Veerle Dickx

Multi Locus Sequence Typing of Chlamydia Reveals an Association between Chlamydia psittaci Genotypes and Host Species

Chlamydia comprises a group of obligate intracellular bacterial parasites responsible for a variety of diseases in humans and animals, including several zoonoses. Chlamydia trachomatis causes diseases such as trachoma, urogenital infection and lymphogranuloma venereum with severe morbidity. Chlamydia pneumoniae is a common cause of community-acquired respiratory tract infections. Chlamydia psittaci, causing zoonotic pneumonia in humans, is usually hosted by birds, while Chlamydia abortus, causing abortion and fetal death in mammals, including humans, is mainly hosted by goats and sheep. We used multi-locus sequence typing to asses the population structure of Chlamydia. In total, 132 Chlamydia isolates were analyzed, including 60 C. trachomatis, 18 C. pneumoniae, 16 C. abortus, 34 C. psittaci and one of each of C. pecorum, C. caviae, C. muridarum and C. felis. Cluster analyses utilizing the Neighbour-Joining algorithm with the maximum composite likelihood model of concatenated sequences of 7 housekeeping fragments showed that C. psittaci 84/2334 isolated from a parrot grouped together with the C. abortus isolates from goats and sheep. Cluster analyses of the individual alleles showed that in all instances C. psittaci 84/2334 formed one group with C. abortus. Moving 84/2334 from the C. psittaci group to the C. abortus group resulted in a significant increase in the number of fixed differences and elimination of the number of shared mutations between C. psittaci and C. abortus. C. psittaci M56 from a muskrat branched separately from the main group of C. psittaci isolates. C. psittaci genotypes appeared to be associated with host species. The phylogentic tree of C. psittaci did not follow that of its host bird species, suggesting host species jumps. In conclusion, we report for the first time an association between C. psittaci genotypes with host species.

Chlamydophila psittaci Zoonotic Risk Assessment in a Chicken and Turkey Slaughterhouse

ABSTRACT Chlamydophila psittaci causes respiratory disease in poultry and can be transmitted to humans. We conducted a C. psittaci zoonotic risk assessment study of a chicken and turkey slaughterhouse. Eighty-five percent of the slaughtered chicken flocks tested positive by PCR and culture. Genotype D was discovered. Fifty-seven percent of the slaughtered turkey flocks tested positive by PCR and culture. Genotype D was present. For the chicken slaughterhouse employees, 7.5% and 6% tested positive for C. psittaci by PCR and culture, respectively. In the turkey slaughterhouse, 87% and 61% of the employees tested positive by PCR and culture, respectively. All genotyped human samples contained genotype D. Using stationary bioaerosol monitoring by means of an MAS-100 ecosampler and ChlamyTrap collection medium, chlamydial DNA, and viable organisms were detected in both the chicken and turkey slaughterhouses. Positive air samples were most frequently found in the animal reception area and evisceration room. Zoonotic transmissions were very common, especially from processed turkeys. Accurate diagnostic monitoring and reporting of C. psittaci infections should be promoted in poultry workers.

Chlamydophila psittaci in homing and feral pigeons and zoonotic transmission

Chlamydiosis is a zoonotic disease in birds caused by Chlamydophila psittaci, an obligate intracellular bacterium. There are seven known avian outer-membrane protein A genotypes, A-F and E/B. The importance of genotyping lies in the fact that certain genotypes tend to be associated with certain hosts and a difference in virulence. Genotype B is the most prevalent in pigeons, but the more virulent genotypes A and D have also been discovered. The current study assessed the prevalence of C. psittaci in 32 Belgian homing-pigeon facilities and in 61 feral pigeons captured in the city of Ghent, Belgium. Additionally, zoonotic transmission of C. psittaci was investigated in the homing-pigeon facilities. Homing pigeons were often infected, as at least one of the lofts was positive in 13 of the 32 (40.6 %) pigeon breeding facilities. Genotypes B, C and D were detected. Zoonotic transmission was discovered in 4 of the 32 (12.5 %) pigeon fanciers, revealing genotype D in two of them, whilst genotyping was unsuccessful for the other two human pharyngeal swabs. This study clearly demonstrates the possible risk of C. psittaci zoonotic transmission from homing pigeons. Pigeon fanciers often (37.5 %) used antibiotics for prevention of respiratory disease. Because of the risk of developing drug-resistant strains, regular use of antimicrobial drugs must be avoided. This study is believed to be the first to detect C. psittaci in Belgian feral pigeons. The prevalence rate in the city of Ghent was extremely low, which is beneficial for public health.

Zoonotic transmission of Chlamydia psittaci in a chicken and turkey hatchery

Chlamydia psittaci is an obligately intracellular Gram-negative bacterium causing respiratory disease (chlamydiosis) or asymptomatic carriage in birds. C. psittaci is a zoonotic agent causing psittacosis or parrot fever in humans. Vertical and/or horizontal transmission via eggs might have serious repercussions on the C. psittaci infection status of poultry flocks and thus on zoonotic risk for all workers along the poultry supply chain. We therefore studied the presence of C. psittaci in a hatchery. In addition, we examined all (n = 4) employees of the hatchery to evaluate the zoonotic risk. We could not detect C. psittaci on either eggshells or eggshell membranes. However, C. psittaci isolates of different outer-membrane protein A (ompA) genotypes were cultured from the air of both turkey (genotypes A and C) and chicken (genotype D) hatching chambers. Zoonotic transmission occurred in all employees and a mixed infection with up to three different genotypes (A, D and C), also found in air samples, was discovered. Diagnostic monitoring and reporting of C. psittaci infections in poultry workers should be promoted. Additionally, an efficient veterinary vaccine and information campaigns on zoonotic risk and preventive measures against C. psittaci transmission would be beneficial to public health.

Risk Assessment and Management of Chlamydia psittaci in Poultry Processing Plants

Chlamydia psittaci causes respiratory disease in poultry and can be transmitted to humans. Historical outbreaks of psittacosis in poultry workers indicated the need for higher awareness and an efficient risk assessment and management. This group reviewed relevant previous research, practical guidelines, and European directives. Subsequently, basic suggestions were made on how to assess and manage the risk of psittacosis in poultry processing plants based on a classical four-step approach. Collective and personal protective measures as well as the role of occupational medicine are described. Despite the finding that exposure is found in every branch, abattoir workstations seem to be associated with the highest prevalence of psittacosis. Complete eradication is difficult to achieve. Ventilation, cleaning, hand hygiene, and personal protective equipment are the most important protective measures to limit and control exposure to C. psittaci. Adequate information, communication, and health surveillance belong to the responsibilities of the occupational physician. Future challenges lay in the rigorous reporting of infections in both poultry and poultry workers and in the development of an avian and human vaccine.

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

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.

Chlamydia Psittaci, Causative Agent of Avian Chlamydiosis and Human Psittacosis: Risk Assessment and Biosafety Recommendations for Laboratory use

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 with infected birds, most frequently in the context of the poultry industry, and from contact with Psittaci-formes (cockatoos, parrots, parakeets, and lories). The zoonotic nature of the bacterium makes it a threat to people in close contact with birds, such as veterinarians, farmers, employees of abattoirs, taxidermists, and pet (shop)keepers, but also to laboratory workers. The current article presents guidelines for appropriate laboratory containment of C. psittaci to prevent zoonotic transmission to humans in a laboratory environment.