riddle

In the land of Knights, Knaves and Liars [KKL], Knights can only tell the truth,
Knaves alternately lie and tell the truth [TLT or LTL], and Liars can only lie.
Except when they are stricken with the Strange Averitas Flu Virus [SAFV]
and become sick. Strangely, as the name implies, when stricken with SAFV,
natives of every position behave differently: Knights behave as Knaves;
Knaves behave as Liars; and Liars behave as Knights.

Again, you are sent to KKL with a limited supply of the costly SAFV vaccine serum. [edit for accuracy et.seq.]
To be certain none of the precious medicine is wasted, you must determine
which of the KKL natives are truly sick, and administer it only to them.

You interview a group of 6 KKL'ers, conveniently named A, B, C, D, E and F.
They are eager, if somewhat cryptic, in their attempts to advise you.
Their eighteen statements, in valid time sequence, follow:

A1. Anyone who, regardless of his state of health, can claim "I am sick" must be a Liar.
A2. B is not a sick Liar.
A3. I cannot claim to be a Liar who can tell the truth.

B1. I am not sick; but take that with a grain of salt, because I am also a Liar.
B2. D is a healthy Liar.
B3. I am a Knight.

C1. Everyone, on becoming sick, must change his story about not being a Knight
C1. Everyone, on becoming sick, changes with regard to his ability to claim he is not a Knight. [edit for accuracy]
C2. Everyone, on becoming sick, must change his story about not being a Liar.
C3. Don't worry about me changing my story, though, I already need a shot.

D1. If a person who needs a shot claims that he is not a Liar, then he is indeed a Knight.
D2. It is only true of those persons who need a shot that the claim "I am not a Knave"
may be made by a person of any position.
D3. You can deduce that I, in fact, am not a Knave.

E1. Anyone who, regardless of his state of health, can claim "I am a Knight who can lie" must be a Knave.
E2. Collectively, the six of us are making equal numbers of true and false statements.
E3. Only one of us cannot claim not to be a Knave.

F1. Anyone who, regardless of his state of health, can claim to be a Knight must be a Knight.
F2. I am a Knave, and I really need a shot.
F3. There are at least two of us who have the same position and state of health.

To whom do you give shots?
Identify the Knights and Liars.

inda n tive tempo d desvendar... mas, n queria perde la!! portanto tou a po la aqui!!
luck!!