The past few years have saw a dramatic increase in tick activity throughout Michigan. Anecdotally, many life-time Michiganders are telling me that they have seen more ticks in the past year than in their whole life. There are several reasons for this. For one, deer ticks have been migrating into Michigan in greater numbers since the 2000s, so there are simply more deer ticks living in the state, especially on the west side. Increased deer populations, decreased hunting, and conversion of farms into residential subdivisions with treed lots are also contributors.
Along with this increased activity comes renewed fears about tick borne illnesses. In this article, we will review the basics about Lyme disease, but also Powassan virus, a little known but very debilitating tick borne illness that people need to be aware of.
Lyme Disease: Causes and Symptoms
Lyme disease is the most common tick borne illness in the United States. Symptoms of Lyme disease can include: chronic fatigue, arthritis-like joint pain; fevers and headaches; neurological disorders; memory loss; heart palpitations; partial facial paralysis. Lyme disease is caused by a corkscrew shaped bacteria called Borrelia burgdorferei. Though the bacteria initially infects the blood, its spirochetal form enables it to travel out of our blood stream and into body tissue. This ability to migrate means that symptoms may pop up in various places in the body. Treatments for Lyme disease are difficult after the bacteria has had time to migrate throughout the body.
Because the symptoms are similar to other disease manifestations, it is sometimes difficult to diagnose Lyme disease. In a recent study, the most obvious symptom, the large red skin rash surrounding the location of the tick bite appeared in only 68% of all cases. The tick bite itself is not often noticed or remembered. At the nymphal stage, when it is most dangerous, the tick is so small – about the size of piece of ground pepper, that most Lyme disease victims do not remember experiencing a bite, or seeing a tick. Blood tests are often inconclusive because the disease generates a weak, and therefore not easily detectable, immune system response. It is difficult to treat if it is not detected early. This makes dealing with Lyme disease a challenge, as early detection and early treatment are the key to recovery.
Powassan (POW) virus is a viral disease transmitted to humans by infected ticks. Approximately 75 cases of POW virus disease were reported in the United States over the past 10 years. Most cases have occurred in the Northeast and Great Lakes region. Signs and symptoms of infection can include fever, headache, vomiting, weakness, confusion, seizures, and memory loss. Long-term neurologic problems may occur. There is no specific treatment, but people with severe POW virus illnesses often need to be hospitalized to receive respiratory support, intravenous fluids, or medications to reduce swelling in the brain.
Powassan virus attacks the nervous system and can infect the brain causing inflammation, a condition known as encephalitis. It can also infect the lining of the brain, causing meningitis. Symptoms of infection range widely from none to death. Serious infections can cause severe headache, muscle weakness, confusion and seizures within a week or more after infection. Long-term neurological effects may also result. Fatalities have been reported in 10 percent of cases with serious neurological disease. Fortunately, most infections appear not to cause serious illness.
You can reduce your risk of being infected with POW virus by using tick repellents, wearing long sleeves and pants, avoiding bushy and wooded areas, and doing thorough tick checks after spending time outdoors. If you think you or a family member may have POW virus disease, it is important to consult your healthcare provider.
Powassan virus has been spreading in recent years. This is due to an important change in the ecology of Powassan virus in that the deer tick has recently become infected with the virus. Until a few decades ago, it was only transmitted by a tick species that does not commonly bite humans and human cases were extremely rare. This recent change in the ecology of Powassan virus has caused concern within the public health community. Powassan is spreading due to the expansion in the range of deer ticks. Because deer ticks can now transmit Powassan virus infection to humans, cases are being reported in areas where they have never occurred before. As the geographic range of Lyme disease expands, so will Powassan.