Changes

Sheep are often kept in an environment that is significantly contaminated with oocysts, and infection follows ingestion of infected food, primarily contaminated pasture. Fields treated with manure or bedding from buildings to which cats have access result in high levels of ovine toxoplasmosis, and insecure storage of supplementary feeds also poses a risk.

Sheep are often kept in an environment that is significantly contaminated with oocysts, and infection follows ingestion of infected food, primarily contaminated pasture. Fields treated with manure or bedding from buildings to which cats have access result in high levels of ovine toxoplasmosis, and insecure storage of supplementary feeds also poses a risk.

As the definitive hosts of ''Toxoplasma gondii'', cats become infected when they hunt and eat infected wild rodents and birds. Between days 3 and 14 post-infection, cats shed over 100 million of oocysts in their faeces. Only 200 oocysts are required to cause abortion in naive pregnant sheep

As the definitive hosts of ''Toxoplasma gondii'', cats become infected when they hunt and eat infected wild rodents and birds. Between days 3 and 14 post-infection, cats shed over 100 million of oocysts in their faeces. Studies have shown an association between ovine toxoplasma infection, and the contamination of feed or grazing with sporulated oocysts¹, highligting the importance of oocysts as a source of infection for sheep. It has also been demonstrated that the prevalence of ovine toxoplasmosis varies with the presence of cats on a farm².

oocysts and experimental studies in sheep have shown

studies showing an association with infection and

contamination of feed or grazing land with sporulated

oocysts (Plant, Richardson and Moyle, 1974;

prevalence of T. gondii in sheep (Skjerve et al. 1998).

Further studies looking at development of specific

antibodies in sheep, as an indicator of exposure to

T. gondii, have shown that there is an increase in seroprevalence

there is extensive environmental contamination with

occur following exposure to the parasite after birth

with T. gondii oocysts (Dabritz et al. 2007).

===Congenital Transmission===

===Congenital Transmission===