Seropositividad a Chlamydophila psittaci en cotorras argentinas (Myiopsitta monachus) invasoras de la ciudad de Santiago de Chile / Seropositivity to zoonotic Chlamydophila psittaci in invasive monk parakeets (Myiopsitta monachus) from Santiago, Chile

INTRODUCCIÓN: Chlamydophila psittaci es una bacteria zoonótica e intracelular estricta, que provoca la psitacosis humana y su principal hospedero son las aves psitácidas. La cotorra argentina es un ave psitácida nativa de Sudamérica y actualmente considerada una especie invasora en 19 países, incluyendo Chile. OBJETIVO: Determinar positividad contra C. psittaci en muestras de suero y torulados de cotorras argentinas de vida libre capturadas en la Región Metropolitana de Chile. MÉTODOS: Se analizaron 95 muestras de suero de pichones e individuos adultos de cotorras argentinas, a través de una prueba de ELISA indirecto utilizando un kit comercial. Posteriormente, se analizaron 40 tórulas nasotraqueales y cloacales de individuos adultos a través de una RPC en tiempo real específica para C. psittaci. RESULTADOS: Se detectaron anticuerpos en muestras de suero de cinco individuos adultos de cotorras argentinas (n = 68), mientras que ninguno de los pichones analizados fue seropositivo (n = 27). Todas las muestras analizadas a través de RPC en tiempo real fueron negativas. CONCLUSIÓN: Estos resultados demuestran por primera vez en Chile la exposición a C. psittaci en cotorras argentinas de vida libre, lo cual puede representar un riesgo importante para la transmisión de este patógeno a poblaciones humanas y animales.

BACKGROUND: Chlamydophila psittaci is a zoonotic obligate intracellular bacterium that causes the human psittacosis, and its main host are psittacine birds. The monk parakeet is a psittacine bird native to South America, currently being considered an invasive species in 19 countries, including Chile. AIM: To determine positivity to C. psittaci in serum samples and swabs from free-ranging monk parakeets captured in the Metropolitan Region of Chile. METHODS: Ninety-five serum samples from nestling chicks and adult monk parakeets were tested using an indirect ELISA test kit. Cloacal and nasotracheal swabs from 40 adult parakeets were further analyzed by C. psittaci-specific real-time PCR. RESULTS: We found antibody titers in sera of five adult monk parakeets (n = 68) while none of the nestlings were seropositive (n = 27). All samples tested with real-time PCR were negative. CONCLUSIONS: Our results demónstrate for the first time in Chile the exposure to C. psittaci in free-ranging monk parakeets which may represent a significant risk of pathogen transmission to human and animal populations.

NK Cell-Mediated Processing Of Chlamydia psittaci Drives Potent Anti-Bacterial Th1 Immunity.

Natural killer (NK) cells are innate immune cells critically involved in the early immune response against various pathogens including chlamydia. Here, we demonstrate that chlamydia-infected NK cells prevent the intracellular establishment and growth of the bacteria. Upon infection, they display functional maturation characterized by enhanced IFN-γ secretion, CD146 induction, PKCϴ activation, and granule secretion. Eventually, chlamydia are released in a non-infectious, highly immunogenic form driving a potent Th1 immune response. Further, anti-chlamydial antibodies generated during immunization neutralize the infection of epithelial cells. The release of chlamydia from NK cells requires PKCϴ function and active degranulation, while granule-associated granzyme B drives the loss of chlamydial infectivity. Cellular infection and bacterial release can be undergone repeatedly and do not affect NK cell function. Strikingly, NK cells passing through such an infection cycle significantly improve their cytotoxicity. Thus, NK cells not only protect themselves against productive chlamydial infections but also actively trigger potent anti-bacterial responses.

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 10(8) 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.

Evaluation of Chlamydophila psittaci infection and other risk factors for atherosclerosis in pet psittacine birds.

OBJECTIVE: To determine whether the presence of Chlamydophila psittaci antigen, plasma cholesterol concentration, diet, sex, species, and age are risk factors for the development of atherosclerosis in pet psittacine birds. DESIGN: Retrospective case-control study. ANIMALS: 31 psittacine birds with atherosclerosis (study birds) and 31 psittacine birds without atherosclerosis (control birds). PROCEDURES: Necropsy reports were reviewed, birds with a histopathologic diagnosis of atherosclerosis were identified, and available medical records were reviewed. Signalment, history, clinicopathologic findings, and other relevant data were recorded and evaluated. Control birds did not have atherosclerosis and were chosen by both convenience sampling and population demographics. Histologic sections of great vessels from all birds (study and control birds) were reviewed and then submitted for immunohistochemical staining for the presence of C psittaci antigen. RESULTS: Result of immunohistochemical staining for C psittaci antigen in blood vessels was significantly associated with atherosclerosis. After adjusting for age, species origin, and type of illness, the odds of atherosclerosis was 7 times as high for birds with positive immunohistochemical staining for C psittaci antigen, compared with that of birds with negative immunohistochemical staining. Study birds and control birds differed significantly only with respect to plasma cholesterol concentrations. The median plasma cholesterol concentration of study birds (421 mg/dL) was significantly higher than that of control birds (223 mg/dL). CONCLUSIONS AND CLINICAL RELEVANCE: Infection with C psittaci and a high plasma cholesterol concentration may be risk factors for developing atherosclerosis in pet psittacine birds.

[The dynamics of detection of antibodies class G against Chlamydia pneumoniae and Chlamydia psittaci in blood serum of patients of different age groups].

The detection of antibodies class G in blood serum of patients of different age groups was carried out in 2005-2010. The analysis permitted to establish the peak of activity of chlamydiae infection in 2006 and increase of activity of morbidity in 2010.

Chlamydia psittaci Infection in nongastrointestinal extranodal MALT lymphomas and their precursor lesions.

Extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) are associated with various infectious pathogens. We analyzed the presence of Chlamydia psittaci, Chlamydia pneumoniae, and Chlamydia trachomatis DNA in 47 nongastrointestinal and 14 gastrointestinal MALT lymphomas, 37 nonmalignant control samples, and 27 autoimmune precursor lesions by polymerase chain reaction amplification and direct sequencing. In 47 nongastrointestinal MALT lymphomas, 13 (28%) were positive for C psittaci DNA compared with 4 (11%) of 37 nonmalignant control samples (P = .09). C psittaci was detected at variable frequencies in MALT lymphomas of different sites: lung, 100% (5/5; P < .01); thyroid gland, 30% (3/10; P > .05); salivary gland, 13% (2/15; P > .05); ocular adnexa, 15% (2/13); and skin, 25% (1/4). Of 27 autoimmune precursor lesions (11 Hashimoto thyroiditis and 16 Sjögren syndrome), 11 (41%) contained C psittaci DNA. Only 1 (7%) of 14 gastrointestinal MALT lymphomas was positive for C psittaci. All specimens were negative for C trachomatis and C pneumoniae. Besides ocular adnexal lymphomas, C psittaci infection is associated with nongastrointestinal MALT lymphomas and autoimmune precursor lesions, suggesting possible involvement of C psittaci-induced antigenic-driven MALT lymphomagenesis.

Chlamydophila psittaci and Toxoplasma gondii infection in pigeons (Columba livia) from São Paulo State, Brazil.

Pigeons (Columba livia) cohabit with humans in urban and rural areas, representing a public health problem since microorganisms are transmitted through the inhalation of dust from their dry feces (chlamydiosis) and through ingestion of their undercooked or poorly refrigerated meat (toxoplasmosis). This study aimed to evaluate the presence of Chlamydophila psittaci and Toxoplasma gondii in pigeons from four cities in São Paulo State, Brazil. C. psittaci was evaluated through hemi-nested polymerase chain reaction (hnPCR) using cloacal and tracheal swabs, whereas T. gondii specific antibodies were assessed by means of modified agglutination test (MAT), mouse brain and muscle bioassay, and polymerase chain reaction (PCR). To confirm the infection in mice, T. gondii antibodies were assayed by using indirect fluorescent antibody test (IFAT). Considering C. psittaci, 40/238 (16.8%; 95%CI 12.6-22.1%) samples were positive according to hnPCR, especially for the cities of São Paulo (42.5%) and Bauru (35%). As regards T. gondii, 12/238 (5%; 95%CI 2.9-8.6%) serum samples were positive according to MAT. Of these, five samples had titer equal to 1:8; six samples, 1:16; and one sample, 1:32. Bioassay, IFAT and PCR were negative for mouse toxoplasmosis. The absence of T. gondii antibodies suggests that pigeons may be infected with a low concentration of the agent, not detected by the antigen test. Thus, C. psittaci represents an actual problem concerning bird health.

Chlamydophila psittaci seropositivity and serum levels of soluble intercellular adhesion molecule-1 in farmers.

Chlamydophila infection is known as an occupational hazard to veterinarians, farmers, poultry workers. Serum levels of the soluble Intercellular Adhesion Molecule-1 (sIC AM-1), is associated with C. seropositivity. Since no data about IC AM-1 levels and C. psittaci infection are known, the aim of this work was to assess if chronic persistent C. psittaci infection constantly stimulates the expression of sIC AM-1, independent of the characteristic symptoms of ornithosis. C. psittaci seropositivity and serum concentrations of sIC AM-1 were investigated in 30 farmers and 20 age-matched healthy public employees as controls. Increased serum sIC AM-1 levels were found in the group of farmers exposed to infectious risk compared to controls, and the serum concentrations of sIC AM-1 was significantly correlated with a high IgG titre against C. psittaci. It is therefore possible to suggest a sIC AM-1 measurement for use as a tool to verify the development of C. psittaci chronic infection in an occupational setting.

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

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

Fulminant psittacosis requiring mechanical ventilation and demonstrating serological cross-reactivity between Legionella longbeachae and Chlamydia psittaci.

Chlamydia psittaci infection typically causes a mild respiratory illness in humans. Severe respiratory failure requiring mechanical ventilation or intensive care therapy is an uncommon development. The aetiological agents causing severe community acquired pneumonia often remain undetermined. Serological tests may aid in diagnosis. We present two cases of fulminant psittacosis, one demonstrating early cross-reactivity with Legionella longbeachae.

[Evaluation of serum KL-6 levels in summer-type hypersensitivity pneumonitis].

A high level of serum KL-6 is a known feature of active pulmonary fibrosis. Some researchers have suggested that KL-6 is produced and secreted by type II pneumocytes. The present study evaluated serum KL-6 levels in patients with summer-type hypersensitivity pneumonitis (summer-type HP) (n = 6, 7 episodes), Mycoplasma pneumoniae pneumonia (n = 16), Chlamydia psittaci pneumonia (n = 3), Chlamydia pneumoniae pneumonia (n = 9), and bacterial pneumonia (n = 12). In addition, transbronchial lung biopsy (TBLB) specimens were examined pathologically in order to identify the site of production and secretion of KL-6. In patients with summer-type HP, the serum KL-6 levels exceeded 500 U/ml (2.996 +/- 2.016 U/ml), but was below 500 U/ml (302 +/- 126 U/ml, p < 0.001) in the patients with other infectious pneumonias, with the exception of two. One of these two patients with a high serum KL-6 level had adult respiratory distress syndrome due to Mycoplasma pneumoniae. The other had organizing pneumonia due to Chlamydia pneumoniae. TBLB specimens showed proliferative type II pneumocytes in all summer-type HP cases. We believe that the high serum KL-6 levels were produced by type II pneumocytes, and may provide a useful indicating serum marker for HP. Although serum LDH, serum CRP and PaO2 are known as monitoring markers in summer-type HP, our findings demonstrated no manifest correlations among these markers. However, serum KL-6 levels showed a strong positive correlation with serum LDH levels and an inverse correlation with serum CRP levels. These results suggest that serum KL-6 may be a better marker of the degree of disease activity than serum LDH, CRP, or PaO2 in summer-type HP.

Mucosal and systemic humoral immune response of turkeys after infection and reinfection with a Chlamydia psittaci serovar D strain.

The purpose of this study was to examine the effects of Chlamydia-specific antibodies in tears and tracheal washings (IgA and IgG) and sera (IgG) on chlamydial excretion during the course of an experimental infection and reinfection of turkeys with Chlamydia psittaci. Two groups of turkeys were experimentally infected with a serovar D strain of Chlamydia psittaci, either at the age of 7 days or at the age of 35 days. A third group was infected at the age of 7 days and reinfected with the same strain at 35 days of age. A control group consisted of sham infected turkeys. All turkeys were observed daily for clinical symptoms. At the age of 49 days, the turkeys were euthanized and examined for macroscopic lesions. Following primary infection and reinfection, turkeys were equally depressed and dyspneic. Necropsy findings revealed no significant differences in the lesions of the birds which received both the prime and challenge infection and the birds, which received only a single infection. Anti-chlamydial antibodies in sera, tears, and tracheal washings were determined by IgA and IgG immunoblot assays. A clear local and systemic antibody response towards a broad range of chlamydial antigens was already seen 10 to 14 days following the experimental infections at both 7 and 35 days of age. In spite of the presence of Chlamydia-specific antibodies in tears, tracheal washings, and sera, chlamydial excretion was observed in all infected and reinfected turkeys throughout the experiment. In most turkeys, this chlamydial excretion was detected in three or four tissues sampled at set times, i.e., the conjunctiva, nostrils, trachea, and cloaca.

[Cross-reactivity between Chlamydia psittaci and Acinetobacter in indirect immunofluorescence assays]. / Reactividad cruzada entre Chlamydia psittaci y Acinetobacter en ensayos de inmunofluorescencia indirecta.

Cross reactivity between Chlamydia psittaci and a strain from genus Acinetobacter was investigated by indirect fluorescent antibody (IFA) technique. Two groups of serum samples were tested: 64 belonged to patients diagnosed as psittacosis and 64 (control group) were non reactive to Chlamydia psittaci by IFA. Samples were incubated on smears prepared with an Acinetobacter suspension for detecting IgG and IgM. 100% reactivity to IgG was found in 1:16 serum dilution among anti-psittacosis sera, whereas 6.25% of control sera reacted at the same dilution. When testing IgM, high rates of reactivity were found in both serum groups, thus it has been discarded as a marker for cross reactivity. Fluorescence pattern suggests that antigens are located at the cell wall.

Elementary body agglutination for rapidly demonstrating chlamydial agglutinins in avian serum with emphasis on testing cockatiels.

The development and use of a stained chlamydial elementary body agglutination (EBA) antigen for detecting antibody activity in avian sera is described. Examples of serologic results on serum samples from various types of birds indicate the usefulness of EBA, latex agglutination (LA), and direct complement fixation (DCF) in diagnosing avian chlamydiosis. Results of tests on 10 cockatiels examined in clinics indicate that a combination of serology, culture, and/or antigen-detection enzyme-linked immunosorbent assay may be helpful when testing this type of bird. Agreement between EBA, LA, and DCF was 81.8% when testing 407 serum samples from cockatiels of unknown health status. The relationship between positive (> or = 10 titer) antibody activity and known health status of 77 cockatiels revealed that agreement between the two criteria was only 59.7%. Of 13 Chlamydia-inoculated cockatiels, seven birds seroconverted from negative to positive by EBA; five seroconverted by DCF. Only the five birds that seroconverted by both EBA and DCF were culture-positive for chlamydiae. None of 15 sham-inoculated control cockatiels developed detectable antibody activity, and none of 10 cultured were positive. In tests with column-separated IgM and IgG, EBA detected only IgM activity, LA detected IgM and IgG activity, and DCF detected only IgG activity.

Enzyme immunoassay with enhanced specificity for detection of antibodies to Chlamydia trachomatis.

Two different methods for preventing the binding of cross-reacting antibodies to the genus-reactive chlamydial lipopolysaccharide (LPS) were used to improve the specificity of an enzyme immunoassay for the determination of antibodies to Chlamydia trachomatis. Coated elementary bodies were treated with either sodium periodate, to oxidize the antigenic sites of the LPS, or Triton X-100, to extract the LPS. By using these new enzyme immunoassays, the standard enzyme immunoassay, and the whole inclusion fluorescence (WIF) assay, antibodies to C. trachomatis were determined in sera from different groups of patients and controls. Paired serum samples from patients with culture-proven urogenital C. trachomatis infections showed similar responses in all three assays. Paired serum samples from patients with Chlamydia psittaci infections showed similar responses in the WIF assay and the standard enzyme immunoassay, whereas significantly reduced titers were obtained in the enzyme immunoassays with treated antigen, especially in the convalescent-phase serum samples. Serum samples from patients with symptoms suggestive of infection with C. trachomatis, pregnant women, and blood donors were evaluated by all three types of assays. Eighty percent of the significant reductions in immunoglobulin G (IgG), IgA, and IgM titers were observed in sera with WIF assay titers in the lower classes (IgG, 1: < or = 256; IgA, 1: < or = 32; IgM, 1: < or = 16). From these results we conclude that oxidation of the antigen by sodium periodate is a simple and effective method of producing an enzyme immunoassay with enhanced specificity that could be useful for diagnostic purposes and seroepidemiological studies.

Antibody prevalence and isolation of Chlamydia psittaci from pigeons (Columba livia).

The isolation of Chlamydia psittaci and serological detection of Chlamydia-specific antibodies in racing pigeons and pigeons from public parks is described. Several serological methods (complement fixation test, indirect microimmunofluorescence test, and enzyme-linked immunosorbent assay) were compared with bacteriological techniques (isolation both in embryonated eggs and McCoy cell monolayers). Tests confirmed that 28.6%, 33.5%, and 35.9% of the pigeons, respectively, were seropositive by the tests mentioned above. Chlamydiae were isolated from 13% of the fecal specimens in ovocultures and from 18% of the fecal specimens in cell cultures. No significant differences between the two groups of pigeons were found (at a 95% confidence level, alpha = 0.05) using the hypothesis test of the difference between proportions of two populations. The serological and bacteriological techniques used are compared and discussed.

Seroepidemiological survey of chlamydial infections in light horses in Japan.

To investigate the overall prevalence of chlamydial infections in light (i.e. non-draught) horses in Japan, 599 sera obtained from 12 localities in 1991 were tested for complement fixation antibodies. The mean antibody positive rates of the all sera were 15.2% (91/599) and the regional positive rates were higher in Honshu (19.1%, 48/251) and Kyushu (20.0%, 20/100) than in Hokkaido (9.3%, 23/248). In Honshu, the highest rate (56.0%, 28/50) was observed in Utsunomiya. Analysis of the positive rate in different age groups showed that the 2-5 years age-group had the highest prevalence of chlamydial infections. This indicates that chlamydial infection is prevalent in light horses in Japan.

Blood concentrations of chlortetracycline in macaws fed medicated pelleted feed.

A trial was conducted to determine the suitability of using a pelleted diet containing chlortetracycline (CTC) for treatment of chlamydiosis in macaws. Macaws, normally fed seed and fruit diets in captivity, are notoriously difficult to treat with CTC-medicated mash diets. Healthy macaws fed a pelleted diet containing 1% or 1.5% CTC for 30 or 45 days maintained adequate food intake and mean blood concentrations of 1-2 CTC micrograms/ml blood throughout the treatment period. There were no significant differences between blood concentrations induced by the different dietary CTC concentrations. Blood concentrations of 1 microgram/ml are considered therapeutic, so it is likely that 1% CTC-medicated pellets will be adequate for treating chlamydiosis in these species.