New evidence has emerged showing that head lice have developed resistance to two types of insecticides that are commonly used in over-the-counter (OTC) treatments for lice infestation, according to a study published in Journal of Medical Entomology (JME), as reported by ParaPRO,a  specialty pharmaceutical company that is leading research into new antiparasitic formulations.   The study, Expansion of the Knockdown Resistance Frequency Map for Human Head Lice (Phthiraptera: Pediculidae) in the U...