chlamydia vs chlamydial

chlamydia is a noun but chlamydial is not a noun.

Word	Noun	Adjective	Verb	Adverb
chlamydia	Yes	No	No	No
chlamydial	No	Yes	No	No

chlamydia (noun)	chlamydial (noun)
coccoid rickettsia infesting birds and mammals; cause infections of eyes and lungs and genitourinary tract
a sexually transmitted infection caused by bacteria of the genus Chlamydia

chlamydia (adjective)	chlamydial (adjective)
	of or pertaining to the sexually transmitted infection or to the parasite