Recent research has suggested that humans might develop allergies as a defense to fight off parasites. According to Yale University Immunologist Dr Ruslan Medzhitov, protease allergens cleave the same sensor proteins that evolved to detect proteases produced by the parasitic worms. Additionally, a new report on seasonal allergies called “Extreme allergies and Global Warming”, have found that many allergy triggers are worsening due to climate change. 16 states in the United States were named as “Allergen Hotspots” for large increases in allergenic tree pollen if global warming pollution keeps increasing. Therefore, researchers on this report claimed that global warming is bad news for millions of asthmatics in the United States whose asthma attacks are triggered by seasonal allergies. Indeed, seasonal allergies are one of the main triggers for asthma, along with colds or flu, cigarette smoke and exercise. In Canada, for example, up to 75% of asthmatics also have seasonal allergies.