Rare deer tick virus identified as cause of death
The death of a man in New York State is a fresh reminder for Islanders and visitors to continue to be vigilant when in areas where contact with deer ticks is possible and to take precautions against the possibility of infection.
A May 15 report in The New England Journal of Medicine (NEJM) confirmed that the 62-year-old man died from a rare deer tick virus. It is the first definitive case describing fatal deer tick virus encephalitis (inflammation of the brain) in humans, according to Norma P. Tavakoli, lead author of the study.
Cases of infection are rare, and some people may contract the virus with no outward signs of ill health. But since diagnostic testing for the virus is not routine, there may be instances that will be missed, according to public health officials.
"In certain locations of the northeastern and north central United States, the prevalence of deer tick virus in adult deer ticks is high, but human infection has not been reported previously," said the study. "This could indicate that the virus does not easily infect humans or that it is not particularly pathogenic."
The victim, a native of Putnam County in New York State, owned horses and spent time outdoors in a wooded area. He was admitted to a hospital in late spring of last year complaining of fatigue, fever, rash, and muscle weakness.
Although the man did not report a tick bite, the study said, transmission likely came from a deer tick in its nymphal, or juvenile, stage. Because nymphal deer ticks are tiny, it is not uncommon for their bites to remain undetected, said the study.
The man's medical history included leukemia, which may have contributed to a weakened immune system. He died 17 days after he was admitted to the hospital.
Deer tick virus is closely related to a number of other tick-borne viruses that include Powassan virus, which can also cause encephalitis. Both are part of a family of viruses that include West Nile virus, St. Louis encephalitis virus, dengue and yellow fever, all of which are transmitted by mosquitoes, according to a report provided by the U.S. Department of Health and Human Services.
Prevention remains the best strategy, said the NEJM study.
Martha's Vineyard and Nantucket are considered hot spots for tick-borne illnesses. As a result, Island physicians are generally well versed in the symptoms associated with a variety of diseases.
The ticks most people are likely to pull off their pant legs after a spring walk in the woods are the adult dog, or wood, tick which can carry Rocky Mountain spotted fever, a rare occurrence on the Vineyard. Dog ticks are also known to spread tularemia, sometimes called rabbit fever, a potentially fatal disease caused by the Francisella tularensis bacterium.