Morphological features of development of Strongyloides westeri (Nematoda, Rhabditida) in vitro
AbstractStrongyloides westeri (Ihle, 1917), a parasitic horse nematode, has an unusual lifecycle, which allows it to exist for a long time in the environment. Morphometric features of eggs, larvae and free-living S. westeri were studied in vitro under different temperature regimes. The optimal temperature for their embryonic development is 25 °С, under which 90% of the first stage rhabditiform larvae are formed and released within 7 hours of cultivation. The temperatures of 20 and 30 °С are less favorable for their development. Embryonic development of Strongyloides has four stages that differ in morphology and size. The eggs of a parthenogenetic female are 3.7% longer and 19.6% wider than eggs isolated from free-living females of S. westeri. In embryogenesis, the eggs shorten by 4.4 μm (6.5%) and widen by 5.35 μm (8.3%). New data were obtained on postembryonic development of S. westeri. The differential morphometric features of stage 1 and 2 rhabditiform larvae which grow both in length and width (33.7% and 30.4% respectively) are established. The development of filariform larvae is associated with loss of bulbous thickening and formation of cylindrical oesophagus. Simultaneously, the body elongates, and the gut becomes shorter. Differential morphometric features of free-living males and females of S. westeri are the length and width of body, length of oesophagus, gut, tail end, and size of spicules. Postembryonic development of the free-living and parasitic generations from rhabditiform larvae is temperature-dependent. Most of the free-living generations of Strongyloides (54.0%) are formed at 20 °С, and filariform larvae mostly (70.0%) develop at 30 °С. The obtained results of morphological studies improve differential diagnostics of the nematode at various stages of development and further advance the study of its intraspecific variability.
Araujo, J. M., Araújo, J. V., Braga, F. R., Tavela, A. O., Ferreira, S. R., Soares, F. E., & Carvalho, G. R. (2012). Control of Strongyloides westeri by nematophagous fungi after passage through the gastrointestinal tract of donkeys. Revista Brasileira de Parasitologia Veterinária, 21, 157–160.
Boyko, A. A., & Brygadyrenko, V. V. (2016). Vlijanie vodnogo nastoja lekarstvennyh rastenij na lichinok Strongyloides papillosus (Nematoda, Strongyloididae) [Influence of water infusion of medicinal plants on larvae of Strongyloides papillosus (Nematoda, Strongyloididae)]. Visnyk of Dnipropetrovsk University. Biology, Ecology, 24(2), 519–525 (in Russian).
Boyko, A. A., & Brygadyrenko, V. V. (2017). Changes in the viability of Strongyloides ransomi larvae (Nematoda, Rhabditida) under the influence of synthetic flavourings. Regulatory Mechanisms in Biosystems, 8(1), 36–40.
Blaxter, M. L., De Ley, P., Garey, J. R., Liu, L. X., Scheldeman, P., Vierstraete, A., Vanfleteren, J. R., Mackey, L. Y., Dorris, M., Frisse, L. M., Vida, J. T., & Thomas, W. K. (1998). A molecular evolutionary framework for the phylum Nematoda. Nature, 392(6671), 71–75.
Carlson, C. J., Burgio, K. R., Dougherty, E. R., Phillips, A. J., Bueno, V. M., Clements, C. F., Castaldo, G., Dallas, T. A., Cizauskas, C. A., Cumming, G. S., Doña, J., Harris, N. C., Jovani, R., Mironov, S., Muellerklein, O. C., Proctor, H. C., & Getz, W. M. (2017). Parasite biodiversity faces extinction and redistribution in a changing climate. Science Advances, 3(9), e1602422.
De Blieck, L., & Baudet, E. A. R. F. (1920). Verdere onderzoekingen over de biologie en den infecticweg von de larven von Strongyloides westeri. Tijdschr Diergeneesk, 47, 497.
Dewes, H. F., & Townsend, K. G. (1990). Further observations on Strongyloides westeri dermatitis: Recovery of larvae from soil and bedding, and survival in treated sites. New Zealand Veterinary Journal, 38, 34–37.
Grant, W. N., Stasiuk, S., Newton-Howes, J., Ralston, M., Bisset, S. A., Heath, D. D., & Shoemaker, C. B. (2006). Parastrongyloides trichosuri, a nematode parasite of mammals that is uniquely suited to genetic analysis. International Journal for Parasitology, 36, 453–466.
Ivashkin, V. M., & Dvojnos, G. M. (1984). Opredelitel' gel'mintov loshadej [Determinant of horse helminths]. Naukova Dumka, Kyiv (in Russian).
Levine, N. D. (1980). Nematode parasites of domestic animals and of man. Burgess Publishing Company, Minneapolis.
Lyons, E. T., Tolliver, S. C., Rathgeber, R. A., & Collins, S. S. (2007). Parasite field study in Central Kentucky on thoroughbred foals (born in 2004) treated with pyrantel tartrate daily and other parasiticides periodically. Parasitology Research, 100(3), 473–478.
Lyons, E. Т., & Tolliver, S. C. (2014). Strongyloides westeri and Parascaris equorum: Observations in field studies in Thoroughbred foals on some farms in Central Kentucky, USA. Helminthologia, 51(1), 7–12.
Malygin, S. A. (1957). Anatomija i morfologija vidov roda Strongyloides (Grassi, 1879) domashnih zhivotnyh [Anatomy and morphology of species of the genus Strongyloides (Grassi, 1879) of domestic animals]. Sbornik Rabot po Gel'mintologii, 388–395 (in Russian).
Santos, K. R., Carlos, B. C., Paduan, K. S., Kadri, S. M., Barrella, T. H., Amarante, M. R., Ribolla, P. E., & da Silva, R. J. (2010). Morphological and molecular characterization of Strongyloides ophidiae (Nematoda, Strongyloididae). Journal of Helminthology, 84(2), 136–142.
Thompson, F. J., Barker, G. L., Hughes, L., Wilkes, C. P., Coghill, J., & Viney, M. E. (2006). A microarray analysis of gene expression in the free-living stages of the parasitic nematode Strongyloides ratti. BMC Genomics, 7, 157.
Vislobokov, V. A. (2008) Migracija lichinok Strongyloides westeri vo vneshnej srede [Strongyloides westeri larvae migration in the external environment]. Materialy Nauchnoj Konferencii VOG RAN “Teorija i praktika bor'by s parazitarnymi boleznjami”, 9, 108–109 (in Russian).
Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons «Attribution» 4.0 License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.