People can get Legionnaires' disease when they breathe in small droplets of water in the air that contain the bacterium.
The bacteria is commonly found in freshwater, groundwater and soil.
The illness, caused by the Legionella bacteria, can lead to pneumonia in people who are at higher risk of getting sick.
The Centers for Disease Control is assisting state health officials in confirming the source of the outbreak.
New Hampshire health officials have identified two more people who have confirmed cases of Legionnaire's Disease in Hampton, New Hampshire, bringing the number of cases to 14, one which proved to be fatal.
These 12 people likely acquired their infections between early June and mid-August in Hampton, NH.
Test results from other locations in the affected area are still pending.
Bagley said this particular bacterial infection can not be passed from person-to-person. It can not be contracted by drinking or coming into physical contact with water containing the bacteria, such as during swimming, for example.
Lisa Morris, Director of the Division of Public Health Services said in a press release, "Even though the information is preliminary, we want to allow the public to make informed decisions about visiting the area and their activities in the area".
Symptoms include fever, cough, chills, muscle aches, headache, fatigue, loss of appetite, confusion and diarrhea. People are advised to observe the exposure for 2 weeks before taking other steps.
Another disease which has made its presence felt for quite some time in the USA is the one caused due to West Nile virus, which has resulted in around a dozen communities in Boston-area being listed as high-risk, after a fourth-case of the virus was discovered.
If an individual visited this area and developed symptoms within 14 days of their stay, they should contact their healthcare provider and seek medical attention.