Teladorsagia
circumcincta parasitizes the abomasum of sheep and goats.
The lifecycles of O. ostetagi and T. circumcincta
are essneially the same (Snyder et al., 2020).
Life cycle is direct, there are no intermediate hosts. Eggs are
deposited in feces of infected cattle. Depending on temperature and
moisture conditions, eggs hatch and juveniles develop as microbivores to the third
stage. During this free-living phase, juveniles migrate to surrounding
grass and other herbage where they are consumed by grazing animals.
Third stage juveniles associated with grass may survive for two years or
more, although numbers decline across time (Rose, 1961).
The L3 exsheath in the rumen and enter the lumen of an abomasal
gland. The L3 molts twice to the L5 that emerges from the gland about 18
days post-infection. The L5 become sexually mature adults on the mucosal
surface. The prepatent period is 3 weeks. However, ingested L3 may
become arrested (hypobiotic or inhibited phase) in development at the
early L4 for periods up to 6 months.
The patterns of early L4 can entering an inhibited phase occur
seasonally in temperate climates with cold winters and hot dry summers.
For example, the seasonal patterns of inhibition of O. ostertagi
in the southern United States occur with a progressive accumulation of
early L4 during spring months and resumption of the development in late
summer and early fall. The opposite occurs for colder regions where L3
ingested in the fall months remain as early L4 in the abomasal glands
over the winter months and resume development in the spring (Snyder et
al., 2020).
Teladorsagia
circumcincta parasitizes the abomasum of sheep and goats and is the
major economic parasite of small ruminants worldwide
Ostertagia ostertagi is a major cause of parasitic gastritis in
abomasum of cattle in temperate areas of the world (Snyder et al.,
2020)...
Anthelminthics.
Beveridge, I., Spratt, D.M., Durette-Desset, M-C. 2013. Order Strongylida
(Railliet & Henry, 1913). Handbook Of Zoology Online. De Gruyter
Drozdz, J., 1995. Polymorphism in the Ostertagiinae Lopez Neyra, 1947 and
Comments on the Systematics of These Nematodes, Syst. Parasitol., 1995,
32:91-99.
Klesius, P.H. 1988. Immunity to Ostertagia ostertagi.
Veterinary parsitology 27: 159-167.
Kuznetsov, D.N. 2011. Taxonomic Revision of the Genus Ostertagia (Nematoda:
Ostertagiinae) Based on an ITS2 rDNA Study. Biology Bulletin, 38:608-614.
Original Russian Text: Kuznetsov, D.N. 2011, in Izvestiya Akademii Nauk,
Seriya Biologicheskaya, 2011, 6: 710-16.
Michel JF. 1963. The phenomena of host resistance and the course of
infection of Ostertagia ostertagi in calves. Parasitology.
1963;53(1-2):63-84. doi:10.1017/S0031182000072541
Ransom. B.H. 1907. Notes of Parasitic
Nematodes, Including Descriptions of New Genera and Species and Observations
on Life Histories. US Govwernment Printing Office 7pp.
Rose, J.H. 1961. Some observations on the free-living stages of
Ostertagia ostertagi, a stomach worm of cattle. Parasitology
51:295-307.
Snyder, D.E.,
Marchiondo, A.A. Cruthers, L.R. 2020. Nematoda, Trichostrongyloidea.
Chapter 2 in Marchiondo, Cruthers and Fourie (eds) Parasiticide
Screening Vol 2. Academic Press.
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