Seite - 77 - in Biodiversity and Health in the Face of Climate Change

77 insecticide-treated livestock or indoor residual spraying in highly VBD endemic areas, which complements other preventive actions such as source reduction and information campaigns. All pest control measures can influence biodiversity in manifold ways, whereas prospective evaluations of positive and negative effects of pest control under global changes is rarely available in the VBD context. 4.4.1 Chemical Insecticides Arthropod pest control in epidemic regions is based on chemical insecticides, which work efficiently against vectors, but are mostly associated with undesirable side effects for biodiversity. The past use of dichloro-diphenyl-trichloroethane (DDT), for example, successfully eliminated malaria in North America and Europe and sig- nificantly decreased the number of deaths in other regions of the world (WHO 2008; Keiser et  al. 2005). However, DDT is highly persistent in the environment, accumu- lates in fatty tissues of organisms, and biomagnifies from low trophic levels to pred- ators such as ice bears and eagles (e.g. reviewed in Van den Berg 2009). The high ecotoxicological risk of DDT for wildlife and ecosystem functioning was first dis- covered by Rachel Carlson in 1962 (Carson 2002). Consequently, the Stockholm Convention on Persistent Organic Pollutants (2001) banned DDT and a number of other chemicals that were used as insecticides in the past (NO 2005). The use of DDT is, however, allowed under the Stockholm Convention for disease vector con- trol, within the recommendations and guidelines of the WHO until locally effective and affordable substitutes and methods are available. Concerted large-scale efforts are now underway to reduce both the burden of VBDs and the use of DDT (Van den Berg 2009). The generations of insecticides following DDT were organophosphates (e.g. parathion), carbamates, pyrethroids (e.g. deltamethrin) and neonicotinoids (e.g. imidacloprid), all designed to increase the efficiency to kill pest insects, overcome problems with insecticide resistance in pest species, and lower the environmental burden by increasing specificity (and thereby decreasing applied amounts for the same efficiency). In every insecticide class, however, negative health effects on human and/or wildlife occurred. For example, pyrethroids are recommended for indoor spraying and bed net treatment by the WHO.  However, pyrethroid resistance evolved in several insect species and hence vector control cannot rely exclusively on this insecticide class in the long term (Hemingway and Ranson 2000). As another example, neonicotinoids, the most recent insecticide class (developed in the 1990s) are discussed as a good candidate (clothianidin) for indoor residual spraying in areas with pyrethroid-resistant mosquito populations (Agossa et  al. 2018). Neonicotinoids are currently under restricted use in the European market due to increasing evidence of toxic effects on honey bees (honey-bee colony-collapse dis- order), wild pollinators and indirectly on insectivorous birds, which are already challenged by climate change (e.g., Le Conte and Navajas 2008; Hladik et  al. 2018). 4 Vector-Borne Diseases