Tick expert addresses Powassan

Sam Telford argues Powassan and its cousin, deer tick virus, aren’t new to Massachusetts, but remain little understood and dangerous.

A vial containing deer tick nymphs that was passed around the audience during a tick talk by several regional experts at the Edgartown Library on the evening of June 27. In the background biologist Dick Johnson shows a diagram of different tick sizes. — Rich Saltzberg

Noted tick researcher Sam Telford said he sees no evidence that true Powassan exists on Martha’s Vineyard; however the pathogen’s close relative, deer tick virus, is extant on the Island.

Mr. Telford joined Michael Loberg, Edgartown health agent Matt Poole, EMT Krystal Rose, Dr. Michael Jacobs, and tick biologist Dick Johnson at a tick talk Tuesday at the Edgartown library. While his colleagues focused on Lyme and tick prevention, Mr. Telford shared knowledge about Powassan and deer tick virus, pathogens he has studied for years.

Powassan is transmitted by a white tick called ixodes cookei, according to Mr. Telford. “It’s a relative of the deer tick, but normally feeds on things like woodchucks. Here it’s actually on things like skunks and racoons,” he said. He has not found Powassan in the brain matter of any samples collected from the Vineyard. He has, however, found deer tick virus in tick samples. He coined the name deer tick virus in the 1990s: “I described a new virus in the tick-borne encephalitis complex that I named deer tick virus … It’s a subtype of Powassan virus.”

Mr. Telford said Powassan first became known in the 1950s in Canada, and between then and the mid-1990s, only 30 cases had been identified in Eastern North America. Of those, 30 percent proved lethal. A second lineage of Powassan — deer tick virus — was discovered in 1996 in deer ticks in New England: northern Connecticut and Ipswich, he told The Times after his talk. It was found by a research team in which Mr. Telford played a major role. He was the lead author of a paper that was published on the virus the next year. Mr. Telford looked for cases of the disease on the Island at that time, and found little until he learned about an unusual medical case.

In 1994, a 42-year-old female came to Dr. Bill Tsikitas’s clinic in Edgartown, where she complained of severe headache, stiff neck, fever, and muscle aches. Dr. Tsikitas assumed Lyme was at play, and gave her amoxicillin, Mr. Telford said. She returned the following day, and the doctor saw that she was declining rapidly. He had her medically evacuated to Massachusetts General Hospital the same day.

“He suspected severe neurologic Lyme disease,” Mr. Telford said.

A day later she went on respiratory support, and remained on it for three weeks. Tests came back from the Centers for Disease Control indicating Powassan virus. “She slowly improved and required six months of outpatient therapy,” he said.

Since her ailment came in the days prior to health privacy laws, Mr. Telford was able to learn her name and telephone her.

“There was this vibrant, happy voice on the answering machine, and then I finally reached her a couple of days later, and it was like speaking to someone with Alzheimer’s disease,” he said. “It was such a striking contrast in what this disease can do.”

Mr. Telford noted after his talk that the pathogen affecting the woman could have been deer tick virus instead of Powassan, but the test at the time would not have offered a distinction.

Deer tick virus has the same vector as Lyme, deer ticks and white-footed mice, Mr. Telford said. One reason he believes that the white tick does not pass on deer tick virus is because ixodes cookei does not exist on Nantucket yet. Deer tick virus does exist there. Concerning deer ticks, he said, “0.4 to 2 percent in Massachusetts are infected” with deer tick virus.

“We haven’t found it in ixodes cookei; we haven’t found it in dog ticks,” he said. He said in the Hudson Valley and in Connecticut, infection rates of deer ticks with deer tick virus range from 0 to 4 percent.

One reason why Powassan, as opposed to deer tick virus, is named as the culprit in recent cases that have made headlines is because the Centers for Disease Control does not distinguish between the two viruses.

“The taxonomic convention for these viruses is that if you can’t tell them apart by antibody tests — regardless of the molecular biology tests — they are considered the same species,” he said. “So they call it Powassan virus; I call it deer tick virus. The two viruses differ by 15 percent of their RNA; they differ by 4 percent of their amino acids. So it’s a very distinct virus, and deserves its own name.”

His lab has been ahead of the scientific community in exploring this virus: “As with many tick-borne encephalitis group viruses, most are asymptomatic — it is our feeling that if we actually went out and bled everybody on Martha’s Vineyard, we’d probably find 5 percent of the people with antibody or evidence of exposure to the virus, but these people would never recall any neurologic disease.”

A relative of West Nile virus, yellow fever, and dengue, according to Mr. Telford, Powassan is part of a pathogen class that can cause tick-borne encephalitis and lead to permanent neurological damage or death. Pathogens responsible for tick-borne encephalitis are common to areas where Lyme is also found, he said. He said the most notorious type in this class is Russian spring-summer encephalitis, which in Russia can have a 40 percent case fatality rate and is considered so dangerous it requires a level 4 biosafety lab to study. It can be asymptomatic and then “fulminate,” or blossom in the brain, he noted; ”those who survive have severe shoulder-girdle paralysis and neurologic deficits for the rest of their life.”

He said a “less nasty variant” is Central European encephalitis.

“Eighty percent of the cases are asymptomatic,” he said, and added that the disease has a mortality rate of up to 5 percent, with survivors also facing shoulder-girdle paralysis and neurological deficits. He noted that an effective vaccine has been used in Austria and Germany for three decades.

“It has cut the incidence of tick-borne encephalitis in Europe to almost nothing,” he said. “It’s one of our best public health successes in the field of vector-borne diseases.”

No such vaccines exist for Powassan or deer tick virus. He told The Times he sees little commercial motivation in the pharmaceutical industry to create any, either. He also said both pathogens resist antivirals. A major portion of his research is bent toward undermining that resistance.

Mr. Telford said thus far he’s had difficulty getting funding from the National Institutes of Health to expand his study of deer tick virus, as they have consistently found the pathogen a low priority for research. He said that perhaps recent headlines about the virus will stimulate a different viewpoint.

Mr. Telford outlined the probable onset symptoms, if they present, along with possible outcomes for those who may contract deer tick virus.

“It’s probably a flu-like illness for most. There’s probably a fever, fatigue, headache, and muscle aches. But in cases that progress and go to the nerves and the brain, then you can have probably a viral meningitis-like infection, with feelings of stiff neck and severe headache, and your eyes can’t stand bright lights, you may get nauseous, and then it may progress to frank [heavy] sleepiness and coma, and if we see other signs of nerve damage, that means either people are going to die or they’re recover and have severe lifelong disability.”

“It is age-related,” he said, noting that children are less affected by tick-borne encephalitis pathogens overall, yet paradoxically “a lot of the cases of Powassan virus have been in children, especially in the Hudson Valley in New York.”

Mr. Telford said there are effective tests for isolating the virus in blood, and that antibodies to the virus can be detected early on. He also said that those who have been infected and possess residual antibodies may be protected for years from later infection. He said it’s likely that the shoulder-girdle paralysis that results from Eurasian tick-borne encephalitis will show up in Massachusetts eventually.

He called Massachusetts “a hotbed in the past three to five years,” with the Department of Public Health reporting 13 cases in that time. He said most cases appeared on Cape Cod or in Southeastern Massachusetts and the Ipswich vicinity.

Data was compiled on eight of these cases. “Of these eight patients, two of them died,” he said. Another two recovered partially with residual deficits: ”meaning they probably will have lifelong neurologic problems, and then three of them improved, meaning that they’re probably going to recover fully.”

Mr. Telford declined to comment on whether recent cases reported on the Cape were indeed the virus, or what the status of the patients was. But he said he’s been working with Massachusetts General to help diagnose the cases. He said he has one of the few labs around — rated at biosafety level 3 — where the virus can can be securely studied.

So far it’s a mystery why cases aren’t presenting themselves on Martha’s Vineyard, given the number of infected ticks, he said. Recently, an Island man sent a tick off to UMass after it bit him, and he learned that it harbored deer tick virus, he said. The man never contracted the disease.

While Michael Loberg described Lyme as an epidemic earlier in the evening, Mr. Telford said deer tick virus is not an epidemic in Massachusetts.

Mr. Telford concurred with an earlier assessment of Dick Johnson’s, that there was a high value to wearing permethrin-laced clothing as a hedge against tick-borne infections.

During his talk, Mr. Telford weighed in on Lyme as well. “This is the height of Lyme disease season. In fact, the next couple of weeks the hospital and the clinics will see their most, you know; they’ll see two or three cases a day at the very least.”

The Lyme rash presents in other ways than the classic bull’s-eye, Mr. Telford said. He produced a photo array from Dr. Tim Lepore of Nantucket Cottage Hospital that showed many un-bull-s-eye-like varieties of Lyme rash. Mr. Telford said what characterizes it as erythema migrans, i.e. moving rash, is expansion across the skin.

He told the audience that the surest way to tell if a rash is indicative of Lyme is to mark its periphery with a pen and wait to see if it crosses the pen mark. “If it doesn’t move, it’s not Lyme disease. It’s just a reaction to the tick bite,” he said. “Well-documented studies show that 60 to 70 percent of people actually do have a rash, but that leaves a good proportion of people who don’t, and those are the most dangerous cases.” Fever, chills, aches, and fatigue are then the primary indicators, and not everyone who contracts Lyme may evidence these symptoms, particularly if they are hale, vigorous people who may tend not to show signs of illness, Mr. Telford said. Such people can run the risk of suffering the deleterious consequences of untreated Lyme going forward, he said.

“Your chances of finding an infected deer tick [adult] is double or triple that of a nymphal tick,”

he said. “Yet 85 percent of all Lyme disease cases result from the summer months, when only the nymphs are around.” He said one’s likelihood of finding an infected tick is greater in the autumn. He said the reason for this is in part that summer clothing covers less of the body than autumn clothing, and also because the adult deer tick is easier to spot and remove.

As a prop to show the audience how minuscule nymphal deer ticks are, Mr. Telford and his colleagues passed around a sealed vial of nymphs collected in Chilmark earlier in the day.