title: When Parasites Are Good for Health: Cestode Parasitism Increases Resistance to Arsenic in Brine Shrimps.
abstract: Parasites and pollutants can both affect any living organism, and their interactions can be very important. To date, repeated studies have found that parasites and heavy metals or metalloids both have important negative effects on the health of animals, often in a synergistic manner. Here, we show for the first time that parasites can increase host resistance to metalloid arsenic, focusing on a clonal population of brine shrimp from the contaminated Odiel and Tinto estuary in SW Spain. We studied the effect of cestodes on the response of Artemia to arsenic (acute toxicity tests, 24h LC50) and found that infection consistently reduced mortality across a range of arsenic concentrations. An increase from 25°C to 29°C, simulating the change in mean temperature expected under climate change, increased arsenic toxicity, but the benefits of infection persisted. Infected individuals showed higher levels of catalase and glutathione reductase activity, antioxidant enzymes with a very important role in the protection against oxidative stress. Levels of TBARS were unaffected by parasites, suggesting that infection is not associated with oxidative damage. Moreover, infected Artemia had a higher number of carotenoid-rich lipid droplets which may also protect the host through the "survival of the fattest" principle and the antioxidant potential of carotenoids. This study illustrates the need to consider the multi-stress context (contaminants and temperature increase) in which host-parasite interactions occur.
authors.affiliation: Department of Wetland Ecology, Estación Biológica de Doñana, (EBD-CSIC), Seville, Spain.
authors.forename: Marta I
authors.initials: MI
authors.lastname: Sánchez
authors.affiliation: Department of Wetland Ecology, Estación Biológica de Doñana, (EBD-CSIC), Seville, Spain.
authors.forename: Inès
authors.initials: I
authors.lastname: Pons
authors.affiliation: Department of Life Sciences, Marine and Environmental Sciences Centre (MARE), University of Coimbra, Coimbra, Portugal.|Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM-JCCM), Ciudad Real, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Martínez-Haro
authors.affiliation: Environmental Contamination and Ecological Health, Environmental Research Institute, University of the Highlands and Islands, Thurso, Scotland, United Kingdom.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Taggart
authors.affiliation: Department of Genetic and Evolutive Ecology, Center of Functional Ecology and Evolution (CEFE), National Centre for Scientific Research (CNRS), Montpellier, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Lenormand
authors.affiliation: Department of Wetland Ecology, Estación Biológica de Doñana, (EBD-CSIC), Seville, Spain.
authors.forename: Andy J
authors.initials: AJ
authors.lastname: Green
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001151:Arsenic / Q000633:toxicity*; D001156:Artemia / Q000187:drug effects / Q000469:parasitology* / Q000502:physiology; D002589:Cestoda / Q000502:physiology*; D057231:Climate Change; D006790:Host-Parasite Interactions; D050356:Lipid Metabolism; D018384:Oxidative Stress; D013030:Spain
chemical_list: D000975:Antioxidants; D001151:Arsenic