The odd thing about the statistics of the fungal infection is that though they can infect any parrot, the Blue front amazon is the one that tops the list for it most of all parrots. Followed by African greys and mynah birds in that order.
In poppers case, the fungal infection affected the gastro-intestinal tract, the eye, sinuses and the central nervous system. Which gave her the stroke/ seizure like symptoms.
It affected the eye, if not treated immediately, she risked permanent damage and loss.
And it did a number on her intestinal tract.
So how does a bird get fungal infection? It can come from bought food ( seeds food mixes...wd ring a bell??) It can come from running your air conditioner, or having birds in humidity. It can come from allowing a cage to be wet after they bath in water bowl after you just cleaned cage. It can come from kissing your bird. ( Yes it's common for humans to carry Candida in their mouth from an infection which becomes secondary infection to birds)
There are variety of ways to get fungal infection. Aspergillosis is a birds worst enemy, oh it's treatable if gotten to vet asap. First sign is loss of voice, and loss of appetite and weight loss. The treatment, most commonly prescribed one, is itraconazole, because it has the least side effects.