Finally, it is possible that elevated parasitism (and/or associated immune system activation) may increase oxidative stress in urban animals. For example, Isaksson and Andersson showed that dietary carotenoid concentration was significantly lower in the urban caterpillars that constitute an important component of the diet of great tits ( Parus major).

Nutritional shifts in urban environments may lead to changes in dietary antioxidant availability and thus the capacity to counteract free-radical damage. Urban pollution elevates oxidative stress in humans and birds. Among the many means of assessing stress in animals, oxidative stress has emerged in recent years as an under-studied component of the stress response system of wild animals, including in relation to urbanization. In addition, we know of no work linking parasites, urbanization, and stress. However, multiple infections have been shown to often cause detrimental effects such as anaemia, reduced body mass and survival in many hostвЂ“parasite systems. For example, a decrease of parasite virulence may occur when an infection with a first parasite provide cross-immunity against other parasites. Free-living animals often carry several parasites species and these multiple infections may increase or decrease parasite virulence. To the best of our knowledge, no studies to date have examined infection prevalence or severity by multiple parasites/pathogens along a gradient of urbanization. Gathering additional information on the host, parasites, and environmental characteristics is central to developing an integrated framework for understanding if and how different animals in urban environments should be influenced by disease. land use types, human population demographics), most often simply categorizing habitats for comparison as вЂњurbanвЂќ or вЂњruralвЂќ. Moreover, they fail to integrate detailed information on the type or degree of urbanization (e.g. However, most of these prior studies center in on only one type of parasite or pathogen and do not consider the severity of their effects on hosts. woodchucks ( Marmota monax) bumblebees ( Bombus terrestris) mice ( Peromyscus spp) northern cardinal ( Cardinalis cardinalis) ). blackbirds, Turdus merula see for a multi-species avian study) compared to their rural counterparts, while others have found higher pathogen/parasite abundance in cities (e.g. Some studies have shown reduced parasitism in urban animals (e.g. To date, comparisons of disease between urban and rural animal populations have yielded mixed results. pollution, impaired nutrition, glucocorticoid elevation, compromised immune system) of urban life. Also, disease severity may rise in city-dwelling animals due to the physiological stresses (e.g. Population thinning in cities can decrease opportunities for horizontal pathogen/parasite transmission, though some animals that thrive in cities may experience the opposite. Due to their broad life-history effects on development, survival, and reproduction, parasites and pathogens have also been argued to contribute to the success of plant and animals species in colonizing or persisting in urban areas. Information on how, for example, stress, disease, expression of ornamental traits, and behavioral plasticity are linked to urbanization can give key insights into short-term urban impacts on the fitness of organisms (which have obvious long-term ties to population persistence).Д¬urrent interest in urban wildlife diseases is far-reaching, as it has direct implications for the spread of zoonoses in humans (which now account for 75% of the worldвЂ™s emerging infectious diseases) and domestic animals.

However, there has been a recent scientific push to understand finer-scale effects of cities on the ecology, physiology, health, and behavior of individual animals. Most studies of urban impacts on wildlife historically have centered on censusing populations and monitoring trends in species distributions and richness. More than half of the worldвЂ™s population now lives in cities, and rapid urbanization in the last few hundred years has dramatically altered natural habitat structure, ecosystem functioning, and faunal and floral biodiversity.

Parasite in city game mega