Hector Berlioz once wrote to a friend that the death of his son Louis from YELLOW FEVER was "the cruelest blow of my life." At the time, Louis was the captain of a merchant ship that ran a trade route between France and Mexico, with a stop in Havana, Cuba. The torrid Cuban and Mexican jungles were the perfect breeding ground for the mosquitoes that carried the disease, which even today has no known effective treatment except vaccination. Symptoms include headaches, dizziness, nausea and the jaundiced appearance of some of its victims, which gives the disease its name. Berlioz's son Louis was just thirty-three years old at the time of his death in 1867 from YELLOW FEVER, and his father never managed to entirely recover from the tragedy.