Stefanie Lagae

Bio: Stefanie Lagae is an academic researcher from Ghent University. The author has contributed to research in topics: Chlamydia psittaci & Psittacosis. The author has an hindex of 5, co-authored 8 publications receiving 143 citations.

Emerging Chlamydia psittaci infections in chickens and examination of transmission to humans

Abstract: Chlamydia psittaci and atypical Chlamydiaceae infections are (re)-emerging in chickens. We therefore examined the prevalence of C. psittaci, atypical Chlamydiaceae and their zoonotic transmission on 19 Belgian chicken farms. Atypical Chlamydiaceae were not detected in chickens but 18 out of 19 farms were positive for C. psittaci by culture and PCR. C. psittaci ompA genotypes A and D were discovered. None of the examined humans (n = 31) was infected with atypical Chlamydiaceae, but 29 (93.5%) of them were positive for C. psittaci by culture and PCR. Genotypes A, D and a mixed infection with genotypes C and D were found. Humans (n = 2) working at the C. psittaci-negative farm never had respiratory complaints, while 25 out of 29 positive farmers (86.2%) reported yearly medical complaints potentially related to psittacosis. Four of them currently experienced respiratory disease and one of them was being treated with antibiotics. Four farmers (12.5%) mentioned that they had pneumonia after starting to keep chickens. Occupational physicians should be aware of emerging Chlamydiaceae infections in chickens.

Pathogenicity of low and highly virulent Chlamydia psittaci isolates for specific-pathogen-free chickens.

Abstract: SUMMARY In commercially raised poultry, chlamydiosis mostly seems to occur on turkey or duck farms, sometimes associated with zoonotic transmission and disease (psittacosis) in humans. However, Chlamydia infections are apparently emerging in chickens, and information on the virulence of Chlamydia in chickens is limited. Up-to-date Chlamydia psittaci genotypes B and D are most frequently found in broilers. We examined the pathogenicity of the well-characterized C. psittaci genotype B (CP3) and D (92/1293) strains in experimentally (aerosol) infected specific-pathogen-free chickens. Both strains caused conjunctivitis, rhinitis, and dyspnea. Pharyngeal and cloacal C. psittaci excretion was observed in all infected animals, indicative for systemic dissemination as proven by immunofluorescence staining of frozen tissue sections. Histopathologic lesions were present in all infected chickens. However, differences in pathology were observed. Genotype D led to mortality and more severe clinical signs and lesions a...

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

Abstract: 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.

Induction of mucosal immunity through systemic immunization: Phantom or reality?

Abstract: Generation of protective immunity at mucosal surfaces can greatly assist the host defense against pathogens which either cause disease at the mucosal epithelial barriers or enter the host through these surfaces. Although mucosal routes of immunization, such as intranasal and oral, are being intensely explored and appear promising for eliciting protective mucosal immunity in mammals, their application in clinical practice has been limited due to technical and safety related challenges. Most of the currently approved human vaccines are administered via systemic (such as intramuscular and subcutaneous) routes. Whereas these routes are acknowledged as being capable to elicit antigen-specific systemic humoral and cell-mediated immune responses, they are generally perceived as incapable of generating IgA responses or protective mucosal immunity. Nevertheless, currently licensed systemic vaccines do provide effective protection against mucosal pathogens such as influenza viruses and Streptococcus pneumoniae. However, whether systemic immunization induces protective mucosal immunity remains a controversial topic. Here we reviewed the current literature and discussed the potential of systemic routes of immunization for the induction of mucosal immunity.

Genital Chlamydia trachomatis: Understanding the Roles of Innate and Adaptive Immunity in Vaccine Research

Abstract: SUMMARY Chlamydia trachomatis is the leading cause of bacterial sexually transmitted disease worldwide, and despite significant advances in chlamydial research, a prophylactic vaccine has yet to be developed. This Gram-negative obligate intracellular bacterium, which often causes asymptomatic infection, may cause pelvic inflammatory disease (PID), ectopic pregnancies, scarring of the fallopian tubes, miscarriage, and infertility when left untreated. In the genital tract, Chlamydia trachomatis infects primarily epithelial cells and requires Th1 immunity for optimal clearance. This review first focuses on the immune cells important in a chlamydial infection. Second, we summarize the research and challenges associated with developing a chlamydial vaccine that elicits a protective Th1-mediated immune response without inducing adverse immunopathologies.

Animal Models for Studying Female Genital Tract Infection with Chlamydia trachomatis

Abstract: Chlamydia trachomatis is a Gram-negative obligate intracellular bacterial pathogen. It is the leading cause of bacterial sexually transmitted disease in the world, with more than 100 million new cases of genital tract infections with C. trachomatis occurring each year. Animal models are indispensable for the study of C. trachomatis infections and the development and evaluation of candidate vaccines. In this paper, the most commonly used animal models to study female genital tract infections with C. trachomatis will be reviewed, namely, the mouse, guinea pig, and nonhuman primate models. Additionally, we will focus on the more recently developed pig model.