(1) Our revised manuscript submitted for review in Physiological and Biochemical Zoology was accepted for publication. We will be back when the online early version is available. Till then, below you can find the abstract of the study. See also News #32 for further details.
Pap PL, Sesarman A, Vágási CI, Buehler DM, Pătraș L, Versteegh MA and Banciu M 2014. No Evidence for Parasitism-linked Changes in Immune Function or Oxidative Physiology over the Annual Cycle of an Avian Species. Physiological and Biochemical Zoology (in press)
Abstract: Temporally changing environmental conditions occur over most parts of the world and can exert strong pressure on the immune defense of organisms. Seasonality may result in changes in physiological traits over the year, and such changes may be essential for the optimization of defense against infections. Evidence from field and laboratory studies suggest links between environmental conditions, such as infection risk, and the ability of animals to mount an immune response or to overcome infections; however the importance of parasites in mediating seasonal change in immune defense is still debated. In this study, we test the hypothesis that seasonal change in immune function and connected physiological traits are related to parasite infection. We sampled captive house sparrows (Passer domesticus) bimonthly over 14 months and compare the annual variation of 12 measures of condition, immune function, antioxidant status and oxidative damage among birds naturally infested with coccidians or medicated against these parasites. We found significant variation in 10 out of 12 traits over the year. However, we found little support for the parasite-mediated change in immune functions and oxidative status in captive house sparrows. Of the 12 measures, only one was slightly affected by the parasite treatment. In support of the absence of any effect of coccidians on the annual profile of the condition and physiological traits, we found no consistent relationships between the intensity of infestation and these response variables over the year. Our results show that chronic coccidian infections have limited effect on the seasonal changing of physiological traits, and that the patterns of these measures are probably more affected by acute infection and/or by virulent parasite strains.