Serpentirhabdias orientalis		Contents		Rev 09/28/2026
Lungworm of snakes		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Serpentirhabdias Menu				Ecosystem Functions and Services
		Distribution		Management
Return to Rhabdiasidae Menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Classification:

Synonyms:

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Morphology and Anatomy:

Serpentirhabdias orientalis is distinguished from other Sepentirhabias species by a combination of characters: the elongate body (up to 5858 um), 6 onchia, a triangular oral opening, and a thin cuticle. Other differences include tail length, distance of the excretory pore from the anterior and the number of eggs in the uteri

Characteristics:

• Body elongate with anterior end rounded and posterior end tapering (Figures 1A and 3A).
• Cuticle thin and smooth
• Oral opening triangular and wide in apical view; six lips similar in shape and size, arranged in 2 lateral groups of 3, each lip with small, cone-like papillae
• Buccal cavity almost as deep as wide, six onchia project outward from top of radial muscle in esophagostome
• Esophagus representing 7 % of body length, with an esophageal bulb.
• Tail 4-7% of body length.

Female:

• Amphidelphic, vulva vlose to mid-body
• Uteri containing eggs.

Ref: Charoennitiwat et al., 2025

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Distribution:

Serpentirhabdias orientalis is a snake lungworm discovered in the respir tory organs of the monocled cobra (Naja kaouthia) in Thailand. This is first record of a Serpentirhabdias species in the Oriental Region (Southeast Asia) and in an elapid snake.

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Feeding:

   Tissues of lungs, trachea and heart.

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Biology and Ecology:

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Life Cycle:

The monocled cobra, Naja kaouthia is widely distributed in the Orient. All species of this genus are venomous and deadly. The snakess are active predators of amphibians, reptiles, small mammals, and birds, which facilitates its role as a host for parasitic helminths. A survey revealed a high prevalence of helminths in the lung, trachea and heart of tmonocled cobras captured from central Thailand. Only parasitic female nematodes were found in the cobras; males are reportedly free-living (Charoennitiwat et al., 2025).

Ecophysiological Parameters:

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Ecosystem Functions and Services:

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Management:

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References:

Charoennitiwat,V., Tongpon, S., Suksuwan, P., Chaisiri., K, Laoungbua, P., Tawan, T., Thaenkham, U., Ratnarathorn, N. 2025. Serpentirhabdias orientalis sp. nov. (nematoda: rhabdiasidae), a new lungworm species in naja kaouthia from Thailand: the first record of the genus from the oriental region and an elapid snake. Parasitology 152, 239-250. https://doi.org/ 10.1017/S0031182025000174

Dias-Souza, M.R., Tkach, V.V., Rebelo, G.L., Neves, J.K.S., Tavares-Costa, L.F.S., Jesus, R.F., Santos, A.S., Trindade, L.F.F., Felix, A.J.S., de Vasconcelos, M.F.T. 2026. Description and phylogenetic position of a new Serpentirhabdias (Nematoda: Rhabdiasidae) from Hydrodynastes gigas (Serpentes: Colubroidea) in Pantanal, Brazil. Parasitology International 14:103297 2026/10/01/ 1383-5769 https://doi.org/10.1016/j.parint.2026.103297

Morais, D.H., Aguiar, A., Muller, M.I., Narciso, R.B., Da Silva, L.A.D. and Da Silva, R.J. 2017. Morphometric and phylogenetic analyses of Serpentirhabdias orientalis n. sp. (Nematoda: Rhabdiasidae) from the lancehead snake Bothrops moojeni Hoge, 1966 (Reptilia: Serpentes: Viperidae) in Brazil.  Journal of Helminthology 91: 360-370

Tkach, V.V., Kuzmin, Y. and Snyder, S.D. 2014. Molecular insight into systematics, host associations, life cycles and geographic distribution of the nematode family Rhabdiasidae. International Journal for Parasitology 44:273-284.

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Revised by Howard Ferris: September 28, 2026.