Detection of Chlamydophila psittaci in asymptomatic animals

Clinical metagenomic sequencing for rapid diagnosis of pneumonia and meningitis caused by Chlamydia psittaci

BACKGROUND

Chlamydia psittaci (C. psittaci) is a gram-negative intracellular parasitic pathogenic bacterium that can infect avian and mammalian hosts, including humans. The detection of C. psittaci infections typically relies on traditional antigen-based immunoassays or serological testing that often lack sensitivity and/or specificity. Metagenomic next generation sequencing (mNGS) is an emerging tool for diagnosis.

AIM

To demonstrate that mNGS represents a valuable tool for rapid, sensitive, and accurate pathogen detection including C. psittaci infections.

METHODS

Four cases of psittacosis pneumonia and one case of pediatric psittacosis meningitis were diagnosed between December 2019 and May 2020 using mNGS at Changzhou Second People’s Hospital affiliated to Nanjing Medical University. Patients’ clinical characteristics, manifestations, and treatment histories were retrospectively evaluated.

RESULTS

All five patients had a history of exposure to wild (psittacine or other birds) or domesticated birds (chickens). All patients had a high fever (> 39℃) and three of them (60%) experienced organ insufficiency during the disease. The laboratory data showed normal to slightly increased leucocyte and neutrophil counts, and elevated procalcitonin levels in all five cases, and very high C-reactive protein levels in psittacosis pneumonia patients. mNGS identified a potential pathogen, C. psittaci, in patients’ bronchoalveolar lavage fluid or cerebrospinal fluid. Computed tomography revealed lung air-space consolidation, pleural thickening, and effusion fluid buildup in psittacosis pneumonia cases, and an arachnoid cyst in the right temporal lobe of the pediatric psittacosis meningitis patient. All patients experienced complete recovery following the administration of targeted anti-chlamydia therapy.

CONCLUSION

This study not only demonstrated that mNGS represents a valuable tool for rapid, sensitive, and accurate pathogen detection, but also raised public health concerns over C. psittaci infections.

Animal sources for zoonotic transmission of psittacosis: a systematic review

Background

Human psittacosis, caused by Chlamydia (C.) psittaci, is likely underdiagnosed and underreported, since tests for C. psittaci are often not included in routine microbiological diagnostics. Source tracing traditionally focuses on psittacine pet birds, but recently other animal species have been gaining more attention as possible sources for human psittacosis. This review aims to provide an overview of all suspected animal sources of human psittacosis cases reported in the international literature. In addition, for each animal species the strength of evidence for zoonotic transmission was estimated.

Methods

A systematic literature search was conducted using four databases (Pubmed, Embase, Scopus and Proquest). Articles were included when there was mention of at least one human case of psittacosis and a possible animal source. Investigators independently extracted data from the included articles and estimated strength of evidence for zoonotic transmission, based on a self-developed scoring system taking into account number of human cases, epidemiological evidence and laboratory test results in human, animals, and the environment.

Results

Eighty articles were included, which provided information on 136 different situations of possible zoonotic transmission. The maximum score for zoonotic transmission was highest for turkeys, followed by ducks, owls, and the category ‘other poultry’. Articles reporting about zoonotic transmission from unspecified birds, psittaciformes and columbiformes provided a relatively low strength of evidence. A genotypical match between human and animal samples was reported twenty-eight times, including transmission from chickens, turkeys, guinea fowl, peafowl, pigeons, ducks, geese, songbirds, parrot-like birds and owls.

Conclusions

Strong evidence exists for zoonotic transmission from turkeys, chickens and ducks, in addition to the more traditionally reported parrot-like animal sources. Based on our scoring system, the evidence was generally stronger for poultry than for parrot-like birds. Psittaciformes should not be disregarded as an important source of human psittacosis, still clinicians and public health officials should include poultry and birds species other than parrots in medical history and source tracing.

SEROPREVALENCE OF Chlamydia psittaci IN CAPTIVE MACAWS (Ara spp.) IN THE DEPARTMENT OF LIMA, PERU

Abstract The presence of Chlamydia psittaci in captive psittacines may have a subclinical presentation, despite its importance in immunosuppressed birds and humans because of its zoonotic potential. The aim of this study was to determine the seroprevalence of C. psittaci in macaws (Ara spp.). Birds were kept in captivity in three zoos in the department of Lima. In total, 34 adult birds (11 Ara macao, 15 Ara ararauna, 5 Ara chloropterus, and 7 Ara severus) were studied. A total of 0.5 mL of blood was obtained from the right jugular vein and placed into a coagulant-free tube. Blood serum was analyzed using an ELISA (Immunocomb Avian Chlamidopophila psittaci kit) in order to determine IgG antibody titers. The presence of antibodies to C. psittaci in macaws are reported for the first time in Peru, with a seroprevalence of 44.74 ± 15.84% (17/38). No significant differences between the origin of birds and the presence of the antibodies were found.

Laboratory methods for case finding in human psittacosis outbreaks: a systematic review

Background

Psittacosis outbreak investigations require rapid identification of cases in order to trace possible sources and perform public health risk assessments. In recent outbreaks in the Netherlands, such investigations were hampered by the non-specificity of laboratory testing methods to identify human Chlamydia psittaci infections.

Method

A systematic search of PubMed and Scopus databases of literature published between 01 January, 1986 and 03 July, 2017 was done to find best practices of laboratory-testing methods used in psittacosis outbreaks of two or more human cases. Reference lists of included articles were hand searched to identify additional articles.

Results

Thirty-seven eligible articles were identified, describing 44 human psittacosis outbreaks in 12 countries. Laboratory tests performed were PCR (with various targets), serologic tests (complement binding reactions, ELISA’s, immunofluorescence tests and immuno-peroxidase tests) and culture, in various combinations. The literature provided no ‘gold standard’ laboratory testing strategy to identify recent human C. psittaci infections. In most psittacosis outbreaks, for a considerable number of cases (or tested individuals in an exposed cohort), C. psittaci infection could not be confirmed, nor excluded as causative pathogen. None of the testing strategies was found to be suitable for (nearly) full case finding.

Conclusion

PCR enables rapid identification of human psittacosis patients and helps source finding by genotyping but has the disadvantage that sensitivity is high only in the acute phase. In outbreak situations, there is often a time delay and therefore, there is a need for new serologic testing methods next to PCR, with good specificity and sensitivity. Moreover, serum is easier to collect than the preferred diagnostic materials for PCR. A serologic test that can reliably confirm infection status without the necessity of convalescent serum sampling would enhance case finding, source tracing, identification of risk factors and assessment of burden of disease in various settings.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3317-0) contains supplementary material, which is available to authorized users.

Chlamydia psittaci EN AVES PSITACIDAS EN DOS PARQUES ZOOLÓGICOS DE VENEZUELA

La determinación de Chlamydia psittaci (Cp) en aves psitácidas en parques zoológicos de Venezuela representa una estrategia de conservación y preservación para este grupo de aves, donde múltiples especies se encuentran amenazadas de extinción y otras han perdido su capacidad de reincorporación a su hábitat natural. A través de la reacción en cadena de la polimerasa anidada (PCR) fue amplificada la subunidad 16S del ADNr de Cp en 50 muestras de hisopado cloacal de aves psitácidas, reportando una frecuencia de 62 %. El trabajo fue realizado en el  Parque Zoológico Las Delicias (PZD) 8 % y el Aquarium de Valencia (AV) 54 %. La elevada frecuencia fue asociada a un genotipo de baja concentración y virulencia debido a la ausencia de signos clínicos de clamidiosis aviar. Estos resultados demuestran la necesidad de promover la detección de Cp, principalmente para el AV que actúa como centro de recepción de ejemplares de decomiso, y, al igual que el PZD, poseen otras especies vulnerables a la extinción con riesgo de infección a Cp. 

Prevalence of antibodies to Chlamydiaceae in pet dogs in Shenzhen, Guangdong Province, China

The prevalence of chlamydiosis in pet dogs was surveyed in Shenzhen, Guangdong Province, China. A total of 442 serum samples were collected from three districts of Shenzhen, namely the Futian, Nanshan, and Luohu Districts, and assayed for Chlamydiaceae antibodies by indirect haemagglutination assay. The results showed that the mean positive rate was 6.11%, and the positive rate for the Futian District was the highest (9.52%), followed by the Nanshan District (7.08%), and the Luohu District (4.02%). The positive rate for male dogs was 6.08%, and for female dogs 6.16%. Out of all the 38 breeds of dogs examined, 14 breeds were positive. The positive rate for the Cocker Spaniel dog was the highest (14.2%), followed by the Pekinese dog (10.71%), and the Border Collie dog (10.34%). This is the first time that the seroprevalence of Chlamydiaceae infection in pet dogs in Shenzhen, Guangdong province, China was reported, and the results indicated that pet dogs may be an important source for human infection by Chlamydiaceae in Shenzhen and other areas of China.

Ornithosis – case report and actual questions

A szerzők egy kritikus állapotú, intenzív osztályon ápolt beteg esetének ismertetése kapcsán foglalják össze az ornithosisdiagnosztika jelenlegi lehetőségeit, epidemiológiai, valamint terápiás vonatkozásait. A kórkép egyéb atípusos bakteriális kórképektől való elkülönítése a klinikai tünetek alapján megbízhatóan nem lehetséges, éppen ezért döntő, olykor életmentő jelentőséggel bír a madárkontaktus felderítése. Az anamnesztikus adatokat rögzítő klinikust mindez egyből a helyes diagnózis felé terelheti, ami az adekvát terápia révén gyors gyógyulást eredményezhet. E bejelentendő kórkép feltehetően mindmáig a gyakran félre- vagy későn diagnosztizált infekciók közé tartozik, így az alulreprezentáltnak tekinthető esetszám nem tükrözi a hazai valós epidemiológiai helyzetet. A szerzők célja, hogy felhívják a figyelmet erre a nem is olyan ritka, ám akár halálos kimenetelű megbetegedésre.

Chlamydial infection: the link with ocular adnexal lymphomas

Chlamydiae are obligate intracellular bacteria that grow in eukaryotic cells and cause a wide spectrum of diseases. They can establish persistent infections, are mitogenic in vitro, promote polyclonal cell proliferation in vivo and induce resistance to apoptosis in infected cells-properties that might contribute to tumorigenesis. In fact, Chlamydophila psittaci (Cp) has been linked to the development and maintenance of ocular adnexal marginal zone B-cell lymphoma (OAMZL). In this indolent malignancy, Cp is transported by monocytes and macrophages and causes both local and systemic infection. Cp elementary bodies are viable and infectious in the conjunctiva and peripheral blood of patients with OAMZL. Bacterial eradication with antibiotic therapy is often followed by lymphoma regression. Despite recent advances in the understanding of this bacterium-lymphoma association, several questions remain unanswered. For instance, prevalence variations among different geographical areas and related diagnostic and therapeutic implications remain a major investigational issue. We will focus on clinical and therapeutic implications of chlamydial infections in patients with lymphomas and summarize the current knowledge on the association between Cp infection and OAMZL. Available data on the epidemiology, biology and pathogenesis of this association are analyzed and new investigative and clinical approaches are discussed.

Detection of Borrelia burgdorferi sensu lato and Chlamydophila psittaci in throat and cloacal swabs from birds migrating through Slovakia

We have screened 91 migratory birds representing 32 species during the autumn of 2003 for the presence of the zoonotic pathogens Borrelia and Chlamydophila. Using polymerase chain reaction (PCR), B. burgdorferi sensu stricto was detected in cloacal swabs and, in two causes, also in throat swabs in 8 individuals (8.7 %) representing 7 birds species; B. garinii and B. afzelii were not detected. C. psittaci was detected only in cloacal swabs; 6 birds (6.6 %) from four species were found to be positive. The PCR products were sequenced and the sequences were compared phylogenetically with the gene sequences of 14 Chlamydophila strains retrieved from nucleotide databases; although the sequenced DNA was only 110 bp long, all obtained sequences created a new cluster with sublines branching from a position close to the periphery of the genus. All tested samples appear distinct within the known species and were most similar to C. felis or C. abortis.