A variety of fungal, bacterial and parasitic infections may affect the skin of both humans and animals. Streptococcal and staphylococcal infections may be transmitted from animals to man. Although lice are host-specific, fleas may leave the preferred animal host and cause local allergic reactions when they bite humans. Ticks and mites commonly infest both humans and animals. A canine variety of Sarcoptes may occasionally cause human scabies.