Blizzard Emily L, Davis Cheryl D, Henke Scott, Long David B, Hall Christopher A, Yabsley Michael J
Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 30602, USA.
J Parasitol. 2010 Dec;96(6):1128-33. doi: 10.1645/GE-2518.1. Epub 2010 Jul 8.
Baylisascaris procyonis is an intestinal nematode of raccoons (Procyon lotor) that can cause fatal larval migrans in numerous species of birds and mammals, including humans. Although this parasite has historically been absent in the southeastern United States, it has been found in isolated regions in the Appalachian Mountains and was recently documented in DeKalb County, Georgia. The first objective of the current study was to investigate the distribution and prevalence of B. procyonis in selected populations of raccoons in Georgia. Intestinal tracts of 312 raccoons from 25 Georgia counties were examined for B. procyonis. The only county where B. procyonis was detected was Clarke County, where 12 of 116 (10.3%) raccoons were infected. In Clarke County, significantly more juveniles (P = 0.049) were infected compared with adults, and no differences in prevalence were noted by sex, season of capture, or land use (rural vs. urban); however, significantly (P = 0.0370) higher worm burdens were found in infected raccoons from urban/suburban locations compared with rural areas. In addition, Toxascaris leonina , a morphologically similar ascarid, was found in 3 raccoons from Clarke County (n = 2) and Morgan County (n = 1). A second objective was to determine if sequence polymorphisms were associated with B. procyonis from different geographic regions. Because sequences from a single worm from Japan had been entered into GenBank, we obtained nematodes from Kentucky and Texas for comparison with our samples from Georgia. Sequence analysis of the 18S and 5.8S rRNA genes and the internal transcribed spacer (ITS) -1 and ITS-2 regions confirmed Georgia samples were B. procyonis. Although several polymorphic bases were observed within both ITS regions, none was associated with a particular geographic location. These data indicate that the distribution of B. procyonis within Georgia is increasing and only limited genetic variation is present in the rRNA and ITS gene regions among B. procyonis from the southern United States and introduced populations in Japan.
浣熊贝蛔虫是浣熊（北美浣熊）的一种肠道线虫，可在包括人类在内的众多鸟类和哺乳动物物种中引发致命的幼虫移行症。尽管这种寄生虫在美国东南部地区历史上并不存在，但已在阿巴拉契亚山脉的一些孤立区域被发现，最近在佐治亚州迪卡尔布县也有记录。本研究的首要目标是调查佐治亚州部分浣熊种群中浣熊贝蛔虫的分布和流行情况。对来自佐治亚州25个县的312只浣熊的肠道进行了浣熊贝蛔虫检测。唯一检测到浣熊贝蛔虫的县是克拉克县，在116只浣熊中有12只（10.3%）被感染。在克拉克县，与成年浣熊相比，幼年浣熊感染率显著更高（P = 0.049），且在性别、捕获季节或土地利用类型（农村与城市）方面未发现流行率差异；然而，与农村地区相比，城市/郊区感染浣熊的虫负荷显著更高（P = 0.0370）。此外，在来自克拉克县（n = 2）和摩根县（n = 1）的3只浣熊中发现了形态相似的狮弓蛔虫。第二个目标是确定序列多态性是否与来自不同地理区域的浣熊贝蛔虫相关。由于来自日本的一条单条线虫的序列已录入GenBank，我们从肯塔基州和得克萨斯州获取了线虫与我们来自佐治亚州的样本进行比较。对18S和5.8S rRNA基因以及内部转录间隔区（ITS）-1和ITS-2区域的序列分析证实佐治亚州的样本为浣熊贝蛔虫。尽管在两个ITS区域均观察到多个多态性碱基，但没有一个与特定地理位置相关。这些数据表明，浣熊贝蛔虫在佐治亚州的分布正在增加，并且在美国南部和日本引入种群的浣熊贝蛔虫的rRNA和ITS基因区域中仅存在有限的遗传变异。
