Daisy Vanrompay

Chlamydophila psittaci infections in birds: a review with emphasis on zoonotic consequences.

The first part of the present review gives an overview on the history of infectious agents of the order Chlamydiales and the general infection biology of Chlamydophila (C.) psittaci, the causative agent of psittacosis. In the second part, the classification of C. psittaci strains, as well as issues of epidemiology of avian chlamydiosis., disease transmission routes, clinical disease, public health significance, present legislation and recommendations for prevention and control are reviewed.

Zoonotic Chlamydophila psittaci infections from a clinical perspective.

Human psittacosis is a zoonotic infectious disease which is caused by the obligate intracellular bacterium Chlamydophila 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 Psittaciformes (cockatoos, parrots, parakeets and lories). Due to a low awareness of the disease and a variable clinical presentation psittacosis is often not recognised as such by general practitioners. This review therefore gives an overview of the epidemiology, symptoms, diagnosis and possible treatments for psittacosis in humans. The current case definition for epidemiological surveillance, as issued by the CDC, is discussed, as well as the possible emergence of Cp. psittaci antibiotic-resistant strains. There is an urgent need for information and for awareness campaigns directed at professional health care workers and the general public. In addition, a broader use of new diagnostic methods in medical laboratories and the development of prophylactics are called for.

Chlamydia psittaci infections: a review with emphasis on avian chlamydiosis.

In the first part of this article the general characteristics of Chlamydia psittaci namely the history, taxonomy, morphology, reproductive cycle, metabolism and genetics are reviewed. For the taxonomy in particular, a considerable amount of new information has become available in recent years, following the application of monoclonal antibodies and restriction enzymes. Using these techniques isolates of Chlamydia psittaci from birds have been subdivided in different serovars, a number of isolates have been classified in a new species (Chlamydia pecorum) and isolates from animals have been classified as Chlamydia trachomatis. In the second part of the article, the current knowledge on avian chlamydiosis is summarized. Emphasis is put on clinical signs, lesions, pathogenesis, epizootiology, immunity, diagnosis, prevention and treatment. Also the public health considerations are reviewed. It is concluded that the diagnosis of avian chlamydiosis is laborious and that there is still a need for more accurate, simple and rapid diagnostic tools, both for antigen and antibody detection in various species of birds.

Chlamydophila psittaci Transmission from Pet Birds to Humans

We studied zoonotic transmission of Chlamydophila psittaci in 39 breeding facilities for Psittaciformes (cockatoos, parrots, parakeets, lories) that frequently used antimicrobial drugs. Genotypes A or E/B were detected in 14.9% of humans at these facilities. Information on antimicrobial drug use in Psittaciformes and a C. psittaci vaccine are urgently required.

Sequencing of the Chlamydophila psittaci ompA gene reveals a new genotype, E/B, and the need for a rapid discriminatory genotyping method

ABSTRACT Twenty-one avian Chlamydophila psittaci isolates from different European countries were characterized using ompA restriction fragment length polymorphism, ompA sequencing, and major outer membrane protein serotyping. Results reveal the presence of a new genotype, E/B, in several European countries and stress the need for a discriminatory rapid genotyping method.

Characterization of avian Chlamydia psittaci strains using omp1 restriction mapping and serovar-specific monoclonal antibodies

In the present study, 60 avian Chlamydia psittaci isolates were characterized using restriction fragment length polymorphism as well as serovar-specific monoclonal antibodies, enabling a comparison between the two characterization methods. Sixty avian C. psittaci isolates were characterized by Alul restriction mapping of the major outer membrane protein gene omp1 obtained after amplification by the polymerase chain reaction. The 60 avian C. psittaci strains were also characterized using serovar-specific monoclonal antibodies in a microimmunofluorescence test. Digestion of 60 avian C. psittaci omp1 amplicons by Alul generated 5 of the 6 known distinct restriction patterns (A, B, D, E and F). Restriction pattern C was not observed. Serotyping revealed 4 avian C. psittaci serovars (A, B, C and D). None of the 60 isolates was typed as serovar E. AluI restriction patterns A, B, D and E corresponded in 98% of the cases to serovars A, B, C and D, respectively. One isolate, classified as serovar A, generated restriction pattern F instead of A. Genotyping enabled a more precise differentiation of avian C. psittaci serovar A strains. Serovar A strains were divided into two groups according to their Alul restriction pattern (A or F). For epidemiological studies, genotyping can thus be a highly valuable alternative to serotyping, especially when applied directly to the clinical samples.

Chlamydiaceae infections in pig

Chlamydiaceae are Gram-negative obligate intracellular bacteria. They are responsible for a broad range of diseases in animals and humans. In pigs, Chlamydia suis, Chlamydia abortus, Chlamydia pecorum and Chlamydia psittaci have been isolated. Chlamydiaceae infections in pigs are associated with different pathologies such as conjunctivitis, pneumonia, pericarditis, polyarthritis, polyserositis, pseudo-membranous or necrotizing enteritis, periparturient dysgalactiae syndrome, vaginal discharge, return to oestrus, abortion, mummification, delivery of weak piglets, increased perinatal and neonatal mortality and inferior semen quality, orchitis, epididymitis and urethritis in boars. However, Chlamydiaceae are still considered as non-important pathogens because reports of porcine chlamydiosis are rare. Furthermore, Chlamydiaceae infections are often unnoticed because tests for Chlamydiaceae are not routinely performed in all veterinary diagnostic laboratories and Chlamydiaceae are often found in association with other pathogens, which are sometimes more easily to detect. However, recent studies have demonstrated that Chlamydiaceae infections in breeding sows, boars and piglets occur more often than thought and are economically important. This paper presents an overview on: the taxonomy of Chlamydiaceae occurring in pigs, diagnostic considerations, epidemiology and pathology of infections with Chlamydiaceae in pigs, public health significance and finally on prevention and treatment of Chlamydiaceae infections in pigs.

Turkeys are protected from infection with Chlamydia psittaci by plasmid DNA vaccination against the major outer membrane protein

Plasmid DNA expressing the major outer membrane protein (MOMP) of an avian Chlamydia psittaci serovar A strain has been tested for its ability to raise an immune response and induce protection against challenge with the same serovar. A combined parenteral (intramuscular injection) and mucosal route (DNA drops administered to the nares) of DNA inoculation was compared with gene gun‐based immunization. The gene gun delivery of pcDNA1/MOMP as well as the intramuscular–intranasal DNA delivery primed both T‐helper and B cell memory, although rMOMP‐expressing cells did not induce high antibody responses. Evidence for the priming of the memory was provided by the fact that the pcDNA1/MOMP inoculations raised antibodies belonging to the IgG and not IgM isotype. However, in response to challenge only five out of 15 vaccinated turkeys showed four‐fold increases in serum IgG after challenge. By contrast, evidence for the priming of T cell memory in response to challenge was found in all vaccinated turkeys, as shown by the significantly heightened proliferative responses of peripheral blood lymphocytes following vaccination. Both immunization methods produced similar serological and lymphocyte proliferative responses. Notwithstanding the immunization method, a significant level of protection was observed in all pcDNA1/MOMP‐immunized turkeys. The efficacy of MOMP‐based DNA vaccination as a means of preventing severe clinical signs, lesions and chlamydia excretion in a turkey model of C. psittaci infection was demonstrated.

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.

Chlamydial infections in duck farms associated with human cases of psittacosis in France.

Five severe cases of psittacosis in individuals associated with duck farms were notified in France between January and March 2006. Diagnostic examination included serology and/or molecular detection by PCR from respiratory samples. As a consequence, we investigated all duck flocks (n=11) that were housed in the three farms where human infections occurred. While serology by complement fixation test was negative for all samples, cloacal and/or tracheal chlamydial excretion was detected by PCR in all three units. Notably, one duck flock was tested strongly positive in 2 of the 3 affected farms, and Chlamydophila (C.) psittaci strains were isolated from cloacal and/or tracheal swab samples from both farms. Human samples and duck isolates exhibited the same PCR-RFLP restriction pattern, which appeared to be an intermediate between genotypes A and B. Analysis of ompA gene sequences and comparison to those of the type strains showed that the isolates could not be strictly assigned to any of the generally accepted genotypes of C. psittaci. Further analysis by MLVA of the PCR-positive human samples revealed two distinct patterns, which were related to previously isolated C. psittaci duck strains.