Massachusetts at moderate-level risk for West Nile Virus

Graphic by Penelope Taylor ’20

Graphic by Penelope Taylor ’20


The state-wide risk level for West Nile Virus (WNV) was raised from low to moderate by the Massachusetts Department of Public Health on Aug. 21 following the discovery of multiple WNV positive mosquito samples. WNV is a viral infection that is spread from mosquitoes to humans or animals. The virus cannot be transmitted between humans. 

According to Cheryl Flynn, Mount Holyoke’s medical director, approximately 80 percent of those infected “experience no symptoms at all, or symptoms so mild they do not even consider themselves ill.” 

About one out of five people who are infected experience a fever alongside other symptoms including headaches, body aches and diarrhea, according to the Center for Disease Control (CDC). Most who experience these symptoms fully recover, though they may remain fatigued for several weeks or months. 

Severe cases, though rare, typically cause fevers and flu-like symptoms. “In these extreme cases, the virus infects the brain or the layers around the nervous system, likely requiring hospitalization,”  said Flynn. Symptoms of severe illness include neck stiffness, disorientation and muscle weakness. Older people and people with chronic illnesses are at a higher risk of developing serious symptoms. 

Approximately one out of every 150 people infected with the virus develop a serious and potentially fatal manifestation of the illness, according to the CDC. 

“Despite the low likelihood of a severe case of WNV for the majority of the MHC student body, we do encourage a prevention strategy of minimizing exposure to mosquito bites that could carry infection,” Flynn said. 

Protective measures include limiting time outdoors and wearing insect repellent that contains DEET — a common ingredient that repels insects — particularly in the early evening and before dawn. Additionally, wearing long sleeves, long pants and socks limits possible exposure to infectious mosquito bites. 

Simone Jacob ’21, who studied the mosquito-borne Dengue virus at the California Academy of Science this summer, said, “I’m alarmed because I don’t really know what the virus (WNV) is. I didn’t think we would be at risk of a major disease at Mount Holyoke.”

“There should be a warning when you go outside,” added Jacob. 

While the risk may fluctuate from year to year, Flynn expects the issue to be a recurring one. 

“Since the identification of WNV in 1999, mosquitos carrying this virus have been found in Massachusetts. The Massachusetts Department of Public Health (MDPH) monitors the prevalence ongoingly and alerts the public when the prevalence rate increases risk to humans. 

The risk level may vary in future years based on the weather. Hot and humid with regular rain, much like the summer of 2018 here, encourages the breeding of the mosquito types that carry WNV, and thus elevated risk of exposure.” 

Additionally, Flynn said, “if the risk levels increase in the future, the MDPH may enact additional community prevention measures.” Possible prevention measures include applying insecticides to kill mosquitoes or larvae and placing greater emphasis on eliminating standing water, which attracts mosquitoes. 

Sonia Zaib ’19, who studies biology, also emphasized the importance of taking preventative measures. “I feel that all Five College students should stay cautious of West Nile virus,” said Zaib. “If you witness any of the symptoms you should go to a doctor. Stay safe of the mosquitos and protect yourself by wearing long sleeves and pants and use bug repellent.”