Ornithosis as a nosocomial infection

Psittacosis Pneumonia: Diagnosis, Treatment and Interhuman Transmission

Psittacosis pneumonia is a zoonosis caused by Chlamydia psittacosis infection, mainly resulting from contact with aerosols of birds or poultry's urine, feces, and excrement. The clinical manifestations range from general symptoms of infection to severe acute respiratory syndrome and systemic diseases, currently diagnosed using metagenomic next-generation sequencing (mNGS) to improve diagnostic accuracy. To date, most reports have only discussed human exposure to poultry disease. However, the latest studies have shown that human-to-human transmission of Chlamydia psittaci occurs not only between infected patients and their close contacts but also between secondary contacts. After looking back on relevant literature at home and abroad in the past ten years, this paper reviews the diagnosis, diagnosis and treatment, and progress in epidemiological research of Psittacosis pneumonia.

The growing repertoire of genetic tools for dissecting chlamydial pathogenesis

Multiple species of obligate intracellular bacteria in the genus Chlamydia are important veterinary and/or human pathogens. These pathogens all share similar biphasic developmental cycles and transition between intracellular vegetative reticulate bodies and infectious elementary forms, but vary substantially in their host preferences and pathogenic potential. A lack of tools for genetic engineering of these organisms has long been an impediment to the study of their biology and pathogenesis. However, the refinement of approaches developed in C. trachomatis over the last 10 years, and adaptation of some of these approaches to other Chlamydia spp. in just the last few years, has opened exciting new possibilities for studying this ubiquitous group of important pathogens.

Human psittacosis: a review with emphasis on surveillance in Belgium

Chlamydia psittaci causes psittacosis in humans, mainly in persons in contact with birds in either the setting of occupational or companion bird exposure. Infection is associated with a range of clinical manifestations from asymptomatic infection to severe atypical pneumonia and systemic disease. This paper reviews new knowledge on psittacosis, its legal and regulatory aspects and presents epidemiological data on psittacosis in Belgium. In Belgium, the number of reported positive laboratory results increased slowly since 2010, and in 2017, the number almost doubled compared to the two previous years. The number of psittacosis cases in Belgium, as in other countries, is probably highly underestimated, because of underdiagnoses and underreporting. Over the 3-year period, the mandatory notification system registered 24% only of all reported positive laboratory result. Therefore, increased awareness among general and occupational physicians, clinicians and the public is needed. Policies aimed at reducing psittacosis disease burden are justified, nevertheless national health authorities should provide more legal and financial support to implement more adequate C. psittaci diagnostic tools.

Multiple human-to-human transmission from a severe case of psittacosis, Sweden, January-February 2013

Proven transmission of Chlamydia psittaci between humans has been described on only one occasion previously. We describe an outbreak which occurred in Sweden in early 2013, where the epidemiological and serological investigation suggests that one patient, severely ill with psittacosis after exposure to wild bird droppings, transmitted the disease to ten others: Two family members, one hospital roommate and seven hospital caregivers. Three cases also provided respiratory samples that could be analysed by PCR. All the obtained C. psittaci sequences were indistinguishable and clustered within genotype A. The finding has implications for the management of severely ill patients with atypical pneumonia, because these patients may be more contagious than was previously thought. In order to prevent nosocomial person-to-person transmission of C. psittaci, stricter hygiene measures may need to be applied.

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.

Mucosal immunity in mice induced by orally administered transgenic rice

Transgenic plants are efficient means of producing and delivering oral vaccines. Rice material shown previously to express the Chlamydophila psittaci (Cp. psittaci) antigen (MOMP) fused to the B subunit of Escherichia coli heat-labile enterotoxin (LTB) was fed to mice and the resulting immune response was investigated. Oral immunization of mice with the transgenic rice elicited MOMP-specific sera IgG and IgA antibodies, a strong increase of the lymphoproliferative response, and significant levels of IFN-gamma, TGF-beta and IL-2 production. Furthermore, the immunization of mice with transgenic rice elicited strong cytotoxic T lymphocyte (CTL) responses in vitro. These results demonstrated that plant-made LTB-MOMP fusion protein could induce significant humoral and cellular Th1 and Th3 immune responses. Moreover, transgenic rice immunization induced partial protection (53.3%) against a lethal challenge with the highly virulent Cp. psittaci 6BC strain in a BALB/c mouse model. These results suggest that expression of protective antigens of Cp. psittaci in transgenic rice has potential as an edible vaccine against avain chlamydiosis.

Construction and immunogenicity of recombinant adenovirus expressing the major outer membrane protein (MOMP) of Chlamydophila psittaci in chicks

Avian chlamydiosis is caused by Chlamydophila psittaci. The major outer membrane protein (MOMP) encoded by the outer membrane protein 1 (omp1) gene is an excellent candidate for genetic engineering of a vaccine against avian chlamydiosis. In this study, the MOMP gene was amplified by PCR and cloned into the transfer vector pShuttle-CMV. The recombinant plasmid was obtained by recombination between the plasmid pShuttle-CMV-MOMP and skeleton vector pAdEasy-1 in Escherichia coli strain BJ5183. The titer of recombinant adenovirus containing the MOMP gene (rAd-MOMP) of C. psittaci was 3.4x10(10)TCID(50)/ml in human embryonic kidney 293 (HEK293) monolayer cells. The expression of the MOMP in HEK293 cells infected with rAd-MOMP was confirmed by an indirect immunofluorescence assay. Specific pathogen free (SPF) chicks were inoculated with 10(6), 10(8), and 10(10)TCID(50) of rAd-MOMP/chick. Inoculated chicks generated antibodies against MOMP of C. psittaci, which were detected by an indirect hemagglutination test (IHA). The vaccinated chicks were challenged with a virulent Chinese field isolate. Nine out of 10 chicks in the vaccinated group were protected, while birds in the wild-type adenovirus control group and the PBS control group all showed clinical signs after challenge. The results indicate that the recombinant adenovirus containing the MOMP gene of C. psittaci might be a candidate vaccine against avian chlamydiosis.

Respiratory chlamydia: the management of an outbreak

This investigation was undertaken in response to the occurrence of nine cases of respiratory chlamydial infection in 8 months within the district of Dudley. All nine cases of respiratory chlamydia were due to Chlamydia psittaci, not Chlamydia pneumoniae. Five cases had avian exposure, but no other aetiological factors were identified. Faecal specimens were obtained from only two of the implicated birds and were negative. Two local aviaries were identified as sources of implicated birds. The two aviaries were themselves linked. Bird faecal specimens were taken from the two implicated aviaries and were both positive for Chlamydia psittaci. Appropriate public health control measures were introduced in these aviaries. A press statement was released to identify and advise, by telephone, those who purchased birds from the aviaries.

An outbreak of psittacosis

An outbreak of chlamydia infection affecting seven people from a small town in Grampian is described. The origin of the outbreak seemed to be a local pet shop. The difficulties of diagnosis and tracing the connections with the pet shop are discussed. The clinical histories of the seven patients are described including those of the two who died.

Superficial thrombophlebitis. II. Secondary hypercoagulable states

Secondary hypercoagulable states are complex clinical conditions associated with an increased risk of thrombosis in which the exact pathophysiology is poorly understood. Secondary causes of superficial thrombophlebitis include malignancy, pregnancy, use of oral contraceptives, infusion of prothrombin complex concentrates, Behçet's disease, Buerger's disease, Mondor's disease, infectious agents, conditions that promote venous stasis, intravenous catheters and intravenous drug use. Conditions that may stimulate superficial thrombophlebitis include dermatophyte cellulitis at saphenous phlebectomy sites, sarcoidal granulomas, cutaneous polyarteritis nodosa, and hyperalgesic pseudothrombophlebitis in patients who test positive for human immunodeficiency virus. The distinguishing features, clinical evaluation, treatment, and histologic characteristics of the various disorders are reviewed.

Serological cross-reactivity among chlamydial strains in a family outbreak of psittacosis

Three members of a family of nine persons contracted psittacosis with severe pneumonia, respiratory failure, delirium, hepatitis and renal involvement. A newly purchased cockatiel was probably the primary source of infection but person-to-person transmission is likely to have taken place between twin brothers who shared a bedroom, one of whom had no direct contact with birds. Type-specific chlamydial serological tests identified the infecting agent as Chlamydia psittaci. The highest titres in the initial samples of serum from the patients, however, were to C. psittaci TWAR (Taiwan Acute Respiratory) and serological cross-reactivity among chlamydial strains was demonstrated. This study of a clearly defined outbreak of psittacosis provides useful information for those undertaking larger population surveys of chlamydial disease and emphasises the need for detailed serological investigation of cases.

A clinical and epidemiological study of "ornithosis" caused by Chlamydia psittaci and Chlamydia pneumoniae (strain TWAR)

Ornithosis is a notifiable disease in Sweden since 1954. In 1981 and 1982 a sharp increase in the number of notifications occurred. Since then the number has declined but is still high. A changed epidemiology characterized by no history of bird contact and no common source, raised the suspicion of a new agent. Serological data now suggest that the epidemic was to a substantial part due to Chlamydia pneumoniae (strain TWAR) (48% of the patients during 1981-1982 compared to 9% during 1984-1987). During recent years TWAR infections have thus become uncommon but reappearance can be expected in the near future. The clinical picture as well as the complications appear to be very similar in infections caused by C. pneumoniae and C. psittaci.

Clinical conditions associated with positive complement fixation serology for Chlamydiae

The hospital records of 242 patients with diagnostic chlamydial complement fixation (CF) titres (seroconversion and/or titre greater than or equal to 64) found among 60,000 patients screened for suspected viral illnesses were reviewed to study the clinical conditions associated with positive CF serology for Chlamydiae. After excluding typical genital C. trachomatis infections, the majority of the remainder were considered to represent C. psittaci infections. Respiratory symptoms were the most common clinical manifestations of chlamydial infections detectable by CF, but the majority (58%) of the patients did not have pneumonia. Abdominal, neurological as well as urinary tract symptoms were common. Cutaneous, joint, cardiac, genital and ocular manifestations were also noted. Fever (greater than or equal to 38.5 degrees C) was present in 62% of the patients. The ESR was raised (greater than or equal to 20 mm/h) in the majority of the patients (83%), but the leucocyte count was usually (86%) within normal limits. Because the clinical spectrum of C. psittaci infections is apparently broad, serological tests for detecting antibodies to C. psittaci (e.g. CF) should be used widely in various clinical conditions and not for patients with pneumonia alone.

Selected aspects of nosocomial infections in the 1980s

Unusual or rare pathogens and syndromes may become significant problems in nosocomial infection. Pathogens that usually produce community-onset disease, particularly respiratory viruses, Legionella, and atypical mycobacteria, also cause nosocomial infection. Conversely, nosocomial pathogens may also produce disease in the community, as has been seen with Clostridium difficile. Contamination of parenteral and antiseptic solutions continues to be a problem in hospitals. Hospital-acquired viral infections are receiving increasing recognition. Nosocomial gastrointestinal infections, although of low frequency, are of major import because of their epidemic potential. Airborne transmission of pathogens is becoming more apparent at the same time that recognition of the importance of hand transmission creates hope for infection control. Antibiotics influence the type of microorganisms that colonize patients, but the host determines superinfection.

Psittacosis/ornithosis in Cambridgeshire 1975-1983

In a population of approximately 300 000 there were 150 illnesses attributable to chlamydial infection from January 1975 to June 1983 and nearly all were presumed due to Chlamydia psittaci. Diagnosis was based on the complement-fixation (CF) test, the disadvantages of which are discussed, especially anamnestic responses. There were 73 cases of pneumonia, 37 febrile respiratory infections, 35 miscellaneous conditions and five asymptomatic seropositive contacts. The annual number of cases was lowest in 1976 (3) and increased to a maximum in 1980 (28) followed by a sustained high level. No seasonal variation was observed. A presumptive bird source was present in only 17% and detailed consideration of cases in one rural practice suggests that the infection may possibly be more endemic than zoonotic.

An outbreak of ornithosis in Norway in 1981

During 1981 there were 508 laboratory confirmed cases of ornithosis in Norway. This represents a 7-fold increase compared with previous years. Among 370 patients examined by the National Institute of Public Health, Oslo, 148 stated some contact with birds. There were also small family outbreaks and cases of ornithosis in school friends etc. where no bird exposure had occurred, suggesting that interhuman transmission might be involved. The clinical picture was that of a respiratory disease with pneumonia in more than half the cases. The clinical course was mild to moderately severe. At present we have no explanation for this change in the epidemiologic pattern of ornithosis in Norway.