Corrigendum to ‘Longitudinal prevalence and faecal shedding of Chlamydia pecorum in sheep’ [The Veterinary Journal 201 (2014) 322–326]

Yang, Rongchang; Jacobson, Caroline; Gardner, G.E.; Carmichael, Ian; Campbell, Angus; Ryan, Una

doi:10.1016/j.tvjl.2015.10.002

Cited by 2 publications

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“…In Australia, C . pecorum is a highly prevalent asymptomatic infection in sheep with longitudinal analysis revealing that more than 30% of the nation’s sheep shed this pathogen [ 7 ]. While the exact costs incurred due to these infections are unclear, the economic impact of bacterial arthritis in lambs, of which C .…”

Section: Introductionmentioning

confidence: 99%

Humoral immune response against two surface antigens of Chlamydia pecorum in vaccinated and naturally infected sheep

2017

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Chlamydia pecorum is a globally recognised livestock pathogen due to the significant clinical and economic impact it poses to livestock producers. Routine serological diagnosis is through a complement fixation test (CFT), which is often criticised for cross-reactivity, poor sensitivity and specificity. Although serology remains the preferred method in veterinary diagnostic laboratories, serological assays based on surface antigens of C. pecorum have not been established until now. In this study, we evaluated the use of two chlamydial recombinant protein antigens (PmpG and MOMP-G) by a direct IgG ELISA method for detection of ovine anti-chlamydial antibodies. Using the Pepscan method we then identified B cell epitopes across PmpG and MOMP-G proteins, in lambs with (a) naturally occurring asymptomatic C. pecorum infections (b) C. pecorum-associated polyarthritis and (c) recombinant PmpG and MOMP-G vaccine. Plasma IgG antibodies to PmpG in natural infection of lambs were detected earlier in infection than CFT and served as an acute phase marker. Antibodies to MOMP-G IgG were significantly heightened in lambs with C. pecorum-associated polyarthritis. PmpG and MOMP-G specific B-cell epitope mapping revealed epitope responses in immunised lambs cluster with some of the epitope responses in naturally infected lambs. B-cell epitope mapping further revealed that lambs with polyarthritis recognised several unique PmpG (50% frequency, peptide 8, 25, 40, 41 and 50) and MOMP (50% frequency, peptide 50) epitopes in comparison to asymptomatic infections. The findings of this study will have implications towards improved serodiagnosis of C. pecorum infections in livestock and inform the downstream development of alternative peptide-based antigens for future C. pecorum vaccine studies.

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Section: Introductionmentioning

confidence: 99%

Humoral immune response against two surface antigens of Chlamydia pecorum in vaccinated and naturally infected sheep

2017

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Molecular and serological dynamics ofChlamydia pecoruminfection in a longitudinal study of prime lamb production

Bommana

Walker

Desclozeaux

et al. 2018

PeerJ

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BackgroundChlamydia pecorum is a globally significant livestock pathogen causing pathology and production losses. The on-farm infection and serological dynamics and the relevance of existing diagnostic tools for diagnosing C. pecorum in livestock remains poorly characterized. In this study, we characterized the antigen and antibody dynamics of this pathogen in a longitudinal study of prime lamb production, utilizing the infection focused C. pecorum-specific 16S rRNA qPCR assay and serology based chlamydial Complement fixation Test (CFT).MethodsThe study consisted of 76 Border Leicester mixed sex lambs (39 females and 37 males) that were sampled bimonthly from 2–10 months of age in a commercial farm operating in Central NSW, Australia. Blood/plasma was analysed for CFT antibodies, and swabs from conjunctival, rectal and vaginal sites were analysed for C. pecorum shedding using qPCR. We assessed the temporal and overall dynamics of C. pecorum in lambs, including detailed description and comparison of qPCR and CFT, the timing of first detection by either diagnostic method, the lag between infection and antibody response; and the distribution of qPCR load and CFT antibody titre over time.ResultsOver the study period, C. pecorum was highly prevalent (71.0% by qPCR, 92.1% by CFT, 96.0% by both), with 21.1% (16/76) lambs shedding ≥1, 000 qPCR copies/µl (denoted as high shedders). C. pecorum shedding (as evidence of infection) were first observed at two months of age (14.4%) with a significant peak of infection occurring at six months of age (34.2%), whereas seroconversions peaked at eight months of age (81.5%). 52.6% of C. pecorum qPCR and CFT positive lambs became qPCR negative by 10 months of age, indicating clearance of chlamydial infection. Although CFT is utilised for on-farm detection of active infection, we confirm that it lagged behind qPCR detection (average lag 1.7 ± 2.1 months) and that the proportion of qPCR positives simultaneously identified by CFT was low with 2/11 (18.1%), 0/13, 17/25 (68.0%), 5/7 (71.4%) and 1/10 (10.0%) concurrent seroconversions occurring at two, four, six, eight and 10 months of age, respectively.DiscussionThis work reveals rapid rates of C. pecorum infection and widespread exposure during lamb production. The comparison of molecular and serological diagnostic agreement longitudinally, supports the use of qPCR as an important ancillary tool for the detection of active infections in conjunction with chlamydial CFT for routine veterinary diagnostics. Development of rapid Point-of-Care (POC) tools for diagnosing active infection would be valuable for producers and veterinarians.

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Corrigendum to ‘Longitudinal prevalence and faecal shedding of Chlamydia pecorum in sheep’ [The Veterinary Journal 201 (2014) 322–326]

Cited by 2 publications

References 1 publication

Humoral immune response against two surface antigens of Chlamydia pecorum in vaccinated and naturally infected sheep

Humoral immune response against two surface antigens of Chlamydia pecorum in vaccinated and naturally infected sheep

Molecular and serological dynamics ofChlamydia pecoruminfection in a longitudinal study of prime lamb production

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