Search

Introduction. Chlamydia psittaci is primarily a pathogen of birds but can also cause disease in other species. Equine reproductive loss caused by C. psittaci has recently been identified in Australia where cases of human disease were also reported in individuals exposed to foetal membranes from an ill neonatal foal in New South Wales. Hypothesis/Gap Statement. The prevalence of C. psittaci in association with equine reproductive over time and in different regions of Australia is not known. Aim. This study was conducted to detect C. psittaci in equine abortion cases in Australia using archived samples spanning 25 years. Methodology. We tested for C. psittaci in 600 equine abortion cases reported in Australia between 1994 to 2019 using a Chlamydiaceae real-time quantitative PCR assay targeting the 16S rRNA gene followed by high-resolution melt curve analysis. Genotyping and phylogenetic analysis was performed on positive samples. Results. The overall prevalence of C. psittaci in material from equine abortion cases was 6.5 %. C. psittaci -positive cases were detected in most years that were represented in this study and occurred in Victoria (prevalence of 7.6 %), New South Wales (prevalence of 3.9 %) and South Australia (prevalence of 15.4 %). Genotyping and phylogenetic analysis showed that the C. psittaci detected in the equine abortion cases clustered with the parrot-associated 6BC clade (genotype A/ST24), indicating that infection of horses may be due to spillover from native Australian parrots. Conclusion. This work suggests that C. psittaci has been a significant agent of equine abortion in Australia for several decades and underscores the importance of taking appropriate protective measures to avoid infection when handling equine aborted material.

Background Chlamydophila felis, formerly known as Chlamydia psittaci var. felis, is frequently associated with ocular, respiratory, and occasionally reproduction tract infections. Even though the infection is sometimes asymptomatic, it potentially results in a latent immunosuppressive infection. Objective This study aimed to identify occurrences of feline chlamydophilosis, rarely reported in cats in Indonesia. Methods The observation was conducted in three cats with clinical signs of Cp. felis infection, particularly relapsing conjunctivitis. The cats' histories were recorded based on owners' information. Conjunctival swabs were sampled for cytology examination and molecular assay detection. A phylogenetic tree was generated using MEGA-X software to reveal group clustering. A post-mortem examination was performed on the cat that died during an examination. Results Cp. felis was detected in both cytological examination and polymerase chain reaction assay. The phylogenetic tree demonstrated that the Cp. felis isolated in this study clustered with several other isolates from the other countries. Cp. felis can be isolated from cats with different clinical manifestations and levels of severity. The chronic fatal infection demonstrated interstitial broncho-pneumonia under histopathological examination. Conclusions Molecular assay of Cp. felis is always recommended to obtain a definitive diagnosis of feline chlamydophilosis since the disease can have various clinical manifestations. Even though it may be subclinical and is often not fatal, an infected cat may be a carrier that could spread the pathogen in the surrounding environment. Serious disease management is suggested to avoid high costs associated with regularly relapsing disease.

Psittacosis is a disease that can be transmitted from birds to humans and is caused by the intracellular bacterium Chlamydia psittaci. C. psittaci has been detected in more than 465 bird species and can cause clinical signs ranging from no symptoms to more severe symptoms such as conjunctivitis and pneumonia to liver failure and death. In humans, infection with C. psittaci can result in a flu-like illness and severe pneumonia, sometimes requiring hospitalisation. In the Netherlands, the disease is notifiable in humans and pet birds (except poultry). The number of human (40-70 per year) and veterinary (60-110 per year) notifications has been stable in recent years, but in 2019 there was a small increase in the number of human cases (91). The Netherlands Food and Consumer Product Safety Authority (NVWA) is responsible for the control in birds in the Netherlands, meaning the NVWA receives the notifications and carries out sampling. The owner of the birds is responsible for contacting a veterinarian to prescribe an antibiotic treatment. Two weeks after the treatment birds are retested. After treatment, birds regularly test positive with PCR, but the cause of these positive retests is unknown. In this report, existing NVWA dossiers were analysed to investigate which factors are associated with a positive retest after treatment. In total, 79 cases could be further analysed, of which 38 tested positive after the first treatment. Factors related to outdoor housing, possible outdoor contact and density appeared to be associated with a positive retest, although no strong relation was found. Additional research would be needed to confirm this relationship. In the data set, a large part of possible risk factors was missing, such as information related to treatment, housing, cleaning and disinfection. These factors could not be analysed. In addition, an improved treatment protocol for field cases was written based on existing literature. This protocol was used in one field case (autumn 2019). During this case study, it turned out that strict cleaning and disinfection is very difficult under field conditions. The analysis of the NVWA dossiers and the case study confirmed that bird husbandries are very diverse, with different types of housing and bird species. In addition, PCR results are sometimes difficult to interpret, as the presence of DNA is detected and not infectious C. psittaci bacteria, which requires a case-dependent approach. Overall, tailor-made advice is probably key in the control of psittacosis in pet birds. This report is the result of a research project within the statutory tasks of Wageningen Bioveterinary Research. This project aimed to improve the current control of psittacosis by evaluating information from available NVWA dossiers and systematically following up a number of field cases. In addition, antibiotic residues in bird feces were investigated. This information is not included in this report but will be reported to the Ministry of Agriculture, Nature and Food Quality via the usual reports. Psittacose is een ziekte die van vogels op mensen kan worden overgedragen en wordt veroorzaakt door de intracellulaire bacterie Chlamydia psittaci. C. psittaci is bij meer dan 465 vogelsoorten aangetoond en kan in vogels tot een variabel ziektebeeld leiden, variërend van geen verschijnselen tot meer ernstige verschijnselen als oog- en longontsteking of leverfalen en sterfte. Bij mensen kan een infectie met C. psittaci aanleiding geven tot een griepachtig beeld en ernstige longontsteking, waarbij ziekenhuisopname soms noodzakelijk is. De ziekte is in Nederland bij gehouden gezelschapsvogels (uitgezonderd pluimvee) en bij mensen meldingsplichtig. Bij vogels geldt ook een bestrijdingsplicht. Het aantal veterinaire (60-110 per jaar) en humane meldingen (40-70 per jaar) is de laatste jaren stabiel, maar in 2019 werd een kleine toename van het aantal humane gevallen (91) gezien. De Nederlandse Voedsel- en Warenautoriteit (NVWA) is in Nederland verantwoordelijk voor de bestrijding in vogels. Dit houdt in dat de NVWA de meldingen ontvangt en de bemonstering van de vogels uitvoert. De eigenaar van de vogels is verantwoordelijk om een dierenarts in te schakelen voor het voorschrijven van een antibioticum behandeling. De controle hierop vindt plaats door vogels twee weken na afloop van de behandeling opnieuw te testen. Regelmatig testen vogels na behandeling opnieuw positief (met PCR). De oorzaak hiervan is niet duidelijk. In dit rapport is daarom een verzameling van bestaande NVWA dossiers geanalyseerd om te onderzoeken welke factoren een rol spelen bij het herhaaldelijk positief testen. In totaal zijn 79 casussen geanalyseerd, waarvan 38 na de eerste antibiotica behandeling opnieuw positief testten. Factoren met betrekking tot buiten huisvesting, mogelijk contact met buiten en bezetting per verblijf leken geassocieerd te zijn met een positieve hertest, hoewel er geen sterke relatie is gevonden in dit onderzoek. Dit zou met aanvullend onderzoek verder bestudeerd kunnen worden. Een groot deel van de mogelijke risicofactoren ontbrak in deze dataset, zoals informatie met betrekking tot behandeling, huisvesting, reiniging en desinfectie. Deze factoren konden niet geanalyseerd worden. Daarnaast is op basis van bestaande literatuur een verbeterd behandelprotocol voor casussen in de praktijk opgesteld. Dit protocol is bij één veldcasus gebruikt (najaar 2019). Tijdens deze casus bleek dat het zeer lastig is om een strikte reiniging en desinfectie uit te voeren onder praktijkomstandigheden. Zowel de veldcasus als de analyse van de NVWA dossiers, laten zien dat de vogelhouderij een diverse sector is, met diverse typen huisvesting en vogelsoorten. Daarnaast blijken PCR uitslagen soms lastig te interpreteren, omdat de aanwezigheid van DNA wordt aangetoond en niet het aantal infectieuze C. psittaci bacteriën, waardoor de beoordeling sterk casus-afhankelijk is. Advies op maat lijkt daarom het sleutelwoord te zijn in de aanpak van psittacose bij gezelschapsvogels. Dit rapport komt voort uit een onderzoeksproject binnen de wettelijke taken van Wageningen Bioveterinary Research (WBVR). Het project is een samenwerking van WBVR met NVWA, WFSR (Wageningen Food Safety Research) en de Faculteit Diergeneeskunde van de Universiteit Utrecht. Naast de evaluatie van de bestrijding, is onderzoek gedaan naar antibioticumresiduen in vogelontlasting. Deze informatie is niet in dit rapport opgenomen, maar wordt wel teruggekoppeld via de gebruikelijke halfjaarlijkse rapportages aan het ministerie van Landbouw, Natuur en Voedselkwaliteit.

The objective of this study was to explore the clinical, laboratory, and imaging features of severe Chlamydia psittaci pneumonia in order to improve early diagnosis and treatment success rates.We conducted a retrospective record review of 14 cases of severe Chlamydia psittaci pneumonia diagnosed by metagenomic next-generation sequencing technology in our hospital. We extracted and analyzed data on the clinical symptoms and signs, contact history, laboratory investigations, chest computed tomography, treatment, and clinical outcomes.Of the 14 patients, 12 (86%) were male and two (14%) were female, with a mean age of 57 years (SD: 7 years). Eleven patients (79%) had a history of poultry contact. The main clinical manifestations were fever (n = 14, 100%), flu-like symptoms (n = 10, 71%), cough, sputum (n = 9, 64%), and dyspnea (n = 5, 36%). Blood tests revealed marked elevation of neutrophil percentage, C-reactive protein, procalcitonin, brain natriuretic peptide, and creatine kinase levels; slight elevation of aspartate aminotransferase, creatinine, urea, fibrinogen, and D-dimer levels; and decreased albumin, sodium, and calcium levels. Chest computed tomography showed bilateral lesions (n = 7, 50%), middle-lower lobe lesions (n = 10, 71%), lesions in multiple lobes (n = 9, 64%), consolidation shadows (n = 11, 79%), and pleural effusions (n = 11, 79%). The median time from disease onset to hospital admission was 4.5 days (interquartile range: 1-17 days); the mean length of hospital stay was 20.9 ± 8.5 days, and the mean time from admission to diagnosis was 5.1 ± 2.6 days. After diagnosis, patients were either treated with doxycycline alone or doxycycline combined with quinolones. All 14 patients developed respiratory failure and received invasive mechanical ventilation; two (14%) received veno-venous extracorporeal membrane oxygenation, four (29%) received continuous renal replacement therapy, and three (21%) died.A poultry contact history and typical flu-like symptoms are early indicators of Chlamydia psittaci pneumonia. Substantial elevations in procalcitonin, creatine kinase, and brain natriuretic peptide indicate severe disease. Metagenomic next-generation sequencing is useful for diagnosis. Early empirical antibiotic therapy with quinolones can reduce the mortality in critically ill patients.

Chlamydia psittaci (C. psittaci) is a common zoonotic agent that affects both poultry and humans. Interleukin 10 (IL-10) is an anti-inflammatory factor produced during chlamydial infection, while dendritic cells (DCs) are powerful antigen-presenting cells that induce a primary immune response in the host. However, IL-10 and DCs regulatory mechanisms in C. psittaci infection remain elusive. In vivo and in vitro investigations of the regulatory mechanisms were performed. IL-10−/− mice, conditional DCs depletion mice (zinc finger dendritic cell-diphtheria toxin receptor [zDC-DTR]), and double-deficient mice (DD, IL-10−/−/zDCDTR/DTR) were intranasally infected with C. psittaci. The results showed that more than 90% of IL-10−/− mice, 70% of wild-type mice, and 60% of double-deficient mice survived, whereas all zDC-DTR mice died. A higher lymphocyte proliferation index was found in the IL-10 inhibitor mice and IL-10−/− mice. Moreover, severe lesions and high bacterial loads were detected in the zDC-DTR mice compared with double-deficient mice. In vitro studies revealed increased OX40-OX40 ligand (OX40-OX40L) activation and CD4+T cell proliferation. Besides, the expression of indoleamine 2, 3-dioxygenase (IDO), and regulatory T cells were significantly reduced in the co-culture system of CD4+ T cells and IL-10−/− DCs in C. psittaci infection. Additionally, the activation of the NLR family pyrin domain-containing 3 (NLRP3) inflammasome increased to facilitate the apoptosis of DCs, leading to rapid clearance of C. psittaci. Our study showed that IL-10−/− upregulated the function of deficient DCs by activating OX40-OX40L, T cells, and the NLPR3 inflammasome, and inhibiting IDO, and regulatory T cells. These effects enhanced the survival rate of mice and C. psittaci clearance. Our research highlights the mechanism of IL-10 interaction with DCs, OX40-OX40L, and the NLPR3 inflammasome, as potential targets against C. psittaci infection.

二代测序对少见感染、新型及复杂病原体感染的检出具有明显优势，对感染性疾病的诊断及抗感染治疗有一定的指导意义。本文报道1例二代测序在鹦鹉热衣原体重症肺炎患者诊治中的辅助作用。.

Occupational respiratory infections can be caused by bacterial, viral, and fungal pathogens. Transmission in occupational settings can occur from other humans, animals, or the environment, and occur in various occupations and industries. In this article, we describe 4 occupationally acquired respiratory infections at the focus of NIOSH investigations over the last decade: tuberculosis (TB), influenza, psittacosis, and coccidioidomycosis. We highlight the epidemiology, clinical manifestations, occupational risk factors, and prevention measures.

Chlamydia psittaci has not been reported to cause disease in domestic cats, to our knowledge. In contrast, C. felis infection is common in domestic cats and typically results in conjunctivitis, upper respiratory tract infection, and less frequently pneumonia. Herein, we report the pathologic findings and diagnostic features of a fatal case of psittacosis in a 7-wk-old domestic kitten. The animal was 1 of a litter of 5 that, together with the queen, were yielded to a pet rescue center in Wyoming. Over a period of ~3 wk, the kittens and queen became sick, thin, and icteric prior to death, despite antimicrobial treatments. Postmortem evaluation of a kitten revealed necrosuppurative hepatitis with Gimenez stain–positive intracellular bacteria, nonsuppurative pneumonia, and mild leptomeningitis. The diagnosis of psittacosis was made by 16S rRNA PCR using multiple primer sets and sequencing from liver. Psittacosis should be considered a differential diagnosis in domestic cats with intracellular bacterial hepatitis and interstitial pneumonia.

Late-term foal loss due to the traditional avian pathogen Chlamydia psittaci recently emerged as a threat to the Australian Thoroughbred industry. A longitudinal study of 14 stud farms was undertaken to better understand C. psittaci infection in pregnant mares and their foals by evaluating C. psittaci prevalence, equine herpesvirus-1 (EHV-1) co-infection, avian reservoirs, and potential risk factors. Mucosal swabs taken from 228 healthy pregnant mares and their foals were tested for C. psittaci and EHV-1 using species-specific qPCR assays. No foal loss was recorded due to either pathogen, and no mare tested positive to either C. psittaci or EHV-1. However, healthy newborn foals tested positive to both pathogens, at low levels, with 13.2% (n = 30/228) and 14.5% (n = 33/228) prevalence for C. psittaci and EHV-1, respectively. Co-infection occurred in 1.3% (n = 3/228) of foals. In avian environmental faecal samples collected from the same studs, C. psittaci was detected at 5.3% (n = 5/94). Multiple logistic regression modelling found that foals born in winter were more likely to be infected with C. psittaci (adjusted odds ratio = 15.83; P < 0.001; Confidence Interval 5.12-48.49). Being a maiden mare, absence of prophylactic vaginal suture, interventions in the last trimester and residing on a farm with prior history of C. psittaci abortion posed no higher risk to infection in the newborn. Analysis of all reported C. psittaci abortion cases (Hunter Valley, 2016-2019) revealed a dominant C. psittaci sequence type (denoted ST24) and a significant correlation with frost events (Spearmans' rho = 0.44; P = 0.002).

Psittacosis is a zoonotic disease caused by Chlamydia psittaci (C. psittaci), leading to high risk for animal industry and human health. Lack of reliable commercial kits and effective vaccines is hampering control of C. psittaci infection. Polymorphic outer membrane protein Gs (PmpGs) are enriched in diverse C. psittaci, and its role are unclear during C. psittaci infection. In the present study, pmp20G gene was cloned into pET-28a vector and then the constructed plasmid was transferred into Escherichia coli Rossetta (DE3). After denaturation and renaturation, the recombinant Pmp20G-N was identified by SDS-PAGE and Western blot. Afterwards Pmp20G-N was used as the coating antigen to develop an indirect ELISA (I-ELISA) assay. Both the specificity and sensitivity of Pmp20G-N ELISA were 100%, while the MOMP-ELISA had 93.65% sensitivity and 98.94% specificity, respectively. The concordance between MOMP-ELISA and Pmp20G-N ELISA assay was 98.1%. Hence, Pmp20G-N ELISA has the potential to be a diagnostic antigen for detection C. psittaci antibody. However, further studies are needed to be done for differentiating C. psittaci from Chlamydia spp. and other C.psittaci-specific serovars using Pmp20G-N ELISA.

A psitacose, também conhecida como ornitose, é geralmente uma doença com manifestações sistémicas proeminentes e alguns sintomas respiratórios, causada por Chlamydia psittaci. Os pássaros psitacinos são o principal reservatório e meio de transmissão da doença para os humanos.Descreve-se o caso clínico de uma doente de 50 anos, trabalhadora num armazém agro-avícola, que foi observada três vezes em contexto de urgência por quadro de dispneia, tosse seca, toracalgia, cansaço generalizado e febre. Relata-se o seu percurso e evolução até ao diagnóstico de pneumonia a Chlamydia psittaci.Este relato de caso reforça a importância de realizar sempre uma adequada anamnese, revelando-se preponderante para o sucesso diagnóstico e terapêutica dirigida.

Background and Objectives: Chlamydia psittaci, an obligate intracellular, Gram-negative zoonotic pathogen, has eight serovars and nine genotypes isolated from avian species with higher frequency in parrots and pigeons. The aim of this study was to characterize Chlamydia spp. using nested PCR and sequencing. Materials and Methods: A total of 270 pharyngeal swab samples collected randomly from asymptomatic pigeons of 30 pigeon aviaries in Tehran province. DNA was extracted with specific kit and amplified by specific primers in the first PCR and outer membrane protein A (ompA) gene in the second PCR. Positive samples were sequenced and phylogenetic tree analyzed based on the ompA gene. Results: Records showed that 16 of 30 (53%) pigeon aviaries were positive for Chlamydia spp. Phylogenetic tree analysis revealed that 15 of 16 (93.7%) positive samples, belonged to C. psittaci genotype B whereas the other sample belonged to C. avium. C. psittaci detected in 50% of pigeon aviaries that is high rate in Tehran province. Conclusion: As C. psittaci is a zoonosis and life threaten pathogen for human being, these results indicate the significance of it detection in asymptomatic pigeons. Also, this is the first report of Chlamydia avium presence in Iranian pigeons which its zoonotic potential is still unknown.

Psittacosis, caused by avian C. psittaci, has a major economic impact in the poultry industry worldwide and represents a significant risk for zoonotic transmission to humans. In the past decade, the tools of genetic manipulation have been improved for chlamydial molecular studies. While several genetic tools have been mainly developed in Chlamydia trachomatis, a stable gene-inducible shuttle vector system has not to date been available for C. psittaci. In this study, we adapted a C. trachomatis plasmid shuttle vector system to C. psittaci. We constructed a C. psittaci plasmid backbone shuttle vector called pCps-Tet-mCherry. The construct expresses GFP in C. psittaci. Importantly, exogeneous genes can be inserted at an MCS and are regulated by a tet promoter. The application of the pCps-Tet-mCherry shuttle vector system enables a promising new approach to investigate unknown gene functions of this pathogen., The obligate intracellular bacterium Chlamydia psittaci is a known avian pathogen causing psittacosis in birds and is capable of zoonotic transmission. In human pulmonary infections, C. psittaci can cause pneumonia associated with significant mortality if inadequately diagnosed and treated. Although intracellular C. psittaci manipulates host cell organelles for its replication and survival, it has been difficult to demonstrate host-pathogen interactions in C. psittaci infection due to the lack of easy-to-handle genetic manipulation tools. Here, we show the genetic transformation of C. psittaci using a plasmid shuttle vector that contains a controllable gene induction system. The 7,553-bp plasmid p01DC12 was prepared from the nonavian C. psittaci strain 01DC12. We constructed the shuttle vector pCps-Tet-mCherry using the full sequence of p01DC12 and the 4,449-bp fragment of Chlamydia trachomatis shuttle vector pBOMB4-Tet-mCherry. pCps-Tet-mCherry includes genes encoding the green fluorescent protein (GFP), mCherry, and ampicillin resistance (AmpR). Target genes can be inserted at a multiple cloning site (MCS). Importantly, these genes can be regulated by a tetracycline-inducible (tet) promoter. Using the pCps-Tet-mCherry plasmid shuttle vector, we show the expression of GFP, as well as the induction of mCherry expression, in C. psittaci strain 02DC15, which belongs to the avian C. psittaci 6BC clade. Furthermore, we demonstrated that pCps-Tet-mCherry was stably retained in C. psittaci transformants. Thus, our C. psittaci plasmid shuttle vector system represents a novel targeted approach that enables the elucidation of host-pathogen interactions. IMPORTANCE Psittacosis, caused by avian C. psittaci, has a major economic impact in the poultry industry worldwide and represents a significant risk for zoonotic transmission to humans. In the past decade, the tools of genetic manipulation have been improved for chlamydial molecular studies. While several genetic tools have been mainly developed in Chlamydia trachomatis, a stable gene-inducible shuttle vector system has not to date been available for C. psittaci. In this study, we adapted a C. trachomatis plasmid shuttle vector system to C. psittaci. We constructed a C. psittaci plasmid backbone shuttle vector called pCps-Tet-mCherry. The construct expresses GFP in C. psittaci. Importantly, exogeneous genes can be inserted at an MCS and are regulated by a tet promoter. The application of the pCps-Tet-mCherry shuttle vector system enables a promising new approach to investigate unknown gene functions of this pathogen.

Chlamydia psittaci is an obligate intracellular zoonotic pathogen that can enter a persistence state in host cells. While the exact pathogenesis is not well understood, this persistence state may play an important role in chronic Chlamydia disease. Here, we assess the effects of chlamydial persistence state in vitro and in vivo by transmission electron microscopy (TEM) and cDNA microarray assays. First, IFN-γ-induced C. psittaci persistence in HeLa cells resulted in the upregulation of 68 genes. These genes are involved in protein translation, carbohydrate metabolism, nucleotide metabolism, lipid metabolism and general stress. However, 109 genes were downregulated following persistent C. psittaci infection, many of which are involved in the TCA cycle, expression regulation and transcription, protein secretion, proteolysis and transport, membrane protein, presumed virulence factor, cell division and late expression. To further study differential gene expression of C. psittaci persistence in vivo, we established an experimentally tractable mouse model of C. psittaci persistence. The C. psittaci-infected mice were gavaged with either water or amoxicillin (amox), and the results indicated that the 20 mg/kg amox-exposed C. psittaci were viable but not infectious. Differentially expressed genes (DEGs) screened by cDNA microarray were detected, and interestingly, the results showed upregulation of three genes (euo, ahpC, prmC) and downregulation of five genes (pbp3, sucB_1, oppA_4, pmpH, ligA) in 20 mg/kg amox-exposed C. psittaci, which suggests that antibiotic treatment in vivo can induce chlamydial persistence state and lead to differential gene expression. However, the discrepancy on inducers between the two models requires more research to supplement. The results may help researchers better understand survival advantages during persistent infection and mechanisms influencing C. psittaci pathogenesis or evasion of the adaptive immune response.

Members of the Chlamydia genus are known to cause disease in both humans and animals. A variety of other species in the order Chlamydiales are increasingly being discovered and emerging as potential pathogens, yet there are scarce data on the diversity, prevalence and impacts of these pathogens in wild birds. To address this gap, we investigated which Chlamydiales species are present in a wild population of a common Australian parrot, the Crimson Rosella (Platycercus elegans). We collected cloacal swabs and serum from 136 individuals in south-eastern Australia, over two years, and tested several predictors of prevalence: age, sex, season and breeding status. We used multiple PCR assays to determine bacterial prevalence in cloacal swabs and a solid-phase ELISA to determine seroprevalence. We found Chlamydiales PCR prevalence of 27.7% (95% CI 20.2, 36.2) and identified at least two families (Chlamydiaceae and Parachlamydiaceae). Regarding known chlamydial avian pathogens, we found C. psittaci at 6.2% (95% CI 2.7, 11.8) and C. gallinacea at 4.6% (95% CI 1.7, 9.8) prevalence. We also identified at least two potentially novel Chlamydiales species, of unknown pathogenicity. Sex and breeding status predicted Chlamydiales PCR prevalence, with females more likely to be infected than males, and non-breeding birds more likely to be infected than breeding birds. Seroprevalence was 16% (95% CI 8.8, 25.9). Season and breeding status were strong predictors of seroprevalence, with highest seroprevalence in autumn and in non-breeding birds. Our results reveal a diversity of Chlamydiales species in this abundant wild host, and indicate that host-specific and temporal factors are associated with infection risk. Our findings suggest that wild parrots are a reservoir of both known and novel Chlamydiales lineages, of zoonotic and pathogenic potential.

During the 2016/2017 winter season, the influenza epidemic in the Netherlands lasted for 15 weeks. This was longer than the nine-week average duration of epidemics in the twenty previous seasons. Influenza subtype A(H3N2) was the dominant influenza virus throughout the season. In general, baseline natural immunity against A(H3N2) is relatively low among the elderly. Indeed, the number of patients older than 65 years, who visited a general practitioner (GP) for influenza-like symptoms, was higher than last year when influenza A(H1N1)pdm09 predominated. In nursing homes, the number of patients with influenza-like symptoms was also high. In total, an estimated 500,000 patients had symptomatic influenza in the period between the beginning of October 2016 and the end of May 2017 and 6,500 patients were admitted to hospital for influenza-related symptoms. During the epidemic, there were 7,500 more deaths than expected in this 15-week period. The effectiveness of the influenza vaccine against the A(H3N2) virus was 47 per cent. The circulating Dutch A(H3N2) viruses displayed a good to moderate match with the strain that was used in the 2016 vaccine. The WHO has recommended that the same strain be used for the trivalent vaccine for the 2017/2018 season in the northern hemisphere. The B component in the 2017 trivalent vaccine also remains the same as it was in 2016, but the A(H1N1)pdm09 component will be replaced with a more recent virus. The effectiveness of the vaccine varies every season because it is never known which influenza virus(es) will dominate in the next influenza season. Also, the circulating influenza viruses can evolve over time and deviate from the chosen vaccine viruses. There were more reports of the notifiable respiratory infectious diseases made in the 2016 calendar year than in previous years: tuberculosis (889 notifications), psittacosis (60 notifications) and legionellosis (454 notifications). The increase in legionellosis notifications may be associated with the warm, wet weather conditions in 2016. However, several geographic clusters were observed whose existence could not be explained by heavy rainfall or other weather conditions and for none of these clusters could the source of infection be found. The number of notifications for Q fever (14 notifications) is still decreasing. However, the notifiable infectious diseases that present as pneumonia are notoriously underreported because most cases of community-acquired pneumonia are managed in primary care without specific diagnostic laboratory tests being made.

During the 2016/2017 winter season, the influenza epidemic in the Netherlands lasted for 15 weeks. This was longer than the nine-week average duration of epidemics in the twenty previous seasons. Influenza subtype A(H3N2) was the dominant influenza virus throughout the season. In general, baseline natural immunity against A(H3N2) is relatively low among the elderly. Indeed, the number of patients older than 65 years, who visited a general practitioner (GP) for influenza-like symptoms, was higher than last year when influenza A(H1N1)pdm09 predominated. In nursing homes, the number of patients with influenza-like symptoms was also high. In total, an estimated 500,000 patients had symptomatic influenza in the period between the beginning of October 2016 and the end of May 2017 and 6,500 patients were admitted to hospital for influenza-related symptoms. During the epidemic, there were 7,500 more deaths than expected in this 15-week period. The effectiveness of the influenza vaccine against the A(H3N2) virus was 47 per cent. The circulating Dutch A(H3N2) viruses displayed a good to moderate match with the strain that was used in the 2016 vaccine. The WHO has recommended that the same strain be used for the trivalent vaccine for the 2017/2018 season in the northern hemisphere. The B component in the 2017 trivalent vaccine also remains the same as it was in 2016, but the A(H1N1)pdm09 component will be replaced with a more recent virus. The effectiveness of the vaccine varies every season because it is never known which influenza virus(es) will dominate in the next influenza season. Also, the circulating influenza viruses can evolve over time and deviate from the chosen vaccine viruses. There were more reports of the notifiable respiratory infectious diseases made in the 2016 calendar year than in previous years: tuberculosis (889 notifications), psittacosis (60 notifications) and legionellosis (454 notifications). The increase in legionellosis notifications may be associated with the warm, wet weather conditions in 2016. However, several geographic clusters were observed whose existence could not be explained by heavy rainfall or other weather conditions and for none of these clusters could the source of infection be found. The number of notifications for Q fever (14 notifications) is still decreasing. However, the notifiable infectious diseases that present as pneumonia are notoriously underreported because most cases of community-acquired pneumonia are managed in primary care without specific diagnostic laboratory tests being made.

This study includes a retrospective analysis of the diagnosis and treatment of a case of severe pneumonia from fulminant psittacosis with multiple organ failure. Next-generation sequencing (NGS) of the pathogen was conducted. The purpose of this study was to summarize the clinical, laboratory, and imaging characteristics of the case and to improve understanding of the value of NGS in the diagnosis of severe community-acquired pneumonia (CAP). Fulminant psittacosis can be manifested as severe pneumonia with rapid progression, acute respiratory distress syndrome, sepsis, and multiple organ failure. Imaging shows unilateral lung consolidation, which is difficult to differentiate from CAP caused by common pathogens. The NGS technology can early detect rare pathogens, thus reducing unnecessary use of antibiotics and shortening the course of the disease.

Avian chlamydiosis, is a highly contagious, systemic disease occuring in domestic and wild birds. Chlamydia psittaci, the causative agent of the disease, is a gram-negative bacterium in the Chlamydiaceae family that can only live within the cell. The agent can be transmitted directly to humans by contact with infected animals or feces of infected animals. It can also be transmitted by inhalation of fecal dust. Since the disease has a zoonotic character, it is also important in terms of public health. By using the monoclonal antibodies against cell wall proteins (OMP) of C.psittaci, six (A-F) and two (WC and M56) serotypes were determined in mammals. The aim of this study was to investigate and genotype the presence of C.psittaci ompA gene in domestic pigeon feces grown in family management style in ten different districts in Ankara in winter and summer seasons. Within the scope of the study, 100 pigeon stool samples were collected from birdhouses in 10 different districts of Ankara (Beypazari, Haymana, Kizilcahamam, Cubuk, Pursaklar, Bala, Cankaya, Polatli, Golbasi and city center) in two different seasons. DNA extraction from fecal samples was performed by classical methods. The presence of the agent in the extracted DNA samples was investigated by polymerase chain reaction (PCR) analysis of the ompA gene. Two-way sequence analysis of the ompA gene was performed with the primers used in the study from the target DNA products amplified by PCR. The results of sequence analysis were compared with the international database and serotyping/genotyping was performed. In the study, C.psittaci ompA gene was detected in 6 (6%) samples of 100 pigeon stool samples. Among these positive samples, two were from Bala (one sample from winter, one sample from summer), two were from Haymana (one sample from winter, one sample from summer) and two were from Golbasi (one sample from winter, one sample from summer); where the same agent was isolated in the same aviaries in different seasons. In this study, no difference was found between the presence of C.psittaci in pigeon droppings and season. In addition when the sequence analysis of the isolated samples were compared with the World database; all isolates were found to be 100% genotype B and 99% genotype E. In this study, the sequence analysis of the ompA gene of C.psittaci from domestic pigeon feces was determined for the first time in Turkey. Although the presence of C.psittaci in domestic pigeons is low, it is a zoonotic bacterium and is important for the public health.

Chlamydiae are obligate intracellular bacteria globally widespread across humans, wildlife, and domesticated animals. Chlamydia psittaci is a primarily zoonotic pathogen with multiple hosts, which can be transmitted to humans, resulting in psittacosis or ornithosis. Since this pathogen is a well-recognized threat to human and animal health, it is critical to unravel in detail the genetic make-up of this microorganism. Though many genomes of C. psittaci have been studied to date, little is known about the variants of chlamydial organisms causing infection in Russian livestock. This research is the first de novo genome assembly of the C. psittaci strain Rostinovo-70 of zoonotic origin that was isolated in Russian Federation. The results were obtained by using standard protocols of sequencing with the Illumina HiSeq 2500 and Oxford Nanopore MinION technology that generated 3.88 GB and 3.08 GB of raw data, respectively. The data obtained are available in NCBI DataBase (GenBank accession numbers are CP041038.1 & CP041039.1). The Multi-Locus Sequence Typing (MLST) showed that the strain Rostinovo-70 together with C. psittaci GR9 and C. psittaci WS/RT/E30 belong to the sequence type (ST)28 that could be further separated into two different clades. Despite C. psittaci Rostinovo-70 and C. psittaci GR9 formed a single clade, the latter strain did not contain a cryptic plasmid characteristis to Rostinovo-70. Moreover, the genomes of two strains differed significantly in the cluster of 30 genes that in Rostinovo-70 were closer to Chlamydia abortus rather than C. psittaci. The alignment of the genomes of C. psittaci and C. abortus in this area revealed the exact boarders of homologous recombination that occurred between two Chlamydia species. These findings provide evidence for the first time of genetic exchange between closely related Chlamydia species. Keywords: Chlamydia psittaci, Genome assembly, de novo genome, Rostinovo-70, Illumina HiSeq 2500 platform, Oxford Nanopore MinION

Chlamydia psittaci is a highly zoonotic bacteria distributed worldwide; it is responsible for psittacosis, one of the most important infectious diseases affecting the Psittacidae, mostly parrots. This work was aimed at determining C. psittaci prevalence and genotype in 177 parrots confiscated in Colombia; cloacal swab (166) and faecal (177) samples were analysed from birds confiscated and housed in a Temporary Wildlife Reception Centre (Centro de Reception de Fauna Temporal). Conventional PCR was run on the samples for amplifying the MOMP gene and then the ompA gene. The C. psittaci genotype A was found in 81.3 % (144/177) of the birds analysed. Cloacal swabs accounted for 129/166 (77.7 %) positive samples and faecal matter for 53/177 (29.9 %), 38 birds proving positive for both types of sample; there was an 8.15 times greater probability of detection for cloacal swabs compared to faecal swabs (p0.05). Clinical examination findings were correlated with the animals' positivity for cloacal swabs, faecal matter or both, finding a statistically significant relationship with low respiratory rate (p0.05) and broken plumage for cloacal swab sample results (p0.1). Even though 85 % seroprevalence has previously been reported in Colombia using indirect ELISA, this study reports for the first time C. psittaci genotype A endemicity in psittacines in captivity in Colombia using molecular techniques, considering the zoonotic risk involved in having these birds as pets.

Chlamydia psittaci is an obligate intracellular pathogen with a biphasic developmental life cycle. It is auxotrophic for a variety of essential metabolites and obtains amino acids from eukaryotic host cells. Chlamydia can develop inside host cells within chlamydial inclusions. A pathway secreting proteins from inclusions into the host cellular cytoplasm is the type III secretion system (T3SS). The T3SS is universal among several Gram-negative bacteria. Here, we show that CPSIT_0959 of C. psittaci is expressed midcycle and secreted into the infected cellular cytoplasm via the T3SS. Recombinant CPSIT_0959 possesses cysteine desulfurase and PLP-binding activity, which removes sulfur from cysteine to produce alanine, and helps chlamydial replication. Our study shows that CPSIT_0959 improve the infectivity of offspring elementary bodies and seems to promote the replication by its product. This phenomenon has inhibited by the PLP-dependent enzymes inhibitor. Moreover, CPSIT_0959 increased expression of Bim and tBid, and decreased the mitochondrial membrane potential of host mitochondria to induce apoptosis in the latecycle for release of offspring. These results demonstrate that CPSIT_0959 has cysteine desulfurase and PLP-binding activity and is likely to contribute to apoptosis of the infected cells via a mitochondria-mediated pathway to improve the infectivity of progeny.

Background: For more than 200 years people in the Faroe Islands have supplemented their food by hunting different species of wild birds in the Faroe Islands. Traditionally, juvenile fulmars (Fulmarus glacialis) are caught at sea in late August. The fulmars may be infected or colonized with the bacterium Chlamydophila psittaci which may infect the hunter by the respiratory route and mostly presents as an atypical pneumonia, also called psittacosis or ornithosis or parrot fever. In the Faroe Islands it is called ‘nátasjúka’ meaning ‘fulmar disease’. Historically, it has also been called ‘September Pneumonia’ in the Faroe Islands. Methods: A case series with patients infected with Chlamydophila psittaci. Results: All four cases presented in this article occurred around the month of September. Improved hygiene measures during the last 50 years in handling the fulmar birds have led to a decline of verified psittacosis in the Faroe Islands. After the last two hunting seasons (2016–2017), four cases of psittacosis were diagnosed and treated in the Faroe Islands. Only nine cases of verified psittacosis have been reported to the Chief Medical Officer of the Faroe Islands during the last 27 years. Conclusions: There is an association between catching and handling Fulmarus glacialis and human psittacosis disease in the Faroe Islands. Clinicians treating patients with contact with fulmars should be aware of this zoonotic disease.

Background Members of the phylum Chlamydiae are obligate intracellular pathogens of humans and animals and have a serious impact on host health. They comprise several zoonotic species with varying disease outcomes and prevalence. To investigate differences in virulence, we focused on Chlamydia psittaci, C. abortus and Waddlia chondrophila. Most threatening is C. psittaci, which frequently infects humans and causes psittacosis associated with severe pneumonia. The closest relative of C. psittaci is C. abortus, which shares the vast majority of genes but less frequently infects humans, and causes stillbirth and sepsis. W. chondrophila is more distantly related, and occasional human infections are associated with respiratory diseases or miscarriage. One possible explanation for differences in virulence originate from species-specific genes as well as differentially expressed homologous virulence factors. Results RNA-sequencing (RNA-Seq) was applied to purified infectious elementary bodies (EBs) and non-infectious reticulate bodies (RBs) in order to elucidate the transcriptome of the infectious and replicative chlamydial states. The results showed that approximately half of all genes were differentially expressed. For a descriptive comparison, genes were categorised according to their function in the RAST database. This list was extended by the inclusion of inclusion membrane proteins, outer membrane proteins, polymorphic membrane proteins and type III secretion system effectors. In addition, the expression of fifty-six known and a variety of predicted virulence and immunogenic factors with homologs in C. psittaci, C. abortus and W. chondrophila was analysed. To confirm the RNA-Seq results, the expression of nine factors was validated using real-time quantitative polymerase chain reaction (RT-qPCR). Comparison of RNA-Seq and RT-qPCR results showed a high mean Pearson correlation coefficient of 0.95. Conclusions It was shown that both the replicative and infectious chlamydial state contained distinctive transcriptomes and the cellular processes emphasised in EBs and RBs differed substantially based on the chlamydial species. In addition, the very first interspecies transcriptome comparison is presented here, and the considerable differences in expression of homologous virulence factors might contribute to the differing infection rates and disease outcomes of the pathogens. The RNA-Seq results were confirmed by RT-qPCR and demonstrate the feasibility of interspecies transcriptome comparisons in chlamydia. Electronic supplementary material The online version of this article (10.1186/s12864-018-4961-x) contains supplementary material, which is available to authorized users.