Wild aquatic birds are the main reservoir hosts harbouring the genetic pool of all influenza A viruses, including pandemic ones. Among waterbirds, wild ducks can contribute to perpetuate these viruses in a well-adapted host/parasite relationship [1]. The goal of this work was to determine how population parameters such as sex and age classes could affect the isolation prevalences of influenza A viruses in ducks trapped in a Mediterranean area during three crucial period of ducks’ biology. Viral RNA was extracted from cloacal swabs taken from 146 dabbling ducks trapped from October 2005 to September 2006 in Laguna di Orbetello WWF Oasis (Central Italy). Avian influenza viruses (AIVs) were detected by a one-step RT-PCR targeting the matrix gene [2] and RT-PCR positive samples were inoculated into specific-pathogen-free embryonated chicken eggs [3]. Harvested allantoic fluids were tested by hemagglutination assay [3] and ELISA test directed to viral nucleoprotein [4]. Chi-square test and Fisher's exact test were used to highlight significant differences in viral isolation prevalences related to ducks age, ducks sex, during an yearly sampling periods (fall migration, wintering period, post-reproductive period). RT-PCR and isolation prevalences for AIVs were 26% (38/146) and 9.6% (14/146), respectively. During the overall sampling period no age- and sex-related differences in virus isolation prevalences were detected. Considering each sampling period, significant differences were only found during the wintering season January–March 2006, when the juvenile ducks showed higher isolation prevalence than the adult ones. The particularly low temperatures recorded in north-eastern Europe during winter 2005-2006 [5] could have caused erratic movements of juvenile ducks, increasing the interaction among different bird subpopulations and the opportunity for virus exchanges. Our results confirm that the juvenile ducks play a key role in the movement of AIVs. Moreover, climatic variations may induce changes in the host species behavior affecting viral populations ecology.
Cotti C. , De Marco M.A. , Raffini E. , Donatelli I. , Delogu M. (2010). Effects of population parameters on yearly circulation of influenza A virus in wild ducks in Italy [10.1016/j.jbiotec.2010.08.034].
Effects of population parameters on yearly circulation of influenza A virus in wild ducks in Italy
COTTI, CLAUDIA;De Marco M. A.;DELOGU, MAURO
2010
Abstract
Wild aquatic birds are the main reservoir hosts harbouring the genetic pool of all influenza A viruses, including pandemic ones. Among waterbirds, wild ducks can contribute to perpetuate these viruses in a well-adapted host/parasite relationship [1]. The goal of this work was to determine how population parameters such as sex and age classes could affect the isolation prevalences of influenza A viruses in ducks trapped in a Mediterranean area during three crucial period of ducks’ biology. Viral RNA was extracted from cloacal swabs taken from 146 dabbling ducks trapped from October 2005 to September 2006 in Laguna di Orbetello WWF Oasis (Central Italy). Avian influenza viruses (AIVs) were detected by a one-step RT-PCR targeting the matrix gene [2] and RT-PCR positive samples were inoculated into specific-pathogen-free embryonated chicken eggs [3]. Harvested allantoic fluids were tested by hemagglutination assay [3] and ELISA test directed to viral nucleoprotein [4]. Chi-square test and Fisher's exact test were used to highlight significant differences in viral isolation prevalences related to ducks age, ducks sex, during an yearly sampling periods (fall migration, wintering period, post-reproductive period). RT-PCR and isolation prevalences for AIVs were 26% (38/146) and 9.6% (14/146), respectively. During the overall sampling period no age- and sex-related differences in virus isolation prevalences were detected. Considering each sampling period, significant differences were only found during the wintering season January–March 2006, when the juvenile ducks showed higher isolation prevalence than the adult ones. The particularly low temperatures recorded in north-eastern Europe during winter 2005-2006 [5] could have caused erratic movements of juvenile ducks, increasing the interaction among different bird subpopulations and the opportunity for virus exchanges. Our results confirm that the juvenile ducks play a key role in the movement of AIVs. Moreover, climatic variations may induce changes in the host species behavior affecting viral populations ecology.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
