According to the WHO: ” Trachoma is the leading infectious disease causing blindness globally. As of June 2021, 136 million people lived in trachoma-endemic areas and are at risk of blindness. It is a public health problem. in 44 countries.
The cause of this disease is infection by a 0.25 to 0.35 micron diameter bacterium called Chlamydia trachomatis . It is the same that causes chlamydia, which will sound familiar to you because it is a sexually transmitted infection. But in this case the disease affects the eyes .
Trachoma normally affects both eyes, but it does so in two phases. Symptoms first appear after an incubation period of 3 to 10 days. These symptoms are watery eye, red eye and mucopurulent discharge . It could be said that it is similar to conjunctivitis, an inflammation of the membrane that covers the surface of the eyeball and the inside of the eyelids.
Subsequently, inflammation of the cornea (keratitis) occurs, the eyelashes begin to grow into the eye (triachiasis) and the eyelid also turns inward (entropion), in such a way that the eyelashes constantly rub against the cornea .
This continuous rubbing of the eyelashes on the cornea produces damage to the lacrimal glands, painful corneal abrasions, edema, ulcers, scarring and, finally, corneal opacity, dry eyes and blindness . This is the second part of the disease that occurs over the years.
There are no manifestations in other parts of the body but, according to Carvajal: “the worsening of its course has been shown in people infected with HIV, tuberculosis or malaria, which shows a notable link between trachoma and other diseases.”
‘Third world blindness’
The American Ophthalmological Association states that ” there are very few cases of trachoma in the United States and Europe .” So, depending on where you live, you may never have heard of this disease. But just because it doesn’t ring a bell or you don’t have it close by, doesn’t mean it’s not important.
Carvajal affirms in his study that “trachoma is the main cause of preventable blindness in the world; the first cause of infectious blindness , and the fifth cause of blindness in general”.
It is part of the group of 20 neglected tropical diseases , diseases that occur mainly in the tropics where there are a series of determining factors for their appearance: heat, humidity, poverty, lack of access to drinking water, sanitation and adequate housing.
Trachoma is currently a public health problem and is endemic in North and sub -Saharan Africa, the Middle East , South Asia , and South America .
Fortunately, as of March 7, 2022, the WHO has validated the elimination of trachoma as a public health problem in twelve countries in the most affected area: Saudi Arabia, Cambodia, China, Gambia, Ghana, Morocco, Mexico, Myanmar, Nepal, Oman, Lao People’s Democratic Republic and Islamic Republic of Iran.
How to avoid trachoma?
Knowing the transmission mechanisms allows us to prevent this infectious blindness that mainly affects women and children. And these trachoma transmission mechanisms are four:
- Direct spread by close contact between the eye of the infected person and the eye of a healthy person.
- Contamination of the fingers with ocular or nasal secretions that contain the bacteria.
- Indirect spread by fomites: for example, sharing towels.
- Transmission by flies.
In addition, according to the WHO, there are also four environmental factors associated with the greater intensity of transmission of Chlamydia trachomatis at the ocular level:
- Poor hygiene.
- Overcrowded homes.
- Insufficient access to water.
- Insufficient access to sanitation and inadequate use of these services.
How to eliminate trachoma?
The WHO created the Program for the Global Elimination of Trachoma in 1998 . They set out to eradicate the disease by 2020 through a strategy. This strategy was called SAFE for its acronym in English:
- Inward turning eyelid surgery .
- Antibiotics to eliminate eye infection.
- Facial hygiene to stop the transmission of eye infection.
- Improvement of the environment, in particular, sanitation and drinking water , and access to it by the inhabitants of endemic areas.
The strategy has not worked 100% but almost. There has been a considerable decrease in the disease: in 1995 there were 146 million affected and it went to 21 million in 2015 . In addition, blindness due to trachoma went from representing 15% of cases in 1995 to 1.4% in 2015.
What antibiotic is good for chlamydia in the eyes?
One of the four legs of the SAFE strategy on which the WHO has focused most is on the massive administration of azithromycin, seeking to achieve the objective of having a minimum coverage of 90% of the affected population. This has meant that in some years more than 55 million people have been given antibiotics.
And it seems to be working: in Tanzania, 97.6% of residents were treated with azithromycin, and the ocular prevalence of the bacteria decreased from 9.5% to 0.1% over a 24-month period.
We hope that the SAFE strategy continues as well as in recent years and that trachoma is completely eradicated. In addition, improvements in sanitation and the population’s access to drinking water will surely improve the statistics of eradication or control of other diseases, since 800 children die every day from diseases linked to lack of water, sanitation and hygiene .
References:
AAO. David Turbert. 2022. What is trachoma? American Academy of Ophthalmology (AAO). https://www.aao.org/ocular-health/diseases/what-is-trachoma
Carvajal et al. 2017. Trachoma: From Basics to Clinical. Iatreia. DOI: 10.17533/udea.iatreia.v30n3a06 .
Evans et al. 2019. Antibiotics for trachoma. Cochrane Database Syst Rev. DOI: 10.1002/14651858.CD001860.pub4.
WHO. 2022. Trachoma. World Health Organization (WHO). https://www.who.int/en/news-room/fact-sheets/detail/trachoma
SEMI. Trachoma. Spanish Society of Internal Medicine (SEMI) https://www.fesemi.org/patient-information/know-your-disease-better/trachoma
