Commentary Artificial Lighting as a Vector Attractant and Cause of Disease Diffusion Alessandro Barghini1,2 and Bruno A. S. de Medeiros 2 1Laboratório de Estudos Evolutivos Humanos, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, and Instituto de Eletrotécnica e Energia, and 2Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil Background : Traditionally, epidemiologists have considered electrification to be a positive factor. In fact, electrification and plumbing are typical initiatives that represent the integration of an isolated population into modern society, ensuring the control of pathogens and promoting public health. Nonetheless, electrification is always accompanied by night lighting that attracts insect vec- tors and changes people’s behavior. Although this may lead to new modes of infection and increased transmission of insect-borne diseases, epidemiologists rarely consider the role of night lighting in their surveys. o Bjectiv : We reviewed the epidemiological evidence concerning the role of lighting in the spread of vector-borne diseases to encourage other researchers to consider it in future studies. d iscusion : We present three infectious vector-borne diseases—Chagas, leishmaniasis, and malaria—and discuss evidence that suggests that the use of artificial lighting results in behavioral changes among human populations and changes in the prevalence of vector species and in the modes of transmission. c onclusi : Despite a surprising lack of studies, existing evidence supports our hypothesis that artificial lighting leads to a higher risk of infection from vector-borne diseases. We believe that this is related not only to the simple attraction of traditional vectors to light sources but also to changes in the behavior of both humans and insects that result in new modes of disease transmission. Considering the ongoing expansion of night lighting in developing countries, additional research on this subject is urgently needed. k ey words : Chagas disease, electricity, insect, leishmaniasis, lighting, malaria, vector. Environ Health Perspect 118:1503–1506 (2010). doi:10.1289/ehp.1002115 [Online 1 August 2010] The expansion of nocturnal lighting has raised many concerns, the most prominent of these are the consumption of fossil fuels for electric power generation and the obstruction of views of the night sky and astronomical observation (Claudio 2009). At present, researchers have raised concerns that light pollution is also related to human health (Chepesiuk 2009; Holzman 2010; Stevens et al. 2007), mainly on the basis of chronobiological disorders. Calling attention to the fact that light pol- lution is also a major source of alterations to ecosystems, Longcore and Rich (2004) and Rich and Longcore (2006) coined the term “ecological light pollution.” By affect- ing the trophic web, light pollution can also, indirectly, influence human health. Alternative energy sources such as solar photovoltaic panels and the new techniques applied in the production of artificial lighting, such as fluorescent bulbs and light-emitting diodes that are more efficient than traditional lighting (incandescent bulbs), will increase the accessibility of these resources to popu- lations in developing countries that did not have access to them in the past (Mills 2004). The alternative forms of energy both will decrease the adverse effects of electricity on the environment and will allow the electrifi- cation of more isolated areas (International Energy Agency 2002). From a social perspec- tive, these initiatives are beyond doubt posi- tive. However, we should not forget that the areas around the world that lack electricity are mainly rural in equatorial and tropical regions where insect-transmitted diseases are prevalent (Jones et al. 2008). Because artificial illumina- tion is a great attractor for insects, we believe that the diffusion of this electrification could constitute a risk of epidemic outbreaks of both existing and emerging diseases. Traditional Views on the Role of Electrification Electrification is doubtless important as a means to develop rural areas, and it also has many beneficial effects. According to the Independent Evaluation Group of the World Bank (2008), for example, it operates through a number of channels: “improvements to health facilities; better health from cleaner air as households reduce use of polluting fuels for cooking, lighting, and heating; improved health knowledge through increased access to television; better nutrition from improved knowledge and storage facilities from refrigera- tion.” Most epidemiological reports cite both electrification and plumbing as positive factors in the control of diseases. As an example, Noor (2008) used “remotely sensed night-time light as a proxy for poverty in Africa,” indirectly assuming that artificial lighting is a good social development index. However, electrification also means artificial lighting, and artificial lighting is a strong insect attractant. Although entomologists and epidemi- ologists traditionally have used light traps to capture insects, the effect on disease diffusion Environmental Health Perspectives • volume 118 | number 11 | November 2010 caused by the expansion of artificial lighting has generally not been considered—sometimes the effects have even been ignored. In fact, ignoring the effects of such light sources is long-standing: In the beginning of the 20th century when electrification started to diffuse in rural areas, epidemiologists did not con- sider its possible effects. For example, during the construction of the Panama Canal, Joseph Le Prince stated that it was man who attracted insects and that artificial lighting did not con- tribute to the diffusion of malaria (Le Prince and Orenstein 1916). Carlos Chagas, who dis- covered Chagas disease, noted that light is a good defense against the diffusion of the dis- ease because Triatoma, its vector, does not bite in lighted areas (Chagas 1909). Indeed, light may inhibit some insects from biting, but to understand its role in the diffu- sion of diseases, we need to take into account the behavioral changes in both human beings and insects. In other words, night lighting pro- motes new lifestyles, which, in turn, may lead to new modes of disease transmission. Of course, we are not claiming that the introduction of modern lighting systems increases the risk of emerging diseases imme- diately and directly. The diffusion of electric- ity is bound to produce changes in human lifestyles, which are brought about by lighting, radio, television, and other electrical equip- ment. As a result of electrification, people may increase their outdoor activities in the evening; they may stay outdoors longer to exercise or to rest in hammocks or engage in other activities close to sources of bright light. Light sources may increase people’s expo- sure to vectors merely by staying outdoors for longer periods of time in the evening, but vectors are also affected by light sources. In Address correspondence to A. Barghini, Instituto de Eletrotécnica e Energia, Ave. Prof. Luciano Gualberto, 1289 Cidade Universitária, CEP 05508-010, Butantã, São Paulo, SP, Brasil. Telephone: 55-11-3091-2549. Fax: 55-11-3812-3352. E-mail: barghini@iee.usp.br. We thank W.A. Neves, D. Natal, P. Urbinatti, and S. Vanin who encouraged the present study and who read a previous version of the manuscript. We also thank an anonymous reviewer whose criticisms greatly improved the manuscript. We are grateful to M.T. Obara for kindly providing the photograph for Figure 1. B.A.S.M. received a scholarship from the National Council for Scientific and Technological Development (CNPq), Brasilia, Brazil. The authors declare they have no actual or potential competing financial interests. Received 2 March 2010; accepted 28 July 2010. 1503