Views on zombie apocalypse?

While a virus might cause a behavioral response, the human brain is too large for a complex response from a simple virus. A virus might have specificity for neurons that trigger hunger, but not multiple primitive centers, simultaneously. Such a virus might cause a specific trait like hunger and a non-specific disease trait like lethargy, but the variation in human receptors (akin to tissue type) would make it unlikely to affect the whole population with the same behavior.