Epidemiology of Chlamydia psittaci infections in pregnant Thoroughbred mares and foals

Anstey, Susan; Lizárraga, David; Nyari, Sharon; Chalmers, Gareth R.L.; Carrick, Joan B.; Chicken, C.; Jenkins, Cheryl; Perkins, Nigel R.; Jelocnik, Martina

doi:10.1016/j.tvjl.2021.105683

Cited by 11 publications

(25 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Molecular and/or cell biology/infection studies to dissect the significant pathogenicity of C. psittaci and to understand the risk posed by C. psittaci to livestock and humans are being increasingly conducted in Australia and worldwide [7,11,14,15,[55][56][57]. In Australia, further studies must focus on understanding the pathogenicity of C. psittaci strains causing equine reproductive loss and the factors that increase the risk of infection spillover [5] but also to assess the genetic diversity of C. psittaci in the broader range of avian and non-avian hosts, including humans [14,15,44,45,58]. The opportunities for ongoing spillover due to habitat degradation/encroachment (or increase) of the wildlife/livestock interface and reduced food/water resources for birds driving them into paddocks to feed on horse food are plausible [59].…”

Section: Discussionmentioning

confidence: 99%

“…In Australia, further studies must focus on understanding the pathogenicity of C. psittaci strains causing equine reproductive loss and the factors that increase the risk of infection spillover [5] but also to assess the genetic diversity of C. psittaci in the broader range of avian and non-avian hosts, including humans [14, 15, 44, 45, 58].…”

Section: Discussionmentioning

confidence: 99%

“…Molecular epidemiology has demonstrated an association of C. psittaci with the annual occurrence of late-term reproductive loss in mares in Australia [3–8]. In Australia, this intracellular pathogen is classified as a Risk Group 3, requiring the second-highest physical containment level (Physical Containment Level 3) [9].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

One clone to rule them all: Culture-independent genomics of Chlamydia psittaci from equine and avian hosts in Australia

et al. 2022

Self Cite

View full text Add to dashboard Cite

Chlamydia psittaci is an avian pathogen with zoonotic potential. In Australia, C. psittaci has been well reported as a cause of reproductive loss in mares which subsequently have been the source of infection and illness in some in-contact humans. To date, molecular typing studies describe the predominant and clonal C. psittaci sequence type (ST)24 strains in horse, psittacine, and human infections. We sought to assess the clonality between ST24 strains and the emergence of equine ST24 with a comprehensive genomics approach. We used culture-independent probe-based and metagenomic whole-genome sequencing to investigate 13 C . psittaci genomes from horses, psittacines, and a pigeon from Australia. Published genomes of 36 C . psittaci strains were also used to contextualise our Australian dataset and investigate lineage diversity. We utilised a single-nucleotide polymorphism (SNP) based clustering and multi-locus sequence typing (MLST) approach. C. psittaci has four major phylogenetic groups (PG1-4) based on core-genome SNP-based phylogeny. PG1 contained clonal global and Australian equine, psittacine, and human ST24 genomes, with a median pairwise SNP distance of 68 SNPs. PG2, PG3, and PG4 had greater genomic diversity, including diverse STs collected from birds, livestock, human, and horse hosts from Europe and North America and a racing pigeon from Australia. We show that the clustering of C. psittaci by MLST was congruent with SNP-based phylogeny. The monophyletic ST24 clade has four major sub-lineages. The genomes of 17 Australian human, equine, and psittacine strains collected between 2008 and 2021 formed the predominant ST24 sub-lineage 1 (emerged circa 1979). Despite a temporal distribution of 13 years, the genomes within sub-lineage 1 had a median pairwise SNP distance of 32 SNPs, suggesting a recent population expansion or potential cross-host transmission. However, two C. psittaci genomes collected in 2015 from Victorian parrots clustered into distinct ST24 sub-lineage 4 (emerged circa 1965) with ovine strain C19/98 from Germany. This work describes a comprehensive phylogenomic characterisation of ST24 and identifies a timeline of potential bird-to-equine spillover events.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

One clone to rule them all: Culture-independent genomics of Chlamydia psittaci from equine and avian hosts in Australia

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…There is evidence for C. psittaci spill-over from wild birds to horses and thereby to humans in Australia, with a highly virulent strain of C. psittaci associated with equine reproductive loss [148] and subsequently disease in humans [21]. This study provided the first evidence for mammal to mammal transmission of C. psittaci [149] and has since prompted further testing of horses in Australia [150,151].…”

Section: Transmission Involving Poultry and Agriculturementioning

confidence: 75%

A Review of Chlamydial Infections in Wild Birds

2021

View full text Add to dashboard Cite

The Chlamydia are a globally distributed genus of bacteria that can infect and cause disease in a range of hosts. Birds are the primary host for multiple chlamydial species. The most well-known of these is Chlamydia psittaci, a zoonotic bacterium that has been identified in a range of wild and domesticated birds. Wild birds are often proposed as a reservoir of Chlamydia psittaci and potentially other chlamydial species. The aim of this review is to present the current knowledge of chlamydial infections in wild avian populations. We focus on C. psittaci but also consider other Chlamydiaceae and Chlamydia-related bacteria that have been identified in wild birds. We summarise the diversity, host range, and clinical signs of infection in wild birds and consider the potential implications of these infections for zoonotic transmission and avian conservation. Chlamydial bacteria have been found in more than 70 species of wild birds, with the greatest chlamydial diversity identified in Europe. The Corvidae and Accipitridae families are emerging as significant chlamydial hosts, in addition to established wild hosts such as the Columbidae. Clarifying the effects of these bacteria on avian host fitness and the zoonotic potential of emerging Chlamydiales will help us to understand the implications of these infections for avian and human health.

show abstract

“…Environmental C. psittaci DNA has been demonstrated in avian feces on stud farms and this could contaminate equine placentas, which almost always have environmental contamination. 3 This could result in a positive PCR test that has no significance as a cause of loss and may affect the significance of C. psittaci detection in tissues where samples from the fetus and placenta are comixed or where poor aseptic collection technique allows cross-contamination. A positive qPCR on separately pooled fetal or placental tissue and positive IHC are likely needed to confirm significant infection where the placental pathology is not typical.…”

Section: Discussionmentioning

confidence: 99%

Fetoplacental pathology of equine abortion, premature birth, and neonatal loss due to Chlamydia psittaci

Begg¹,

Carrick²,

Chicken³

et al. 2022

Vet Pathol

View full text Add to dashboard Cite

This report describes the fetoplacental pathology of Chlamydia psittaci-associated abortion, premature birth, and neonatal loss in 46 of 442 equine abortion investigations between 2015 and 2019. Seven abortions, 26 premature births, and 13 neonatal deaths with positive C. psittaci polymerase chain reaction (PCR) were evaluated. In 83% of cases (38/46), C. psittaci infection was considered as the primary cause of loss based on quantitative PCR (qPCR) confirmation, pathological findings, and exclusion of other causes, and was supported by Chlamydia spp immunolabeling in fetoplacental lesions. Lymphohistiocytic placentitis with vasculitis (36/38) affected the amnion, umbilical cord, and chorioallantois at the umbilical vessel insertion and/or cervical pole. Lymphohistiocytic chorionitis in the subvillous stroma extended to the allantois mostly without villous destruction. Lymphohistiocytic amnionitis and funisitis occurred at the amniotic cord attachment. Lymphohistiocytic hepatitis was observed in 19/38 cases and pneumonia was identified in 26 cases. Chlamydia spp immunolabeled in placenta, lung, liver, or splenic tissue in the cases that were tested (14/38). C. psittaci infection was not the cause of loss in 2 cases with other diseases and of uncertain significance in 6 cases with no conclusive cause of loss. immunohistochemistry (IHC) was negative for 6 of these cases (6/8). The highest Chlamydia load was detected in pooled placental tissues by qPCR. qPCR and IHC had 83% congruence at a qPCR cut-off of 1 gene copy. IHC limits of detection corresponded to infections with 2 × 102 gene copies identified by qPCR. This study confirms the etiological role of C. psittaci as a cause of naturally occurring equine reproductive loss.

show abstract

Epidemiology of Chlamydia psittaci infections in pregnant Thoroughbred mares and foals

Cited by 11 publications

References 36 publications

One clone to rule them all: Culture-independent genomics of Chlamydia psittaci from equine and avian hosts in Australia

One clone to rule them all: Culture-independent genomics of Chlamydia psittaci from equine and avian hosts in Australia

A Review of Chlamydial Infections in Wild Birds

Fetoplacental pathology of equine abortion, premature birth, and neonatal loss due to Chlamydia psittaci

Contact Info

Product

Resources

About