Lecture 8: Trachoma and Teamwork Flashcards
What is trachoma?
an infectious eye disease caused by chlamydia trachomatis
It is the leading infectious cause of ____ worldwide
blindness
What is unique about trachoma?
No animal reservoir, only found in humans
Which 3 countries recently eliminated trachoma in 2017?
Mexico, Oman, Morocco
Where is trachoma most highly prevalent and in what population?
5 countries in Sub Saharan Africa
Children with ocular infection <10y/o are primary reservoir
What kinds of diseases is chlamydia trachomatis associated with?
ocular (trachoma)
genitourinary (pelvic inflammatory diseases)
respiratory (pneumonia)
What are 4 characteristics of diseases caused by chlamydia trachomatis?
- infections that are long lasting w/out tx
- repeated infections (body does not retain immunologic memory of chlamydia)
- infections that are asymptomatic or minimal sx.
- infections that produce inflammation and scarring without tx (blindness in trachoma occurs over time- can often be minimally symptomatic until that point, scarring of fallopian tubes can result in ectopic pregnancy)
What kind of bacteria is chlamydia trachomatis?
obligate intracellular bacterium
What are the target cells of chlamydia trachomatis?
epithelial cells of endocervix and upper genital tract in women
conjunctiva, urethra, rectum in men and women
Does natural infection with chlamydia trachomatis protect against reinfection?
No
How is trachoma infection spread?
- direct contact with eye secretions
- spread via fomites (inanimate objects)
- eye seeking flies
What occurs for trachoma to be considered “active trachoma”?
ocular infection with chlamydia occurs
conjunctivital inflammation and follicle formation
transmission can lead to repeat infections
What is cicatricial disease and how does it occur?
Long term effects of chronic trachoma/reinfection:
- chronic inflammation and recurring infections leads to eyelid scarring and ingrown eyelashes
- longer exposure occurs leads to corneal opacification (scar tissue over the eye) and blindness
2 main clinical manifestations of trachoma?
active trachoma (inflammation) and cicatricial disease (scarring)
What criteria do flies need to be considered a vector of trachoma?
- be present in area
- come into contact with disease
- spread disease
- transfer disease to new hosts