Avian chlamydiosis

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Genotipovi bakterije Chlamydia psittaci u golubova u Hrvatskoj.

In this investigation fecal samples from a total of 232 homing pigeon lofts, belonging to both racing and breeding pigeons, were examined by specific real-time PCR to reveal the presence of Chlamydiaceae, and randomly collected Chlamydia positive samples were genotyped by two different molecular methods; C. psittaci-specific restriction fragment length polymorphism (RFLP) and Multiple-Locus Variable number tandem repeat Analysis (MLVA), in order to obtain relevant information about the prevalence of different genotypes, and to reveal the potential threat to humans that come into close contact with homing pigeons. Chlamydiosis in birds manifests as an acute, unapparent, sub-clinical, and chronic disease, but frequently also as an asymptomatic infection, which represents an additional danger for public health. Currently, nine different genotypes of C. psittaci have been generally accepted, based on PCR amplification, as well as an additional six provisional genotypes, based on DNA microarray. The predominant serotype/genotype in pigeons is B, but also other genotypes were discovered, such as A, C and D, as well as mixed infection. Out of 232 examined samples, 30 (12.9%) of them were PCR positive. DNA from six random positive fecal samples was further examined and the presence of C. psittaci was confirmed in all of them. According to RFLP genotyping, from 6 C. psittaci positive samples, 4 of them belonged to genotype B, and 2 strains remained untyped, due to the low concentration of DNA isolated. Regarding the MLVA typing, the pattern assigned as 22146334 could be described as a classical “pigeon” MLVA pattern. The presence of 12.9% homing pigeons positive to Chlamydiaceae by PCR clearly demonstrates the presence of zoonotic microorganisms and a possible risk for pigeon fanciers that come in close contact with the birds.Ukupno su bila pretražena 232 uzorka izmeta golubova na prisutnost bakterija porodice Chlamydiaceae pomoću za Chlamydiaceae specifične lančane reakcije polimerazom u stvarnom vremenu. Nasumično odabrani pozitivni uzorci pretraženi su i na prisutnost bakterije Chlamydia psittaci (C. psittaci), te su u slučaju pozitivnog nalaza i genotipizirani pomoću dvije različite molekularne metode - MLVA i RFLP, kako bi dobili svrsishodne informacije o učestalosti različitih genotipova, te otkrili potencijalnu prijetnju za zdravlje ljudi koji dolaze u bliži kontakt s golubovima. Klamidioza u ptica očituje se kao akutna, inaparentna, supklinička ili kronična bolest, ali često i kao asimptomatska zaraza, što predstavlja dodatnu opasnost za javno zdravstvo. Novijim istraživanjima, temeljenim na lančanoj reakciji polimerazom (PCR) nađeno je devet različitih genotipova C. psittaci. Prevladavajući serotip/genotip u golubova je B, ali su u njih nađeni i drugi genotipovi, kao što su A, C i D, te mješovite infekcije. Od 232 pregledana uzorka, njih 30 (12,9%) bilo je pozitivno na prisutnost bakterija iz porodice Chlamydiaceae. Nasumično izabrana DNK šest pozitivnih uzoraka dodatno je pretražena i na prisutnost C. psittaci, te je nalaz bio pozitivan u svih šest uzoraka. Pomoću PCR-RFLP metode, od 6 uzoraka pozitivnih na bakteriju C. psittaci, četiri su pripadala genotipu B, dok se dva uzorka nisu mogla pretražiti zbog niske koncentracije izdvojene DNK. Pomoću MLVA metode, četiri pretražena uzorka označena su oznakom 22146334, što se opisuje kao “golublji” genotip. Nalaz 12,9% golubova pozitivnih na prisutnost bakterija porodice Chlamydiaceae jasno pokazuje prisutnost uzročnika u jatima golubova u Hrvatskoj, te mogući rizik za uzgajivače koji dolaze u bliski kontakt s pticama

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

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

Editorial on the Research Topic

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La psittacose en milieu professionnel avicole

La psittacose est due à une bactérie de petite taille : Chlamydia psittaci. Chez l’homme, elle intervient de façon sporadique ou par foyers groupés. Elle est le plus souvent bénigne et se traduit par des symptômes qui rappellent la grippe. Mais celle-ci peut s’aggraver sous la forme d’une pneumopathie atypique sévère, qui peut être mortelle si un traitement antibiotique n’est pas rapidement mis en place. Le projet "AIRCHLAM" visait à caractériser l’exposition à C. psittaci en milieu professionnel

Detection of a novel genotype of ChlamydiaChlamydia buteonisbuteonis in falcons from the Emirates

Chlamydiaceae are a family of obligate intracellular bacterial pathogens that affect both humans and animals. Recently, a new species named Chlamydia (C.) buteonis was isolated from hawks. In this study, we aimed to investigate the prevalence of Chlamydiaceae in 60 falcons that underwent a routine health check at a specialized clinic in Dubai, United Arab Emirates. Using real-time PCR, we analyzed cloacal and tracheal swabs from these birds and found that 39 of them tested positive for Chlamydiaceae. Subsequent real-time PCR assays specific for C. psittaci, C. abortus, C. avium, and C. gallinacea yielded negative results, while testing positive for C. buteonis. Analysis of ompA and MLST sequences indicated a highly conserved group of strains within this set of samples, but with sequences distinct from the C. buteonis RSHA reference strains and other C. buteonis strains isolated from hawks in the United States. Two strains were further isolated by cell culture and sequenced using whole-genome sequencing, confirming the clustering of these falcon strains within the C. buteonis species, but in a separate clade from the previously identified hawk strains. We also developed a SNP-based PCR-HRM assay to distinguish between these different genotypes. Overall, our findings suggest a high prevalence of C. buteonis in falcons in Dubai and highlight the importance of monitoring this pathogen in birds of prey

Identifikacija i MLVA genotipizacija vrste Chlamydia abortus iz slučajeva pobačaja malih preživača u Hrvatskoj

In addition to zoonotic potential, Chlamydia (C.) abortus is a very important bacterium causing serious disease in small ruminants. The main outcome of the disease is abortion in the late stages of pregnancy and the economic impact for farms is significant. During a three-year period (2015–2017), 191 vaginal swabs, 24 placentas, 210 foetal organs and 2 milk samples from small ruminant abortion cases were tested for C. abortus by real-time PCR. Positive samples were detected on eight sheep farms and two goat farms, with 8.4% of total samples testing positive samples. These samples were characterised using the MLVA method, and a single MLVA genotype (genotype [2]) was identified from sheep and goat samples, suggesting highly conserved C. abortus strains among the national flock. This study is the first description of C. abortus as a causative agent of abortion in goats in Croatia. More detailed study is required to recognize the epidemiological relevance of the abortion chlamydiosis. An open register of farms with defined health status should be established for each farm at the national level for better disease(s) control.Osim zoonotskog potencijala, vrsta Chlamydia (C.) abortus je vrlo važna bakterija koja može prouzročiti tešku bolest malih preživača. Dominantni klinički znak bolesti je pobačaj u kasnom stadiju graviditeta sa znatnim ekonomskim učinkom za farme. Tijekom trogodišnjeg razdoblja (2015.-2017.) metodom Real time (RT) PCR na C. abortus testiran je 191 vaginalni obrisak, 24 placente, 210 organa fetusa i 2 uzorka mlijeka iz slučajeva pobačaja malih preživača. Pozitivni uzorci ustvrđeni su u 8 farmi ovaca i 2 farme koza, što ukupno predstavlja 8,4 % pozitivnih uzoraka. Ovi uzorci su tipizirani metodom MLVA i identificiran je jedinstveni genotip MLVA (genotip [2]). Dobiveni rezultat ukazuje na visok stupanj podudarnosti sojeva C. abortus u nacionalnom stadu ovaca i koza. Ovo istraživanje prvi je opis vrste C. abortus kao uzročnika pobačaja u koza u Hrvatskoj. Temeljem ustvrđenog rezultata bilo bi uputno provesti daljnja, detaljnija istraživanja da bi se prepoznalo epidemiološko i ekonomsko značenje infekcija vrstom C. abortus. Radi kvalitetnijeg nadzora bolesti potrebno je uspostaviti otvoreni registar gospodarstava s definiranim zdravstvenim statusom za svaku pojedinu farmu

A severe case of pneumopathy in a duck breeder due to Chlamydia psittaci diagnosed by 16S rDNA sequencing

Introduction: Psittacosis is a zoonotic infectious disease contracted from birds and caused by Chlamydia psittaci, an obligate intracellular pathogen. In humans, the symptoms of the disease range from inapparent illness to systemic illness with severe pneumonia. Case presentation: A severe case of atypical pneumonia requiring extra‐corporeal membrane oxygenation in a duck breeder is described. Because of the critical urgency of the case described here, and without any clear identification of the pathogen during the first days of hospitalization, treatment had to be adjusted daily. While conventional clinical methods failed to identify the causative agent, C. psittaci was finally identified using broad‐range 16S rDNA PCR analysis performed on a sample of broncho‐alveolar fluid. Conclusion: Owing to the non‐specific clinical signs of psittacosis, early identification of cases of the disease remains a challenge. C. psittaci should be sought in patients presenting severe acute respiratory distress syndrome without any evidence of other infectious causes and especially when exposure to birds or bird products is reported. PCR is a very useful method to help identify fastidious organisms of this kind

Limited transmission of avian influenza viruses, avulaviruses, coronaviruses and Chlamydia sp. at the interface between wild birds and a free-range duck farm

Recent outbreaks of highly pathogenic avian influenza in Europe have raised questions regarding the epidemiological role of commensal wild birds on free-range poultry farms. This study aimed to assess the prevalence of avian influenza viruses (AIV), avulaviruses, coronaviruses and Chlamydia sp. in commensal wild birds on a free-range duck farm in southwestern France and to evaluate possible transmission events at the wild‒domestic interface. From 2019 through 2021, a longitudinal study was conducted on wild birds, domestic ducks and their shared environment on farms. Commensal wild birds were captured and sampled for blood and swabs, and fresh feces from cattle egrets visiting the farm were collected. In parallel, domestic ducks were sampled, and environmental samples were collected. The presence of the four pathogens was tested by q(RT-)PCR, and the immunity of wild birds to AIV and Newcastle disease virus (NDV) was tested by ELISA. Wild birds were found to shed AIV and Chlamydia only, with a low prevalence (< 3%). The seroprevalence rates were less than 10% for AIV and less than 4.5% for NDV. No significant temporal trend was identified. Ducks and their environment frequently test simultaneously positive for the same pathogens (19 to 44% of flocks), mostly during fall‒winter. In addition to unrelated temporal patterns, the identification of pathogens in wild birds seemed unrelated to that in domestic ducks. These results suggest a low transmissibility of the avian pathogens tested in our study at the wild‒domestic interface and highlight the limited contribution of commensal wild birds in comparison with free-range poultry to the global microbiological pressure on the environment