Dr. Sam Telford Talks Ticks – Part II

By Ann Kiessling, PhD

According to Dr. Telford, the tick problem in Bedford has increased markedly in the past 10 years, like many other communities in Massachusetts.  The re-forestation of farm land that heightened during the 1970s has not only allowed the increase in the deer population, but has also provided ideal, moist habitat for Ixodes scapularis, the deer tick that carries Lyme disease (Borrelia burgdorferi).  I.  scapularis requires humidity of greater than 85% to survive, conditions provided by forest leaf litter, unmowed grass in wetlands areas, tree shade, etc.

To avoid Lyme disease, Dr. Telford stressed personal safety measures — protect legs and ankles from tick passengers, use the repellent DEET and the pyrethrin family of pesticides, and search carefully for ticks with every shower.  Permethrin is the commercial form of the natural insecticide, pyrethrins, produced by chrysanthemums.  Walking paths should be cleared of leaf litter and at least 10’ wide to avoid tick contact.  He noted that I scapularis can only tolerate a few minutes of humidity less than 85% before it dies — hence the clothes in the dryer suggestion.

Dr. Telford pointed out that I. scapularis also transmits Anaplasmosis, Babesiosis, and Powasan virus.  Like Lyme disease, the incidence of all I. scapularis transmitted diseases is highest in the Northeast (www.cdc.gov/ticks/diseases).  Anaplasmosis is caused by the bacterium Anaplasma phagocytophilum and has more recently been called human granulocytic anaplasmosis; it is characterized by severe flu-like symptoms and can be treated with antibiotics.  Babesiosis is caused by a microscopic parasite, Babesia microti, that infects red blood cells.  Babesia infection may not cause any symptoms, but if it does (flu-like symptoms), effective treatment is available.  Powasan virus infection also causes flu-like symptoms, is very rare, with only 50 cases reported in the U. S. in the past 10 years.  Dr. Telford emphasized that a flu-like illness that occurs during tick season (e.g. June/July) rather than flu-season (fall/winter) should not be ignored in New England.

According to Dr. Telford, the Lone Star tick (Ambylomma americanum), a more aggressive beastie that actually jumps several feet to land on a host, is becoming more common in New England, especially on Naragansett Bay.  It can transmit Borrelia Lonestar and a Rickettsia, similar to Rocky Mountain Spotted Fever.  Woodchucks also have a tick that can transmit a form of Powasan virus.

Several Massachusetts communities have formed Lyme Task Forces through their Public Health Departments to develop a Lyme disease strategy, including reducing the local deer population, some summaries of which can be foundhttps://www.deerfriendly.com/deer/massachusetts/herd-population-and-management .

But not all Public Health experts support deer population control as the principal management of Lyme disease, instead pointing to the key role played by field mice (https://www.greenwichtime.com/news/article/Letters-A-dismissal-of-correlation-between-deer-4802993.php).  Reducing deer populations to control Lyme disease may be more effective on islands, where deer populations increase to very high densities because of the lack of natural predators.

During his talk in Bedford, Dr. Telford pointed out the advantage of placing cardboard tubes (e.g. empty toilet paper rolls) filled with permethrin-soaked cotton at strategic places around the yard to allow field mice to carry it back to their nests and thereby reduce the tick population.  Other efforts at treating mice to rid them of ticks are also under development.  https://www.cdc.gov/ticknet/ltdps/ltdps_bait.html

Massachusetts appointed a Special Commission to study Lyme Disease in Massachusetts, their comprehensive report was published in February, 2013:  https://malegislature.gov/Content/Documents/Committees/H46/LymeDiseaseCommissionFinalReport-2013-02-28.pdf.

Bottom Line as tick season approaches:

1. Deer populations need to be controlled for many reasons, including improving native bird habitat, reducing car accidents, reducing Lyme disease hosts, and maintaining the health of the deer herds themselves.  Massachusetts Fish and Wildlife have target animal densities for each region of the state, most of which in the Eastern portion of the state remain too high because of the outlawing of gun-hunting in many communities.
2. Controlling deer populations alone is probably not the total solution; some form of tick control on local field mouse populations needs to be included in any comprehensive public health strategy.
3. Although the incidence of tick-borne diseases is higher in the northeast than other regions of the country, and Bedford could be in a hot spot at estimates of 300 to 500 cases per 100,000 population, according to the Massachusetts Special Commission report, most of us will blissfully tromp through our woods for years without contracting a tick borne disease.

But whatever we can do to eliminate the risk entirely to future generations should be considered.