Straight to your questions:
1) There are not precise data on this, but virtually all persons with chlamydia will have positive tests within 4-5 days of infection. Perhaps as early as 1-2 days, but no data to know for sure.
2) Chlamydia is rare in the throat; CDC recommends against even testing sexually active people for oral chlamydial infection. To my knowledge, there has never been a proved case of urethral chlamydia in someone whose only possible exposure was by receiving oral sex. Nobody can say for sure that something never observed cannot happen--but at least it is very rare.
3) No data available to answer for sure, but prsumably it has to do with the mechanics exposure. Fellatio typically lasts longer than the average kiss, and the urethra often is exposed to the back of the throat, which is where oral gonorrhea is located. Just as kissing is not known to transmit gonorrhea, women rarely if ever acquire genital gonorrhea by receiving oral sex. In other words, cunnilingus acts like kissing in this regard--presumably, again, because there is no exposure to secretions at the back of the throat. (Other STDs are more readily transmitted by either fellatio or cunnilingus--syphilis and herpes for example, for which the infected tissues often include the lips, tongue, etc.)
4) In general, the window period is just a few days for infections diagnosed by detecting the organism itself and that cause early symptoms (gonorrhea, chlamydia, herpes if there are symptoms). It is a few weeks for all infections that are detected by blood test (syphilis, HIV, herpes without symptoms).
I hope this helps. Best wishes-- HHH, MD
Although I saw in a previous post the Chlamydia window period was up to 3 months, the Seattle-King County Health board (which I bet you give guidance to) says "Tests for chlamydia usually become positive 3 - 7 days after catching the infection." Thus I thought this question would be useful to clear up any inconsistencies.
Can one assume then that a penis swab at 18 days (negative) is reliable?
18 days is plenty. the window is 72 hours.
Thanks for the feedback. I see on the this site (which I find extremely informative) that the window period is approximately 5 days. Why though, do other sites state that the time is weeks or months? Additionaley, other sites such as the San Francisco Clinic site state that Chlamydia is transmitted by fellatio. Is that just theoretically possible, but never ever happens?
Amazing. I was searching for this exact information. You're right Shygirl, the different sites are inconsistent on the window issue.
In fact, I was told, after being tested 10 days after possible exposure with no symtoms except emotional agony, that the Chlamydia test would not be conclusive and that I should return at six weeks from the possible exposure for a retest.
I like the answer here because it would mean that I could rely on my negative 10 day result without further invasion of my urethra by that nasty cotton swab, but I have to wonder why I was given different information and why several credible web sites have differing window periods.
This is from Dr. HHH's response from Risk and Test on Nov. 18th..."chlamydia unnecessary, never proved to be transmitted by oral sex; too rare to worry about after a single exposure with no symptoms, but 3 months if you insist".
How come 3 months there and 5 days okay for others?
Just wondering....are all the responses written by Dr. HHH personally, or are assistants used. I ask because some responses seem to take a different tone and the writting styles seem different, and the different response to the window period as stated above.
Either way, excellent resource!