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Biting insects are likely the most common method of transmission (Akey etВ al. While these lesions are not normally visible unless the interior of the oral cavity is examined, they may produce a systemic and often fatal infection. A diphtheritic form of pox also occurs when the virus spreads to mucosal membranes of the mouth or upper respiratory tract. As avian pox lesions heal, permanent deformities including loss of toes or feet can occur (hereafter called old pox).

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This typically slow-developing disease forms localized cutaneous lesions (hereafter called active pox) on the skin of toes, legs, and head of infected hosts (van Riper and Forrester 2007). 2002, Atkinson and LaPointe 2009).ДЄvian pox virus is mechanically transmitted on the penetrating mouthparts of arthropods that feed on infectious blood or tissues of their avian hosts (Kligler etВ al. In particular, ornithologists reported dramatic declines in bird abundance following introduction of the virus in the late 1800s (van Riper etВ al. 2015), the evidence that avian pox played a significant role in this decline has been largely circumstantial.

1986, Atkinson and Samuel 2010, LaPointe etВ al. While avian malaria has been extensively studied (Warner 1968, van Riper etВ al. The introduction of a mosquito vector, Culex quinquefasciatus, and two vector-borne avian diseases, avian malaria ( Plasmodium relictum) and avian pox ( Avipoxvirus spp.), have been implicated as important factors responsible for the drastic decline, limited altitudinal distribution, and extinction of native Hawaiian birds over the last century (Warner 1968, van Riper etВ al. 1987), but currently face one of the highest rates of extinction in the world (Jacobi and Atkinson 1995, Buchanan etВ al. Native Hawaiian forest birds, particularly the endemic Hawaiian honeycreepers (Drepanidinae), are frequently cited as a premier example of adaptive radiation and speciation (Freed etВ al. The Hawaiian Islands have a highly endemic avifauna that evolved in response to geographical isolation, diverse topography ranging from sea level to high mountains, and habitats ranging from tropical lowland rain forests to subalpine tundra over distances as small as 40В km (Giambelluca and Schroeder 1998). Because pox infection can be assessed visually, and birds have a high recovery rate, this disease may be a sensitive indicator of the seasonal and annual risk of transmission of malaria in HawaiК»i.

Birds with chronic malaria infection were more likely to have both active pox infection and healed pox lesions suggesting a synergistic interaction that may influence the evolution of pox virulence.

Contrary to our expectations, we found no direct evidence that pox is a substantial mortality factor in any of the three native bird species we studied. Most native Hawaiian birds recovered from pox infection within 6В months frequently without permanent lesions. Seasonal and elevation patterns of pox infection are like those for avian malaria, strongly implicating mosquito vectors, rather than other biting arthropods or contact transmission, as the primary source of transmitting both diseases. These seasonal changes occurred in low- and mid-elevation forests, but not in high elevations where pox infection was low. We also found seasonal changes in pox prevalence throughout the annual cycle typically increasing from spring through summer, peaking in fall, and declining in winter. Pox infection rates were typically highest in low-elevation forests, followed by mid-elevation forests, and lowest in high-elevation forests. We also used multi-state capture-recapture (longitudinal) models to estimate pox infection rates, recovery rates, and potential pox-related mortality. Our goal was to understand how species, season, elevation, malaria infection, and other biological characteristics influenced pox infection in К»Apapane, HawaiК»i К»Amakihi, К»IК»iwi, and Japanese White-eye across low-, mid-, and high-elevation forests on the island of HawaiК»i. We conducted four longitudinal studies of 3вЂ“7В yr in length and used generalized linear models to evaluate cross-sectional prevalence of active pox infection and individuals with healed deformities that had recovered from pox. Despite the purported role of avian pox ( Avipoxvirus spp.) in the decline of endemic Hawaiian birds, few studies have been conducted on the dynamics of this disease, its impact on free-living avian populations, or its interactions with avian malaria ( Plasmodium relictum).