Understanding uveitis: The impact of research on visual outcomes

Evidence for the existence of two new members of the family Chlamydiaceae and proposal of Chlamydia avium sp. nov. and Chlamydia gallinacea sp. nov.

Psittacosis, also known as parrot fever and ornithosis, is a bacterial infection that can cause severe pneumonia and other serious health problems in humans. It is caused by Chlamydia psittaci. Reclassification of the order Chlamydiales in 1999 into 2 genera (Chlamydia and Chlamydophila) was not wholly accepted or adopted. This resulted in a reversion to the single, original genus Chlamydia, which now encompasses all 9 species including Chlamydia psittaci. During 2003–2014, 112 human cases of psittacosis were reported to the Centers for Disease Control and Prevention through the Nationally Notifiable Diseases Surveillance System. While many types of birds can be infected by C psittaci, in general, the literature suggests that human cases can most often occur after exposure to infected parrot-type birds kept as pets, especially cockatiels, parakeets, and conures. In birds, C psittaci infection is referred to as avian chlamydiosis. Infected birds shed the bacteria through feces and nasal discharges, and humans become infected from exposure to these materials. This compendium provides information about psittacosis and avian chlamydiosis to public health officials, physicians, veterinarians, the pet bird industry, and others concerned with controlling these diseases and protecting public health. The recommendations in this compendium provide standardized procedures to control C psittaci infections. This document will be reviewed and revised as necessary, and the most current version replaces all previous versions. This document was last revised in 2010. Major changes in this version include a recommendation for a shorter treatment time for birds with avian chlamydiosis, additional information about diagnostic testing, including genotyping, clearer language associated with personal protective equipment recommended for those caring for confirmed or exposed birds, and incorporating a grading scale with recommendations generally based on the United States Preventive Services Task Force's methods.

/pdf/compendium-of-measures-to-control-chlamydia-psittaci-12tvmsg0cg.pdf

Compendium of Measures to Control Chlamydia psittaci Infection Among Humans (Psittacosis) and Pet Birds (Avian Chlamydiosis), 2017.

Chlamydia (C.) psittaci is an economically relevant pathogen in poultry and pet birds, where it causes psittacosis/ornithosis, and also a human pathogen causing atypical pneumonia after zoonotic transmission. Despite its well-documented prevalence, the agent has received less attention by researchers than other Chlamydia spp. in the last decades. In the present paper, we review recently published data on C. psittaci infection and attempt to single out characteristic features distinguishing it from related chlamydial agents. It is remarkable that C. psittaci is particularly efficient in disseminating in the host organism causing systemic disease, which occasionally can take a fulminant course.

 At the cellular level, the pathogen's broad host cell spectrum (from epithelial cells to macrophages), its rapid entry and fast replication, proficient use of intracellular transport routes to mitochondria and the Golgi apparatus, the pronounced physical association of chlamydial inclusions with energy-providing cell compartments, as well as the subversive regulation of host cell survival during productive and persistent states facilitate the characteristic efficient growth and successful host-to-host spread of C. psittaci.

 At the molecular level, the pathogen was shown to upregulate essential chlamydial genes when facing the host immune response. We hypothesize that this capacity, in concert with expression of specific effectors of the type III secretion system and efficient suppression of selected host defense signals, contributes to successful establishment of the infection in the host.

 Concerning the immunology of host–pathogen interactions, C. psittaci has been shown to distinguish itself by coping more efficiently than other chlamydiae with pro-inflammatory mediators during early host response, which can, to some extent, explain the effective evasion and adaptation strategies of this bacterium.

 We conclude that thorough analysis of the large number of whole-genome sequences already available will be essential to identify genetic markers of the species-specific features and trigger more in-depth studies in cellular and animal models to address such vital topics as treatment and vaccination.

/pdf/chlamydia-psittaci-update-on-an-underestimated-zoonotic-2zpip6mtpy.pdf

Chlamydia psittaci: update on an underestimated zoonotic agent.

https://biblio.ugent.be/publication/5967065/file/7202782.pdf

Bacterial Zoonoses Transmitted by Household Pets: State-of-the-Art and Future Perspectives for Targeted Research and Policy Actions

Chlamydia psittaci is a zoonotic pathogen with a wide range of avian hosts and worldwide geographical spread. Zoonotic transfer occurs by inhalation or direct contact and may cause psittacosis or parrot disease. Host reservoirs of particular epidemiological interest include gregarious or migratory species, as colonial behavior facilitates microbial spread amongst conspecifics and a migratory ecology permits disperse over a wide geographic region. The current study detected C. psittaci antibodies in 76 of 81 (93.8%) feral Canada geese (Branta canadensis) using a species-specific enzyme-linked immunosorbent assay. Viable C. psittaci were isolated from pharyngeal swabs of 47 of 81 (58%) birds, and subsequent ompA-based genotyping revealed genotypes E, B, and E/B. Absence of clinical symptoms in these geese could reflect a strong natural protection or a persistent infection. Canada geese are considered an important alien species in Europe. Current results denote that this avian reservoir poses a considerable risk to native wildlife as a potential source of C. psittaci.

Prevalence and Genotype Distribution of Chlamydia psittaci in Feral Canada Geese (Branta canadensis) in Belgium

Human psittacosis is a zoonotic infectious disease, which is caused by the obligate intracellular bacterium Chlamydia psittaci. Transmission of the disease usually originates from close contact wit...

https://journals.sagepub.com/doi/pdf/10.1177/153567601201700206

Chlamydia psittaci, causative agent of avian chlamydiosis and human psittacosis: risk assessment and biosafety recommendations for laboratory use

Y. Pannekoek, D.S.A. Beeckman, V. Dickx, E. Vretou, D. Vanrompay and A. van der Ende 1 Academic Medical Center, Center for Infection and Immunity Amsterdam (CINIMA), Department of Medical Microbiology, Amsterdam, the Netherlands; 2 Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium; 3 Laboratory of Biotechnology, Department of Microbiology, Hellenic Pasteur Institute, Athens, Greece

https://biblio.ugent.be/publication/1037702/file/1038233.pdf

Veerle Dickx

Papers

Prevalence and Genotype Distribution of Chlamydia psittaci in Feral Canada Geese (Branta canadensis) in Belgium

Chlamydia psittaci, causative agent of avian chlamydiosis and human psittacosis: risk assessment and biosafety recommendations for laboratory use

Multi locus sequence typing of Chlamydiales: clonal groupings within Chlamydophila abortus and host associated genotypes of Chlamydophila psittaci