The Massachusetts Department of Public Health on Aug. 23 designated the Medford/Somerville area as a "high" threat level of the West Nile Virus (WNV) in response to a case that popped up in nearby Cambridge.
The mosquito-borne illness is found all over the globe, but was introduced to the United States in 1999, according to the U.S Centers for Disease Control and Prevention (CDC). Since then WNV has spread from New York City to the West Coast and is now considered an endemic virus, meaning that it has found a permanent home in the U.S, according to Sam Telford, associate professor at the Cummings School of Veterinary Medicine.
Threat levels for WNV have been raised all over the Boston area, according to Somerville Director of Public Health Paulette Renault-Caragianes. Though alert levels for the virus typically increase in the fall, the warm winter months of 2012 allowed mosquitoes in the area to breed especially easily, resulting in one of the highest alert levels in recent years.
"A lot of natural controls weren't in place," Renault-Caragianes said. "There was no significant amount of snow, meaning that a large group of mosquitoes never died off. It really led to it being an optimal environment for them to breed in."
Medical Director of Tufts Health Service Margaret Higham, who issued the WNV warning to the Tufts community on Aug. 24, listed the most common symptoms as the flu and a mild headache. Most people who contract the virus are not aware of it, she said, though the infected have a small chance of developing encephalitis, a more serious illness.
Geoffrey Bartlett, director of emergency management at the Tufts Department of Public and Environmental Safety, said that the risk of developing serious illness from West Nile Virus is minimal and that only 67 people in Massachusetts have been diagnosed with the virus in the past 11 years.
Though WNV is usually not a serious illness, students should do all they can to avoid contracting the virus, Bartlett said, citing the use of insect repellant as one way to avoid getting bit.
"We've worked with Patti Klos [of Tufts Dining Services] to get EPA-approved insect repellant on sale in the [Mayer] Campus Center," Bartlett said. "It's not always there, but we want to allow students to follow the right precautions."
Renault-Caragianes said that students should protect themselves with adequate layers of clothing and repellant, particularly if they are outside during the dawn and dusk, when mosquitoes often swarm in greater numbers.
"People should always be cautious," she said. "Club teams may even want to rethink their practice schedules and train indoors during the nights; it makes sense to limit time spent outdoors when mosquitoes are most out and about."
Stephen Larson, the director of Environmental Health and Safety, said the university is keeping an eye on areas that attract virus-carrying mosquitoes, such as clogged sewer drains and puddles on the sidewalk where stagnant water collects.
"We are eliminating risks by eliminating breeding grounds," he said.
Larson noted that students can do their part by not collecting rainwater in buckets, inflatable pools or other areas where still water could attract mosquitoes.
"It only takes four days for mosquitoes to breed, so if you're collecting water outdoors, it can take only four days to cause this problem," he said. "Pour that water out, and you'll keep it from ever happening."
