2020, Janurary/February Adirondac
IN THE LAST ISSUE, we began to review the host of other disorders associated with tick exposure besides Lyme disease, starting with anaplasmosis and ehrlichlosis. This time, we will focus on a few more of these rarer, yet far more severe, “non-Lyme” complications of tick bites.
Babesiosis, although spread between mammals by ticks, differs from the diseases we have already discussed because it is caused by a protozoan rather than a bacteria. Worldwide, a number of species of protozoa cause babesiosis; most are in the genus Babesiosis. After the bite of an infected tick, about one to four weeks are needed for the parasite to multiply and infect; many of these infections are so minor the patient is unaware of them.
In mild disease, fever, fatigue, and other non-specific symptoms are predominant; unlike in other tick-borne diseases, rash is rarely present. Severe disease, which may carry a mortality rate of 20 percent, causes multiple organ failure, with anemia, respiratory failure, and liver, heart, and kidney disease. Laboratory confirmation of diagnosis is complicated, and generally requires consultation with specialists. Similar to malaria, identification of the parasite in red blood cells by microscope examination is definitive. Mild babesiosis may not require treatment. More severe cases are generally treated with combinations of antibiotics and drugs used in the treatment of malaria. In 2017, there were 697 cases of babesiosis reported in New York State.
Rocky Mountain Spotted Fever is one of many diseases caused by an unusual group of bacteria called Rickettsia, others of which cause such exotic conditions as typhus. Since the specific bacteria causing RMSF is typically spread by ticks, it is included here.
After a period of up to two weeks, the causal bacteria establishes itself in the patient. The organism is particularly fond of the cells lining blood vessels. This causes damage and leaking from small blood vessels, one of the results of which is the spotty rash which gives RMSF its name. As with many tickborne diseases, fever, non-specific headache, and generalized achiness appear at the start of infection. Things can rapidly go downhill, especially if diagnosis is delayed, with brain inflammation, kidney and heart failure, liver damage, and respiratory distress.
Laboratory testing to confirm diagnosis is difficult, and generally only definitive after infection resolves. Since one of the risk factors for death is late recognition and treatment, it requires an astute clinician to diagnose RMSF and start treatment early.
As for many tick-borne diseases, antibiotics such as doxycycline are the mainstay of treatment. Thirty-six cases of RMSF were reported in New York State in 2017; many of these were probably acquired elsewhere.
Powassan virus disease is one of a large group of viruses that cause encephalitis- inflammation and swelling of the brain. Most spread by mosquitoes, but PVD is included in the tickborne disorders. Symptoms of encephalitis include fever, severe headache, and alteration in state of consciousness. The disease is difficult to diagnose, and there are no comprehensive data for New York as yet. There was at least one fatality from tick-borne PVD in New York State last summer, and it claimed the life of former North Carolina Senator Kay Hagan in late October. As with most diseases caused by viruses, there is no specific treatment.
New tick-borne diseases are being discovered and reported regularly; “Borrelia miyamotoi” and Bourbon virus disease are among these. Columns such as this one run the risk of being outdated nearly as soon as they are written.
If all of this information scares you, you are not alone. A number of individuals with whom I have spoken have told me they are limiting their backcountry travels because of concern about ticks. For those folks, let me end with some reassuring news. Last summer, I attended a lecture by a major tick researcher. This individual has spent the better part of the past few decades tracking down ticks in their habitats-literally crawling around in tick-infested areas for days at a time. He has never acquired a tick-borne illness. What is his secret? Nothing, really. He just follows all of the regular advice on tick avoidance, which is widely available in publications such as this one.
Tom Welch, MD, is a physician at Upstate Medical University in Syracuse, and a member of the Wilderness Medical Society. He is a licensed professional guide and Wilderness Education Association instructor, and has guided groups in the Adirondacks, Montana, and Alaska. More information is available on his website and blog, www.adirondoc.com. SUNY infectious disease expert Leonard Weiner, MD, reviewed this column and provided helpful suggestions.
General First Aid, Insects & Spiders