Toxoplasmosis
By Dr Mackie Hobson BSc(Agric),BVSc

1. Diseases

Toxoplasmosis as a cause of abortion in Angora goats in South Africa has not been diagnosed.

It potentially could be a cause in South Africa where goats and cats may be in close proximity. Toxoplasma has been diagnosed as a cause of abortions in Angora goats in Europe ( Slosarkova, Literak, et al) and New Zealand (K.D. McSporran,C. McCaughan,J.H.S. Currall &A. Demsteegt 1984)

The cause of abortion in Angora goats in South Africa was extensively investigated by Malherba and Van Heerden in the 1950’s and Toxoplasmosis was discarded as a potential cause of Abortions in Angora goats in South Africa for the following reasons.

1. The general post mortem appearance of the necrotic foci on reddish cotyledons weren’t found.
2. Histopathology examinations of sections of the foetal cotyledons failed to reveal the presence of intra- or extra-cellular Toxoplasma-like bodies
3. Perinatal deaths are extremely rare, especially in comparison to the number of abortions occurring;
4. No febrile reaction with abortion in Angora goats have been noticed:
5. There is no evidence of any immunity developing. It has been noticed that an Angora ewe might abort up to three times during one season, and goats aborting four years in succession are not uncommon
6. While abortion might be as high as 80 per cent on some affected farms, Boergoats and sheep are free of this condition. It is inconceivable that Toxoplasma gondii should exhibit such a marked host specificity
7. Angora goats are farmed with mainly in the arid regions of South Africa
8. There is no evidence of widespread abortion amongst Angora goats in the United States of America or any other country where Angoras are farmed with and Toxoplasmosis is known to occur.

What is Toxoplasmosis?

Toxoplasmosis is a cause of abortion in sheep and goats in many countries around the world and occurs in South Africa.

Toxoplasma gondii is an intracellular parasite with a coccidian type life cycle associated more with cats but can be spread by birds and rodents. Sheep have become infected when cat faeces has contaminated water or feed or transmitted. Ram semen has been demonstrated in New Zealand to be a source of transmission.

How does it cause abortion?

Toxoplama oocytes are ingested and oocysts excyst and release sporozoites. These penetrate the intestinal wall and infect the placenta and foetus to cause abortion. Transmission through ram semen directly to the ewe may also occur.

Clinical signs

• Infection early in pregnancy is likely to cause resorption
• Infection in late pregnancy (>120 days) will result in a normal kid
• Infection in mid pregnancy (day 60-120) will cause foetal death and abortion

Diagnosis:

• Pathology of placental cotyledons- grey-white (1-3mm) foci of necrosis
• Histopath of placenta, foetal brain, lung and liver
• Serology

Control:

• Toxoplasma may be susceptible to Sulphonamides and ionophores
• In New Zealand a vaccine is available
• Control of domestic and wild cats

Zoonosis:

Humans can become infected from cat faeces or by ingestion of bradyzoites in raw meat or ingestion via the placenta. Hence the reason pregnant woman avoid handling cat faeces.

References:

Toxoplasmosis and iodine deficiency in Angora goats.

Slosárková S1, Literák I, Skrivánek M, Svobodová V, Suchý P, Herzig I

Toxoplasmosis in goats

K.D. McSporran,C. McCaughan,J.H.S. Currall &A. Demsteegt

Pages 39-40 | Received 22 Dec 1984, Published online: 23 Feb 2011

INVESTIGATIONS INTO THE CAUSE OF ABORTIONS IN

ANGORA GOATS IN SOUTH AFRICA *

KAREL MALHERBE VAN HEERDEN.•• Senior Research Fellow.

Stock Diseases Research Fund. Graaff-.Reinct