Yeah I'm going to have to chime in and say that that's not a definable sign of Anavar whatsoever. Plenty of other anabolic substances can cause an increase in libido... i.e. Dianabol, Winstrol, etc.
There are other determining signs & symptoms that can help with distinguishing what the substance is...but even then it's not a reason to think it's Anavar, as every female experiences different side effects to AAS. Personally, I don't notice THAT much of an increase in libidio, and when I do it's usually not until week 3-4.
If she's experiencing that much of an increase in that little of a time...I'd be veryyyy cautious of virilization (especially because you mentioned "tingling" sensation) because her Testosterone levels are probably through the roof, so she will experience other sides as well soon enough.
What are your wife's stats/goals and why did she decide to choose the AAS route?