Morphological and molecular identification of a new record species of Heterakis from Rattus norvegicus in China

doi:10.12140/j.issn.1000-7423.2025.06.013

Abstract

Abstract:

Objective To characterize the nematode specimens collected from large intestines of wild Rattus norvegicus in Shijiazhuang City by means of morphological and molecular biological techniques assays. Methdos Nematodes were sampled from large intestines of wild R. norvegicus in Gaocheng District, Shijiazhuang City, Hubei Province, and the morphological characteristics of nematodes were examined using light and scanning electron microscop to identify the nematode species. A female worm and a male worm were sampled for extraction of genomic DNA, and internal transcribed spacer 1 (ITS-1) and mitochondrial cytochrome c oxidase subunit 1 (cox1) genes were amplified. Following sequencing of amplification products, phylogenetic trees were created using Bayesian inference and maximum likelihood methods. Results A total of 35 nematodes were identified, including 16 males and 19 females. The worms were small and cylindrical, tapered at both ends. The thin cuticles exhibited fine and transverse striations and lateral alae, with the latter originating from the pharyngeal region. The head featured three well-developed lips, including a dorsal lip with two papillae and two ventrolateral lips, each with one papilla. The anterior esophagus was narrow and cylindrical, expanding posteriorly into a bulb. The body length was 7.083 mm to 9.708 mm in males and 9.541 mm to 12.208 mm in females. Males were further characterized by two spicules of approximately equal length (0.250 mm to 0.310 mm) and nine pairs of caudal papillae. The vulva of female worms was situated in the posterior body region, surrounded by 3 to 5 cuticular folds. The tail terminated in a slender point adorned with a pair of terminal papillae and the distance from the anus to the tail tip measured 0.916 mm to 1.083 mm. The nematode eggs were elliptical in shape, with a length measuring 0.050 mm to 0.058 mm and a width measuring 0.033 mm to 0.041 mm. Sequencing revealed that the sequence of the ITS-1 gene was 430 bp in length (GenBank accession No. PX622390), and shared 99.91% similarity with Heterakis dahomensis (GenBank accession No. JX845277) and 82.4% to 90.3% similarity with other 6 Heterakis species. The sequence of the cox1 gene was 345 bp in length (GenBank accession No. PX622389), and shared 82.0% to 96.7% similarity with other 7 Heterakis species. Phylogenetic analysis based on the cox1 sequence of Heterakis revealed that nematode obtained from this study was closely related to H. spumosa but independent of each other, and was distantly related to other species of Heterakis. Phylogenetic analysis based on the ITS-1 gene sequence showed that the nematode sampled from this study was most closely related to H. dahomensis, and was clustered with Heterakis spumosa into a clade, but was distantly to other species of Heterakis. Conclusion Based on morphological characteristics, gene sequencing, and phylogenetic analysis, the nematode obtained from this study was identified as H. dahomensis, which is a newly recorded species in China.

Key words: Heterakis, Rattus norvegicus, Morphological identification, Molecular identification, Phylogenetic tree

CLC Number:

R383.19

JÜ Huidong, LI Yang, JIAN Rui, DU Xin, SUN Jing, YAN Zihan, MENG Jiaxuan, LIU Shanshan, ZHAI Shiyong. Morphological and molecular identification of a new record species of Heterakis from Rattus norvegicus in China[J]. CHINESE JOURNAL OF PARASITOLOGY AND PARASITIC DISEASES, 2025, 43(6): 835-842.

Figures/Tables 7

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5

Fig. 6

Fig. 7

References 24

[1]	Yousaf MA, Sun YN, Chen HX, et al. Morphology, complete mitochondrial genome and molecular phylogeny of Heterakis pucrasia sp. n. (Nematoda ∶ Ascaridida) from the koklass pheasant Pucrasia macrolopha (Lesson) (Galliformes ∶ Phasianidae) in Pakistan[J]. Front Vet Sci, 2025, 12: 1519092.
[2]	Smales LR. Two new species of the genus Heterakis (Heterakidae) from the genera Echymipera, Isoodon and Perameles (Peramelidae), bandicoots from Papua New Guinea and Australia[J]. Acta Parasitol, 2023, 68(4): 782-792.
[3]	Upadhyay SK. Morphotaxometry of a new roundworm Heterakis equispiculis n.sp. (Nematoda ∶ Heterakidae) from rodents of Bundelkhand Region at Uttar Pradesh, India[J]. Proc Zool Soc, 2019, 72(2): 171-179.
[4]	Menezes RC, Tortelly R, Gomes DC, et al. Nodular typhlitis associated with the nematodes Heterakis gallinarum and Heterakis isolonche in pheasants: frequency and pathology with evidence of neoplasia[J]. Mem Inst Oswaldo Cruz, 2003, 98(8): 1011-1016.
[5]	Li HC. Report on a collection of parasitic nematodes, mainly from North China. part Ⅰ. filarioidea[J]. Parasitology, 1933, 25(2): 192-223.
[6]	Chin TH. On helminth parasites of rats in Kweiyang[J]. Chin Med J, 1939, 56(6): 548-558.
[7]	徐?南. 广东几种鸟类寄生线虫的研究[J]. 动物学报, 1957, 3(1): 47-78, 103-111.
	Xu HN. Studies on some parasitic nematodes of birds in Guangdong Province[J]. Acta Zool Sin, 1957, 3(1): 47-78, 103-111. (in Chinese)
[8]	徐?南. 南京脊椎动物寄生线虫志略[J]. 动物学报, 1960, 6(1): 101-108, 112-113, 162-167.
	Xu HN. Notes on parasitic nematodes of vertebrates in Nanjing[J]. Acta Zool Sin, 1960, 6(1): 101-108, 112-113, 162-167. (in Chinese)
[9]	吴淑卿, 沈守训. 海南岛鸟类寄生线虫的研究及一新种的记述[J]. 动物分类学报, 1966(1): 19-24.
	Wu SQ, SHEN SX. Notes on the parasitic nematodes of birds from Hainan island with description of a new species[J]. Acta Zootaxonomica Sin, 1966(1): 19-24. (in Chinese)
[10]	尹文真. 云南省临沧专区鸟兽寄生蠕虫的研究Ⅱ. 兽类寄生线虫[J]. 动物学报, 1973, 19(4): 354-364.
	Yin WZ. Helminthes of birds and wild animals from Lin-tsan prefecture, Yunnan Province, China Ⅱ. parasitic nematodes of mammals[J]. Acta Zool Sin, 1973, 19(4): 354-364. (in Chinese)
[11]	尹文真, 张乃新. 北京地区啮齿类和食虫类的寄生线虫[J]. 动物分类学报, 1981, 6(1): 16-21.
	Yin WZ, Zhang NX. On some parasitic nematodes from rodents and insectivor in Peking, China[J]. Acta Zootaxonomica Sin, 1981, 6(1): 16-21. (in Chinese)
[12]	汪溥钦. 福建尖尾类线虫的研究[J]. 动物分类学报, 1980, 5(3): 242-252.
	Wang PQ. Studies on some new nematodes of the suborder oxyurata from Fujian, China[J]. Acta Zootaxonomica Sin, 1980, 5(3): 242-252. (in Chinese)
[13]	汪溥钦, 蒋学良. 四川省脊椎动物寄生蠕虫区系二、鼠类寄生蠕虫[J]. 四川动物, 1986, 5(3): 2-8.
	Wang PQ, Jiang XL. Studies on the helminth fauna of vertebrate in Sichuan. part 2. helminths of insectivora and Rodentia[J]. Sichuan J Zool, 1986, 5(3): 2-8. (in Chinese)
[14]	张路平, 兰敬国. 灰斑角雉寄生异刺属线虫的研究[J]. 河北师范大学学报, 1993, 17(2): 74-77.
	Zhang LP, Lan JG. Study on the genus Heterakis dujardin, 1845, from grimson-bellied Tragopan[J]. J Hebei Norm Univ Nat Sci, 1993, 17(2): 74-77. (in Chinese)
[15]	史梅青, 张莉, 张路平. 山西和陕西两省鸟类寄生异刺属线虫的研究 (线虫纲 ∶ 异刺科)[J]. 四川动物, 2010, 29(4): 527-535.
	Shi MQ, Zhang L, Zhang LP. Study on some species of the genus Heterakis (Nematoda ∶ Heterakidae) from birds in Shanxi and Shaanxi, China[J]. Sichuan J Zool, 2010, 29(4): 527-535. (in Chinese)
[16]	剧慧栋, 马宁, 菅蕊, 等. 褐家鼠寄生鼠异刺线虫形态描述与分子鉴定[J]. 医学动物防制, 2019, 35(9): 873-875, 879.
	Ju HD, Ma N, Jian R, et al. Morphological description and molecular identification of Heterakis spumosa from Rattus norvegicus[J]. J Med Pest Control, 2019, 35(9): 873-875, 879. (in Chinese)
[17]	Smales LR. The gastrointestinal helminths of Rattus giluwensis and Rattus novaeguineae (Rodentia ∶ Muridae) with descriptions of two new species (nematoda) from Papua new Guinea[J]. Comp Parasitol, 2016, 83(2): 162-172.
[18]	刘路瑶, 杨聪山, 章翔, 等. 孔雀源异刺线虫的形态学特征及分子鉴定[J]. 中国寄生虫学与寄生虫病杂志, 2021, 39(6): 816-820, 831.
	Liu LY, Yang CS, Zhang X, et al. Morphological characteristics and molecular identification of Heterakis sp. peacock origin[J]. Chin J Parasitol Parasit Dis, 2021, 39(6): 816-820, 831.
[19]	Thompson JD, Gibson TJ, Plewniak F, et al. The CLUSTAL_X windows interface: Flexible strategies for multiple sequence alignment aided by quality analysis tools[J]. Nucleic Acids Res, 1997, 25(24): 4876-4882.
[20]	Tamura K, Stecher G, Peterson D, et al. MEGA6: Molecular evolutionary genetics analysis version 6.0[J]. Mol Biol Evol, 2013, 30(12): 2725-2729.
[21]	Ronquist F, Teslenko M, van der Mark P, et al. MrBayes 3.2: Efficient Bayesian phylogenetic inference and model choice across a large model space[J]. Syst Biol, 2012, 61(3): 539-542.
[22]	Inglis WG. The comparative anatomy and systematic significance of the head in the nematode family Heterakidae[J]. Proc Zool Soc Lond, 1957, 128(1): 133-144.
[23]	del Rosario Robles M, Navone GT, Villafa?e IEG. New morphological details and first records of Heterakis spumosa and Syphacia muris from Argentina[J]. Comp Parasitol, 2008, 75(1): 145-149.
[24]	Ribas A, de Bellocq JG, Ros A, et al. Morphometrical and genetic comparison of two nematode species: H. spumosa and H. dahomensis (Nematoda, Heterakidae)[J]. Acta Parasitol, 2013, 58(3): 389-398.