Assessment of climate change impact on the malaria vector Anopheles hyrcanus, West Nile disease, and incidence of melanoma in the Vojvodina Province (Serbia) using data from a regional climate model

During the period 2001–2030 in which the spread and population growth of An. hyrcanus is expected, the intensity of UVR is likely to increase in the VPS (Fig 4A). Positive trends which are present in our observations might indicate that the findings on the negative influ- ence of UVR and blue-light radiation (this radiation has a wavelength between approximately 380nm and 500nm; it has a very short wavelength, and so produces a higher amount of energy) on adult mosquitoes under laboratory conditions [58,59] could not be simply translated to the field. This experimental evidence does not mean unavoidably that the blue light radiation has a significant influence on adult mosquitoes in field conditions since they can actively escape over-exposure to radiation. The WNV transmission cycle involves mosquito vectors and birds, but equines and humans are also susceptible to infection [60,61]. Although WNV infections have been described in a wide variety of vertebrates, birds are the main natural reservoir. Hundreds of wild and domes- tic avian species have been described as susceptible to WNV infection, but many of these showed only subclinical infection [62]. In horses, WNV infection is also frequently clinically unapparent, but around 10% of cases develop neurological disorders with up to 50% mortality rates [61,63]. An increasing number of severe outbreaks in horses have been reported in Europe in the past decade, including a large one that took place in northeast Italy in 2008 involving 251 stables with 794 cases and five deaths [63].

From the first detection of WNV in 8 out of 81 dead wild birds found in Serbia [45], each year WNV nucleic acid was detected in dead or captured wild birds during summertime [8]. Serological testing of horses sampled during 2009–2010 showed that 12% of 349 horses from the northern part of Serbia had neutralising WNV antibodies [44]. After that, each year horse WNV cases were detected by the positive serological response (IgG and IgM antibody serocon- verted horses) [8] or as a clinical manifestation of West Nile neuroinvasive disease [64]. A positive association between WNV disease and temperature was already reported in Europe [15,65] where climate and landscape were critical predictors of WNV disease out- breaks [66]. Our focus was not on the number of human WNV cases, but the suitability of sites/microhabitats with different air temperatures for WNV circulation in mosquitoes, which may well correspond to a higher risk of transmission. We found that sites with higher TOA and Ta were characterized with the higher frequency of WNV presence in mosquitoes. Clustering of cases with an incidence higher than one in six years coincided with an area of a significant grouping of mosquito, bird, horse, and human cases in 2014 and 2015 [9] (Fig 5). This is in concurrence with Tran et al. [67] and Marcantonio et al. [66], who found that average summer temperatures are positively correlated with WNV human incidence. It seems that temperature in semi-urban areas is an essential environmental factor influencing WNV circulation (land-

scape suitability for reservoir host and mosquito vector, host availability, and precipitation/ water availability are somewhat similar in investigated semi-urban areas of VPS), as it affects both mosquito vector abundance [9] and virus replication. Prediction of a two-fold increase in virus incidence for each 0.5˚C increase in TOA indicates but does not necessarily means, that the number of human cases could increase too. Therefore, our findings support the statement that climate change is likely to intensify the re-emergence of WNV in Europe [68]. Melanoma incidence and UVR According to World Health Organization (WHO) (1992) and many other authors [69,70], exposure to UVR radiation is considered to be a major etiological factor for all three forms of melanoma (i) basal cell carcinoma (BCC), (ii) squamous cell carcinoma (SCC), and (iii) malig- nant melanoma (MM). We found the correlation between MM and climate changes impact on UVR and also the number of HD. We see the impact as a modification of ambient UVR Impact of climate change on malaria vector, West Nile disease, and incidence of melanoma PLOS ONE | https://doi.org/10.1371/journal.pone.0227679 January 15, 2020 11 / 17