Deer ticks and Lyme disease
Lyme disease is a condition transmitted through the bite of an infected tick. The species most often involved in North America is Ixodes scapularis, the black legged or deer tick. It can be found mostly in the northern Midwest and the eastern American states, and in Canada from southeastern Manitoba through Nova Scotia. In British Columbia and the Pacific Northwest the western black legged tick, Ixodes pacificus is known to spread Lyme disease.
Lyme disease has been a concern in the United States for years, but in Canada both governmental surveillance and public awareness of the problem have been lacking until very recently. Much of the population was unaware the disease spreading ticks were present in our country, including medical practitioners. Lyme disease was not reportable in Canada until this year, and health ministries are only now beginning to put out public service announcements about the condition.
In the United States Lyme disease is subject to voluntary reporting, and the Centers for Disease Control and Prevention have noted a steady increase of the number of cases. Over a 15-year period the number of cases rose by 101 percent. The CDC states these figures, “underscore the continued emergence of Lyme disease and the need for tick avoidance and early treatment interventions.”
Research in Canada over roughly the same period has similarly shown expansion of known tick populations. Migrating birds have also been linked to transporting infected ticks from established populations to regions where ticks and Lyme disease had previously been unknown. This suggests a need for increased public awareness and training of medical personnel, even in areas previously considered at low risk.
Symptoms and diagnosis of Lyme disease
Early symptoms of Lyme disease mimic the flu: headache, fever or chills, fatigue, and muscle stiffness or pain. Some people will experience a characteristic bulls-eye rash (erythema migrans) but this is not always the case. According to the Mayo Clinic, only 70 to 80 percent of people infected will have a rash. The rash may go unnoticed if it is on a part of the body the individual cannot see, and if the person has a tan or is dark skinned.
Lyme disease is difficult to diagnose. Several factors play a role in this difficulty, including the fact that the most commonly used laboratory tests can produce both false negatives and false positives. Other complicating factors are the nonspecific symptoms and a possible delay of up to a month, between the bite and the onset of those symptoms. Both adult and nymph tick bites can spread the infection. Nymphs can be smaller than the size of a poppy seed, and often go unnoticed. In some cases people who contract Lyme disease are not even aware they were bitten by a tick.
Prevention and treatment of Lyme disease
If diagnosed early, Lyme disease can be effectively treated with antibiotics, but when diagnosis is delayed it can lead to severe fatigue and joint pain, inflammation around the heart, and neurological symptoms such as extreme fatigue and cognitive impairments similar to those of Alzheimer’s disease. Lyme disease can go unrecognized for months or even years. It can be misdiagnosed as any number of conditions, from malaria to fibromyalgia to menopause.
Prevention of tick bites is fairly simple. The public is encouraged to wear light coloured clothing while out in wooded or overgrown areas. Long pants and shirts should be worn, with pant legs tucked into socks or hiking boots and shirts tucked in at the waist. A hat is also recommended. Clothing can be sprayed with a personal insect repellent containing permethrin.
When coming out of areas known to have significant deer or tick populations, it is best to remove clothing and to do a thorough check for ticks. If one is found it should be gently removed with tweezers – not burned or smeared with petroleum jelly. Flu-like symptoms in summer after a camping trip or hike should be reported to a doctor, and the classic bulls-eye rash is an indication for immediate antibiotic treatment without waiting for laboratory testing.
“Lyme disease.” CBC Radio One, The Current
“Lyme disease.” Mayo Clinic
N.G. Ogden, et al, “Ixodes scapularis Ticks Collected by Passive Surveillance in Canada.” Journal of Medical Entomology
Sonja Puzic, “Lyme disease on rise.” Windsor Star
“Surveillance for Lyme disease – United States, 1992-2006.” Morbidity and Mortality Weekly Report (CDC)
“Ticks and Lyme disease.” Public Health Agency of Canada