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Toxoplasmosis in Sheep
The Relative Importance of the Infection as a Cause of Reproductive Loss in Sheep in Norway
Acta Veterinaria Scandinavica volume 17, pages 412–425 (1976)
Abstract
The importance of toxoplasmosis as a cause of reproductive loss was examined during the period 1968—1973, based on diagnostic materials submitted from 126 flocks. Toxoplasmosis was diagnosed in 81 of these. Reliable information of the number of breeding ewes and their reproductive performance was obtained from 117 flocks, where 858 of 7812 breeding ewes failed to produce viable lambs. About 80 % of the total loss in these flocks was attributed to toxoplasmosis, 4 % to bacterial infections, and 16 % to non-infectious and/or unidentified causes.
The frequency of loss within individual flocks was higher from toxoplasmosis than from any other cause, reaching a maximinn of 78 % of the breeding ewes. In 21 of 42 flocks of at least 20 breeding ewes and a high frequency of loss (≥ 10 %) from toxoplasmosis, 20 % or more of the ewes lost their lambs, whereas a loss of this order only occurred in 1 of the 13 flocks in which some other diagnosis was made.
In addition to abortion, toxoplasmosis was also associated with returns to service, barrenness, stillbirth, and delivery of weak lambs that died soon after birth.
White spots were observed on the cotyledons of nearly 2/3 of the placentas expelled from toxoplasmosis. No evidence was found that these changes occurred in any other disease.
The incidence of abortion was higher among young ewes than among the older ones. No clinical symptoms of infection were observed prior to abortion from toxoplasmosis, and the ewes kept for breeding behaved normally in later pregnancies.
References
Beverley J. K. A. & R. R. Mackay: Ovine abortion and toxoplasmosis in the East Midlands. Vet. Rec. 1962, 74, (499–501).
Beverley J. K. A. & W. A. Watson: Ovine abortion and toxoplasmosis in Yorkshire. Vet. Rec. 1961, 73, (6–11).
Beverley J. K. A. & W. A. Watson: Further studies on toxoplasmosis and ovine abortion in Yorkshire. Vet. Rec. 1962, 74, 548–552.
Beverley J. K. A., W. A. Watson & J. M. Payne: The pathology of the placenta in ovine abortion due to toxoplasmosis. Vet. Rec. 1971a, 88, (124–128).
Beverley J. K. A., W. A. Watson & J. B. Spence: The pathology of the foetus in ovine abortion due to toxoplasmosis. Vet. Rec. 1971b, 88, (174–178).
Hartley W. J. & B. W. Boyes: Incidence of ovine perinatal mortality in New Zealand with particular reference to intra-uterine infections. N.Z. vet. J. 1964, 12, (33–36).
Hartley W. J. & J. C. Kater: The pathology of Toxoplasma infection in the pregnant ewe. Res. vet. Sei. 1963, 4, 326–332.
Hortemo O. & J. Overâs: Personal communication 1968.
Jacobs L. & W. J. Hartley: Ovine toxoplasmosis: Studies on paraisitaemia, tissue infection, and congenital transmission in ewes infected by various routes. Brit. vet. J. 1964, 120, (347–364).
Kristiansen F. B. F.: Personal communication 1968.
Munday B. L.: The epidemiology of toxoplasmosis with particular reference to the Tasmanian environment. Thesis, University of Melbourne, Melbourne 1970.
Nærland G. & O. Helle: Unpublished data 1958.
Sabin A. B. & H. A. Feldman: Dyes as microchemical indicators of a new immunity phenomenon affecting a protozoan parasite (Toxoplasma). Science. 1948, 108, (660–663).
Smith L. D.: Ovine toxoplasmosis as a cause of reproductive wastage. Preliminary observations. Aust. vet. J. 1961, 37, (18–21).
Stamp J. T., A. D. McEwen, J. A. A. Watt &. D. L. Nisbeth: Enzootic abortion in ewes. I. Transmission of the disease. Vet. Rec. 1950, 62, (251–254).
Waldeland H.: Toxoplasmosis in sheep. The reliability of a microtiter system in Sabin and Feldman’s dye test. Acta vet. scand. 1976a, 17, (426–431).
Waldeland H.: Toxoplasmosis in sheep. The prevalence of Toxoplasma antibodies in lambs and mature sheep from different parts of Norway. Acta vet. scand. 1976b, 17, (432–440).
Waldeland H.: Toxoplasmosis in sheep. Influence of various factors on the antibody contents. 1977a. To be published.
Waldeland H.: Toxoplasmosis in sheep. Long-term epidemiological studies of 4 breeding flocks. 1977b. To be published.
Waldeland H. & J. Overâs: Toxoplasma-abort hos sau. (Toxoplasma abortion in sheep). Medlemsbl. nórske Vet.-foren. 1968, 20, (497–500).
Watson W. A.: Ovine abortion. Vet. Rec. 1962a, 74, 1403–1408.
Watson W. A.: Abortion and stillbirth in sheep. Part I. Vet. Bull. 1962b, 32, (259–264).
Watson W. A. & J. K. A. Beverley: Ovine abortion due to experimental toxoplasmosis. Vet. Rec. 1971, 88, (42–45).
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Waldeland, H. Toxoplasmosis in Sheep. Acta Vet Scand 17, 412–425 (1976). https://doi.org/10.1186/BF03547896
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DOI: https://doi.org/10.1186/BF03547896