I think that the werewolf bite represents a biological disorder, and like most biological disorders there are many factors that effect its progression or strength (not actually getting the disease or werewolf status, but how bad you are when you transform), such as genetic, social support, stress, personality etc. Therefore any effects of Blood status can't be ruled out completely, given that wizards are somewhat immune to muggle disease (I really should find that quote) but probably only representing a small or predispositionary factor, which is subsequently triggered etc by social/personality factors
Personality etc - I think that the individuals own personality has a strong bearing on how they react to it (as will a majority of things), but even remus is understandably bitter, not only concerning his transformations themselves but especially the way in which werewolves are regarded by the wizarding community. However his strong personality and loyalty (I'm a big lupin fan

) stops him from succumbing to the 'dark side'
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Mix of stress, social etc - However, his transformations are horrid, he is typically viscous and dangerous when he is a werewolf. But, he wasn't so bad when he had his friends (in animagus form) around him. Perhaps it was the presence of other animals.
But I think that it was the sense of love and friendship that made the transformations easier. And at particularly stressed time may make them worse.
Consider Cancer, for example, it has been shown that stress, lack of social support etc, can adversely affect the effects of treatments and the progression of the disease.
So perhaps the animosity toward wizards (and how they treat werewolves), stress of being a werewolf and an outcast as well as many other stressful circumstances may make those under Greyback particularly dangerous, it may be harder to control the wolf within when your mind is weak.
However, given all of the above, say that a non-wizard with no knowledge of werewolves etc was bitten, perhaps the lack of disapproval from the entire wizarding community would not be a stressful factor to increase the effects of the biological changes being bitten by a werewolf give (stress has been shown to increase the effects of many diseases/disorders and diminish health further, making it even easier, in turn, for the disease disorder - its very circular).
Anyway, or maybe having no knowledge at all might make it even more stressful and scary, with no knowledge of how to have the self-control to diminish the effects.
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Biological - Perhaps the gene (or whatever) that makes magic possible in a wizard also helps to decrease the werewolf from taking over (I think that it was said somewhere that wizards are not prone to disease), so perhaps their immune system is changed somehow by being a wizard, which would also fight off any full effects of the bite, on the other hand, maybe it make it transfer of the (I hate to use the word disease) more efficient
perhaps it is purely a wizarding disease and muggle might just feel 'dog tired' (sorry bad pun) or very ill without actually transforming, thus, with Lupin being a half-wizard, it might mean that he does not get the full impact?
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I'm sort of comparing wizarding disease and Human disease in the way that a cat might not get the common cold from a human - it has been said that they don't really get out illnesses, so maybe it could be related.
Personally I think that the first statements relating to personality, social and developmental factors are more likely that purely biological.
I think that the social etc factors would effect the biological change by means of secondary factors such as the effects of stress on Cancer, so that blood status wouldn't really have a biological effect but the response of friends etc could, by secondary means, have a biological impact upon how dangerous or bad a transformation might be. sorry for mumbling on and on again and thanks for reading all my mumbles
So I guess that in some small was blood status ir genetic factors might predispose an individual to be more aggressive than another werewolf, but external factors such as social support is what triggers the onset of 'being a bad werewolf' as opposed to regaining some control when not transformed (such as setting yourself away so you don't hurt anyone) as well as when transformed (remus' friend being present made him less violent).
Thanks for reading