Monitoring clinical outcomes, pathological changes and shedding of Chlamydophila abortus following experimental challenge of periparturient ewes utilizing the natural route of infection

Chlamydia abortus: New Aspects of Infectious Abortion in Sheep and Potential Risk for Pregnant Women

“…However, this immunity is not sterile and some animals may shed organisms during the following periovulation period and at subsequent lambing [54,55], although more recent molecular evidence suggests that this risk is minimal [56,57]. Venereal transmission by males is not thought to play an important role in the spread of infection [51,58], although direct intravaginal infection of ewes has been demonstrated suggesting that it is possible [59], while infection of rams or semen failed to establish infection in ewes or result in abortion [60,61].Vertical transmission of infection from ewe to lamb can occur, although it is currently unknown whether this plays any role in the epidemiology of this disease as there is little or no conclusive experimental evidence to support this one way or the other.…”

Chlamydiaceae and chlamydial infections in sheep or goats

“…This may explain the increased incidence of abortions in newly infected caprine herds. The shedding may persist several weeks after abortion, but is often intermittent and the number of Chlamydiae shed too low to have an impact on transmission of the organism (Gutierrez et al, 2011).…”

“…Oral (Gutierrez et al, 2011), intradermal or subcutaneous (Papp and Shewen, 1996) inoculation of non-pregnant females is often asymptomatic and induces abortion during later gestation only in a small proportion of animals, but it provides protection against reinfection during pregnancy (Papp and Shewen, 1996). The consequences of intranasal inoculation vary according to the inoculated dose, but surprisingly, smaller doses induced higher abortion rates than an increased dose, possibly because that might stimulate protective immunity : 95% of ewes produced liveborn lambs after intranasal inoculation of 5×10 7 inclusion forming units before pregnancy, whilst intranasal inoculation of 5×10 3 or 5×10 5 inclusion forming units led to 59% or 67% abortion rates, respectively; subcutaneous inoculation of 4×10 6 inclusion forming units at the 70th day of pregnancy has led to 50% abortion rate.…”

Identification of Immunologically Relevant Proteins ofChlamydophila abortusUsing Sera from Experimentally Infected Pregnant Ewes

“…Alternative routes of infection, including intranasal and oral challenges, have recently been validated and may facilitate the identification of additional antigens expressed during infection (13,25). This might explain why the infected fetus reacts with different antigens compared to the ewe, since it was infected in utero.…”