to avoid the long-term consequences of chronic Lyme disease.
Homeowners should be aware that ticks could hitch a ride indoors on firewood, especially if it has been stacked outside in the vicinity of deer, mice and other rodents. Ticks have been found on at least 7 different species of trees in Maryland’s woodlands, with some of the smallest ticks found on more than 45 percent of the tree trunks. Ticks are often found in hardwood habitats like oak and mixed forests, but mice, the ticks preferred host, can be found nesting under fallen logs, in hardwood or pine forests, and in houses and barns.
Once inside the home, shed or vehicle, ticks can survive for months in carpets, walls, wooden floors or in tiny crevices before requiring their next blood meal. One female tick can produce 2,000 or more offspring causing an infestation that can be difficult to eradicate.
Elevated temperatures and/or immersion in hot water containing chemicals fails to kill many ticks. Researchers at the Department of Agriculture placed ticks in automatic washers and dryers to determine if they would survive a typical wash cycle. At the time of their removal from the washer, the ticks had been affected by the hot water, but 65% were still alive 20-24 hours later.
A large percentage was able to survive several hot water washes in which two detergents were used. All ticks were eventually killed in the hot dryer cycle, but only after a full hour of spinning at extremely hot temperatures. The researchers concluded that clothing washed and dried using the normal procedures should not be considered to be free of living ticks.
Blood bank experiments were performed to determine if spirochetes would be killed using the current preparation and storage methods. The American Red Cross reported spirochetes were shown to survive when temperatures ranged from zero to 75 F degrees, with some spirochetes surviving for at least 45 days in adverse conditions. Therefore, they concluded, they cannot exclude the possibility of transmission of Lyme disease through blood transfusion.
Lyme disease support group leaders report the winter months can be the busiest time of the year. Patients who were not properly diagnosed in the summer and those whose antibiotic treatment was stopped too soon, causing a relapse, often look for more accurate information and a doctor trained in the complexities of Lyme and tick borne diseases. A record-breaking number of requests for help were noted this past January, especially from people who have been bitten since the holidays.
It appears bad weather, a time span of 20 million years, extreme heat, below freezing temperatures, lengthy storage in blood banks, the intact human immune system, and even short-term antibiotics won’t stop the progression or spread of Lyme. With approximately 230,000 new cases occurring annually in the United States, Lyme disease continues to be a national health crisis.
Lucy Barnes