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Trachoma, also called granular conjunctivitis, Egyptian ophthalmia, and blinding trachoma, is an infectious disease caused by the bacterium ''Chlamydia trachomatis''.〔 The infection causes a roughening of the inner surface of the eyelids. This roughening can lead to pain in the eyes, breakdown of the outer surface or cornea of the eyes, and possibly blindness.〔 The bacteria that cause the disease can be spread by both direct and indirect contact with an affected person's eyes or nose.〔 Indirect contact includes through clothing or flies that have come into contact with an affected person's eyes or nose.〔 Many infections are usually needed over a period of years before scarring of the eyelid becomes so great that the eyelashes begin to rub against the eye.〔 Children spread the disease more often than adults.〔 Poor sanitation, crowded living conditions, and not enough clean water and toilets also increase spread.〔 Efforts to prevent the disease include improving access to clean water and decreasing the number of people infected by treatment with antibiotics.〔 This may include treating, all at once, whole groups of people in whom the disease is known to be common.〔 Washing by itself is not enough to prevent disease but may be useful with other measures. Treatment options include oral azithromycin and topical tetracycline. Azithromycin is preferred because it can be used as a single oral dose. After scarring of the eyelid has occurred, surgery may be required to correct the position of the eyelashes and prevent blindness.〔 Globally, about 80 million people have an active infection. In some areas infections may be present in as many as 60–90% of children and it more commonly affects women than men likely due to their closer contact with children.〔 The disease is the cause of a poor ability to see in 2.2 million people of which 1.2 million are completely blind.〔 It commonly occurs in 53 countries of Africa, Asia, Central and South America with about 230 million people at risk. It results in 8 billion USD of economic losses a year.〔 It belongs to a group of diseases known as neglected tropical diseases.〔 ==Signs and symptoms== The bacterium has an incubation period of 5 to 12 days, after which the affected individual experiences symptoms of conjunctivitis, or irritation similar to "pink eye." Blinding endemic trachoma results from multiple episodes of reinfection that maintains the intense inflammation in the conjunctiva. Without reinfection, the inflammation will gradually subside.〔 The conjunctival inflammation is called “active trachoma” and usually is seen in children, especially pre-school children. It is characterized by white lumps in the undersurface of the upper eyelid (conjunctival follicles or lymphoid germinal centres) and by non-specific inflammation and thickening often associated with papillae. Follicles may also appear at the junction of the cornea and the sclera (limbal follicles). Active trachoma will often be irritating and have a watery discharge. Bacterial secondary infection may occur and cause a purulent discharge. The later structural changes of trachoma are referred to as “cicatricial trachoma”. These include scarring in the eyelid (tarsal conjunctiva) that leads to distortion of the eyelid with buckling of the lid (tarsus) so the lashes rub on the eye (trichiasis). These lashes will lead to corneal opacities and scarring and then to blindness. Linear scar present in the Sulcus subtarsalis is called Arlt's line (named after Carl Ferdinand von Arlt). In addition, blood vessels and scar tissue can invade the upper cornea (pannus). Resolved limbal follicles may leave small gaps in pannus (Herbert’s Pits). Most commonly children with active trachoma will not present with any symptoms as the low grade irritation and ocular discharge is just accepted as normal. However, further symptoms may include: *Eye discharge *Swollen eyelids *Trichiasis (turned-in eyelashes) *Swelling of lymph nodes in front of the ears *Sensitivity to bright lights *Increased heart rate *Further ear, nose and throat complications. The major complication or the most important one is corneal ulcer occurring due to rubbing by concentrations, or trichiasis with superimposed bacterial infection. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「trachoma」の詳細全文を読む スポンサード リンク
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