There has been a confirmed positive human case of Eastern Equine Encephalitis (EEE) in Southern Plymouth County, and officials say that Wareham is now at critical risk for human exposure to the virus.

The virus, which is transmitted by mosquitos, is rare but serious, and can lead to the swelling of the brain and death. Those under the age of 15 and over the age of 50 are most at risk.

The county began aerial spraying on August 8 to reduce human risk and will continue spraying tonight, Saturday, August 10. For a map of areas that will be sprayed, click here. Spraying will take place after dusk until about midnight.

According to the Massachusetts Department of Public Health’s guide to aerial spraying, the spray has no adverse impact on people, pets, and vegetable gardens. It can harm some insects like dragonflies and beetles as well as fish, although the larger the body of water, the safer the fish are. There should be no risk to honeybees, because they are usually inside the hive at night.

The department recommends avoiding mosquito bites by being aware of peak mosquito hours which last from dusk to dawn, wearing long sleeves, long pants, and socks when outdoors, and wearing insect repellent that contains DEET, permethrin, picaridin, IR3535, or oil of lemon eucalyptus. The department also recommends mosquito-proofing the home by draining standing water and installing or repairing screens.

EEE-positive mosquitos were found in Wareham on August 5, and the county began spraying from trucks on August 9. Parts of Wareham were sprayed aerially on August 8 and 9.

Other communities that are deemed to be at critical risk are Acushnet, Carver, Freetown, Lakeville, Marion, Middleborough, New Bedford, and Rochester.

The last human case of EEE in Massachusetts was in 2013.

The Department of Public Health encourages people to take “all possible precautions when outside after dusk.” The bulletin also stated that “all activities from dusk to dawn are cancelled.”