A Medford resident was diagnosed with West Nile Virus (WNV) earlier this month.
It is the city's first-known human instance of the mosquito-borne illness since 2002, according to the Massachusetts Department of Public Health (MDPH).
The infected Medford resident, a 49-year-old man, fell ill with WNV in late September, but the virus was not detected until later.
WNV had previously been detected in Medford this summer, but it was not the type that could be transferred to humans.
Human infections in the Bay State are certainly not unheard of. This was the fourth occurrence of WNV among humans in Massachusetts this year, and over 50 people in the state were infected with the virus over the six-year period starting in 2000, according to the MDPH.
Six of these latter cases proved fatal. But since the majority of people with WNV do not have any symptoms, it is hard to determine exactly how many have gotten it.
The virus is most commonly transmitted through a bite from an infected mosquito, and when symptoms manifest, they can be as minor as fever, aches and nausea.
But a small fraction of WNV cases trigger severe, potentially fatal, illnesses such as encephalitis, an inflammation of the brain.
Close to 10 percent of those who develop these severe illnesses die as a result of the virus.
Because WNV is a virus, there are no direct means of treatment. Victims generally recover in their own time, although more severe cases result in hospitalization.
"Treatment is more supportive," Susan Carpenter, the assistant director of communications at the Boston Public Health Commission, said. "This is not a bacteria, it's a virus. So [the primary method of treatment] would be lots of fluids."
In a press release from the MDPH, Dr. Al DeMaria, the organization's director of communicable disease control, said that the chance of contracting WNV locally is always a concern with the current weather patterns. "Massachusetts has only had a few of the 2,511 cases that have been diagnosed nationwide," he said. "But even one case is too many. With continuing warm weather, people are still spending significant amounts of time outdoors and the mosquitoes are still active. This means that there is still the chance for people to get bitten and infected."
Carpenter said that as the Boston area prepares for winter, the threat of WNV is decreasing. "Probably with three hard frosts we'll see the concern go down," she said.
While the virus can infect people of all age ranges, students at Tufts do not have a particularly grave risk of contracting it.
According to Kathleen O'Dea, a clinic manager and physician assistant at Tufts' Health Service, people over 50 are the most vulnerable population.
And students at Tufts do not seem to be particularly worried by the human case.
"I'm not extremely concerned about getting it because I feel like the chances of me catching it are minimal," freshman Elizabeth Oka said. "I'm not planning on changing my daily routine."
Still, some plan on taking some precautions.
"I don't think it's a huge threat, but ... just knowing that it was so close to campus, I'm a little more cautious when I see mosquitoes," freshman Jennica Allen said. "It's just a little more nerve-wracking because I feel that people don't know that much about the disease."
Carpenter said that these cautionary steps would not need to be extensive to be effective. She suggested that students wear long clothing, wear bug repellent and avoid going out near dusk.
Giovanni Russonello contributed reporting to this article.
