The best answers I have found are as follows:
The human papilloma virus (HPV) is not a single virus, but a family of over 100 different strains of viruses. Different types of HPV are passed on in different ways.
Warts (on the body and hands) and verrucas (on the feet) are more likely to be spread when a visible wart/verruca is present. So, if she does not have verrucas on her feet it is very unlikely that she would spread the HPV virus to you from her feet even if she had the HPV that causes verrucas.
So, if your girlfriend does not have visible verrucas it is generally safe to kiss her feet.
You may find it helpful to know that warts that appear on specific parts of the body (hands/feet/genitals) are generally more likely to stick to those specific areas.
Genital warts are also caused by HPV. The HPV that causes genital warts are different to the HPV that causes verrucas.
Genital warts are usually spread through vaginal and anal sex, or close skin-to-skin genital contact. It is more common to pass on the virus when someone has visible warts but it is also possible when someone has no visible symptoms. It is possible, but very rare, to develop warts in the mouth or throat, or on the lips from oral sex.
While there is a tiny possibility of a verruca virus infecting your mouth, that strand of HPV obviously prefers the hard dry skin of the foot, and probably wouldn’t adapt well to the moist conditions in the mouth.
There are around 90 to 100 types of human papilloma virus (HPV). The various HPV types will be found on particular parts of the body e.g. genital warts, hand warts and verrucas on the feet. The different types prefer different types of skin (e.g the harder skin on the foot for verrucas and softer skin in the mouth for mouth warts). HPV is usually transmitted through skin to skin contact. Therefore if you were to catch a HPV type from an infected person, the same part of your body would have come in direct contact with the same part as the other person's body. Therefore, it is highly unlikely that you will get the HPV type that causes verrucas infecting your mouth.
This website has been very useful in answering hpv related to the mouth.
emedicine.medscape.com/article/1079920-overview
Thanks for the reply, what I'm worried about is if developed Verrucas (foot wart) can be transferred to my mouth, if I kiss her feet.
Interesting to know that I cannot catch genital warts form the foot (verrucae).
Yes, you are correct that all forms of warts are caused by HPV. And that there are many strains of HPV. But the strains that cause hand and plantar (foot) warts does NOT affect the genitals.
Likewise, the kind that affect and cause genital warts only affect genital areas. So to put it simply, to get genital warts or genital HPV, you need to have sexual contact with someone who has genital HPV.
I would be more worried about transmitting plantar (foot) warts to your feet or hands, then genitals.