Ciência & Saúde Coletiva ISSN: 1413-8123 [email protected] Associação Brasileira de Pós-Graduação em Saúde Coletiva Brasil Liberato da Silva, Guilherme; Nunes Pereira, Thiago; Juarez Ferla, Noeli; Santos da Silva, Onilda The impact of insecticides management linked with resistance expression in Anopheles spp. populations Ciência & Saúde Coletiva, vol. 21, núm. 7, julio, 2016, pp. 2179-2188 Associação Brasileira de Pós-Graduação em Saúde Coletiva Rio de Janeiro, Brasil Available in: http://www.redalyc.org/articulo.oa?id=63046188019 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative DOI: 10.1590/1413-81232015217.00922015 2179 The impact of insecticides management TEMAS LIVRES FREE THEMES linked with resistance expression in Anopheles spp. populations O impacto do manejo de inseticidas relacionado com a expressão de resistência em populações de Anopheles spp. Guilherme Liberato da Silva 1 Thiago Nunes Pereira 1 Noeli Juarez Ferla 2 Onilda Santos da Silva 1 Abstract The resistance of some species of Resumo A resistência de algumas espécies de Anopheles to chemical insecticides is spreading Anopheles a inseticidas químicos está se espalhan- quickly throughout the world and has hindered do rapidamente por todo o mundo e tem dificul- the actions of prevention and control of malaria. tado as ações de prevenção e controle da malária. The main mechanism responsible for resistance in O principal mecanismo responsável pela resistência these insects appears to be the target site known as nestes insetos parece ser o sítio-alvo conhecido como knock-down resistance (kdr), which causes muta- resistência knock-down resistance (kdr), que cau- tions in the sodium channel. Even so, many coun- sa mutações no canal de sódio. Mesmo assim, tries have made significant progress in the preven- muitos países fizeram progressos significativos na tion of malaria, focusing largely on vector control prevenção da malária, concentrando-se em grande through long-lasting insecticide nets (LLINs), in- parte no controle do vetor através redes inseticidas door residual spraying and (IRS) of insecticides. de longa duração (RILD), e de pulverização residu- The objective of this review is to contribute with al interna (PRI) de inseticidas. O objetivo desta re- information on the more applied insecticides for visão é contribuir com informações sobre os inseti- the control of the main vectors of malaria, its ef- cidas mais aplicados para o controle dos principais fects, and the different mechanisms of resistance. vetores da malária, seus efeitos, e os diferentes me- Currently it is necessary to look for others alterna- canismos de resistências. Atualmente é necessário tives, e.g. biological control and products derived olhar para outras alternativas, como por exemplo, from plants and fungi, by using other organisms controle biológico e produtos derivados de plantas e as a possible regulator of the populations of ma- fungos, pela utilização de outros organismos como laria vectors in critical outbreaks. um possível regulador de populações de vetores da 1 Departamento de Key words Malaria, Anopheles, Knock-down re- malária em surtos críticos. Microbiologia, Imunologia e sistance (kdr), Pesticides, Public Health. Palavras-chave Malária, Anopheles, Knock- Parasitologia, Universidade Federal do Rio Grande do down resistance (kdr), Pesticidas. Saúde Pública Sul. R. Sarmento Leite 500, Centro Histórico. 90050-170 Porto Alegre RS Brasil. [email protected] 2 Laboratório de Acarologia, Museu de Ciências Naturais, Centro Universitário UNIVATES. Lajeado RS Brasil. 2180 et al. Silva GL Silva Background mental conditions, and reports of host preference also vary depending upon the methods used to According to the World Health Organization measure this poorly defined behavior9-11. (WHO), Malaria kills over a million people per In an effort to malaria transmission re- year and other 3.2 billion people are living in ar- duction, some countries have implemented eas at risk. Over 80% of deaths occur in Africa, indoor residual spraying (IRS) and universal where approximately 66% of this population is distribution of insecticide-treated nets ITNs in at risk area1. In the Americas, 14% of the pop- combination in years12,13. Many countries have ulation is at risk of transmission. Since the year made significant progress in preventing malar- 1990, the number of malaria cases reported in ia by focusing largely on vector control through South and Central America and the Caribbean long-lasting insecticidal nets (LLINs) and indoor remain relatively low, however there is a risk of residual spraying (IRS) of insecticides and use of malaria transmission in nine countries that are DDT has been compromised, not only because of part of the Amazon region and in eight countries resistance, but also because of its environmental in Central America and the Caribbean1. effects14,15. In areas with insecticide-susceptible Malaria is a disease caused by Plasmodium mosquito populations, the insecticide on LLINs species which are transmitted by several species mitigates the loss of personal protection if the net of Anopheles mosquitoes. There are approxi- becomes holed. mately 400 species of Anopheles world-wide and The reduction in disease burden of malaria of these about 50 species are exclusive vectors of in recent years has in large part been attributed human malaria2,3. The most important vectors in to the massive scale up of the two main vector Sub-Saharan Africa and the most efficient ma- control interventions, LLINs and IRS, particu- laria vectors world-wide belong to the Anopheles larly in Africa south of the Sahara. A number of gambiae Complex. In this complex, A. gambiae countries have deployed the two interventions and Anopheles arabiensis are the most import- in combination in an attempt to further reduce ant vectors of Plasmodium falciparum (the most transmission16. severe malarial pathogen) in Africa. At level of However, both IRS and LLINs face the de- Americas, Anopheles darlingi is one of the most velopment of physiological resistance (against important malaria vectors4, occurring mainly in insecticide) and ‘behavioural resistance’ in mos- Amazon region and showed high degree of vari- quitoes, which can reduce effectiveness of these ability in behavioral traits and capable of main- interventions and possibly reverse the gains taining a relatively high transmission of malaria made in reducing malaria morbidity17, but there even when found in low densities5,6. This makes it are currently not enough data to determine the difficult to predict the impact of ongoing chang- impact of resistance on the effectiveness of such es in the environment on the mosquito popula- combinations16. Maybe, IRS has some utility in tions. Due to their anthropophilic behavior and areas with low resistance as part of an overall re- physiological feasibilities, they possess a higher sistance management strategy aimed at preserv- vector capacity than other closely related sibling ing the effectiveness of pyrethroids16. Although species with no or low vector capacity. Falavig- such resistance may be inevitable with successful na-Guilherme et al.4 carry out the reported au- control programmes, new strategies need to be tochthonous cases of malaria after construction developed to mitigate development and spread of the Itaipu Hydroelectric in Foz do Iguacu. The of insecticide resistance and to preserve the ef- impact of dams and irrigated schemes Anopheles ficacy of currently available insecticides and the populations has been elucidated by Sanchez-Ri- effectiveness of malaria control interventions. bas et al.7 revealing the proliferation of Anopheles The aim of this review is to elucidate the species in anthropogenic environments. Anopheles spp. literature about the mainly vector Apparently, pathogen/parasite and vector species of malaria disease, what insecticides are (mosquito) either adapted to each other during applied, their effects and the different mecha- the course of evolution, resulting in coexistence, nisms resistances arising in these species. or the pathogen/parasite was repelled8. Anopheles gambiae has been considered the most anthropo- Approach about Anopheles philic species, followed by A. arabiensis, Anoph- in agricultural fields eles melas, and Anopheles merus. However, host preference likely varies considerably within spe- Agricultural practices have significant influ- cies owing to population structure and environ- ence on mosquito species diversity and abun- 2181 Ciência & Saúde Coletiva, 21(7):2179-2188, 2016 21(7):2179-2188, Coletiva, & Saúde Ciência dance and that certain habitat characteristics fa- Anopheles species to the four families of insecti- vor production of malaria vectors. For example, cides available for public health use (organochlo- the creation of fishponds basins and the develop- rines, organophosphates, carbamates, and pyre- ment of market-gardening activities, which also throids) is a genuine concern throughout Afri- serves as breeding sites, can increase drastically ca18,42-44. In Anopheles gambiae sensu stricto, there proliferation of Anopheles species, especially A. are two point mutations at the voltage-gated so- gambiae18. These factors should be considered dium channel gene confer knockdown resistance when implementing larval control