Mainly in tropical and subtropical environments of all continents.
Stephanurus dentatus infects the kidneys,
perirenal tissues, liver, pancreas, and other abdominal organs of swine.
Wild and domestic swine.
Parasite of the peritoneal fat, the pelvis of the kidney, the walls of
ureters and the liver of both domestic and wild swine (Singh and Kaushal,
1995). Adults are large nematodes and food consumpion is considerable.
Stepanurus.dentatus has a direct life cycle; the host acquires
the infection either by ingesting free-living larvae or percutaneously.
Earthworms can act as paratenic hosts.
Adult worms are encysted in nodules in
the wall of the ureters that open directly or via a fistula into the urinary
tract; eggs are excreted in the urine.
Nematodes in nodules in the ureter tissues of the infected host, mature,
mate, and produce eggs that are passed from the host in urine. Eggs hatch in
soil and water. They may be cosumed by earthworms which are ingested by the
pigs, or ingested directly from contaminated water. Larvae may also
penetrate throgh the skin.. Ingested larvae penetrate into the host blood
stream and then to infection sites: kidneys, ureters, amd even liver where
they aggregate in nodules and continue development to adults. Adults may
live in the host for 2-3 years (Marchiondo et al., 2020).
Swine stephanurosis caused by S. dentatus is responsible for
economic losses in tropical and subtropical countries in traditional pig
production systems (Islam et al., 2015) and also occurs at a high prevalence in wild populations (Sato et al., 2008; Cleveland et al., 2017;
Moratal et al., 2018).
After entering the pig, the
L3 molt to an L4 that migrates to the liver. Larvae may migrate
within the liver for 4-9 months, which causes
massive, widespread fibrosis. Economic loss to
swine producers results from condemnation of the damaged liver
(Marchiondo et al., 2020).
Migrating larvae affect mainly the hepatic parenchyma, while adults
establish in the urinary system. Loss of apetite, damage to tissues dur to
migration, fibrosis and abscess formation (Olsen, 1977; Wang, 2003; Islam et al.,
2015).
Diagnosis through detection of nematode eggs in urine samples.
Ivermectin anthelmintic treatment of infected pigs.
Reduce infection and transmission by restricting access of pigs to
potentially contaminated areas of soil and water.
Cleveland, C.A., DeNicola, A., Dubey, J.P., Hill, D.E., Berghaus, R.D.,
Yobsley, M.J. 2017.
Survey for selected pathogens in wild pigs (Sus
scrofa) from Guam, Marianna Islands, USA. Vet. Microbiol.205:22-25.
Daubney, R. 1923. The kidney worm of swine: a short redescription
of Stephanusrus dentatus Diesing 1839, J Comp. Path and Therap. 36-37:
97-103
Deng, Y-P., Zhang, X-L., Li, L-Y., Yang, T., Liu, G-H., Fu, Y-T. 2021.
Characterization of the complete mitochondrial genome of the swine kidney worm
Stephanurus dentatus (Nematoda: Syngamidae) and phylogenetic implications. Vet.
Parasitol. 295 (2021) 109474
Islam, A., Anisuzzaman, Roy, J.R., Yasin, M.G., Labony, S.S.,
Hossain, M.M., Alim, M.A., 2015. Swine kidney worm in Bangladesh: an
abattoir survey. Eurasian J. Vet. Sci. 31: 222-226
Marchiondo, A.A., Cruthers L.R., Reinemeyer, C.R. 2020. Nematoda,
Strongyloidea. Chapter 2 in Marchiondo, Cruthers and Fourie (eds) Parasiticide
Screening Vol 2. Academic Press.
Moratal, S., Ruiz de Ybanez, R., Barroso, P., Granados, J.E.,
Hofle, U., Martinez, Carrasco, C.,
Acevedo, P., Vicente, J., 2018. High prevalence and intensity of Stephanurus
dentatus in a population of wild boar (Sus scrofa) in south western Spain.
Vet. J. 240:47-49
.Sato, H., Suzuki, K., Yokoyama, M., 2008. Visceral helminths of
wild boars (Sus scrofa leucomystax) in Japan, with special reference to a
new species of the genus Morgascaridia Inglis, 1958 (Nematoda:
Schneidernematidae). J. Helminthol. 82: 159-168.
Verrill, A.E. 1870. Description of Sclerostoma pinguicola. A new species
of entozoa from the hog. Amer J Sci and Arts: 223-224
Wang, M., 2003. Veterinary Parasitology, 3rd edition. Chinese
Agricultural Press, Beijing, pp. 1-490. in Chinese
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