Other data Forecast: The majority of patients who follow the treatment manage to overcome conjunctivitis without any sequelae. The period normally given until recovery is one month. Chlamydial infections are one of the most common worldwide. There are three species that cause infections in humans: C. trachomantis, C. pneumoniae and C. psittaci. C. psittaci comes from birds and can lead to psittacosis, a febrile illness characterized by pneumonitis and systemic manifestations. C. trachomatis and pneumoniae are transmitted from human to human. Chlamydia trachomatis is transmitted sexually and causes about four million infections per year and 25,000 cases of infertility in the United States. The pathogen is the etiologic agent of trachoma, one of the leading causes of blindness that can be prevented, which affects 150 million people worldwide and has left 6 million individuals blind. Chlamydia pneumoniae causes countless respiratory diseases including pharyngitis, sinusitis and bronchitis. It also affects the lower respiratory tract and is responsible for a quarter of pneumonias. Recently, it has also been discovered that it is a risk factor for arteriosclerosis. Chlamydiae are small intracellular organisms dependent on the host cell for replication and prolonged survival. Its life cycle allows the pathogen to produce persistent infections, escaping immune processes and also causing chronic inflammations. In addition, reinfections are common since no long-term immunity develops. In ophthalmology, these characteristics have allowed chlamydiae to cause a wide spectrum of diseases, from follicular conjunctivitis to trachoma, often with sequelae of blindness.