Cook Courtney A, Netherlands Edward C, Smit Nico J
Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa.
Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, 3000, Leuven, Belgium.
Parasit Vectors. 2016 Jun 16;9(1):347. doi: 10.1186/s13071-016-1600-8.
Within the African monitor lizard family Varanidae, two haemogregarine genera have been reported. These comprise five species of Hepatozoon Miller, 1908 and a species of Haemogregarina Danilewsky, 1885. Even though other haemogregarine genera such as Hemolivia Petit, Landau, Baccam & Lainson, 1990 and Karyolysus Labbé, 1894 have been reported parasitising other lizard families, these have not been found infecting the Varanidae. The genus Karyolysus has to date been formally described and named only from lizards of the family Lacertidae and to the authors' knowledge, this includes only nine species. Molecular characterisation using fragments of the 18S gene has only recently been completed for but two of these species. To date, three Hepatozoon species are known from southern African varanids, one of these Hepatozoon paradoxa (Dias, 1954) shares morphological characteristics alike to species of the family Karyolysidae. Thus, this study aimed to morphologically redescribe and characterise H. paradoxa molecularly, so as to determine its taxonomic placement.
Specimens of Varanus albigularis albigularis Daudin, 1802 (Rock monitor) and Varanus niloticus (Linnaeus in Hasselquist, 1762) (Nile monitor) were collected from the Ndumo Game Reserve, South Africa. Upon capture animals were examined for haematophagous arthropods. Blood was collected, thin blood smears prepared, stained with Giemsa, screened and micrographs of parasites captured. Haemogregarine morphometric data were compared with the data for named haemogregarines of African varanids. Primer set HepF300 and HepR900 was employed to target a fragment of the 18S rRNA gene and resulting sequences compared with other known haemogregarine sequences selected from the GenBank database.
Hepatozoon paradoxa was identified infecting two out of eight (25 %) V. a. albigularis and a single (100 %) V. niloticus examined. Phylogenetic analyses revealed that H. paradoxa clustered with the 'Karyolysus' clade, and not with those of reptilian Hepatozoon spp.
In addition to this being the first morphological and molecular characterisation of a haemogregarine within the African Varanidae, it is the first report of a species of Karyolysus infecting the monitor lizard family. Furthermore, this constitutes now only the third described and named Karyolysus species for which there is a nucleotide sequence available.
在非洲巨蜥科(Varanidae)中,已报道了两个血簇虫属。其中包括1908年米勒命名的5种肝簇虫属(Hepatozoon)和1885年丹尼列夫斯基命名的1种血簇虫属(Haemogregarina)。尽管已报道其他血簇虫属,如1990年佩蒂、朗道、巴卡姆和兰森命名的血变虫属(Hemolivia)以及1894年拉贝命名的核虫属(Karyolysus)寄生于其他蜥蜴科,但尚未发现它们感染巨蜥科。迄今为止,核虫属仅从蜥蜴科(Lacertidae)的蜥蜴中得到正式描述和命名,据作者所知,该属仅包括9个物种。仅在最近才完成了对其中两个物种使用18S基因片段的分子特征分析。迄今为止,已知来自南部非洲巨蜥的3种肝簇虫属物种,其中一种肝簇虫(Hepatozoon paradoxa,迪亚斯,1954年)与核虫科(Karyolysidae)物种具有相似的形态特征。因此,本研究旨在对肝簇虫进行形态学重新描述并进行分子特征分析,以确定其分类地位。
2002年从南非恩杜莫野生动物保护区采集了白喉巨蜥(Varanus albigularis albigularis,达丁)和尼罗河巨蜥(Varanus niloticus,林奈,1762年)的样本。捕获后检查动物是否有吸血节肢动物。采集血液,制作薄血涂片,用吉姆萨染色,进行筛查并拍摄寄生虫的显微照片。将血簇虫的形态测量数据与非洲巨蜥已知血簇虫的数据进行比较。使用引物对HepF300和HepR900靶向18S rRNA基因片段,并将所得序列与从GenBank数据库中选择的其他已知血簇虫序列进行比较。
在检查的8只白喉巨蜥中有2只(25%)和1只尼罗河巨蜥(100%)中发现感染了肝簇虫。系统发育分析表明,肝簇虫与“核虫属”分支聚类,而不与爬行动物肝簇虫属物种聚类。
这不仅是非洲巨蜥科内血簇虫的首次形态学和分子特征分析,也是核虫属物种感染巨蜥科的首次报道。此外,这现在仅构成第三个有核苷酸序列可用的已描述和命名的核虫属物种。