Do you think you're safe from ticks in the city? Think about it again.
Thanks to the growing urban sprawl in the suburbs, the forests are subdivided into smaller vegetation valleys. Suburban parks and backyards are now the perfect size for keeping mice, but not big enough to keep foxes. This means that mice can rampage without natural enemies to keep their populations at bay. And there are ticks in mice.
"The spread of suburbia is a fairly new phenomenon," said University Distinguished Professor of Biology Kim Lewis, who heads Northeastern's Antimicrobial Discovery Center. "You get more ticks for the ticks, and of course you get more ticks."
Mosquito, flea and tick-borne diseases in the United States tripled from 2004 to 201
While ticks can crawl slowly, their main means of transport is hitchhiking, Lewis said. Ticks like to take deer, dogs and humans. But its chief host is the white-footed mouse, which is found in the forests, towns, courts, and cities of New England, and is the primary carrier of Lyme disease.
Massachusetts is one of the 14 states where, according to the CDC, in 2015, 95 percent of cases of Lyme disease have been reported. Experts estimate that 87,000 people a year in Massachusetts are infected with the bacteria Borrelia burgdorferi which causes Lyme disease.
How serious is the disease? Lewis said it all depends, because Lyme disease occurs in two "flavors". One is the acute illness: you're bitten by a tick, the pathogen causes a rash around the bite that looks like a porthole, and you mildly flu-like symptoms. As long as you are treated with antibiotics within a few days, the disease will disappear.
But for about 10-20 percent of people, the antibiotic does not work. These patients develop Lyme Disease Syndrome, also known as Chronic Lyme, after treatment.
"People get joint pain, muscle pain, fatigue, insomnia, a whole host of symptoms," said Lewis. "It can be a really debilitating condition."
Researchers do not know what causes chronic Lyme disease, or why some patients get it and others do not. There is currently no cure, but Lewis and his research team are working to change that.
One of the problems in the treatment of Lyme disease is that doctors prescribe a broad-spectrum antibiotic that was originally developed to treat other infectious diseases, Staph or E. coli. These potent antibiotics are unfriendly to the human gut microbiota – the symbiotic bacteria that affect the immune system. Lewis suspects that chronic Lyme disease is partly destroyed by the microbiome, while Borrelia burgdorferi simultaneously destroys the immune system
His team sought a compound that selectively produced Borrelia burgdorferi Kills bacteria that cause Lyme disease without destroying our intestinal bacteria. And they found one that works in mice. The next step is to test the connection in another animal and then in humans. This will take another two years, Lewis said.
Until then, use an insect repellent that contains DEET, take a shower after taking walks in the forest and follow other tips to avoid ticks – and do not assume that you are immune to the city.