What is Mycoplasma Infection? Mycoplasma infection is a contagious disease caused by the infection of the human body by mycoplasma. Currently, the mycoplasmas known to be pathogenic to humans include Mycoplasma pneumoniae, Ureaplasma urealyticum, and Mycoplasma hominis. Clinically, Mycoplasma pneumoniae primarily causes mycoplasmal pneumonia, which is an acute upper respiratory tract infection. Ureaplasma urealyticum and Mycoplasma hominis can cause infections in the reproductive and urinary systems. Generally, the incubation period for mycoplasma infections is quite long, ranging from 2 to 3 weeks. Mycoplasmal pneumonia is more common in the winter. Genital mycoplasma infections are mainly transmitted through sexual contact. Newborns can become infected during childbirth through the mother's reproductive tract. In adults, the site of infection is the urethral mucosa in males and the cervix in females.