Anaesthesia (11), bacchanalia (11), cafeteria (9), dystopia (8), encyclopaedia (13), fraxinella (10), guerrilla (9), hybridoma (8), intelligentsia (14), jacaranda (9), kookaburra (10), lollapalooza (12), mitochondria (12), nirvana (7), orchestrina (11), penumbra (8), quinquina (9), referenda (9), salmonella (10), telaesthesia (12), urticaria (9), vendetta (8), woomera (7), xylorimba (9), yakuza (6), zareeba (7).
Revised Total - 248
'a' is actually quite easy, as a lot of latin words has plural ending with 'a' (e.g. all words ending with -um and -ium). Quite a few diseases and a lot of plants and fish have names ending with 'a' as well
Here's what I've come up with (including some medical terms I could think of, just in case somone's interested)
anesthesia 10 ( was addenda 7 ) / achondroplasia 14
balalaika 9 ( was bourkha 6 ) / bacteremia 10
camellia 8 ( was comma 5 ) / cephalalgia 11
demetia 7 ( was delta 5 ) / differentia 11
euthanasia 10 ( was enchilada 9 ) / epithelioma 11
fantasia 8
guerrilla 9 / galactosemia 12
hypothermia 11 ( was hysteria 8 ) / hypercholesterolemia 20
isometropia 11 ( was iota 4 )
jellaba 7 ( was jura 4 )
katakana 8 [i guess kleptomania is not allowed] ( was karma 5 )
lollapalooza 12 ( was lytta 5 )
marginalia 10 ( was myopia 6 ) / macroglobulinemia 17
nirvana 7 / nyctalopia 10
onomatopoeia 12 ( was ocarina 7 ) / oligodendroglia 15
paraphernalia 13 ( was phobia 6 )
quinella 8 ( was quanta 6 )
reticula 8 ( was replica 7 )
stigmata 8 ( was salsa 5 ) / schizophrenia 13
termitaria 10 ( was tuba 4 )
ultimata 8 ( was uvula 5 )
vendetta 8 / varicella 9
watcha 6 ( was whoa 4 )
xenia 5
yoga 4 ( was yea 3 )
zebra 5