Ascarididae Barid, 1853 »
Ascaridinae (Baird, 1853) Hartwich, 1974 »
Ascaris Linnaeus, 1758 »
Ascaris suum, Geoze 1782
Sus (scrofa domestica)
Shillong (Meghalaya), Nongstoin (Meghalaya), Markasa (Meghalaya), Riangdo (Meghalaya), Jowai (Meghalaya), Mairang (Meghalaya), Sohiong (Meghalaya)
Large, yellowish-brown, fairly rigid worms; body tapers gradually towards each end. Cuticle relatively thick with faint transverse striations; cervical alae absent. Anterior end provided with three well-developed semicircular lips, one dorsal, two ventro-lateral; dorsal lip bears on its outer surface pair of large lozenge-shaped papillae, with double terminations; each of ventro-lateral lips carrying one double papilla ventrally; pulp of each lip produced anteriorly as pair of blunt lobes with shallow groove, additional round median lobe present towards inner surface of lip; inner surface of each lip bearing transverse series of minute dentigerous ridges; interlabia absent. Oesophagus well developed, simple, club shaped, muscular; spherical bulb without internal valve.
Body 185-210 mm in length , 3-5.5 mm in width. Caudal end conical, without alae, almost invariably curled towards ventral side. Caudal papillae 70-75 pairs; five pairs post-anal, two anterior pairs large with double terminations, three posterior papillae arranged, in triangle on either side; pre-anal papillae very irregularly arranged, forming single longitudinal row on each side for short distance in front of anus, then several irregular rows, finally at anterior part single row again; pair of double papillae in series at some distance from anus, situated in asymmetrical manner; large, median, cushion-like papilla also present just in front of anal aperture. Spicules equal, broad, dorso-ventrally flattened, somewhat widened in their distal half, without alae. Gubernaculum absent.
Longer than males, 215-318 mm in length, 4-6 mm in width at mid body region. Tail short, straight, obtusely conoid. Vulva opens near anterior third of body, frequently in shallow annular constriction. Vagina short, running forward for short distance from vulva, then doubling back sharply close to ventral body wall, passing into unpaired portion of uterus which widens gradually giving off two relatively wide uterine branches running back, parallel to each other till short distance from posterior end, where they touch forward and pass into narrower ovarian tubes; these forming several antero-posterior loops, thrown into innumerable secondary loops in transverse direction. Eggs dark brown, thick shelled, albuminous layer bearing prominent projections,0.06-0.07 x 0.04-0.05 mm.
The species has also been recorded from wild boars, man, chimpanzee etc., byBaylis and Daubney (1922) and is cosmopolitan in distribution.
Morphologically similar worms occur very commonly in human hosts as well. The form of human origin has been known as A. lumbricoides Linnaeus, 1758. As early as the work of Rudolphi (1809) A. suum was believed to bea synonym of A. lumbricoides and since then the controversy as to whether or not the two strains are identical has been raised. The early history of this controversy is reviewed by several workers, such as Mozgovoi et al.(1960) and (1960). Baylis and Daubney (1922) and Thornton (1924) considered the human and pig forms on experimentation morphologically identical, while Martin (1926) and Caldwell and Caldwell (1926) advocated these to be biologically distinct an experimental and epidemiological grounds. However, biochemical studies performed by Vasilev et.al. (1972) and Kurimoto (1974) showed differences between the human and pig forms.>
NEHU/Z - NM/1
Baylis, H. A. and Daubney, R.(1922) Report on the parasitic nematodes in the collection of the Zoological Survey of India. Memories of the Indian Museum, Calcutta. 7:pp 263-347.
Rudolphi, C. A. (1809) Entozoorum sive, vermium intestinalium historia naturalis, Vol.II, Amstelaedami. pp 457.
Mozgavoi, A. A., Popova, T. I., Shalaeva, N. M. and Shmitova, G. Y. (1960) On the independence of species of certain ascarids of man and animals. Trudy Gel'mintologicheskoi Laboratorii. 10:pp 153-165.
Schwartz, B. (1960) Evolution of knowledge concerning the roundworm Ascaris lumbricoides. Smithsonian Institution Annual Report. pp 465-481
Martin, H. M. (1926) Studies on Ascaris lumbricoides. Research Bulletin, University of Nebraska Agriculture Experimentation Station. 37:pp 1-78.
Caldwell, F. C. and Caldwell, E. L. (1926) Are Ascaris lumbricoides and Ascaris suum identical? Journal of Parasitology. 13:pp 141-145.
Vasilev, I. A., Komandarev, S. K. and Mihov, L. D. (1972). Comparative electrophoretic studies of the water soluble proteins in certain ascarids. Comptes Rendus de l'Academie des Bulgarian Sciences. 25:pp 427-429.
Kurimoto, H. (1974). Morphological, biochemical and immunological studies on the differences between Ascaris lumbricoides and A. suum. Japanese Journal of Parasitology. 23:pp 251-267.