Increasing prevalence of avian poxvirus in Darwin's finches and its effect on male pairing success

Abstract

. Increasing prevalence of avian poxvirus in Darwin's finches and its effect on male pairing success. Á/ J. Avian Biol. 37: 69 Á/76.Island populations harbour a comparatively species-poor pathogen community, often resulting in naïve host species that experience compromised immunity when faced with novel diseases. Over 95% of the Galápagos avifauna have survived 400 years of human settlement, yet currently face threats due to introduced diseases such as avian poxvirus. On Hawaii, declining populations of birds and even some extinctions have been attributed to avian poxvirus, and hence, identifying the prevalence and fitness costs of avian poxvirus on the Galápagos is a conservation priority. Surveys of avian poxvirus in Darwin's finches on Santa Cruz Island between 2000 and 2004 found a 33% annual increase in the prevalence of pox lesions in ground finches. Comparisons of pox prevalence on three islands (Santa Cruz, Floreana, and Isabela) were made in 2004, which indicated significant variation in pox prevalence across islands (Isabela/Santa Cruz/Floreana). Darwin's finch species were found to be differentially affected by poxvirus, with a higher prevalence in ground finches than in tree finches. There was a significant effect of habitat, even within species, with higher prevalence in the lowlands than highlands. Pox prevalence was not correlated with sex or body condition. However, male small ground finches Geospiza fuliginosa with evidence of pox were less likely to have a mate (16.6% paired) compared with males without pox (77% paired), indicating fitness costs associated with poxvirus infection.

Causes of Mortality of Wild Birds Submitted to the Charles Darwin Research Station, Santa Cruz, Galápagos, Ecuador from 2002–2004

“…data). Kleindorfer and Dudaniec (2006) observed a 33% increase in suspected (visual diagnosis) pox-like lesions between 2000 and 2004 in Santa Cruz ground finches and higher apparent lesion prevalence in lowland, as compared to highland, habitats from Isabela, Floreana, and Santa Cruz Islands. The origin of poxvirus infection in Galá pagos-endemic birds is unknown, but recent genetic studies suggest that it is most closely related to canarypox viruses (Thiel et al, 2005).…”

Worldwide Phylogenetic Relationship of Avian Poxviruses

“…Effects of avian pox on wild bird species can also be severe. The infection may produce several negative effects including elevated predation among affected birds (8), secondary infections, trauma, reduced male mating success (9) and death (10). The lifestyle of wild birds allows avian poxviruses to reach new hosts through bird migration, species introductions, and habitat change.…”

Diversity of avipoxviruses in captive-bred Houbara bustard

“…In wild birds, the infection can compromise survival and breeding success by decreasing the ability to escape predators [9], to fledge and rear chicks [10], by impairing the pairing success [11] or by increasing mortality [12]. Recently, emergence of APV infections in great tits in Europe and especially in the UK has been described and could represent a threat for the species [13,14].…”