Biological invaders are threats to human health: an overview

Invasive alien species are one of the major agents of human-accelerated global change: they threaten biodiversity, alter ecosystem structure, functions and services, inflict large economic costs and cause serious problems to human health. The effects on human health are indeed a major problem and also cause substantial costs but, surprisingly, very few studies have analyzed this topic. The paper describes and analyses the hazards to human health associated with species introductions, and discusses major correlates and possible responses. Four categories were identified: invasive species (1) causing diseases or infections; (2) exposing humans to wounds from bites/stings, biotoxins, allergens or toxicants; (3) faciliting diseases, injuries or death; and (4) inflicting other negative effects on human livelihood. Invasive species affect human health via several ways, i.e. as alien pathogens and invaders that bring/facilitate parasites or produce toxins. Others cause denutrition/ malnutrition or exert displaced or deferred impacts. Their negative impacts are expected to intensify in the near future due to the increased opportunities of invasions associated with climate change, the augmented pathways of introductions and the synergic effects of climate change. It is imperative to improve our understanding of the pathways of arrival of invasive species affecting human health, their biological patterns and the mechanisms of impact, because all this information is essential to develop more effective and stringent policies for preventing and mitigating the negative effects that these species cause. © 2013 Dipartimento di Biologia, Università di Firenze, Italia.