Pathogenicity of avian malaria in experimentally-infected Hawaii Amakihi
Pathogenicity of avian malaria in experimentally-infected Hawaii Amakihi
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DOI：
10.7589/0090-3558-36.2.197
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发表时间：
2000-04-01
影响因子：
1.3
通讯作者：
Iko, WM
中科院分区：
文献类型：
--
作者：
Atkinson, CT;Dusek, RJ;Iko, WM
据信，将禽疟疾（残留疟原虫）和蚊子（致倦库蚊）引入夏威夷群岛（美国）对夏威夷本地食蜜鸟（Drepanidinae）的减少和灭绝起了重要作用。这种引入的疾病被认为是限制1 200米以下海拔地区的采蜜鸟恢复的主要因素之一，那里的原生森林栖息地仍然相对完整。为数不多的几种分布在海拔较广的采蜜鸟之一是夏威夷山蜂（Hemignathus virens）。我们测量了发病率和死亡率在实验感染的夏威夷Amakihi，被抓获的高海拔，干旱的栖息地，高于目前的范围内的蚊子载体。暴露于单一感染性蚊虫叮咬的鹅膏蕈蚊死亡率为65%（13/20）。在60天的实验过程中，所有受感染的鸟的食物消耗量显著下降，体重相应减轻。死于疟疾的鸟类的肉眼和显微镜下病变包括脾脏和肝脏的肿大和变色以及高达50%的循环红细胞的寄生虫血症。实验感染的amakihi的死亡率与在Apapane（血吸虫）中观察到的死亡率相似，但低于在类似条件下用相同寄生虫分离株感染的Iiwi（球虫）中观察到的死亡率。我们的结论是，目前的海拔和地理分布的夏威夷蜜是由相对易感性禽疟疾。
The introduction of avian malaria (Plasmodium relictum) and mosquitoes (Culex quinquefasciatus) to the Hawaiian Islands (USA) is believed to have played a major role in the decline and extinction of native Hawaiian honeycreepers (Drepanidinae). This introduced disease is thought to be one of the primary factors limiting recovery of honeycreepers at elevations below 1,200 m where native forest habitats are still relatively intact. One of the few remaining species of honeycreepers with a wide elevational distribution is the Hawaii Amakihi (Hemignathus virens). We measured morbidity and mortality in experimentally-infected Hawaii Amakihi that were captured in a high elevation, xeric habitat that is above the current range of the mosquito vector. Mortality among amakihi exposed to a single infective mosquito bite was 65% (13/20). All infected birds had significant declines in food consumption and a corresponding loss in body weight over the 60 day course of the experiment. Gross and microscopic lesions in birds that succumbed to malaria included enlargement and discoloration of the spleen and liver and parasitemias as high as 50% of circulating erythrocytes. Mortality in experimentally-infected amakihi was similar to that observed in Apapane (Himatione sanguinea and lower than that observed in Iiwi (Vestiaria coccinea) infected under similar conditions with the same parasite isolate. We conclude that the current elevational and geographic distribution of Hawaiian honeycreepers is determined by relative susceptibility to avian malaria.