Pathogenic outcome following experimental infection of sheep with Chlamydia abortus variant strains LLG and POS

Livingstone, Morag; Wheelhouse, Nicholas; Ensor, Hannah; Rocchi, Mara; Maley, S.W.; Aitchison, Kevin; Wattegedera, Sean; Wilson, Kim; Sait, Michelle; Siarkou, Victoria I.; Vretou, Evangelia; Entrican, Gary; Dagleish, Mark P.; Longbottom, David

doi:10.1371/journal.pone.0177653

Cited by 16 publications

(25 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This suggests that, at least in terms of gross placental pathology, the lesions found in these vt infected placentas are very similar to those resulting from a typical wt infection. Furthermore, although there is a difference in the extent of the placenta affected, a very similar number of C. abortus genome copies were found by real-time qPCR within a specific pathological lesion.This is consistent with what has been observed in other studies [6], where although there has been little evidence of gross pathology we still observe high bacterial loads following qPCR analysis. Therefore, qPCR analysis of placental tissue, while not necessarily directly related to the extent of the gross pathology or the clinical outcome, is important for assessing any potential risk of transmission of infection to other naive animals.…”

Section: Plos Onesupporting

confidence: 93%

“…(typically 60-100% of the placental surface) the more likely that an abortion will occur (due to placental insufficiency resulting in a lack of nutrients and oxygenated blood getting to the fetus), but conversely there are instances where a heavily infected placenta is delivered following the birth of an 'apparently normal' live lamb [6]. Indeed, in this study, although vt-P1 exhibited around 60% gross pathology, the ewe delivered what appeared to be normal healthy lambs.…”

Section: Plos Onementioning

confidence: 99%

“…The disease is characterised by late-term abortions (generally occurring in the last 2-3 weeks before expected lambing), stillbirths, or the delivery of weak lambs that fail to survive beyond 48 hrs [6,7]. The most significant sources of infection for transmission of the disease are the products of abortion, in particular, the heavily infected placentas, vaginal fluids, and the coats of dead fetuses or live lambs born from infected ewes.…”

Section: Introductionmentioning

confidence: 99%

“…Bacterial loads present in or on these products of abortion/lambing are extremely high, reaching greater than 10 7 chlamydial genomes per μl of extracted material [7]. These products can contaminate the bedding and pasture with C.abortus, facilitating the transmission of infectious organisms to naïve animals through inhalation and ingestion [6].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The 1B vaccine strain of Chlamydia abortus produces placental pathology indistinguishable from a wild type infection

et al. 2020

Self Cite

View full text Add to dashboard Cite

Chlamydia abortus is one of the most commonly diagnosed causes of infectious abortion in small ruminants worldwide. Control of the disease (Enzootic Abortion of Ewes or EAE) is achieved using the commercial live, attenuated C. abortus 1B vaccine strain, which can be distinguished from virulent wild-type (wt) strains by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Published studies applying this typing method and whole-genome sequence analyses to cases of EAE in vaccinated and non-vaccinated animals have provided strong evidence that the 1B strain is not attenuated and can infect the placenta causing disease in some ewes. Therefore, the objective of this study was to characterise the lesions found in the placentas of ewes vaccinated with the 1B strain and to compare these to those resulting from a wt infection. A C. abortus-free flock of multiparous adult ewes was vaccinated twice, over three breeding seasons, each before mating, with the commercial C. abortus 1B vaccine strain (Cevac® Chlamydia, Ceva Animal Health Ltd.). In the second lambing season following vaccination, placentas (n = 117) were collected at parturition and analysed by C. abortus-specific real-time quantitative PCR (qPCR). Two placentas, from a single ewe, which gave birth to live twin lambs, were found to be positive by qPCR and viable organisms were recovered and identified as vaccine type (vt) by PCR-RFLP, with no evidence of any wt strain being present. All cotyledons from the vt-infected placentas were analysed by histopathology and immunohistochemistry and compared to those from wt-infected placentas. Both vt-infected placentas showed lesions typical of those found in a wt infection in terms of their severity, distribution, and associated intensity of antigen labelling. These results conclusively demonstrate that the 1B strain can infect the placenta, producing typical EAE placental lesions that are indistinguishable from those found in wt infected animals.

show abstract

Section: Plos Onesupporting

confidence: 93%

Section: Plos Onementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The 1B vaccine strain of Chlamydia abortus produces placental pathology indistinguishable from a wild type infection

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Lesions in the fetal lung consisted of neutrophil infiltration in alveoli, suppurative interstitial inflammation and interlobular edema and hemorrhage. The latter experimental study by Longbottom et al 97 was performed using the C. abortus strain S26/3, isolated from the placenta of a sheep that aborted due to OEA in Scotland, while the same authors 93 used strains LLG and POS, which have been isolated in Greece from aborted goat and sheep fetuses and which are genetically different to S26/3, in a recent comparative study. In doing so, they showed that the placental pathology, infectious load and serological response was clearly less pronounced for the strains LLG and POS than for the C. abortus strain S26/3.…”

Section: Chlamydia Abortus In Ruminants and Other Hostsmentioning

confidence: 99%

A Review on Chlamydial Diseases in Animals: Still a Challenge for Pathologists?

2018

View full text Add to dashboard Cite

Chlamydiae have a worldwide distribution causing a wide range of diseases in human hosts, livestock, and companion animals as well as in wildlife and exotic species. Moreover, they can persist in their hosts as asymptomatic infections for extended periods of time. The introduction of molecular techniques has revolutionized the Chlamydia field by expanding the host range of known chlamydial species but also by discovering new species and even new families of bacteria in the broader order Chlamydiales. The wide range of hosts, diseases, and tissues affected by chlamydiae complicate the diagnosis such that standard diagnostic approaches for these bacteria are rare. Bacteria of the Chlamydiales order are small and their inclusions are difficult to detect by standard microscopy. With the exception of avian and ovine chlamydiosis, macroscopic and/or histologic changes might not be pathognomic or indicative for a chlamydial infection or even not present at all. Moreover, detection of chlamydial DNA in specimens in the absence of other methods or related pathological lesions questions the significance of such findings. The pathogenic potential of the majority of recently identified Chlamydia-related bacteria remains largely unknown and awaits investigation through experimental or natural infection models including histomorphological characterization of associated lesions. This review aims to summarize the historical background and the most important developments in the field of animal chlamydial research in the past 5 years with a special focus on pathology. It will summarize the current nomenclature, present critical thoughts about diagnostics, and give an update on chlamydial infections in domesticated animals such as livestock, companion animals and birds, as well as free-ranging and captive wild animals such as reptiles, fish, and marsupials.

show abstract