Lyme Disease, West Nile Virus and You

One of the joys of warm weather is spending more time outdoors.  Unfortunately, with that comes more exposure to biting insects that have the potential to be more than just an annoyance.  These little critters can spread diseases like Lyme disease and West Nile Virus. 

Lyme disease is caused by a bacterium that is spread by ticks, predominately deer or black ticks.  These are slightly different than the ticks that commonly infest household pets.  It is particularly common in the Northeast, Mid-Atlantic, and Pacific coast areas of the United States.  The bacteria live in the salivary glands of the tick and are spread to humans when the tick feeds for two or more days.

            The most common early symptom of Lyme disease is the “bulls-eye rash.”  Other early symptoms are fever, headache, joint pains, muscle aches and fatigue.  If it is not treated, it can progress to multiple “bulls-eyes”, meningitis, involvement of the nervous system, and heart disease.  If it progresses further to chronic Lyme disease, it can cause arthritis involving one or more joints, personality changes, sleep disturbances and altered mental functioning.  It is, however, rarely, if ever, fatal.

            Diagnosis of Lyme disease may be based strictly on the patient’s symptoms, especially if there is a history of a tick bite.  If there is uncertainty, a blood test can be used to confirm the diagnosis. 

            Once the diagnosis is made, the treatment for Lyme disease is antibiotics.   The treatment usually lasts for 3-4 weeks if the disease is caught early.  Four weeks or more of intravenous antibiotics is indicated if the disease has progressed to a later stage, especially if the patient has neurological symptoms.  Treatment failures have been known to occur, and re-treatment may be necessary.

            Prevention of tick bites is essential in the prevention of Lyme disease.  Wear protective clothing, such as long pants, boots and long socks when in wooded areas where ticks are likely to be present.  Tucking pants into the socks adds another layer of protection.  Also, wear light-colored clothing so that ticks are more visible.  Wear insect repellant such as DEET on any exposed clothing, and consider coating clothing with permethrin (which kills ticks on contact).  After being in a tick-prone area, examine all areas of the skin for ticks, especially within skin folds, as soon as possible.  Remove any visible ticks with fine-tipped tweezers.  There is no need for concern if the mouth remains attached because the bacteria are present in the ticks midgut and salivary glands.

            West Nile Virus is caused by a virus that is carried in the salivary glands of mosquitoes.  It is spread when a mosquito carrying the virus bites a susceptible animal, such as birds, dogs, cats, horses, bats skunks, squirrels, and rabbits.  There have been rare cases in humans.  While the majority of human cases are believed to have come from mosquito bites, in 2002 there were a few, extremely rare cases of spread via blood transfusions, transplanted organs and occupational exposure.  Thus far, West Nile Virus has been very rare in humans, and less than 1% of infected humans develop severe illness.

            The illness usually begins with non-specific symptoms, such as fever, headache, muscle aches and a rash.  The symptoms usually begin 3-14 days following the mosquito bite.  As the infection progresses, the patient may develop high fevers, severe headache, stiff neck, disorientation, tremors, muscle weakness, paralysis, and may even progress to coma and/or death.  The diagnosis is made via a blood test, which becomes positive within eight days of symptom onset. 

            There is no treatment specifically for West Nile Virus.  The treatment involves managing the symptoms, and preventing any complications, such as other infections, dehydration, and breathing difficulties.

            As with Lyme disease, prevention of the insect bite is key to disease prevention.  Wear insect repellant, such as DEET, during all outdoor activities, especially those at dusk or after dark, and consider using permethrin on clothing for high-risk activities. When sleeping outside in infested areas, consider the use of mosquito netting.  Repair all window and door screens in your home, to decrease entry of mosquitoes.  Participate in global decrease in the mosquito population, by ridding your property of any standing water which may be used as a breeding ground. 

            Fear of diseases such as Lyme disease or West Nile Virus should not be a deterrent to enjoying the summer season.  By taking a few precautions, you and your family can participate in outdoor activities and still remain healthy.