Efficacy of a bacterin prepared from Chlamydia psittaci grown in cell culture for experimental immunization of ewes

Waldhalm, Donald G.; DeLong, Walter J.; Hall, Richard F.

doi:10.1016/0378-1135(82)90066-9

Cited by 10 publications

(2 citation statements)

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“…Proportion of C. abortus -associated reproductive failures and ewes shedding C. abortus post-reproductive outcome (in vaginal swabs and/or their fetuses/dead lambs) were limited in all groups (<45 and <56%, respectively, Table 1) compared with previous studies that reported rates between 40 and 90% for reproductive failure (4, 48–52) and 40 and 100% for C. abortus shedding (4, 20, 42, 50). This finding could be explained at least in part by several factors.…”

Section: Discussioncontrasting

confidence: 54%

Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally

et al. 2016

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Ovine enzootic abortion, caused by Chlamydia abortus, leads to important economic losses worldwide. In addition to reproductive failures, infection may impact lamb growth during the first weeks after birth, yet this effect has not been well characterized. Vaccination can help to control the disease but variable efficacy values have been described, possibly related with factors associated with the host, the vaccine, the parameter used for efficacy determination, and the challenge conditions. In this context, we evaluated the efficacy of an inactivated standard commercial vaccine and a 1/2 diluted dose in pregnant sheep challenged with C. abortus by examining multiple indicators of vaccine effect (including incidence of reproductive failures, bacterial excretion, and evolution of weight gain of viable lambs during the first month of life). Three groups of ewes [control non-vaccinated, C (n = 18); vaccinated with standard dose, SV (n = 16); and vaccinated with 1/2 dose, DV (n = 17)], were challenged approximately 90 days post-mating and tested using direct PCR (tissue samples and vaginal swabs) and ELISA (serum) until 31 days post-reproductive outcome. There were not significant differences in the proportions of reproductive failures or bacterial shedding after birth/abortion regardless the vaccination protocol. However, a beneficial effect of vaccination on offspring growth was detected in both vaccinated groups compared with the controls, with a mean increase in weight measured at 30 days of life of 1.5 and 2.5 kg (p = 0.056) and an increase in the geometric mean of the daily gain of 8.4 and 9.7% in lambs born from DV and SV ewes compared with controls, respectively. Our results demonstrate the effect of an inactivated vaccine in the development of the offspring of C. abortus-infected ewes at a standard and a diluted dose, an interesting finding given the difficulty in achieving sufficient antigen concentration in the production of enzootic abortion of ewes-commercial vaccines.

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Section: Discussioncontrasting

confidence: 54%

Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally

et al. 2016

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“…Experimental vaccines prepared from C. psittaci grown in cell culture and administered to ewes have conferred satisfactory, albeit incomplete, levels of protection against challenge (Waldham, Delong and Hall, 1982;Aitken, Anderson and Robinson, 1986;Anderson, Tan, Jones and Herring, 1990). Differences between vaccines produced in the UK and in West Germany relate to the 'strain' or 'strains' of C. psittaci used rather than to the manner in which the vaccines are formulated.…”

Section: Chlamydial Abortionmentioning

confidence: 99%

Sheep health: research developments and emerging problems

Aitken

1990

BSAP Occas. Publ.

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Relative to other livestock sectors sheep production has a high wastage through mortality, suboptimal husbandry practices and premature culling. A significant but unquantified component of this loss is attributable to infectious and parasitic disease. Some common infectious diseases (e.g. those caused by Clostridia) are amenable to effective control but regular sporadic outbreaks indicate that, from time to time, control measures fail or are improperly applied. Other diseases, notably those causing abortion, continue to present problems, particularly chlamydial abortion and toxoplasmosis. Inability to diagnose infection before the onset of clinical signs hinders the control of scrapie and pulmonary adenomatosis (jaagsiekte) and the only vaccine against orf is of limited efficacy.However, the new information being generated by application of molecular biological techniques in some of these problem areas carries promise of improved control. Good examples are provided by research which has led to a blood test for discriminating between sheep that are genetically susceptible or resistant to scrapie and by studies on Chlamydia psittaci which have identified essential protective antigens and which thereby improve prospects for significant vaccine enhancement.The world-wide importance of gastrointestinal parasitism and the emergence of anthelmintic resistance have spurred efforts, internationally, to develop an alternative biological control system. Evidence that protective vaccination may be feasible is accruing but the time scale to a real product may be long.Factors to be considered in assessing future disease trends include the impact of a ‘frontier-free’ Europe, changes in husbandry practices, introduction of new livestock species, altered land use and climatic change resulting from global warming. Some predictions are made.

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Efficacy trials with tissue-culture grown, inactivated vaccines against chlamydial abortion in sheep

Jones

Machell

et al. 1995

Vaccine

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Efficacy of a bacterin prepared from Chlamydia psittaci grown in cell culture for experimental immunization of ewes

Cited by 10 publications

References 1 publication

Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally

Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally

Sheep health: research developments and emerging problems

Efficacy trials with tissue-culture grown, inactivated vaccines against chlamydial abortion in sheep

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