Browsing by Subject "immunocompetence"

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  • Dickel, Franziska; Freitak, Dalial; Mappes, Johanna (2016)
    Hundreds of insect species are nowadays reared under laboratory conditions. Rearing of insects always implicates the risk of diseases, among which microbial infections are the most frequent and difficult problems. Although there are effective prophylactic treatments, the side effects of applied antibiotics are not well understood. We examined the effect of prophylactic antibiotic treatment on the overwintering success of wood tiger moth (Parasemia plantaginis) larvae, and the postdiapause effect on their life-history traits. Four weeks before hibernation larvae were treated with a widely used antibiotic (fumagillin). We monitored moths' survival and life-history traits during the following 10 mo, and compared them to those of untreated control larvae. Prophylactic antibiotic treatment had no effect on survival but we show effects on some life-history traits by decreasing the developmental time of treated larvae. However, we also revealed relevant negative effects, as antibiotic treated individuals show a decreased number of laid eggs and also furthermore a suppressed immunocompetence. These results implicate, that a prophylactic medication can also lead to negative effects on life-history traits and reproductive success, which should be seriously taken in consideration when applying a prophylactic treatment to laboratory reared insect populations.
  • Kortet, Raine; Lautala, Tiina; Kekalainen, Jukka; Taskinen, Jouni; Hirvonen, Heikki (2017)
    Hatchery-reared fish show high mortalities after release to the wild environment. Explanations for this include potentially predetermined genetics, behavioral, and physiological acclimation to fish farm environments, and increased vulnerability to predation and parasitism in the wild. We studied vulnerability to Diplostomum spp. parasites (load of eye flukes in the lenses), immune defense (relative spleen size) and antipredator behaviors (approaches toward predator odor, freezing, and swimming activity) in hatchery-reared juvenile Arctic charr (Salvelinus alpinus) using a nested mating design. Fish were exposed to eye-fluke larvae via the incoming water at the hatchery. Fish size was positively associated with parasite load, but we did not find any relationship between relative spleen size and parasitism. The offspring of different females showed significant variation in their parasite load within sires, implying a dam effect in the vulnerability to parasites. However, the family background did not have any effect on spleen size. In the mean sire level over dams, the fish from the bolder (actively swimming) families in the predator trials suffered higher loads of eye flukes than those from more cautiously behaving families. Thus, the results indicate potentially maternally inherited differences in vulnerability to eye-fluke parasites, and that the vulnerability to parasites and behavioral activity are positively associated with each other at the sire level. This could lead to artificial and unintentional selection for increased vulnerability to both parasitism and predation if these traits are favored in fish farm environments.
  • Pyöriä, Lari; Valtonen, Maarit; Luoto, Raakel; Gröönroos, Wilma; Waris, Matti; Heinonen, Olli J.; Ruuskanen, Olli; Perdomo , Maria (2021)
    Exercise-induced immune perturbations have been proposed to increase susceptibility toviral infections. We investigated the replication of persisting viruses as indicators of immune functionin elite cross-country skiers after ten months of sustained high-performance exercise. The virusesevaluated, nine human herpesviruses (HHVs) and torque teno virus (TTV), are typically restrainedin health but replicate actively in immunosuppressed individuals. We collected sera from 27 Finnishelite cross-country skiers at the end of the competition’s season and 27 matched controls who performmoderate exercise. We quantified all the HHVs and—TTV via highly sensitive qPCRs. To verifyequal past exposures between the groups, we assessed the IgG antibody prevalences toward HHV-4(Epstein–Barr virus, EBV) and HHV-5 (human cytomegalovirus, HCMV). We found equal TTV DNAprevalences in athletes (63%) and controls (63%) and loads with respective geometric means of1.7×103and 1.2×103copies/mL of serum. Overall, the copy numbers were low and consistentwith those of healthy individuals. Neither of the groups presented with herpesvirus viremia despitesimilar past exposures to HHVs (seroprevalences of EBV 70% vs. 78% and HCMV 52% vs. 44%in athletes and controls, respectively). We found no evidence of increased replication of persistentviruses in elite athletes, arguing against impaired viral immunity due to high-performance exercise