Infection by Chlamydophilia avium in an elderly couple working in a pet shop

Occurrence of Chlamydiaceae in Raptors and Crows in Switzerland

Bacteria of the family Chlamydiaceae are globally disseminated and able to infect many bird species. So far, 11 species of Chlamydia have been detected in wild birds, and several studies found chlamydial strains classified as genetically intermediate between Chlamydia (C.) psittaci and C.abortus. Recently, a group of these intermediate strains was shown to form a separate species, i.e., C.buteonis. In the present study, 1128 samples from 341 raptors of 16 bird species and 253 corvids representing six species were examined using a stepwise diagnostic approach. Chlamydiaceae DNA was detected in 23.7% of the corvids and 5.9% of the raptors. In corvids, the most frequently detected Chlamydia species was C.psittaci of outer membrane protein A (ompA) genotype 1V, which is known to have a host preference for corvids. The most frequently detected ompA genotype in raptors was M56. Furthermore, one of the raptors harbored C.psittaci 1V, and two others carried genotype A. C.buteonis was not detected in the bird population investigated, so it remains unknown whether this species occurs in Switzerland. The infection rate of Chlamydiaceae in corvids was high compared to rates reported in other wild bird species, but neither Chlamydiaceae-positive corvids nor raptors showed overt signs of disease. Since the Chlamydiaceae of both, raptors and crows were identified as C.psittaci and all C.psittaci genotypes are considered to be zoonotic, it can be suggested that raptors and crows pose a potential hazard to the health of their handlers.

Chlamydiosis in a Gouldian Finch (Erythrura gouldiae)

Avian chlamydiosis is an infection caused by obligate intracellular and Gram-negative bacteria belonging to the family Chlamydiaceae and has been reported in more than 450 avian species distributed in 30 orders. In particular, a high prevalence of infection has been demonstrated in wild passerine populations, including both asymptomatic and clinically ill individuals, suggesting a role of these avian species as important carriers. In May 2018, avian chlamydiosis was diagnosed in a 1-year-old male Gouldian finch (Erythrura gouldiae) at the Turlock Branch of the California Animal Health and Food Safety Laboratory System. The bird belonged to an outdoor aviary with mixed avian species, including Gouldian finches, doves (Geopelia cuneata and Spilopelia chinensis), and psittacines (Aratinga, Psittacula, Pyrrhura, and Trichoglossus sp.). Severe respiratory distress and mortality were noted among the finches. Gross and histopathologic lesions were concentrated in the liver and spleen, with a mild involvement of the upper respiratory tract. Chlamydia spp. were detected in the spleen and kidney by real-time PCR and were further confirmed by immunohistochemistry. Subsequently, Chlamydia psittaci was isolated from the liver and spleen and characterized as a CP3-like strain (genotype B). In addition, viral particles compatible with circovirus were identified in the liver by direct electron microscopy. To the authors' knowledge, this is the first report of avian chlamydiosis with hepatic viral particles consistent with circovirus infection in a Gouldian finch.

Risk factors associated with Chlamydia psittaci infections in psittacine birds and bird handlers

AIMS

The aim of this study was to determine the prevalence and potential risk factors associated with Chlamydia psittaci infections in psittacine birds and bird handlers in Egypt.

METHODS AND RESULTS

A total of 190 swabs were collected from psittacine birds (n = 120) and bird handlers (n = 70) and were tested by polymerase chain reaction to detect the C. psittaci ompA gene. Chlamydia psittaci DNA was detected in 63 (52·5%) of 120 samples collected from psittacine birds. The occurrence of C. psittaci infections was high in Cockatiel birds (60%), followed by Fischer's lovebird (51%) and Rosy-faced lovebird (47·5%). Bird age, location (pet markets and households), housing (caged and aviary), and sampling season were considered significant risk factors for C. psittaci infections in psittacine birds. Of the 70 sputum swabs collected from bird handlers, only 4 (6%) were positive for C. psittaci. Positive cases were closely associated with older persons (≥30 years) who had respiratory signs and handled birds in pet markets. Further, wearing protective gloves and washing hands when handling psittacine birds decreased the frequency of C. psittaci infections in bird handlers.

CONCLUSIONS

The prevalence of C. psittaci infections in psittacine birds in Egypt is high, which has a potential threat to human health in this area. Thus, dissemination of effective prevention and control measures is essential to prevent the spread of C. psittaci among psittacine birds, as well as among humans in contact with birds.

SIGNIFICANCE AND IMPACT OF THE STUDY

Results from this study highlighted the risk factors associated with C. psittaci infections in psittacine birds and bird handlers in Egypt and will aid in developing prevention and control measures to reduce the risk of C. psittaci infection.

Laboratory methods for case finding in human psittacosis outbreaks: a systematic review

Background

Psittacosis outbreak investigations require rapid identification of cases in order to trace possible sources and perform public health risk assessments. In recent outbreaks in the Netherlands, such investigations were hampered by the non-specificity of laboratory testing methods to identify human Chlamydia psittaci infections.

Method

A systematic search of PubMed and Scopus databases of literature published between 01 January, 1986 and 03 July, 2017 was done to find best practices of laboratory-testing methods used in psittacosis outbreaks of two or more human cases. Reference lists of included articles were hand searched to identify additional articles.

Results

Thirty-seven eligible articles were identified, describing 44 human psittacosis outbreaks in 12 countries. Laboratory tests performed were PCR (with various targets), serologic tests (complement binding reactions, ELISA’s, immunofluorescence tests and immuno-peroxidase tests) and culture, in various combinations. The literature provided no ‘gold standard’ laboratory testing strategy to identify recent human C. psittaci infections. In most psittacosis outbreaks, for a considerable number of cases (or tested individuals in an exposed cohort), C. psittaci infection could not be confirmed, nor excluded as causative pathogen. None of the testing strategies was found to be suitable for (nearly) full case finding.

Conclusion

PCR enables rapid identification of human psittacosis patients and helps source finding by genotyping but has the disadvantage that sensitivity is high only in the acute phase. In outbreak situations, there is often a time delay and therefore, there is a need for new serologic testing methods next to PCR, with good specificity and sensitivity. Moreover, serum is easier to collect than the preferred diagnostic materials for PCR. A serologic test that can reliably confirm infection status without the necessity of convalescent serum sampling would enhance case finding, source tracing, identification of risk factors and assessment of burden of disease in various settings.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3317-0) contains supplementary material, which is available to authorized users.

Detection of Chlamydophila psittaci from pigeons by polymerase chain reaction in Ahvaz

BACKGROUND AND OBJECTIVE

Chlamydophila psittaci is a lethal bacterium that causes endemic avian chlamydiosis, and respiratory psittacosis. Laboratory diagnosis of Chlamydophila psittaci is difficult by culture. This study was design to investigate the presence of Chlamydophila psittaci in collected pharyngeal swabs from asyptomatic pigeons by PCR.

MATERIALS AND METHODS

Pharyngeal samples from pigeons with no symptoms of disease (n=280) were collected during hot and cold seasons in different parts of Ahvaz. DNA was extracted from specimens and subjected to PCR targeting pmp genes and 16s-23s rRNA intergenic spacer of Cp. psittaci and chlamydiales specific primers.

RESULTS

Of 280 samples 2 (0.7%) harbor were positive for chlamydiales (16s-23s intergenic spacer) and Cp. psittaci specific genes (pmp gene).

CONCLUSIONS

In this research the pigeons were asymptomatic carriers for Cp. psittaci in their respiratory discharges. These results suggest that Cp. psittaci infection of human can occur in very close and continuous contact with pigeons.

Psittacosis

Psittacosis, also known as ornithosis, is an acute infectious disease caused by Chlamydia psittaci (Cps) and commonly prevails in poultry and other species of bird. Humans infected by Chlamydia psittaci may suffer from unapparent subclinical infection, with symptoms ranging from mild flulike illness to severe SARS. As a typical animal-based infectious disease, psittacosis rarely has pulmonary signs but a long illness course, despite its clinical manifestation characterized by severe pulmonary lesions. Repeated onsets of psittacosis may lead to chronic diseases.

Chlamydia psittaci in ducks: a hidden health risk for poultry workers

Chlamydia psittaci is a zoonotic pathogen associated primarily with avian chlamydiosis also referred as psittacosis. Human psittacosis can lead to severe cases of respiratory disease. The mule duck is one of the main bird hybrids associated with human cases of psittacosis in France. In order to better understand the epidemiology of avian chlamydiosis, monitoring studies were performed in both breeder flocks and mule duck flocks. Surveys conducted in one professional duck bredding organization revealed little shedding in breeder flocks, whereas heavy but asymptomatic C. psittaci shedding was observed in most of the mule duck flocks, mostly when birds were reared in open range conditions on farms. Human cases of psittacosis linked to duck breeder flocks and their progeny led to detection of heavy shedders in all the suspected flocks despite no birds showing clinical signs. Offspring of one of the infected female flocks was analyzed and also proved to be infected by C. psittaci. Field studies suggest that C. psittaci infections in duck farms involve horizontal and probably vertical transmission but that the environment also plays an important role in maintaining infection on farms. In the light of the widespread occurrence of C. psittaci on duck farms, it has become urgent to clearly identify sources of contamination in order to take appropriate field management measures to minimize worker exposure.

The prevalence and genetic characterization of Chlamydia psittaci from domestic and feral pigeons in Poland and the correlation between infection rate and incidence of pigeon circovirus

Chlamydiosis is a zoonotic disease caused by Chlamydia psittaci that occurs in a wide range of bird species. High infection rates with C. psittaci are found in pigeons, which can act as vectors transmitting this bacterium to poultry and humans. Chlamydia shedding by pigeons is intermittent and can be activated by stressors or immunosuppression. The most common immunosuppressive factor for pigeons is a pigeon circovirus (PiCV) infection. The main aim of the study was to evaluate the prevalence of C. psittaci in Polish populations of domestic and feral pigeons (Columba livia) in the context of its correlation with PiCV infections. The second objective was to determine the genetic characteristics of Polish C. psittaci isolates. The study was conducted on 377 pigeon samples (276 domestic and 101 feral pigeons) collected from pigeons from different regions of Poland. The average prevalence of C. psittaci in the Polish pigeon population was determined at 6.8%, and it was higher in domestic than in feral pigeons. This is the first ever study to suggest a potential correlation between C. psittaci and PiCV infections, which could be attributed to the fact that there are 2 to 3 times more pigeons infected with C. psittaci and coinfected with PiCV than pigeons infected with C. psittaci alone. This trend was observed mainly in the population of sick pigeons. As many as 88.2% of isolates were recognized as belonging to genotype B, and the remaining isolates were identified as belonging to genotype E. The isolates analyzed in this study demonstrated low levels of genetic variation (96-100% homology among the isolates and in relation to reference strains). Chlamydia psittaci could be expected to spread across pigeon populations due to the high probability of mutual infections between birds and the increasing number of PiCV infections.

Risk factors associated with Chlamydia psittaci infection in psittacine birds

Chlamydia psittaci is the aetiological agent of chlamydiosis in birds, especially Psittaciformes. The objective of the present study was to detect C. psittaci by means of semi-nested PCR among psittacine birds sold at pet markets and kept as pet birds in Salvador, Bahia, Brazil. Questionnaires were used to identify risk factors involved in the epidemiology of the disease. In addition, the management of birds and cages was observed at each location studied. The frequency of C. psittaci infection was 10.6 % (33/311) in the psittacine birds studied. Birds kept in households were less frequently positive (3.4 %; 5/148) than those at pet markets (17.2 %; 28/163). Among the several factors analysed in the epidemiology of the disease, only population density (P = 0.001) and cage hygiene (P = 0.041) in birds at pet markets were significantly associated with C. psittaci infection. These results demonstrate the presence of C. psittaci infection in Psittaciformes kept as pets and held at pet markets in Salvador, Bahia, showing that this micro-organism is a public health concern. Control measures should be encouraged to prevent the spread of the agent among birds, as well as among employees and customers.

Healthy animals, healthy people: zoonosis risk from animal contact in pet shops, a systematic review of the literature

Background

Around 67 million pets are owned by households in the United Kingdom, and an increasing number of these are exotic animals. Approximately a third of pets are purchased through retail outlets or direct from breeders. A wide range of infections can be associated with companion animals.

Objectives

This study uses a systematic literature review to describe the transmission of zoonotic disease in humans associated with a pet shop or other location selling pets (incidents of rabies tracebacks and zoonoses from pet food were excluded).

Data sources

PubMed and EMBASE.

Results

Fifty seven separate case reports or incidents were described in the 82 papers that were identified by the systematic review. Summary information on each incident is included in this manuscript. The infections include bacterial, viral and fungal diseases and range in severity from mild to life threatening. Infections associated with birds and rodents were the most commonly reported. Over half of the reports describe incidents in the Americas, and three of these were outbreaks involving more than 50 cases. Many of the incidents identified relate to infections in pet shop employees.

Limitations

This review may have been subject to publication bias, where unusual and unexpected zoonotic infections may be over-represented in peer-reviewed publications. It was also restricted to English-language articles so that pathogens that are more common in non-Western countries, or in more exotic animals not common in Europe and the Americas, may have been under-represented.

Conclusions/implications

A wide spectrum of zoonotic infections are acquired from pet shops. Salmonellosis and psittacosis were the most commonly documented diseases, however more unusual infections such as tularemia also appeared in the review. Given their potential to spread zoonotic infection, it is important that pet shops act to minimise the risk as far as possible.

Seroprevalence of antibodies to Chlamydophila psittaci in zoo workers in Brazil

To evaluate the prevalence of antibodies to Chlamydophila psittaci 364 serum samples were collected from veterinarians, biologists, animal scientists, veterinary students, animal keepers and others employees in 20 zoos, and from veterinary practitioners in 10 Brazilian states. Subjects ranged from 15 to 64 years of age, with 268 (74%) males and 96 (26%) females. Chlamydial antibodies were determined by the complement fixation test (CFT) and specific anti-C. psittaci IgG antibodies were determined by the microimmunoflurescence (MIF) test. Complement fixation test showed 23.9% (87/364) and MIF test showed 4.7% (17/364) positive serum samples. Titres ranged from 16 to 256 in both assays, demonstrating evidence of recent or current infection. Although chlamydial antibodies were detected in workers of seventeen zoos, MIF test only detected specific C. psittaci antibodies in seven of them. Previous psittacosis infection was suspected in eight workers of two zoos, five of whom reported having pneumonia, while employed at the zoos. However, diagnosis was not established in any of these cases in the past. Results indicated the occurrence of infection and previous contact of Brazilian zoo workers with C. psittaci, as well as the zoonotic potential of psittacosis in this risk population. Other studies are necessary to evaluate the risk factors of infection in this population. This seroepidemiological survey confirmed the need to adopt preventive measures to control avian chlamydiosis and protect the health of zoo workers in the country.

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 phylogenetic 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.

Genotyping of Chlamydophila psittaci by real-time PCR and high-resolution melt analysis

Human infection with Chlamydophila (Chlamydia) psittaci can lead to psittacosis, a disease that occasionally results in severe pneumonia and other medical complications. C. psittaci is currently grouped into seven avian genotypes: A through F and E/B. Serological testing, outer membrane protein A (ompA) gene sequencing, and restriction fragment length polymorphism analysis are currently used for distinguishing these genotypes. Although accurate, these methods are time-consuming and require multiple confirmatory tests. By targeting the ompA gene, a real-time PCR assay has been developed to rapidly detect and genotype C. psittaci by light-upon-extension chemistry and high-resolution melt analysis. Using this assay, we screened 169 animal specimens; 98 were positive for C. psittaci (71.4% genotype A, 3.1% genotype B, 4.1% genotype E, and 21.4% unable to be typed). This test may provide insight into the distribution of each genotype among specific hosts and provide epidemiological and epizootiological data in human and mammalian/avian cases. This diagnostic assay may also have veterinary applications during chlamydial outbreaks, particularly with respect to identifying the sources and tracking the movements of a particular genotype when multiple animal facilities are affected.

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.

Real-time PCR detection and quantitation of Chlamydophila psittaci in human and avian specimens from a veterinary clinic cluster

We report three cases of psittacosis in staff working in a veterinary surgery, which was related to exposure to a sick, wild psittacine bird. Chlamydial genus- and chlamydial species-specific DNA was detected in clinical specimens, including throat swabs, whole blood and urine. The organism load was quantified by real-time PCR (RT-PCR), which revealed 10(5)-fold more organisms in conjunctival swabs from the source bird than in the human samples. One clinic attendant was infected despite using personal protective equipment when handling the bird. This is the first report of PCR analyses of blood and urine samples being used to diagnose human psittacosis, and the first time that the organism load in humans has been compared to that of the infecting bird.

A pmp genes-based PCR as a valuable tool for the diagnosis of avian chlamydiosis

In a previous study we described the use of a new set of PCR primers (CpsiA/CpsiB) specific of the conserved pmp-family genes of Chlamydophila abortus as an efficient tool for the detection of these bacteria in ruminants including also preliminary results on avian strains. In this work, the use of this set of primers was extended to representative strains of the six major avian serovars (serovars A-F) and to field isolates of C. psittaci. For all the studied representative strains, using purified genomic DNA as a template, CpsiA/CpsiB primers allowed, as observed for C. abortus, a minimal 10-fold PCR signal increase compared to the one observed with ompA specific primers. In comparison to primers targeting the 16S-23S rRNA intergenic spacer, similar or increased sensitivity was observed depending on the strain. All the field isolates were amplified with CpsiA/CpsiB primers. On clinical samples, our primers are the best among those tested for detection of C. psittaci by simple conventional PCR. RFLP experiments performed using PCR fragments amplified with the CpsiA/CpsiB primers gave promising results demonstrating that these primers may provide an interesting tool for molecular typing when the bacterium cannot be grown from pathological samples.