Data from: The epidemiology of avian pox and interaction with avian malaria in Hawaiian forest birds

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). We conducted four longitudinal studies of 3-7 years 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. Our goal was to understand how species, season, elevation, malaria infection, and other biological characteristics influenced pox infection in ‘Apapane, Hawai`i ‘Amakihi, ‘I‘iwi, and Japanese White-eye across low-, mid-, and high-elevation forests on the island of Hawai`i. We also used multi-state capture-recapture (longitudinal) models to estimate pox infection rates, recovery rates, and potential pox-related mortality. Pox infection rates were typically highest in low-elevation forests, followed by mid elevation, and lowest in high-elevation forests. 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. These seasonal changes occurred in low- and mid-elevation forests, but not in high elevations where pox infection was low. 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. Most native Hawaiian birds recovered from pox infection within 6 months; frequently without permanent lesions. 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. 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. 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 Hawai`i.

尽管禽痘（Avipoxvirus spp.）被认为参与了夏威夷特有鸟类的种群衰退过程，但目前针对该疾病的传播动态、其对野生鸟类种群的影响，以及与禽疟疾（Plasmodium relictum）的互作机制的研究仍较为匮乏。
本研究实施了4项为期3~7年的纵向研究（longitudinal studies），通过广义线性模型（generalized linear models）评估活动性禽痘感染的横断面患病率（cross-sectional prevalence），以及从痘病康复后遗留愈合畸形的个体占比。本研究旨在明确物种、季节、海拔、疟原虫感染状态及其他生物学特征，对夏威夷岛低、中、高海拔森林中‘Apapane、Hawai`i ‘Amakihi、‘I‘iwi与日本绣眼鸟（Japanese White-eye）禽痘感染情况的影响。此外，本研究还采用多状态标记重捕（纵向）模型（multi-state capture-recapture models）估算禽痘感染率、康复率及潜在的痘病相关死亡率。
研究结果显示，禽痘感染率通常在低海拔森林中最高，其次为中海拔森林，高海拔森林的感染率最低。研究同时发现，禽痘患病率在全年周期中呈现季节动态：通常自春季至夏季逐步升高，秋季达到峰值，冬季则逐渐下降。这类季节变化仅见于低海拔与中海拔森林，在感染率本就较低的高海拔森林中并未出现。
禽痘感染的季节与海拔分布模式与禽疟疾高度一致，这强烈提示蚊媒（mosquito vectors）是这两种疾病的主要传播媒介，而非其他吸血节肢动物（biting arthropods）或接触传播（contact transmission）途径。大多数夏威夷本土鸟类可在6个月内从禽痘感染中康复，且通常不会留下永久性病灶。与研究预期相悖的是，本研究未发现直接证据证明禽痘是所研究的3种本土鸟类的主要致死诱因。慢性疟原虫感染的个体更易同时出现活动性禽痘感染与愈合后的痘病病灶，这提示二者存在协同互作（synergistic interaction），或可影响痘病毒的毒力（virulence）演化。由于禽痘感染可通过肉眼直观评估，且鸟类康复率较高，该疾病或可作为夏威夷地区禽疟疾年度与季节性传播风险的敏感指示指标。