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Researchers Discover Novel Bacteria Linked To Deadly Fever In New England Ticks

UMass Amherst researchers have discovered a new bacteria in Maine rabbit ticks linked to an infection that can be deadly for humans, the university announced Wednesday.

The researchers discovered the novel bacteria while testing ticks collected from the backyard of a Maine home for pathogens, UMass Amherst said in a press release. Though rabbit ticks can be found across North and South America, the scientists were surprised to encounter them at all, as they are uncommon in New England.

UMass Amherst microbiology Professor Guang Xu tested the ticks for bacteria that can cause Rocky Mountain spotted fever — which has a death rate of 20 to 30% when untreated — and discovered they were infected, the university said. The professor then sequenced the bacteria's DNA and found that, though it was unlike any other strain previously identified, it was similar to one identified in California a few years ago that has caused severe cases of Rocky Mountain spotted fever.

The University of Maine soon sent Xu more ticks to test. He ultimately found that just over 6% of the nearly 300 rabbit ticks that were collected from nine Maine counties tested positive for the new bacteria, UMass Amherst said.

"This wasn't a needle in a haystack. It looks like lots of the rabbit ticks there have this pathogen," UMass Amherst microbiology Professor Stephen Rich said in the release.

Cases of Rocky Mountain spotted fever have climbed in recent years, from 495 in 2002 to a peak of 6,248 in 2017, though most of these cases occurred in the South and Midwest, according to UMass Amherst. Dog ticks are the usual vector for bacteria that can cause the infection, but despite the fact that the bacteria has yet to be found in New England dog ticks, the region has still had a few cases of Rocky Mountain spotted fever.

"It was a mystery. Why are there some cases of Rocky Mountain spotted fever in New England?" Xu said in the release. "This finding may solve part of the puzzle. Maybe the rabbit ticks are the vector."

Rabbit ticks typically don't feed on humans, but there are other ticks common in New England that feed on both rabbits and humans, Rich explained in the release. The researchers posit that the rabbit ticks may be infecting the rabbits, who then pass the bacteria on when a different tick feeds on them, and that that tick could then infect a human when it feeds on them.

Rich plans to collaborate with rabbit hunters in Massachusetts to collect more rabbit ticks from the region, UMass Amherst said. The hope is that this will advance scientists' understanding of the bacteria's impact on public health.

"While these rabbit ticks don't feed on people very often, there's a possibility that they could spill over into systems where people could get exposed. We're interested in figuring out the nature of this environmental risk," Rich said in the release.

Read the original article on MassLive.

What You Need To Know About Rocky Mountain Spotted Fever

What you need to know about the tick-borne illness

INDIANAPOLIS, Indiana (WABC) -- Tick-borne illnesses are once again a major concern this summer, especially after the death of a young girl in Indiana.

The 2-year-old girl's death in early June was blamed on Rocky Mountain Spotted Fever, which is caused by a tick bite and the bacterium Rickettsia rickettsia.

The Indiana health commissioner issued an alert to physicians, telling them to be on the lookout for additional cases and not rule out tick-borne diseases even if patients, especially children, have no evidence or recollection of a tick bite.

The young girl who died tested positive for Rocky Mountain Spotted Fever a few days before her death. She had been previously diagnosed with other conditions.

Cases have been reported all across North and South America, however, 60 percent of known exposures tend to occur in either North Carolina, Tennessee, Oklahoma, Arkansas or Missouri.

Much like Lyme disease, Rocky Mountain Spotted Fever is spread through ticks, specifically the American Dog tick (Dermacentor variabilis), the Rocky Mountain Wood tick (Dermacentor andersoni) and the Brown Dog tick (Rhipicephalus sanguineus).

You can read more about Rocky Mountain Spotted Fever on AccuWeather.Com and find additional information on the CDC's website.

UMass Researchers Discover Rare Rabbit Ticks In Maine That Carry New Strain Of Bacteria

University of Massachusetts researchers have uncovered rabbit ticks in Maine that harbor a new strain of bacteria related to pathogens known to cause spotted fever in humans. Credit: CBG Photography Group/Wikimedia Commons

AMHERST — University of Massachusetts researchers have uncovered rabbit ticks in Maine that harbor a new strain of bacteria related to pathogens known to cause spotted fever in humans.

The discovery of Rickettsia sp. ME2023 raises questions about the human impact of the bacteria strain, as well as the role that rabbit ticks play in maintaining and transmitting the bacteria. Rabbit ticks rarely bite humans, and even then bacteria transfer is highly unlikely if promptly removed.

"It's as if we were taking net into a pond and just sort of dipped in the net and we caught something," said Stephen Rich, a microbiologist and investigator of Project ITCH, referring to the discovery made in residential backyard.

"The work of figuring out the underlying biology, like how frequent it is in rabbits, do all rabbits get infected and just infect a small number of the ticks, do most ticks get infected and only infect a small number of rabbits — all those questions are much deeper and to require a more focused effort," Rich said.

Finding this type of ricksettsia was an surprise result of Project ITCH, an initiative of the UMass-based New England Center of Excellence in Vector-borne Diseases (NEWVEC) that investigates best practices for tick control in residential backyard.

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Researchers survey properties with varying levels of tick control, from professional treatments to complete neglect. Ticks are collected from backyards and tested for a litany of common tick-borne illnesses such as anaplasmosis and Lyme disease, but the researchers run some open-ended tests for an unusual or unknown pathogens.

"We just keep it on our radar," said Rich, who serves as the executive director of NEWVEC. "In this instance, the 'keeping it on our radar' approach paid off because we found that these rabbit ticks had something that looks very similar to Rocky Mountain spotted fever or reasonably similar."

Curiously about the identity of the bacteria, Project ITCH researchers conducted DNA sequencing tests on the new bacteria and learned it didn't exactly match any of the ricksettsia strains in the database. The Center for Disease Control, which partners and helps fund NEWVEC, recognized the recently-published paper and believes the new Rickettsia strain should be its own species, Rich said.

"This was a success story of how Project ITCH served this secondary role," he continued. "We didn't have that expectation that we were going to find this thing. That was serendipitous."

While spotted fever rickettsioses, particularly Rocky Mountain spotted fever, can be deadly for humans, Rich clarifies that the role rabbit ticks play in spreading this pathogen in humans and other animals remains unclear. Rabbit ticks mainly feed on wild rabbits, so they are rarely seen by humans, let alone bit by them.

However, indirect infection is theoretically possible and requires further study, Rich said. If a rabbit tick fed on a rabbit, exposing it to Rickettsia, and a human-biting tick picked up the bacteria after feeding on the same rabbit, it might be transferred to a human.

"Ticks are biological entities and so not all ticks can support all bacteria," Rich said. "It may be that deer ticks feed on rabbits all the time and they just do not provide a suitable environment for this Ricksettsia to grow."

A study completed by Project ITCH researchers, most notably lead author Guang Xu, indicate that rabbit ticks carrying pathogenic Rickettsia may be a more widespread phenomenon. When scientists tested samples of 296 ticks collected across 38 Maine towns, 6.1% of them tested positive for Rickettsia sp. ME2023. A year prior, evidence that a genetically similar bacteria called Candidatus Rickettsia lanei found in California was also found in rabbit ticks.

"It didn't surreptitiously end up in rabbits ticks in California and Maine," Rich said. "It's probably that these two things, rabbit ticks and Rickettsia, have been associated for a long time in the evolution and we're just starting to get glimpse of it."

Emilee Klein can be reached at eklein@gazettenet.Com.

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