TOXOPLASMA INFECTION AND ABORTION IN SHEEP ASSOCIATED WITH FEEDING OF GRAIN CONTAMINATED WITH CAT FAECES

Epidemiological Study ofToxoplasma gondiiInfection in Ovine Breeding

“…Toxoplasmosis cannot be considered completely under control because of several aspects: (i) it remains an important zoonotic infection, causing abortion in humans and congenital abnormalities in children (Dubey, 1996); (ii) the economic losses linked to the presence of toxoplasmosis in the herd are due to early embryonic loss leading to barren ewes, abortion, mummified foetuses, stillbirths and neonatal deaths (Scott et al., 2007); (iii) the wild and semi‐wild rearing style can facilitate the ingestion of feed and/or pasture contaminated with cat faeces. Outbreaks of clinical ovine toxoplasmosis are the end result of a combined spectrum of events: (i) contamination of feed or pasture with sporulated oocysts (Plant et al., 1974; Faull et al., 1986); (ii) exposure of sheep to T. gondii derived by the presence of cats on farms or by the circulation of stray cats (Behymer et al., 1985) and (iii) shedding of oocysts in cat faeces, which may remain viable and infective in the environment following sporogony, depending on temperature and relative humidity (Dubey and Beattie, 1988).…”

“…In the agricultural setting, toxoplasmosis has a considerable economic relevance, considering that ovine species are particularly susceptible to infection (Beverley and Watson, 1971; Buxton, 1990). Toxoplasma sheep abortion has been linked to feed or pasture contamination with sporulated oocysts (Plant et al., 1974; Faull et al., 1986), and associations have been made between exposure of sheep to T. gondii and the presence of cats in farms or the circulation of stray cats. In fact, oocysts shed in cat faeces may remain viable and infective in the environment, following sporogony, for up to 18 months, depending on temperature and relative humidity (Dubey and Beattie, 1988).…”

Neurological diseases of ruminant livestock in Australia. III: bacterial and protozoal infections

“…A 13% prevalence rate was found in a limited survey, 38 and a flock prevalence of 22–58% was reported in New South Wales, with higher prevalence rates being found in intensively managed flocks 39 . Infection and abortion were shown to be linked to the presence of cat faeces and outbreaks can occur in native animals after consumption of feed contaminated with cat faeces 40 . The unique sensitivity of Australian marsupials to fulminating toxoplasmosis has been well documented 41 …”

Veterinary vaccines against Toxoplasma gondii

“…Each infected cat may shed 100 million oocysts into the environment and as few as 200 sporulated oocysts can cause congenital disease in naïve sheep (McColgan et al 1988). Infection in sheep is associated with contamination of feed or grazing land with sporulated oocysts (Plant et al 1974, Faull et al 1986). There is also an increasing likelihood of seroprevalence related to age of the animal indicating that there is extensive environmental contamination with oocysts and that most infections in sheep occur following birth (Waldeland 1977, Lunden et al 1994.…”