Shedding and serologic responses following primary and secondary inoculation of house sparrows (Passer domesticus) and European starlings (Sturnus vulgaris) with low-pathogenicity avian influenza virus

Abstract

Waterfowl and shorebirds are well-recognized natural reservoirs of low-pathogenicity avian influenza viruses (LPAIV); however, little is known about the role of passerines in avian influenza virus ecology. Passerines are abundant, widespread, and commonly come into contact with free-ranging birds as well as captive game birds and poultry. We inoculated and subsequently challenged house sparrows (Passer domesticus) and European starlings (Sturnus vulgaris) with wild-bird origin LPAIV H3N8 to evaluate their potential role in transmission. Oropharyngeal shedding was short lived, and was detected in more starlings (97.2%) than sparrows (47.2%; n=36 of each). Cloacal shedding was rare in both species (8.3%; n=36 of each) and no cage-mate transmission occurred. Infectious LPAIV was cultured from oropharyngeal and cloacal swabs and gastrointestinal and respiratory tissues from both species. Seroconversion was detected as early as 3 days post inoculation (d.p.i.) (16.7% of sparrows and 0% of starlings; n=6 each); 50% of these individuals seroconverted by 5 d.p.i., and nearly all birds (97%; n=35) seroconverted by 28 d.p.i. In general, pre-existing homologous immunity led to reduced shedding and increased antibody levels within 7 days of challenge. Limited shedding and lack of cage-mate transmission suggest that passerines are not significant reservoirs of LPAIV, although species differences apparently exist. Passerines readily and consistently seroconverted to LPAIV, and therefore inclusion of passerines in epidemiological studies of influenza outbreaks in wildlife and domestic animals may provide further insight into the potential involvement of passerines in avian influenza virus transmission ecology.

Experimental Infection of European Starlings (Sturnus vulgaris) and House Sparrows (Passer domesticus) with Pandemic 2009 H1N1 and Swine H1N1 and H3N2 Triple Reassortant Influenza Viruses

“…While the potential for peridomestic passerines to contribute to the maintenance, spread, or evolution of swine-adapted influenza A viruses within and among swine herds exists, results from our study of pandemic H1N1, swine-origin H1N1, and triple reassortant influenza viruses in Starlings and Sparrows indicate that these common passerines pose little risk as a source of transmission of swine influenza viruses to other wildlife, including conspecifics, as well as to livestock and humans. These results are consistent with a previous study in Starlings and Sparrows experimentally inoculated with a low pathogenicity avian influenza virus, in which low-level shedding was short-lived and there was no cage mate transmission (Nemeth et al, 2010).…”

Eurasian Tree Sparrows, Risk for H5N1 Virus Spread and Human Contamination through Buddhist Ritual: An Experimental Approach

“…Passerine species are known to be susceptible to HPAI H5N1 infection [9]–[16], even though their susceptibility can vary depending on the bird species or the viral strain. Natural infections were also described [12], [17]–[21].…”

Surveillance for highly pathogenic H5 avian influenza virus in synanthropic wildlife associated with poultry farms during an acute outbreak

“…While wild aquatic birds have long been considered the natural maintenance hosts of avian IAV8, increasing attention has been focused on synanthropic wildlife as spillover hosts that could act as bridge hosts, potentially capable of moving these viruses from natural maintenance hosts to poultry or between poultry farms. Previous studies of peridomestic mammals91011121314151617 and birds16181920212223242526272829303132 have provided strong evidence that a number of these species are able to shed high levels of some IAVs. Nonetheless, only a few studies101331 have examined the potential of any of these species to transmit influenza A viruses to poultry species.…”