High costs of infection: Alphavirus infection reduces digestive function and bone and feather growth in nestling house sparrows (Passer domesticus)

Abstract

Increasingly, ecoimmunology studies aim to use relevant pathogen exposure to examine the impacts of infection on physiological processes in wild animals. Alphaviruses are arthropod-borne, single-stranded RNA (ssRNA) viruses (“arboviruses”) responsible for millions of cases of human illnesses each year. Buggy Creek virus (BCRV) is a unique alphavirus that is transmitted by a cimicid insect, the swallow bug, and is amplified in two avian species: the house sparrow (Passer domesticus) and the cliff swallow (Petrochelidon pyrrhonota). BCRV, like many alphaviruses, exhibits age-dependent susceptibility where the young are most susceptible to developing disease and exhibit a high mortality rate. However, alphavirus disease etiology in nestling birds is unknown. In this study, we infected nestling house sparrows with Buggy Creek virus and measured virological, pathological, growth, and digestive parameters following infection. Buggy Creek virus caused severe encephalitis in all infected nestlings, and the peak viral concentration in brain tissue was over 34 times greater than any other tissue. Growth, tissue development, and digestive function were all significantly impaired during BCRV infection. However, based on histopathological analysis performed, this impairment does not appear to be the result of direct tissue damage by the virus, but likely caused by encephalitis and neuronal invasion and impairment of the central nervous system. This is the first study to examine the course of alphavirus diseases in nestling birds and these results will improve our understanding of age-dependent infections of alphaviruses in vertebrate hosts.

Experimental removal of nematode parasites increases growth, sprint speed, and mating success in brown anole lizards

“…Growth costs of parasitism have been found in a variety of taxa, including birds (Fassbinder‐Orth et al, 2018 ; O'Brien & Dawson, 2007 ), amphibians (Finnerty et al, 2017 ), mammals (Sacks & Blejwas, 2000 ; Stien et al, 2002 ), fish (Hansen et al, 2006 ; Hoffnagle et al, 2006 ), arthropods (Botto‐Mahan et al, 2017 ; Polak, 1998 ), annelids (Field & Michiels, 2005 ), and molluscs (O'Connell‐Milne et al, 2016 ). These studies also encompass a broad range of parasite types, suggesting that growth reduction is a general cost of parasitism.…”

Numbers of invasive House Sparrows Passer domesticus in a rural landscape of Limpopo province, South Africa

“…Based on these findings, it is recommend that additional studies be undertaken in rural landscapes outside the natural range, because they can harbour large numbers of House Sparrows. Feeding behaviour, competition by this species with native species, and impacts on human livelihoods through the possible transmission of diseases, because they are known to harbour zoonotic diseases transferable to humans and other birds (Zhu et al 2010;Fassbinder-Orth et al 2018) must be considered. This is crucial, because the House Sparrow consumes human stored grain and fouls on buildings (TCS pers.…”

“…House Sparrows are also known to harass, compete for nesting sites, and displace native species, such as Bluebirds Sialia currucoides, American Cliff Swallows Petrochelidon pyrrhonota, Purple Martins Progne subis, and House Wrens Troglodytes aedon (Pimentel et al 2005;Leasure 2013;Baker et al 2014). Furthermore, the species has been reported to be a carrier of ~29 diseases, including Alphavirus and Newcastle disease virus that can be transmitted to humans and livestock (Pimentel et al 2005;Zhu et al 2010;Fassbinder-Orth et al 2018). However, studies on diseases or viruses found on other species shown to originate from House Sparrows are limited.…”

Emerging and Novel Viruses in Passerine Birds

“…The main known avian reservoirs are two passerines, colonially nesting American cliff swallow ( Petrochelidon pyrrhonota ) and house sparrow, that nest in cliff swallow colonies. BCRV can cause encephalitic infections, especially in chicks [ 230 ], and selectively infects brain tissue [ 231 ]. The prevalence of naturally-acquired BCRV is lower in nestling cliff swallows (~2%) than in nestling house sparrows (20%) [ 232 ].…”