Immune Responses of a Native and an Invasive Bird to Buggy Creek Virus (Togaviridae: Alphavirus) and Its Arthropod Vector, the Swallow Bug (Oeciacus vicarius)

Carol A Fassbinder-Orth,Virginia A Barak,Charles R Brown,Lark L Coffey

doi:10.1371/journal.pone.0058045

Carol A Fassbinder-Orth, Virginia A Barak + Show 2 more

Open Access

https://doi.org/10.1371/journal.pone.0058045

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Journal: PLoS ONE	Publication Date: Feb 27, 2013
Citations: 67	License type: CC BY 4.0

Affiliation: Creighton University, University of Tulsa

Abstract

Invasive species often display different patterns of parasite burden and virulence compared to their native counterparts. These differences may be the result of variability in host-parasite co-evolutionary relationships, the occurrence of novel host-parasite encounters, or possibly innate differences in physiological responses to infection between invasive and native hosts. Here we examine the adaptive, humoral immune responses of a resistant, native bird and a susceptible, invasive bird to an arbovirus (Buggy Creek virus; Togaviridae: Alphavirus) and its ectoparasitic arthropod vector (the swallow bug; Oeciacus vicarius). Swallow bugs parasitize the native, colonially nesting cliff swallow (Petrochelidon pyrrhonota) and the introduced house sparrow (Passer domesticus) that occupies nests in cliff swallow colonies. We measured levels of BCRV-specific and swallow bug-specific IgY levels before nesting (prior to swallow bug exposure) and after nesting (after swallow bug exposure) in house sparrows and cliff swallows in western Nebraska. Levels of BCRV-specific IgY increased significantly following nesting in the house sparrow but not in the cliff swallow. Additionally, house sparrows displayed consistently higher levels of swallow bug-specific antibodies both before and after nesting compared to cliff swallows. The higher levels of BCRV and swallow bug specific antibodies detected in house sparrows may be reflective of significant differences in both antiviral and anti-ectoparasite immune responses that exist between these two avian species. To our knowledge, this is the first study to compare the macro- and microparasite-specific immune responses of an invasive and a native avian host exposed to the same parasites.

Highlights

Different host species often vary considerably in their ability to immunologically resist certain parasites [1,2]
Specific antibody levels in birds at the primary study area were compared to samples from a Buggy Creek virus (BCRV) and the swallow bug- unexposed control group of house sparrows
Post-nesting BCRV-specific antibody levels displayed a trend of significance when compared to pre-nesting levels (P,0.079), and were significantly higher than the house sparrow control group (P,0.018)

Summary

Introduction

Different host species often vary considerably in their ability to immunologically resist certain parasites [1,2]. Invasive host species may introduce a new pathogen (with which the invasive has coevolved), causing naıve, native species to become susceptible hosts for the novel pathogen (the Novel Weapon Hypothesis [6,7]). In these cases, the invasive host may be at an advantage over the native hosts who have had no evolutionary history with the introduced parasite. On the other hand, when an invasive species invades a new environment, it may encounter a novel parasite and be a more susceptible host than those native hosts that have co-evolved with the parasite [8,9]

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