animals and humans or indirectly transmit infection by contaminating food consumed by domestic animals and humans. In particular, they noted that in the Amazon region, humans have become infected with Chagas disease by eating sugarcane or fruit juice contaminated with the feces of sylvatic Triatominae. Leishmaniasis Leishmaniasis is another disease whose spread appears to be augmented by artificial light- ing. Sand flies (phlebotomines), the vectors of Leishmania, are poor flyers (Dias-Lima et al. 2002) that are attracted to lighted sur- roundings but are usually not found directly on lamps. In periurban areas, street lighting attracts sand flies to small farms or kitchen gardens, where dogs, chickens, and other small animals become the hosts. Campbell-Lendrum et al. (1999) showed that both Lutzomyia inter- media and Lutzomyia whitmani phlebotomine flies are attracted to light. Later, dos Santos et al. (2003) argued that this attraction may increase the risk of Leishmania transmission “in houses where an external light source is situated close to a light-color wall that reflects light, and that have adjacent bushes or trees and domestic animal shelters within 50 meters.” Moreover, we cannot forget that sand flies are the vectors of a large number of arbo- viruses that are common in tropical and equa- torial regions (Travassos da Rosa et al. 1998), which are the cause of a large number of dis- eases, generally called “wild fevers.” They are also vectors of infectious diseases in temperate regions, including West Nile encephalitis and equine encephalitis. Malaria The case of malaria is more problematic. Unlike Chagas disease and leishmaniasis, there have as yet been no specific studies published on the relationship between night lighting and vector attraction. Although mosquitoes are seldom found near lamps and almost never captured by static light traps, they can be captured using suction light traps without heat or carbon diox- ide bait (Govella et al. 2009; Jawara et al. 2008; Lee et al. 2009; Suárez-Mutis et al. 2009). Malaria vectors are therefore probably just as attracted to lights as are Chagas and leish- maniasis vectors, and we should then expect a corresponding change in modes of transmis- sion with increased use of artificial light. We also know that electrification is chang- ing lifestyles in all isolated areas throughout the world. In Amazonia, for example, elec- tric lights allow people to spend more time outdoors when vectors are active, particu- larly between sunset and the first hours of the night. Sports and gymnastics are practiced outdoors in the evening under strong artifi- cial lights, and one may observe people rest- ing in hammocks on their porches along the banks of the Amazon River, their electric lights shining brightly. These are all condi- tions that could affect vector attraction and also facilitate malaria transmission. However, we found no epidemiological studies on this matter relating to the Amazon. Taylor (1997) proposed that increased time spent outdoors at night may have con- tributed to a resurgence in malaria infections among Solomon Island residents in the early 1980s, which followed substantial declines in infection rates resulting from in-home use of DDT (dichlorodiphenyltrichloroethane) in the 1960s. As Taylor (1975) observed, “Traditionally, the Melanesian peoples retired indoors at sunset but in more ‘enlightened’ areas this habit broke down (a combination of changed working hours and the money to buy artificial lighting).” Malaria control was regained in the Solomon Islands only ten years later when spraying was no longer limited to bed nets and households (Over et al. 2003). This suggests that night light- ing augments human exposure to vectors by enabling people to stay outdoors longer. It is not clear if the vectors themselves were also attracted to lights or if lights affected their feeding behavior, but given that Anopheles are indeed attracted to light traps, these possibili- ties could be tested with additional research. Other examples have come from two recent studies. Yamamoto et al. (2010), work- ing in Burkina Faso, found that living in a home < 10 years old and in a home with elec- tricity were both associated with an increased risk of malaria, whereas socioeconomic status was not a factor. The authors suggested that vectors might be more likely to bite residents of homes with electricity than residents of nonelectrified homes where greater use of bio- mass fuels would produce smoke that might prevent insects from biting. However, a recent review concluded that smoke does not reduce biting in homes (Biran et al. 2007). In South Africa, Coleman et al. (2010) found that open- ing windows at nighttime increases the risk of malaria transmission, but the authors did not evaluate electrification as an independent risk factor for disease transmission. In both studies, the researchers did not collect the necessary data to evaluate the role of artificial light. Conclusion Although we have presented evidence that arti- ficial light may increase the transmission of three diseases, we strongly believe that this is a consequence of a lack of studies rather than a lack of an effect and that the three diseases we have discussed may reflect a general pattern. Artificial night lighting changes the behavior of both people and insects and thereby promotes contact between human beings and vector spe- cies, including some that have not tradition- ally been involved in transmitting disease to Environmental Health Perspectives • volume 118 | number 11 | November 2010 Artificial lighting as a vector attractant humans. This may lead to new and unpre- dictable ecological relationships that need to be understood so that electrical energy can be offered to rural populations in areas where vec- tor-borne diseases are endemic without increas- ing their risk of acquiring such diseases. 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