Evidence for changes in the occurrence, frequency or severity of human health impacts resulting from exposure to alien species in Europe: a systematic map


Alien species are frequently considered a serious environmental threat but negative impacts on human health through injury, allergy, or as vectors of disease sometimes have the most dire consequences for human livelihoods. Climate change and the increasing magnitude and frequency of introductions of species across geographic barriers as a result of international trade are likely to change their establishment, spread, abundance, physiology or phenology, potentially also altering their human health impacts. Yet despite receiving increasing attention in the scientific literature, there have been few attempts to quantify recent changes in human health impacts. Here we report the findings from a systematic map of the literature identifying evidence of any change in the occurrence, frequency or severity of impacts of alien species on human health in Europe over the last 25 years.


We conducted a systematic search of the ecological and medical literature using English language search terms to identify potentially relevant studies. Search results were assessed against inclusion criteria published in an a priori protocol at title, abstract and full-text to determine their suitability for inclusion in the review. Repeatability was checked at each stage by comparing a subset between reviewers and testing for inter-rater agreement using Cohen’s kappa test. Studies deemed relevant at full text were coded against bibliographic, inclusion and study design criteria to create a searchable database of evidence.


Searches retrieved over 15,700 results yet only sixteen cases met criteria for inclusion in the systematic map. Most of this evidence represents first records of impacts from different areas, and in particular first reports of transmission of exotic diseases by introduced mosquito species.


There is currently limited published evidence demonstrating a change in the occurrence, frequency or severity of human health impacts caused by alien species in Europe over the last 25 years. Relevant studies relate to only a few species, often report specific cases and rarely link health impacts with ecology, distribution or spread of the species. Difficulties in attributing human health impacts, such as stings or allergies, to a specific alien species likely complicate attempts to measure changes, as may differences in professional interests between the environmental and health professions. Future studies could helpfully compare spread or abundance with reported, rather than potential, health impacts. Better cooperation between invasion ecologists and health professionals working in affected areas are likely to be necessary to improve the evidence base on this topic for the future.




Invasive alien species are of global concern due to their impacts on biodiversity, related ecosystem services and on economy. A number of invasive alien species are also responsible for human health impacts, either as carriers (vectors) of pathogens, as causal agents of toxic or allergic reactions (e.g. to pollen or insect stings) or injuries. However, there has been relatively little attention given to these human health effects in invasion ecology literature, with no attempts to systematically identify and quantify evidence of impacts. It is likely that further invasive alien species will benefit from global change as some invasive traits provide high plasticity and therefore support adaptation capacities to cope with changing conditions. Thus, global change may lead to new public health concerns as invasive alien species expand their range or enter new areas, or may alter the severity of health impacts by changing the physiology or quantity of potential allergens or irritants produced. This mapping review aims at identifying any evidence for changes in the occurrence, frequency or severity of human health impacts resulting from exposure to invasive alien species in Europe over the last 25 years.


A systematic search of both ecological and medical literature will be used to identify potentially relevant studies using three a priori inclusion criteria, i.e. (i) affected human population in Europe, (ii) exposure to alien species, (iii) change in health impact. Studies will be assessed against inclusion criteria at title, abstract and full text to determine relevance to the mapping review. Studies deemed relevant will be coded using predetermined categories relating to the review inclusion criteria and study design, and recorded in a searchable database. Depending on the information available, studies may also be geo-referenced to create a geographic map of the evidence. Descriptive statistics will be used to explore key trends in the evidence base. The searchable database of studies and their main characteristics will be made available with the final report. It is intended that this systematic map will be useful in informing decision making related to the future human health impacts of invasive alien species in Europe.