Detection of chlamydiosis in a shipment of pet birds, leading to recognition of an outbreak of clinically mild psittacosis in humans

Application of environmental sampling to investigate a case of avian chlamydiosis in a pet store and breeding facility leading to mass bird exposures

Chlamydia psittaci is a bacterium that causes chlamydiosis in birds and can cause zoonotic psittacosis in people. In November 2017, we received notification of a suspected case of avian chlamydiosis in a captive cockatiel (Nymphicus hollandicus) that was sold by an online pet bird retail and breeding facility in Washington State. We describe the investigation with emphasis on how environmental sampling was used to guide veterinary and public health interventions. Bird samples were collected either from pooled droppings, pooled plumage or individual nasal and choanal swabs. Environmental samples were obtained by swabbing cleaning mops, tables and cage structures. All samples were tested by polymerase chain reaction and positive samples underwent genotyping. Approximately 1000 birds representing four taxonomic orders were kept within an open-space warehouse. Eight of 14 environmental samples and one of two pooled faecal samples were positive for Chlamydia spp. The contaminating strain of Chlamydia spp. was identified as genotype A. The facility was closed for environmental disinfection, and all psittacines were treated with oral doxycycline for 45 days. Ten of 10 environmental and two of two pooled faecal samples were negative for C. psittaci 11 months after the completion of environmental disinfection and antimicrobial treatment. This investigation highlights the importance of preventing and mitigating pathogen incursion in an online pet retail and breeding facility. Environmental sampling is valuable to guide animal and public health interventions for control of C. psittaci, particularly when large numbers of birds are exposed to the pathogen.

Atypical Pathogens in Adult Community-Acquired Pneumonia and Implications for Empiric Antibiotic Treatment: A Narrative Review

Atypical pathogens are intracellular bacteria causing community-acquired pneumonia (CAP) in a significant minority of patients. Legionella spp., Chlamydia pneumoniae and psittaci, Mycoplasma pneumoniae, and Coxiella burnetii are commonly included in this category. M. pneumoniae is present in 5-8% of CAP, being the second most frequent pathogen after Streptococcus pneumoniae. Legionella pneumophila is found in 3-5% of inpatients. Chlamydia spp. and Coxiella burnetii are present in less than 1% of patients. Legionella longbeachae is relatively frequent in New Zealand and Australia and might also be present in other parts of the world. Uncertainty remains on the prevalence of atypical pathogens, due to limitations in diagnostic means and methodological issues in epidemiological studies. Despite differences between CAP caused by typical and atypical pathogens, the clinical presentation alone does not allow accurate discrimination. Hence, antibiotics active against atypical pathogens (macrolides, tetracyclines and fluoroquinolones) should be included in the empiric antibiotic treatment of all patients with severe CAP. For patients with milder disease, evidence is lacking and recommendations differ between guidelines. Use of clinical prediction rules to identify patients most likely to be infected with atypical pathogens, and strategies of narrowing the antibiotic spectrum according to initial microbiologic investigations, should be the focus of future investigations.

Spreading of Pasteurella multocida Infection in a Pet Rabbit Breeding and Possible Implications on Healed Bunnies

The number of pets such as dogs, cats, rabbits, and parrots has increased in European families. Social benefits to owners such as decreasing feelings of loneliness and anxiety are provided by pets which are also used in Animal-assisted Therapy (AAT). Nevertheless, human-animal interactions are also associated with health problems including allergies, asthma, and zoonosis. Rabbits may carry potential pathogens for humans. One of the most common bacteria that colonizes the oro-pharynx and the upper respiratory tract of rabbits is Pasteurella (P.) multocida. Transmission of the infection to humans results from scratches, licks, and bites but it also can occur from the inhalation of air particles containing the microorganism. Immunocompromised people or persons with pulmonary disorders are particularly susceptible to the infection. Infected rabbits may carry P. multocida with or without clinical signs. In this paper, the sensitivity to antibiotics and the invasiveness ability of P. multocida identified in a farm of pet rabbits affected by severe pasteurellosis were investigated. The strain was P. multocida belonging to capsular type A which is the type most often detected in humans. The identified strain was susceptible to the tested antibiotics, but it appeared equipped with several virulence genes which are responsible for fimbriae production, adhesion processes to host cells, enzyme production, and are involved in iron acquisition processes. These findings are of particular interest because rabbits recovered from pasteurellosis very often become carriers of the bacteria. Therefore, we suggest considering P. multocida screening in the routine medical checks of rabbits, especially if they are meant to be companion animals for children and elder people, given that the transmission of the pathogen cannot be excluded.

The Application Value of Metagenomic and Whole-Genome Capture Next-Generation Sequencing in the Diagnosis and Epidemiological Analysis of Psittacosis

Background

To evaluate the value of metagenomic next-generation sequencing (mNGS) for the early diagnosis of psittacosis, and to investigate its epidemiology by whole-genome capture.

Methods

Twenty-one bronchoalveolar lavage fluid (BALF) and blood samples of 16 psittacosis patients from multiple centers during August 2019 to September 2021 were analyzed retrospectively. mNGS with normal datasets (10 M 75-bp single-end reads after sequencing) and larger datasets (30 M 150-bp paired-end reads after sequencing) as well as quantitative real-time polymerase chain reaction (qPCR) were used to detect the pathogen. Also, whole-genome capture of Chlamydophila psittaci was applied to draw the phylogenetic tree.

Results

mNGS successfully detected the pathogen in all 16 cases (100%), while qPCR was positive only in 5 out of 10 cases (50%), indicating a significantly higher sensitivity of mNGS than qPCR (p < 0.01). BALF-mNGS performed better than blood-mNGS (16/16 versus 3/5, p < 0.05). In addition, larger datasets (the read counts have tripled, and the base number was 12-fold larger compared to clinical mNGS with a normal dataset) of mNGS showed significantly increased contents of human DNA (p < 0.05) and decreased reads per million of the pathogen, suggesting no improvement. Whole-genome capture results of five samples (>60% coverage and >1 depth) were used to construct the phylogenetic tree.

Conclusion

Significant advantages of mNGS with normal datasets were demonstrated in early diagnosing psittacosis. It is the first study to use whole-genome capture to analyze C. psittaci epidemiological information.

Severe psittacosis progressing to suspected organizing pneumonia and the role of corticosteroids

Background

Psittacosis is a systemic disease usually with respiratory involvement, caused by the obligate intracellular bacterium Chlamydia psittaci. Exposure to birds, the main zoonotic reservoir, is a major risk factor for infection. The spectrum of disease is highly variable, ranging from subclinical infection to severe pneumonia requiring mechanical ventilation. There is limited data on psittacosis progressing to organizing pneumonia and management of such cases.

Case presentation

A 63-year-old man was referred to a rural hospital with 11 days of fevers to 39 °C, myalgia, lethargy and several days of dry cough. After initial treatment with benzylpenicillin and doxycycline for left lower pneumonia found on CXR, the patient deteriorated with extensive bilateral consolidation on chest CT requiring mechanical ventilation. Atypical pneumonia screening was negative, however, exposure to a sick bird prior to symptom onset triggered testing for C. psittaci which was positive. Doxycycline was recommenced with minimal benefit, and organizing pneumonia was later suspected. The patient slowly improved with a weaning course of corticosteroids started after 19 days and was discharged from hospital. He unfortunately was re-admitted and died several months later.

Conclusion

Severe pneumonia is a rare, but potentially life-threatening complication of psittacosis. We present a case of psittacosis which progressed to suspected organizing pneumonia despite appropriate antibiotics, and subsequent treatment with corticosteroids. This case suggests it may be useful to consider corticosteroids early in therapy for patients with severe psittacosis. Our paper underlines the need for further research to determine the best management of severe psittacosis to improve patient outcomes.

Metagenomic next-generation sequencing in the family outbreak of psittacosis: the first reported family outbreak of psittacosis in China under COVID-19

Chlamydia psittaci infection in humans, also known as psittacosis, is usually believed to be an uncommon disease which mainly presents as community-acquired pneumonia (CAP). It is usually sporadic, but outbreaks of infection may occasionally occur. In outbreaks, diagnosis and investigations were usually hampered by the non-specificity of laboratory testing methods to identify C. psittaci. In this study, we use metagenomic next-generation sequencing (mNGS) in the diagnosis of a family outbreak of psittacosis under COVID-19. Three members of an extended family of 6 persons developed psittacosis with pneumonia and hepatic involvement with common symptoms of fever and weakness. Two newly purchased pet parrots, which had died successively, were probably the primary source of infection. Imagings show lung consolidations and infiltrates, which are difficult to be differentiated from CAP caused by other common pathogens. mNGS rapidly identified the infecting agent as C. psittaci within 48 h. The results of this work suggest that there are not characteristic clinical manifestations and imagings of psittacosis pneumonia which can differentiate from CAP caused by other pathogens. The use of mNGS can improve accuracy and reduce the delay in the diagnosis of psittacosis especially during the outbreak, which can shorten the course of the disease control. Family outbreak under COVID-19 may be related to the familial aggregation due to the epidemic. To our knowledge, this is the first reported family outbreak of psittacosis in China, and the first reported psittacosis outbreak identified by the method of mNGS in the world.

A patient with psittacosis from a pigeon: A reminder of the importance of detailed interviews and relative bradycardia

A 43-year-old man was brought to our hospital with fever. The initial diagnosis was bacterial pneumonia, and ampicillin/sulbactam was administered. However, defervescence was not achieved, and relative bradycardia was observed. Detailed history-taking revealed that the patient had been involved in caring for a wild pigeon before hospitalization. We changed the antimicrobial therapy to minocycline and the patient' s condition improved. Chlamydophila psittaci antibody was subsequently found to be increased four-fold, and psittacosis was diagnosed. This case acts a reminder to clinicians of the importance of both the history of exposure to any birds and vital signs, including relative bradycardia.

Challenges in using serological methods to explore historical transmission risk of Chlamydia psittaci in a workforce with high exposure to equine chlamydiosis

Introduction

This report describes the challenges encountered in using serological methods to study the historical transmission risk of C. psittaci from horses to humans.

Methods

In 2017, serology and risk factor questionnaire data from a group of individuals, whose occupations involved close contact with horses, were collected to assess the seroprevalence of antibodies to C. psittaci and identify risk factors associated with previous exposure.

Results

147 participants were enrolled in the study, provided blood samples, and completed a questionnaire. On ELISA testing, antibodies to the Chlamydia genus were detected in samples from 17 participants but further specific species-specific MIF testing did not detect C. psittaci-specific antibodies in any of these samples.

Conclusion

No serological evidence of past C. psittaci transmission from horses to humans was found in this study cohort. There are major challenges in using serological methods to determine the prevalence of C. psittaci exposure.

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.

Gestational Psittacosis Resulting in Neonatal Death Identified by Next-Generation RNA Sequencing of Postmortem, Formalin-Fixed Lung Tissue

Psittacosis is a rare zoonosis that can cause severe disease and adverse outcomes during pregnancy. We identified a previously elusive case of psittacosis causing premature delivery and infant death by next-generation RNA sequencing of postmortem tissues. Hypothesis-free pathogen detection in postmortem specimens can increase the yield of epidemiologic and cause-of-death studies.

Equine chlamydiosis-An emerging infectious disease requiring a one health surveillance approach

Psittacosis is a rare but potentially fatal zoonosis caused by Chlamydia psittaci, an organism that is typically associated with bird contact. However C. psittaci is capable of infecting other non-avian hosts, such as horses, sheep, cattle and goats. Stud staff and veterinarians have significant exposure to parturient animals and reproductive materials in their routine work. To investigate the zoonotic potential associated with the emergence of C. psittaci as an abortifacient agent in horses, we established a programme of joint human and animal surveillance in a sentinel horse-breeding region in Australia. This programme comprised cross-notification of equine cases to public health agencies, and active follow-up of known human contacts, including stud workers, foaling staff, veterinarians and laboratory staff. We identified no confirmed cases of acute psittacosis despite intensive surveillance and testing of heavily exposed contacts; however, further work in the area is needed.

Infectious Diseases

The chapter describes bacerial, viral, parasitic and fungal infections commonly detected in pet birds. The chapter includes history, etiology, susceptible hosts, transmission, pathogenesis, clinical symptoms, lesion, diagnosis, zoonosis, Treatment and control strategy of Tuberculosis, Salmonellosis, Chlamydiosis, Campylobacteriosis, Lyme disease, other bacterial infection, Newcastle disease, Avian Influenza infection, West Nile Virus infection, Usutu virus infection, Avian Borna Virus infection, Beak and feather disease, other viral infection, Toxoplasmosis, Giardiasis, Cryptosporidiosis, other parasitic infection, Cryptococcosis, Aspergillosis, Other fungal infections.

Managing a cluster outbreak of psittacosis in Belgium linked to a pet shop visit in The Netherlands

In July 2013, a Belgian couple were admitted to hospital because of pneumonia. Medical history revealed contact with birds. Eleven days earlier, they had purchased a lovebird in a pet shop in The Netherlands. The bird became ill, with respiratory symptoms. The couple's daughter who accompanied them to the pet shop, reported similar symptoms, but was travelling abroad. On the suspicion of psittacosis, pharyngeal swabs from the couple were taken and sent to the Belgian reference laboratory for psittacosis. Culture and nested polymerase chain reaction (PCR) tests were positive for the presence of Chlamydia psittaci, and ompA genotyping indicated genotype A in both patients. The patients were treated with doxycycline and the daughter started quinolone therapy; all three recovered promptly. Psittacosis is a notifiable disease in Belgium and therefore local healthcare authorities were informed. They contacted their Dutch colleagues, who visited the pet shop. Seven pooled faecal samples were taken and analysed using PCR by the Dutch national reference laboratory for notifiable animal diseases for the presence of Chlamydia psittaci. Four (57%) samples tested positive, genotyping revealed genotype A. Enquiring about exposure to pet birds is essential when patients present with pneumonia. Reporting to health authorities, even across borders, is warranted to prevent further spread.

SINC, a type III secreted protein of Chlamydia psittaci, targets the inner nuclear membrane of infected cells and uninfected neighbors

SINC, a new type III secreted protein of the avian and human pathogen Chlamydia psittaci, uniquely targets the nuclear envelope of C. psittaci-infected cells and uninfected neighboring cells. Digitonin-permeabilization studies of SINC-GFP-transfected HeLa cells indicate that SINC targets the inner nuclear membrane. SINC localization at the nuclear envelope was blocked by importazole, confirming SINC import into the nucleus. Candidate partners were identified by proximity to biotin ligase-fused SINC in HEK293 cells and mass spectrometry (BioID). This strategy identified 22 candidates with high confidence, including the nucleoporin ELYS, lamin B1, and four proteins (emerin, MAN1, LAP1, and LBR) of the inner nuclear membrane, suggesting that SINC interacts with host proteins that control nuclear structure, signaling, chromatin organization, and gene silencing. GFP-SINC association with the native LEM-domain protein emerin, a conserved component of nuclear "lamina" structure, or with a complex containing emerin was confirmed by GFP pull down. Our findings identify SINC as a novel bacterial protein that targets the nuclear envelope with the capability of globally altering nuclear envelope functions in the infected host cell and neighboring uninfected cells. These properties may contribute to the aggressive virulence of C. psittaci.

Managing parrot bite injuries to the hand: not just another animal bite

Bites and scratches are common injuries, frequently sustained from humans, dogs and cats. Exotic pet-related harm however is an important and increasingly emerging class of injury. Whilst the principles of prompt and thorough medical assessment, antibiotics and potential surgical washout and debridement apply, exotic pet wounds require further consideration. Standard antibiotic prophylaxis with amoxicillin/clavulanic acid (also known as co-amoxiclav) is not sufficient for the pathogens transmitted by parrot bites. We illustrate the importance of adequate consideration of microbiological pathogens with a case report of an open finger fracture resulting from a parrot bite. We intend this to be a valuable resource for healthcare professionals in their effective management of such injuries.

LEVEL OF EVIDENCE

V.

Chlamydia genomics: providing novel insights into chlamydial biology

Chlamydiaceae are obligate intracellular pathogens that have successfully evolved to colonize a diverse range of hosts. There are currently 11 described species of Chlamydia, most of which have a significant impact on the health of humans or animals. Expanding chlamydial genome sequence information has revolutionized our understanding of chlamydial biology, including aspects of their unique lifecycle, host-pathogen interactions, and genetic differences between Chlamydia strains associated with different host and tissue tropisms. This review summarizes the major highlights of chlamydial genomics and reflects on the considerable impact these have had on understanding the biology of chlamydial pathogens and the changing nature of genomics tools in the 'post-genomics' era.

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.

Infection, disease, and transmission dynamics in calves after experimental and natural challenge with a Bovine Chlamydia psittaci isolate

Chlamydia (C.) psittaci is the causative agent of psittacosis, a zoonotic disease in birds and man. In addition, C. psittaci has been repeatedly found in domestic animals and is, at least in calves, also able to induce respiratory disease. Knowledge about transmission routes in cattle herds is still deficient, and nothing is known about differences in host response after either experimental or natural exposure to C. psittaci. Therefore, our recently developed respiratory infection model was exploited to evaluate (i) the presence of the pathogen in blood, excretions and air, (ii) the possibility of transmission and (iii) clinical symptoms, acute phase and immune response until 5 weeks after exposure. In this prospective study, intrabronchial inoculation of 10⁸ inclusion-forming units of C. psittaci (n = 21 calves) led to reproducible acute respiratory illness (of approximately one week), accompanied by a systemic inflammatory reaction with an innate immune response dominated by neutrophils. Excretion and/or exhalation of the pathogen was sufficient to transmit the infection to naïve sentinel calves (n = 3) co-housed with the infected animals. Sentinel calves developed mild to subclinical infections only. Notably, excretion of the pathogen, predominantly via feces, occurred more frequently in animals naturally exposed to C. psittaci (i.e. sentinels) as compared to experimentally-inoculated calves. The humoral immune response was generally weak, and did not emerge regularly following experimental infection; however, it was largely absent after naturally acquired infection.

The Chlamydia psittaci genome: a comparative analysis of intracellular pathogens

BACKGROUND

Chlamydiaceae are a family of obligate intracellular pathogens causing a wide range of diseases in animals and humans, and facing unique evolutionary constraints not encountered by free-living prokaryotes. To investigate genomic aspects of infection, virulence and host preference we have sequenced Chlamydia psittaci, the pathogenic agent of ornithosis.

RESULTS

A comparison of the genome of the avian Chlamydia psittaci isolate 6BC with the genomes of other chlamydial species, C. trachomatis, C. muridarum, C. pneumoniae, C. abortus, C. felis and C. caviae, revealed a high level of sequence conservation and synteny across taxa, with the major exception of the human pathogen C. trachomatis. Important differences manifest in the polymorphic membrane protein family specific for the Chlamydiae and in the highly variable chlamydial plasticity zone. We identified a number of psittaci-specific polymorphic membrane proteins of the G family that may be related to differences in host-range and/or virulence as compared to closely related Chlamydiaceae. We calculated non-synonymous to synonymous substitution rate ratios for pairs of orthologous genes to identify putative targets of adaptive evolution and predicted type III secreted effector proteins.

CONCLUSIONS

This study is the first detailed analysis of the Chlamydia psittaci genome sequence. It provides insights in the genome architecture of C. psittaci and proposes a number of novel candidate genes mostly of yet unknown function that may be important for pathogen-host interactions.

Psittacosis infection and tracheobronchomalacia in a patient undergoing thyroidectomy

A 34-year-old woman with papillary thyroid carcinoma underwent total thyroidectomy with central and lateral lymphadenectomy. Immediate airway compromise required re-intubation immediately after surgery. Marked tracheal and bronchial collapse of greater than 50% of the lumen indicated tracheobronchomalacia. Subsequent attempts at extubation failed over the next week. The patient soon developed evidence of a lower respiratory tract infection. Empirical treatment with penicillins was unsuccessful. A clinical suspicion of chlamydia infection prompted initiation of macrolide treatment followed by resolution of both the patient's respiratory infection and tracheobronchomalacia. Serology returned positive for Chlamydophila psittaci infection. It later transpired that the patient had symptoms of an upper respiratory tract infection just prior to surgery. This case demonstrates an interesting and unreported cause of tracheobronchomalacia as well as providing a good lesson on the importance of preoperative screening for infection.

Psittacosis outbreak after participation in a bird fair, Western France, December 2008

In December 2008, three hospitalized cases of suspected psittacosis infection were notified by respiratory disease clinicians from a local hospital to the Regional Epidemiology Unit of Pays de la Loire, France. They all had attended a bird fair. A retrospective cohort study was conducted among exhibitors and organizers to identify potential risk factors in relation to this fair. Environmental and veterinary investigations were implemented to trace potential sources of infection. We identified two confirmed, two probable and 44 possible cases among participants. The attack rate in exhibitors and organizers was 38% (33/86). The median incubation period was 11 days (range 6-22 days). Individuals located in two particular sectors of the showroom were found to be at double the risk of developing psittacosis (relative rate 2·1, 95% confidence interval 1·03-4·18) than those in other sectors. Pooled faecal samples of birds belonging to a possible case exhibitor tested positive for Chlamydiaceae by PCR. Ventilation conditions in the showroom were inadequate. This investigation allowed the formulation of recommendations to prevent psittacosis in bird exhibitions which are held weekly in France.

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.

Chlamydophila psittaci zoonotic risk assessment in a chicken and turkey slaughterhouse

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.

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.

Pet birds and risks of respiratory disease in Australia: a review

OBJECTIVE

Exposure to birds has long been associated with disease in humans. Three respiratory diseases (psittacosis, allergic alveolitis and asthma) were reviewed in association with pet bird ownership with the aim to clarify the spectrum of avian-related respiratory illnesses.

APPROACH

Nineteen studies were selected for review based on recreational bird exposure in relation to psittacosis, allergic alveolitis and asthma.

CONCLUSION

Literature reveals little consensus on the relationship between pet bird ownership and respiratory illness.

IMPLICATIONS

Future studies should aim to clarify the spectrum of avian-related illnesses, and to direct the dissemination of public health information to clinicians and members of the public who keep birds as pets.

Border health: who's guarding the gate?

Changes in the global trade market have led to a thriving international pet trade in exotic animals, birds, and puppies. The flood of animals crossing the United States' borders satisfies the public demand for these pets but is not without risk. Imported pets may be infected with diseases that put animals or the public at risk. Numerous agencies work together to reduce the risk of animal disease introduction, but regulations may need to be modified to ensure compliance. With more than 280,000 dogs and 183,000 wildlife shipments being imported into the United States each year, veterinarians must remain vigilant so they can recognize potential threats quickly.

Chlamydophila psittaci infections in humans during an outbreak of psittacosis from poultry in Germany

In 2005, an outbreak of severe respiratory disease in a mixed poultry flock that was infected with Chlamydophila (C.) psittaci led to dissemination of the infection to at least 100 small poultry farms in 11 districts of Central Germany. At the same time, a total of 24 persons in contact with poultry from one of the flocks reported flu-like symptoms to their physician, thus suggesting zoonotic transmission. Within 3 weeks, seven individuals had to be hospitalized, with three of them requiring intensive care. Analysis of ompA sequences from chlamydial isolates and directly from clinical samples revealed the presence of both genotype A and E/B of C. psittaci at the source of the outbreak and in contact flocks. Genotype A was also detected in the three severely ill patients. The findings of the present study demonstrate the high zoonotic potential of avian chlamydiae. To ensure speedy eradication of psittacosis in poultry flocks and effective treatment of infected humans, fast, sensitive and species-specific detection of the causative agent is essential, as well as close collaboration between regional public health services, attending physicians and the diagnostic laboratories involved.

Genotyping of Chlamydophila psittaci using a new DNA microarray assay based on sequence analysis of ompA genes

Background

The currently used genotyping system for the avian zoonotic pathogen Chlamydophila (C.) psittaci has evolved from serology and is based on ompA sequence variations. It includes seven avian and two non-avian genotypes. Restriction enzyme cleavage of the amplified ompA gene and, less frequently, ompA sequencing are being used for examination, but, beside methodological limitations, an increasing number of recently tested strains could not be assigned to any established genotype.

Results

Comprehensive analysis of all available ompA gene sequences has revealed a remarkable genetic diversity within the species C. psittaci, which is only partially covered by the present genotyping scheme. We suggest adjustments and extensions to the present scheme, which include the introduction of subgroups to the more heterogeneous genotypes A, E/B and D, as well as six provisional genotypes representing so far untypable strains. The findings of sequence analysis have been incorporated in the design of a new DNA microarray. The ArrayTube™ microarray-based ompA genotyping assay has been shown to discriminate among established genotypes and identify so far untyped strains. Its high specificity, which allows detection of single-nucleotide polymorphisms, is due to the parallel approach consisting in the use of 35 hybridization probes derived from variable domains 2 and 4 of the ompA gene.

Conclusion

The traditional genotyping system does not adequately reflect the extent of intra-species heterogeneity in ompA sequences of C. psittaci. The newly developed DNA microarray-based assay represents a promising diagnostic tool for tracing epidemiological chains, exploring the dissemination of genotypes and identifying non-typical representatives of C. psittaci.

Chlamydophila psittaci DNA Detection in the Faeces of Cage Birds

In this study, we investigated the shedding of Chlamydophila psittaci in faecal samples from cage birds using PCR testing. A total of 47 faeces samples were collected from four different aviaries. Main symptoms determined after clinical investigation and owner histories of the birds showed that the birds had respiratory system problems changing from mild to severe. They also showed conjunctivitis, diarrhoea or no symptoms at all. DNA extractions from faeces were performed with the QIAamp DNA Stool Mini Kit. Following PCR with Cp. psittaci specific primers, 43 (91.5%) samples were determined to harbour-specific DNA. Only one bird from each aviary was found to be negative by PCR. As all the samples from birds showing clinical signs were PCR positive, these signs could be correlated to psittacosis in these birds. Cp. psittaci shedding in faeces was detected in all the aviaries. After restriction analysis of PCR amplicons with AluI enzyme, all the isolates showed the same RFLP (Restriction Fragment Length Polymorphism) patterns with the control Cp. psittaci DNA. PCR following QIAamp DNA stool mini kit extraction of faecal samples was found to be a rapid, specific, sensitive, reproducible test, which did not need additional nested PCR of samples.

An outbreak of psittacosis in a bird park in Japan

An outbreak of psittacosis related to a bird park occurred in Matsue City, Shimane Prefecture, Japan, during winter 2001. Seventeen cases of psittacosis (12 visitors, three staff, and two student interns) were confirmed. A cohort study was conducted among the park staff and students to determine the risk factors for the development of acute serologically confirmed psittacosis (SCP) infection. Being 'bird staff' had an increased risk of SCP infection (RR 3.96, 95% CI 1.48-10.58). Entering the staff building, where ill birds were maintained without proper isolation, was also associated with an increased risk of SCP infection (RR 3.61, 95% CI 1.03-12.6). Isolation of ill birds and quarantine measures were found to be insufficient. Dehumidifiers and a high-pressure water spray under a closed ventilation environment may have raised the concentration of Chlamydophila psittaci in the hothouses. Bird park staff and visitors should be educated about psittacosis.

Exacerbation of Chlamydophila psittaci pathogenicity in turkeys superinfected by Escherichia coli

Both Chlamydophila psittaci and Escherichia coli infections are highly prevalent in Belgian turkeys and therefore they both might contribute to the respiratory disease complex observed in turkeys. C. psittaci can infect turkeys within the first week of age, even in the presence of maternal antibodies. However, the first C. psittaci outbreaks occur mostly at the age of 3 to 6 weeks, the period when also E. coli infections appear on the farms. Therefore, we examined in this study the pathogenicity of an E. coli superinfection on C. psittaci predisposed turkeys. Turkeys were infected with C. psittaci, E. coli or with C. psittaci followed by E. coli. Simulating the impact of an E. coli infection during the acute phase or the latent phase of a C. psittaci infection, turkeys received E. coli at 1 or 5 weeks post C. psittaci infection, respectively. E. coli superinfection during the acute phase of C. psittaci infection increased C. psittaci excretion and stimulated chlamydial replication in the respiratory tract resulting in exacerbated clinical disease. Interestingly, E. coli superinfection during the latent phase of C. psittaci infection induced chlamydial replication, leading to increased C. psittaci-specific antibody titres. In addition, chlamydial predisposition gave higher E. coli excretion compared with turkeys that had only been infected with E. coli. Overall, the present study clearly demonstrates the pathogenic interplay between C. psittaci and E. coli resulting in more severe respiratory disease.

Chlamydophila psittaci in Fulmars, the Faroe Islands

Chlamydophila psittaci was detected in 10% of 431 fulmars examined from the Faroe Islands. Analysis of ompA showed a sequence almost identical to that of the type strain. The origin of C. psittaci outbreaks in fulmars is discussed. Despite a high level of exposure, the risk for transmission of C. psittaci to humans is low.

PNEUMONIA | Atypical

‘Atypical pneumonia’ refers to a clinical syndrome associated with pneumonia (typically mild, nonlobar) and diverse upper respiratory tract and extrapulmonary manifestations. Clinical features overlap with bacterial pneumonia, and co-infection with both typical (e.g., Streptococcus pneumoniae or other bacteria) and atypical pathogens may occur. ‘Atypical’ pathogens include Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella spp. In large epidemiological studies, Mycoplasma pneumoniae has been implicated in 2–18% of community-acquired pneumonias; Chlamydia pneumoniae, in 2–8%; Legionella sp., 1–4%. Atypical pathogens lack cell walls and are resistant to β-lactam antibiotics but are usually susceptible to tetracyclines, macrolides, ketolides, and fluoroquinolone antibiotics. In this article, we also review other unusual causes of pneumonia which are transmitted by insects or vectors (e.g., Rocky Mountain spotted fever, cat scratch fever, Q fever, ehrlichiosis, Lyme disease, and tularemia). These diverse organisms are not found on Gram stain, and diagnosis requires special culture techniques or serological assays. We review the salient clinical and laboratory features of these various disorders, and discuss diagnostic and therapeutic strategies.

Use of a nested PCR-enzyme immunoassay with an internal control to detect Chlamydophila psittaci in turkeys

Background

Laboratory diagnosis of Chlamydophila psittaci, an important turkey respiratory pathogen, is difficult. To facilitate the diagnosis, a nested PCR-enzyme immunoassay (PCR-EIA) was developed to detect the Cp. psittaci outer membrane protein A (ompA) gene in pharyngeal swabs.

Methods

The fluorescein-biotin labelled PCR products were immobilized on streptavidin-coated microtiter plates and detected with anti-fluorescein peroxidase conjugate and a colorimetric substrate. An internal inhibition control was included to rule out the presence of inhibitors of DNA amplification. The diagnostic value of the ompA nested PCR-EIA in comparison to cell culture and a 16S-rRNA based nested PCR was assessed in pharyngeal turkey swabs from 10 different farms experiencing respiratory disease.

Results

The sensitivity of the nested PCR-EIA was established at 0.1 infection forming units (IFU). Specificity was 100%. The ompA nested PCR-EIA was more sensitive than the 16S-rRNA based nested PCR and isolation, revealing 105 out of 200 (52.5%) positives against 13 and 74 for the latter two tests, respectively. Twenty-nine (23.8%) out of 122 ompA PCR-EIA negatives showed the presence of inhibitors of DNA amplification, although 27 of them became positive after diluting (1/10) the specimens in PCR buffer or after phenol-chloroform extraction and subsequent ethanol precipitation.

Conclusion

The present study stresses the need for an internal control to confirm PCR true-negatives and demonstrates the high prevalence of chlamydiosis in Belgian turkeys and its potential zoonotic risk. The ompA nested PCR-EIA described here is a rapid, highly sensitive and specific diagnostic assay and will help to facilitate the diagnosis of Cp. psittaci infections in both poultry and man.

Probable psittacosis outbreak linked to wild birds

Residence in the upper Blue Mountains, age of 50–64 years, direct contact with wild birds, and lawn mowing without a grass catcher were associated with psittacosis.

In autumn 2002, an outbreak of probable psittacosis occurred among residents of the Blue Mountains district, Australia. We conducted a case-control study to determine independent risk factors for psittacosis by comparing exposures between hospitalized patients and other residents selected randomly from the telephone directory. Of the 59 case-patients with laboratory results supportive of psittacosis, 48 participated in a case-control study with 310 controls. Independent risk factors were residence in the upper Blue Mountains (odds ratio [OR] = 15.2, 95% confidence interval [CI] 5.6–41.7), age of 50–64 years (OR = 3.9, 95% CI 1.5–10.5), direct contact with wild birds (OR = 7.4, 95% CI 2.5–22), and mowing lawns without a grass catcher (OR = 3.2, 95% CI 1.3–8.0). Protective equipment is recommended for residents in areas frequented by free-ranging birds if contact with birds and their droppings is likely when performing outdoor activities such as lawn mowing.

Animal origins of SARS coronavirus: possible links with the international trade in small carnivores

The search for animal host origins of severe acute respiratory syndrome (SARS) coronavirus has so far remained focused on wildlife markets, restaurants and farms within China. A significant proportion of this wildlife enters China through an expanding regional network of illegal, international wildlife trade. We present the case for extending the search for ancestral coronaviruses and their hosts across international borders into countries such as Vietnam and Lao People's Democratic Republic, where the same guilds of species are found on sale in similar wildlife markets or food outlets. The three species that have so far been implicated, a viverrid, a mustelid and a canid, are part of a large suite of small carnivores distributed across this region currently overexploited by this international wildlife trade. A major lesson from SARS is that the underlying roots of newly emergent zoonotic diseases may lie in the parallel biodiversity crisis of massive species loss as a result of overexploitation of wild animal populations and the destruction of their natural habitats by increasing human populations. To address these dual threats to the long-term future of biodiversity, including man, requires a less anthropocentric and more interdisciplinary approach to problems that require the combined research expertise of ecologists, conservation biologists, veterinarians, epidemiologists, virologists, as well as human health professionals.

Psittacosis/avian chlamydiosis

Considerable progress continues to be made in understanding chlamydial organisms, their host species, diagnosis, and treatment. (1-3) Thus, national guidelines are updated annually to provide a standardized approach to handling infections in humans and birds. (2-3) Prior to development of these guidelines, considerable variation in approach by state agencies has been documented. (39) A more recent national assessment of state regulations and procedures has not been conducted. Decreasing imports of birds and increasing education may contribute to a reduction in human risk from avian infections. Keeping new birds separate from old birds in aviaries and poultry production facilities may reduce the incidence of avian chlamydiosis. Although wide-scale testing of birds may not be cost effective, (28) focal testing and treatment may help reduce human risk. The recent loss of a major source for pelleted feed for small birds, such as budgerigars, was a severe setback for veterinarians and local agencies in managing this disease. However, new medication formulas under development may help to address this problem. (2-3)

Fever and pneumonia in a steroid treated patient with systemic lupus erythematosus

Systemic lupus erythematosus is reported to affect the lungs in almost half of patients, but pleuritis is most commonly encountered. Acute pneumonitis is an uncommon but recognized manifestation of SLE. Infection and drug reactions are more frequently diagnosed. The case discussed below permits consideration of the dilemmas typical of the SLE patient who presents with an acute pulmonary process.

Exotic pulmonary infections

Pulmonary infections are the commonest type of illnesses seen in everyday practice. Although most infections are caused by a few familiar pathogens, an increase in global travel has led to the occurrence of rare and exotic diseases that often do not manifest until after the traveller returns home. Previously innocuous organisms may also be the cause of exotic infections in patients undergoing transplantation, or very aggressive immunosupression. Such treatment regimes may reactivate quiescent organisms acquired years previously, for example melioidosis and strongyloides stercoralis. In most developed countries there is also an increasing incidence of zoonotic infections, with a number of these presenting with mainly pulmonary symptoms. A carefully taken history of recent travel, exposure to wild or domestic animals or the presence of immunosuppression, is extremely helpful in identifying problematic infections that fall into the realm of the exotic. This review discusses some of the respiratory infections in each of these groups with an emphasis on imported infections.

Chlamydia Species and Mycoplasma pneumoniae

Chlamydia psittaci, Chlamydia pneumoniae, and Mycoplasma pneumoniae are a group of respiratory pathogens that have similar pulmonary and extrapulmonary manifestations. Recent studies suggest that C. pneumoniae and M. pneumoniae may play a role in the pathogenesis of asthma, but further studies are needed to delineate the importance of these organisms in this disease. The diagnosis of C. pneumoniae infection is hindered by the lack of a gold standard: Asymptomatic carriage of C. pneumoniae lowers the specificity of culture and polymerase chain reaction, and the current use of single high titers to identify infection also has specificity problems. Newer antibiotics simplify the management of infection with C. psittaci, C. pneumoniae, and M. pneumoniae and offer the potential for prophylaxis.