David Hartstein, a Long Island chiropractor, was in good health until two weeks ago when he started feeling ill with symptoms of what appeared to be the flu or Lyme disease. On Friday, he started shaking and sweating and had trouble breathing. Although his wife called an ambulance and he was rushed to Southampton Hospital, doctors couldn’t figure out what the problem was in order to properly treat him. He died on Friday night, a victim of an extremely rare rodent virus, the hantavirus pulmonary syndrome. His was the second confirmed case in New York State ever, the first being in 1995, which explains the doctors’ confusion. There were only twenty confirmed hantavirus cases in the United States in 2010, and Hartstein’s appears to be isolated. (The disease cannot be passed between humans, but is often contracted from cleaning homes or outdoor spaces, where people can come in contact with rodent droppings, saliva, or urine.) Hantavirus infections are often, but not always, lethal.