During the 20th century agricultural landscapes have undergone major alterations due to agricultural intensification, which has been linked to population decline of plants, arthropods, birds and mammals. Agricultural intensification has led to a significant homogenisation of the landscape due to land consolidation, and to the entry of more and more chemical pesticides and fertilisers into the environment. Pesticides directly and indirectly destroy many target organisms for which they were designed, altering the food chains in natural ecosystems. But they also have lethal and sub-lethal effects on non-target organisms. Sub-lethal effects are related to chronic exposures and can have consequences in the health status of individuals, being able to affect the immune system. The immune system is particularly relevant to protect organisms against pathogens such as those that cause infectious diseases. A good study model of this relationship is found in the lagomorphs of the Iberian Peninsula, as the Iberian hare (Lepus granatensis) and the effect of myxoma virus (MYXV, genus Leporipoxvirus, family Poxviridae). For that, blood samples were collected from hunted animals during the 2021/22 hunting season in the southwestern Spain from animals with and without lesions compatible with myxomatosis. For this study the levels of immunoglobulin G, together with MYXV antibodies in serum, and viral presence, were analysed for a first immune system characterisation in animals from pesticides-treated and untreated areas. Overall, the results show that hares from treated areas have lower mean IgG concentrations than those from untreated areas. In addition, the results show particularly low IgG concentrations in animals with lesions, viral presence, and absence of antibodies, suggesting that this disease may be occurring more severely in individuals living in areas treated with pesticides.

Project funded by the Junta de Comunidades de Castilla-La Mancha and the European Regional Development Fund (SBPLY/21/180501/000182).

Resumen del póster presentado al SETAC Europe 35th Annual Meeting, celebrado en Viena (Austria) del 11 al 15 de mayo de 2025.

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