Detection and characterization of Shiga toxin-producing Escherichia coli in feral pigeons

Escherichia coli strains producing a variant of Shiga toxin 2 (Stx2), designated Stx2f, have been recently described in the stools of feral pigeons. During 1997-1998, 649 pigeons were trapped and examined in three different squares of Rome. Stool samples were collected from each bird and enrichment cultures were examined for the presence of Stx by the vero cell assay. Stx-producing E. coli (STEC) were isolated from the positive cultures and characterized by serotyping and PCR analysis of stx and other virulence-related genes. Stx was detected in 10.8% of the stool enrichment cultures. The percentage of positive birds did not differ significantly for the three flocks considered and the season of sample collection. Conversely, STEC carriage was significantly more frequent in young than in adult birds (17.9 versus 8.2%). None of the birds examined showed signs of disease. STEC strains were isolated from 30 of 42 Stx-positive cultures examined. All the strains produced Stx2f, and most of them possessed genes encoding for intimin and the cytolethal distending toxin (CLDT). Six serogroups were identified, but most of the isolates belonged to O45, O18ab, and O75. Molecular typing indicated that most of the isolates within a flock were clonally-related. This work confirms that pigeons represent a natural reservoir of STEC strains characterized by the production of the toxin variant Stx2f, and by the frequent presence of eae and cldt genes. Further work is needed to clarify whether these STEC may represent a cause of avian disease or even a potential health hazard for humans.

Lactobacillus agilis is an important component of the pigeon crop flora

AIMS

To examine the presence of lactic acid bacteria (LAB: enterococci, streptococci and lactobacilli) in the pigeon crop.

METHODS AND RESULTS

The crops of 10 pigeons were sampled and inoculated on agar plates for isolation of streptococci, enterococci and lactobacilli. The isolates were identified using tDNA-PCR. Lactobacillus agilis, a species described in 1981 from municipal sewage, was the dominant component in eight of these pigeon crop sacs. A Lactobacillus species related to L. fermentum and L. mucosae but probably not belonging to one of these species was isolated from five birds. Three pigeons carried Enterococcus cecorum. Minor species found were E. columbae, E. faecalis, E. hirae, L. johnsonii, L. salivarius, and Streptococcus gallolyticus. A description is given of the phenotypic characteristics of the L. agilis pigeon strains.

CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY

L. agilis is found to be the main component of the LAB flora in the pigeon crop.

Colonization of a voice prosthesis by Cryptococcus neoformans

Tracheoesophageal voice prostheses in laryngectomized patients commonly deteriorate due to the presence of yeasts, particularly Candida species. We describe the first case of colonization of such a device by Cryptococcus neoformans in a patient with a history of glottic carcinoma. The isolate showed an identical genomic pattern with C. neoformans from pigeon excreta in the patient's environment.

Seroprevalence of Toxoplasma gondii and Chlamydia psittaci in domestic pigeons (Columbia livia domestica) at Sebele, Gaborone, Botswana

High antibody titres to Toxoplasma gondii and Chlamydophila psittaci were demonstrated in serum collected from domestic pigeons at average titres of 1:128 and 1:64 respectively. The public health implications of these findings are discussed.

[Evidence of Cryptococcus neoformans in domestic and sports pigeons in Thyringia]

19 strains of Cryptococcus neoformans var. neoformans were isolated from 17 (= 40.5%) of 42 investigated pigeon breeder flocks in Thuringia.

Prevalence of Campylobacter and Salmonella at a squab (young pigeon) processing plant

Microbiological testing for Campylobacter and Salmonella was performed at a processing plant for squab (young pigeon) in three separate trials. Live birds, carcasses, and equipment were targeted for sampling during the preslaughter, pre-evisceration, and postevisceration stages of processing. The three trials represented 18 farms (1,110 squab), 1 farm (250 squab), and 23 farms (2,900 squab). The overall prevalence of positive samples in Trial 1 was 1.4% for Salmonella spp. and 11.1% for C. jejuni; in Trial 2, 4.3 and 0% for Salmonella spp. and C. jejuni; and in Trial 3, 4.1 and 4.8% for Salmonella spp. and C. jejuni, respectively. These observations represent a significantly greater likelihood of having a positive sample for Campylobacter (twofold) or Salmonella (eightfold) at processing, compared with prevalences observed in our previous on-farm study. This finding suggests an overall increase in the number of carcasses contaminated or in the concentration of contamination during transport and processing. In the multifarm trials, only Trial 3 demonstrated a significant increase in the prevalence of positive samples from the preslaughter to the postevisceration stages of processing (P = 0.02), and only for Campylobacter. The prevalence of positive cultures from equipment surfaces were not different than carcasses during processing, therefore no additional critical control points were identified within this system. When pooled swabs were compared (Trial 1) to individual swabs (Trials 2 and 3), no statistical difference in the prevalence of Salmonella or Campylobacter was observed between trials. Direct plating from a pooled sample onto selective agar media (Trial 1) and single swab culture with enrichment followed by plating on selective agar (Trials 2 and 3) were compared for Campylobacter isolation. No statistical difference in C. jejuni prevalence was observed using either method; however, when the detection limit of each method was determined, single swabs with enrichment had greater sensitivity.

Farm and management variables linked to fecal shedding of Campylobacter and Salmonella in commercial squab production

A cross-sectional study was performed to determine the relationship of farm variables and management practices to fecal shedding of Campylobacter or Salmonella on commercial squab (young pigeon) farms. A detailed survey provided information on biosecurity, cleaning and disinfection, bird health, vector control, and loft and pen. Twenty pigeons on each of 12 farms were cultured before and after the producers completed a voluntary quality assurance training program (QAP), based on principles of hazard analysis critical control point (HACCP). The prevalence of positive samples for Salmonella and C. jejuni was 1/480 (0.21%) and 19/480 (3.96%), respectively. Campylobacter was present on one farm during both visits; three farms during the first visit, and three farms during the second visit. Analysis by fixed-effects logistic regression showed the probability of having a positive C. jejuni culture was increased by not using dry manure in the nesting material, not cleaning shipping crates, cleaning landing boards, and by increased frequency of chemical disinfection of water. Having a positive parent and higher numbers of squab per pen (density) were also associated with higher odds of being positive for C. jejuni. Factors not associated with a positive C. jejuni culture included, other avian species on the farm, type of shipping crate, covered drinkers, fly problems, bird age, level of nest box within the loft, and QAP training. Prevalence of food safety pathogens was extremely low on the squab facilities tested as compared with reports from commercial broiler or turkey flocks. This observation suggests that one or more farm variables or management practices were effectively reducing infection, or possibly a species-related difference existed in carriage rates and shedding of pathogens. These results emphasize critical control points for food safety pathogens may vary widely, and the formulation of effective QAP programs are dependent on science-based knowledge of diverse animal production systems.

Experimental enteric infection of gnotobiotic piglets with a Chlamydia psittaci strain of avian origin

The pathogenicity of a Chlamydia psittaci isolate of pigeon origin was assessed using a litter of gnotobiotic piglets. At 3 days of age, six piglets were inoculated intragastrically with egg-grown chlamydiae, the remaining six pigs were sham-inoculated. The animals were observed for clinical signs, and they were killed and necropsied sequentially between 4 and 15 days of age. Clinical manifestations consisted of slight softening of the faeces between 6 and 10 days post-inoculation (DPI). Immunohistochemistry revealed chlamydial replication predominantly in the small intestine, initially within villous enterocytes, after 4 DPI mostly in the lamina propria. Histopathology showed villous atrophy and increased numbers of inflammatory cells in the gut up to 6 DPI. Chlamydial stages of normal morphology were identified within enterocytes using transmission electron microscopy. An enzyme-linked immunosorbent assay (ELISA) run on faecal samples revealed shedding of chlamydial antigen from 3 until 11 DPI. Systemic dissemination of Chlamydia occurred to a limited extent according to polymerase chain reaction and immunohistochemistry results of several extraintestinal organs. Corresponding histopathological changes were minimal. Sera of all pigs were negative for anti-chlamydial antibodies using a complement fixation test. In conclusion, inoculation of this isolate in gnotobiotic piglets resulted in a productive enteric infection with mild lesions, weak systemic dissemination, and faecal shedding, indicating the pig as a potential host for avian chlamydiae.

Environmental isolation of Cryptococcus neoformans var. gattii and C. neoformans var. neoformans in the city of São Paulo, Brazil

In order to determine the environmental occurrence of both varieties of Cryptococcus neoformans in the city of São Paulo, pigeon droppings and vegetable material from trees of the genus Eucalyptus were collected at typically crowded places. A total of 38 sites downtown where large heaps of pigeon droppings could be found were selected for sampling. Pigeon droppings from 10 (26.3%) of these sites were positive for C. neoformans var. neoformans in at least one sample. Twelve eucalyptus woods located within four municipal parks were also surveyed; vegetable material from Eucalyptus spp. trees were collected monthly over a 2-year period. C. neoformans var. gattii was recovered from a wood in Ibirapuera Park during the same season on two different occasions (November 1996 and November 1997); this park contained specimens of Eucalyptus camaldulensis, a natural habitat of C. n. var. gattii. C. n. var. neoformans was detected in a wood in Ibirapuera Park and Aclimação Park. The results show that both C. n. var. neoformans and C. n. var. gattii are present in the urban environment of São Paulo city at sites where large numbers of people normally gather.

Occurrence of Cryptococcus spp. in excreta of pigeons and pet birds

In pooled samples of faeces from 25 pet bird flocks in Thuringia, a high rate of contamination with Cryptococcus neoformans var. neoformans was found. The prevalence of Cr. neoformans in the bird-breeding establishments correlated with the numbers of the different pet bird species in these flocks. The differentiation between varieties of Cr. neoformans by means of proline assimilation and canavanine resistance detection as well as with the aid of Cr. neoformans factor sera, polymerase chain reaction (PCR) fingerprinting, sequencing of PCR products as well as Fourier transform infrared spectroscopy showed uniform results which also corresponded to the serological differentiation between serovars A and D. A predominance of serovar A could be observed among the pet bird breeding flocks. This corresponded to the frequency distribution of serovars A and D in cases of human diseases in Germany. In 50% of the samples of pigeon excreta examined (n = 30) in Innsbruck (Austria), Cryptococcus albidus could be isolated but not Cr. neoformans. However, this Cryptococcus species is of minor pathogenetic importance for man. Cryptococcus albidus may be clearly distinguished from Cr. neoformans by means of microbiological methods, PCR and Fourier transform infrared spectroscopy.

In vitro susceptibility of environmental Cryptococcus neoformans variety neoformans isolates from Turkey to six antifungal agents, including SCH56592 and voriconazole

The in vitro antifungal susceptibility of 27 environmental (pigeon droppings) isolates of Cryptococcus neoformans var. neoformans, isolated from throughout Turkey, to six antifungal agents (amphotericin B, flucytosine, fluconazole, voriconazole, itraconazole, and SCH56592) was studied. Voriconazole, itraconazole, and SCH56592 all showed comparable activity and were more active than the remaining three antifungal agents tested. Overall, SCH56592 was the most active agent (MIC90, 0.015 microg/ml, at both 48 and 72 h), followed by itraconazole (MIC90, 0.03 microg/ml, at both 48 and 72 h) and voriconazole (MIC90, 0.25 microg/ml, at both 48 and 72 h), respectively. Antifungal susceptibility data for environmental isolates may reflect patterns for the clinical isolates recovered from patients from the same geographic area.

Killer activity at different pHs against Cryptococcus neoformans var. neoformans serotype A by environmental yeast isolates

Yeast isolates that share the same habitats as Cryptococcus neoformans var. neoformans serotype A in a restricted Mediterranean area were assayed in order to verify their killer activity against Cr. neoformans strains isolated from clinical and environmental sources. Many of the environmental yeast isolates expressed the killer phenomenon against the assayed strains of Cr. neoformans. Two species of Candida: Candida parapsilosis and Candida famata, and Pichia carsonii, were the most active killers at pH 4.6, 5.0 and 5.6 levels encountered in pigeon and canary guanos. Killer activity by C. parapsilosis is reported for the first time. The authors hypothesized that the killer phenomenon exerted by yeast species with heavy killer activity against Cr. neoformans would lend themselves for use as biological control agents against sensitive strains of Cr. neoformans when directly inoculated into the habitats of Cr. neoformans.

A new Shiga toxin 2 variant (Stx2f) from Escherichia coli isolated from pigeons

We have isolated Shiga toxin (Stx)-producing Escherichia coli (STEC) strains from the feces of feral pigeons which contained a new Stx2 variant gene designated stx(2f). This gene is most similar to sltIIva of patient E. coli O128:B12 isolate H.I.8. Stx2f reacted only weakly with commercial immunoassays. The prevalence of STEC organisms carrying the stx(2f) gene in pigeon droppings was 12.5%. The occurrence of a new Stx2 variant in STEC from pigeons enlarges the pool of Stx2 variants and raises the question whether horizontal gene transfer to E. coli pathogenic to humans may occur.

Molecular analysis of CAP59 gene sequences from five serotypes of Cryptococcus neoformans

The nucleotide sequences of CAP59 genes from five serotypes of Cryptococcus neoformans were analyzed for their phylogenetic relationships. Approximately 600-bp genomic DNA fragments of the CAP59 gene were amplified from each isolate by PCR and sequenced. The CAP59 nucleotide sequences of C. neoformans showed more than 90% similarity among the five serotypes. By phylogenetic analysis, their sequences were divided into three clusters: serotypes A and AD, serotypes B and C, and serotype D. In addition, the results of reduced amino acid sequences were similar to the nucleotide sequence data. These data revealed that serotype AD was genetically close to serotype A rather than serotype D, although it had been considered to be a mixed type of serotype A and D by serological analysis. Furthermore, the nucleotide sequences of the serotype B and C isolates of C. neoformans were very similar to each other. These results indicated that serotype B and C isolates belonging to C. neoformans var. gattii were genetically homogeneous and closely related. The molecular analysis of the CAP59 gene will provide useful information for the differentiation of serotypes of C. neoformans and for an understanding of their phylogenetic relationships.

Genomic fingerprinting of pigeon Streptococcus gallolyticus strains of different virulence by randomly amplified polymorphic DNA (RAPD) analysis

Randomly amplified polymorphic DNA (RAPD) analysis was performed on 95 pigeon S. gallolyticus strains of different virulence and belonging to different biotypes and different culture supernatant phenotypes as determined by SDS-PAGE. Four distinct RAPD patterns, designated A, B, C and D, were distinguished using primer OPM6 (5'CTGGGCAACT). All 76 strains generating RAPD pattern A or B were designated highly virulent on the basis of their SDS-PAGE pattern. Five of seven strains generating RAPD pattern C and 11 of 12 strains generating RAPD pattern D belonged to the moderately virulent and low virulent culture supernatant phenotype groups, respectively. Only one RAPD group C strain belonged to a highly virulent culture supernatant phenotype group. There was a correlation between biotype and RAPD patterns. These findings indicate that there is a high correlation between RAPD pattern and virulence for pigeons. Therefore, RAPD typing seems a rapid, reliable method to distinguish pigeon S. gallolyticus strains of high, moderate and low virulence.

First environmental isolation of Cryptococcus neoformans var. neoformans and var. gatti from the Gharbia Governorate, Egypt

Flowers from two Eucalyptus camaldulensis trees in the Qutur area and one tree from the Tanta area yielded three isolates of Cryptococcus neoformans var. gattii. Pigeon and sparrow droppings were also investigated for the occurrence of C. neoformans within the study area. Ninety five isolates of the neoformans variety of C. neoformans were recovered from 550 samples of avian droppings.

Feral pigeons as carriers of Cryptococcus laurentii, Cryptococcus uniguttulatus and Debaryomyces hansenii

We collected fresh droppings and cloaca samples from feral pigeons Columba livia in the southern Swedish city of Malmö, and isolated the following fungi: Debaryomyces hansenii var. hansenii, Cryptococcus laurentii and Cryptococcus uniguttulatus. The first two species are known to be pathogenic to humans. No strains of Cryptococcus neoformans var. neoformans were found. Our results indicate that feral pigeons can be carriers of medically significant fungi other than Cryptococcus neoformans var. neoformans.

Shiga toxin-producing Escherichia coli O157 in feedlot cattle and Norwegian rats from a large-scale farm

A total of 365 faecal samples from different categories of cattle, 12 samples of untreated slurry, 50 samples of fresh droppings of feral domestic pigeons, 20 samples of fresh droppings of domestic sparrows and stool samples of 19 synanthropic rodents were examined for the presence of Escherichia coli by broth enrichment culture and a subsequent immunomagnetic separation. Escherichia coli O157 was found in 72 (20%) bovine samples, six (50%) samples of untreated slurry and four (40%) of 10 rats (Rattus norvegicus). Significant differences were found in the E. coli O157 shedding frequency between different age categories of bulls. Genes stx2 and eaeA were detected in all isolates, and the stx1 gene in all but 10 isolates.

Ultrastructure of surface components of Streptococcus gallolytics (S. bovis) strains of differing virulence isolated from pigeons

Virulence of Streptococcus gallolyticus (S. bovis) strains isolated from pigeons is associated with the presence of the extracellular proteins A, T1, T2 and T3. Based on the presence or absence of these proteins, six supernatant-phenotypes are distinguished. Experimental infection studies have indicated that strains belonging to the A-T1, A+T1, A+T2 and A+T3 groups are highly virulent for pigeons, strains belonging to the A-T3 groups are moderately virulent and A-T2 strains are of low virulence. In this study the surface structure of 15 pigeon S. gallolyticus strains representing high, moderate and low virulence supernatant-phenotypes was examined by electron microscopy. The presence of capsular material was determined by transmission electron microscopy after polycationic ferritin labelling and immunostabilization. Capsules from cells labelled with polycationic ferritin were usually thicker than those from cells exposed to antiserum. The capsule of the virulent strains had a regular, continuous appearance whilst irregularity of the capsule was a characteristic of the low virulence A-T2 strains. Negative staining revealed the presence of fimbriae in all strains belonging to the high virulence A-T1, A+T1, A+T2 and A+T3 supernatant groups and in one strain of the moderately virulent A-T3 group. The fimbriae were thin, flexible structures with a diameter of approximately 3-4 nm and a length of up to 700 nm. Fimbriae as described above were absent in two other A-T3 strains examined and in the low virulence A-T2 strains. Results from this study indicate that morphological differences in surface structure exist among virulent and low virulence pigeon S. gallolyticus strains, and that the capsule and/or fimbriae are possibly involved in virulence.

Isolation of Cryptococcus neoformans var. neoformans from pigeon droppings collected throughout Turkey

The six hundred and thirty-four samples of pigeon droppings were collected throughout Turkey, from 54 of 80 provinces. Cryptococcus neoformans was isolated from 29 (4.6%, overall) of 634 samples and 29 isolates were from 18 provinces. Interestingly, 16 (88.9%) of these provinces occur on the three different coastlines of Turkey, therefore the ecological role of a humid climate was speculated. Almost all isolates [28/29] were recovered from samples collected from roofs (n=14) and dovecotes (n=14). All isolates were found to be C. neoformans var. neoformans.

Isolation of Cryptococcus neoformans from pigeon (Columbia livia droppings in northern Iran

Nine hundred and eighty three specimens of pigeon droppings, collected in different regions of northern Iran, were examined. Of these samples, 175 (17.8%) were positive for Cryptococcus neoformans. All isolates obtained were C. neoformans var. neoformans. Most of these isolates of C. neoformans were from pigeon shelters. There were significant differences in isolation frequency between pigeon shelters and the other collection sites.

Pelistega europaea gen. nov., sp. nov., a bacterium associated with respiratory disease in pigeons: taxonomic structure and phylogenetic allocation

Twenty-four strains isolated mainly from infected respiratory tracts of pigeons were characterized by an integrated genotypic and phenotypic approach. An extensive biochemical examination using conventional tests and several API microtest systems indicated that all isolates formed a phenotypically homogeneous taxon with a DNA G + C content between 42 and 43 mol%. Whole-cell protein and fatty acid analysis revealed an unexpected heterogeneity which was confirmed by DNA-DNA hybridizations. Four main genotypic sub-groups (genomovars) were delineated. 16S rDNA sequence analysis of a representative strain indicated that this taxon belongs to the beta-subclass of the Proteobacteria with Taylorella equigenitalis as its closest neighbour (about 94.8% similarity). A comparison of phenotypic and genotypic characteristics of both taxa suggested that the pigeon isolates represented a novel genus for which the name Pelistega is proposed. In the absence of differential phenotypic characteristics between the genomovars, it was preferred to include all of the isolates into a single species, Pelistega europaea, and strain LMG 10982 was selected as the type strain. The latter strain belongs to fatty acid cluster I and protein electrophoretic sub-group 1, which comprise 13 and 5 isolates, respectively. It is not unlikely that the name P. europaea will be restricted in the future to organisms belonging to fatty acid cluster I, or even to protein electrophoretic sub-group 1, upon discovery of differential diagnostic features.

Extracellular proteins and virulence in Streptococcus bovis isolates from pigeons

The association between virulence and the occurrence of the extracellular proteins A, T1, T2 and T3 in the culture supernatant of pigeon Streptococcus bovis strains, was examined in experimental infection studies. Fourteen groups of 10-17 pigeons were inoculated intravenously with 1 x 10(9) CFU of S. bovis strains that belonged to the phenotypes A + T1, A - T1, A + T2, A - T2, A + T3 and A - T3, respectively. The overall postinoculation morbidity in the phenotype groups was 85%, 87%, 70%, 5%, 100% and 37%, respectively. These results indicate that strains producing A or T1 are of high virulence, those producing T3 only are of moderate virulence and those producing T2 are of low virulence. Virulence of S. bovis for pigeons was more clearly correlated with supernatant-phenotype than with serotype.

Environmental isolation of Cryptococcus neoformans var. neoformans from Vellore

We have isolated C. neoformans from various environmental niches, including our hospital environment. Twenty one samples of weathered pigeon droppings and 86 samples of Eucalyptus bark and debris were collected from various sites around the hospital and college. C. neoformans var. neoformans was isolated from 14 of the 21 (67%) samples of weathered droppings of pigeons collected from the ledges of windows of wards and departmental buildings in the hospital. C. neoformans was not isolated from any of the Eucalyptus samples. These findings document for the first time the presence of C. neoformans var. neoformans in the hospital environment. Although ubiquitous in the environment, its presence in hospital surroundings stresses the need for systematic cleaning of sites inhabited by pigeons. However, we failed to isolate C. neoformans from the limited number of Eucalyptus samples examined.

DNA typing suggests pigeon droppings as a source of pathogenic Cryptococcus neoformans serotype D

The unusual proportion of serotype D strains of Cryptococcus neoformans infecting patients diagnosed with cryptococcosis in some parts of France prompted the analysis of DNA fingerprints obtained with 26 clinical and 29 environmental isolates from the same area. Our results suggest that pigeon droppings are a potential source of pathogenic strains of C. neoformans serotype D, as previously demonstrated for serotype A.

Serotyping of Cryptococcus neoformans isolates from environmental and clinical sources in extreme southern Italy (Calabria and Sicily, central Mediterranean area)

Ninety-seven environmental and four clinical isolates of Cryptococcus neoformans from several localities in extreme southern Italy were serotyped. All proved to be Cr. neoformans var. neoformans serotype A. The homogeneity of the serotypes suggests that geographical climatological conditions may play a role in Cr. neoformans serotype diffusion. It was furthermore revealed that, unlike the data reported for the serotypes of Cr. neoformans in mainland Italy, Cr. neoformans serotype D was not present in the examined sites in extreme southern Italy.

Isolation of mycoplasmas from fantail pigeons

Isolation of mycoplasmas from the oropharynxes of 60 fantails reared under natural conditions at different zoological parks in Miyazaki prefecture was carried out. Mycoplasma columbinum, M. columborale and M. columbinasale were isolated from 28 (46.7%), 22 (36.7%), and 1 (1.7%) of 60 oropharynxes, respectively, but no Mycoplasma was isolated from 5 cloacas tested. Ureaplasma was not isolated from any of the 28 oropharynxes or 5 cloacas examined. We report that 41 (68.3%) of 60 fantails had one or two species of mycoplasmas in their oropharynxes, and make the first confirmation of M. columbinasale inhabiting a Japanese pigeon.

Separation of Salmonella typhimurium DT2 and DT135: molecular characterization of isolates of avian origin

In Denmark, 0.4 and 3.4% of the human Salmonella Typhimurium cases registered between 1988 and 1993 were caused by DT2 and DT135, respectively. Separation of these two phage types was, however, problematic as only minor differences in lysis pattern and lysis strength occurred. Molecular characterization of 23 Danish isolates, 10 German isolates and the two type strains have subsequently been performed. With only minor exceptions, strains examined could be separated by combination of 0.5 agglutination, ribotyping, and PFGE typing into two major groups in conformity with their phage types. The differences between the two groups were, however, very small and it has not been completely clarified whether this grouping is the result of two independent types or of two related lines developing in different environments. It is concluded that the classification of related phage types DT2 and DT135 has to be supported by molecular methods.

[Appearance of antibodies against Borrelia burgdorferi in different populations of pigeons (Columba livia var. domestica vel urbana]

Borrelia burgdorferi, the causative agent of Lyme borreliosis, can infect both mammals and birds. The purpose of the present survey was to determine the presence of antibodies against B. burgdorferi in different populations of pigeons. 1043 sera from pigeons (carrier-, urban-, show-pigeons) were examined by standard serological methods. B.burgdorferi shows crossreaction with B. anserina. Therefore all sera were evaluated by IFAT and ELISA for both Borrelia species. The results demonstrate no evidence for the pigeons (Columba livia var. domestica vel urbana) to be reservoir for Borrelia burgdorferi.

Two new serovars of Chlamydia psittaci from North American birds

Five Chlamydia psittaci isolates (1 turkey, 1 psittacine, 1 human, and 2 pigeon isolates) failed to react with serovar-specific monoclonal antibodies to known avian and mammalian C. psittaci serovars and were presumed to represent 1 or more new serovars. The isolates were characterized using restriction endonuclease analysis of the whole genome, polymerase chain reaction-restriction fragment length polymorphism of the major outer membrane protein genome, monoclonal antibody comparisons, and growth in tissue culture. Monoclonal antibodies were produced to the human isolate (MP) and to the psittacine isolate (VS225). The monoclonal antibody results show that the isolates represent 2 new avian serovars (serovars E and F). The restriction fragment length polymorphism analysis of the major outer membrane protein genome demonstrated that the isolates are distinct. The whole genome restriction endonuclease analysis data and the growth patterns in tissue culture indicate that the new serovars are similar to avian serovars recognized previously. A subspecies monoclonal antibody that reacted with serovars A and B also reacted with serovar E, indicating that these serovars are closely related. The results show that these isolates represent 2 new avian serovars, making them the fifth and sixth avian serovars identified in North American birds.

Secreted antigens as virulence associated markers in Streptococcus bovis strains from pigeons

SDS-PAGE and Western blot analysis were performed on the culture supernatant of 7 pigeon S. bovis reference strains belonging to the serotypes 1, 2, 3 and 5. The culture supernatant of highly virulent serotype 1, 2 and 5 strains contained four antigens that were absent in low virulent serotype 3 strains, notably a 185 kDa minor protein band (A) and a triplet (T1) of 70 kDa. The less virulent serotype 3 strains on the other hand contained protein triplets, that had a molecular mass of either 68 kDa (T2) or 74 kDa (T3). The prevalence of A, T1, T2 and T3 was examined in 68 S. bovis strains isolated from healthy pigeons and in 68 S. bovis strains isolated from pigeons that died of S. bovis septicaemia. Six supernatant phenotypes were identified: A-T1 (32 strains), A- T2 (10 strains), A- T3 (7 strains), A+ T1 (84 strains), A+ T2 (1 strain) and A+ T3 (2 strains). Ninety-four percent of the strains lacking the A and T1 proteins were isolated from healthy pigeons, and only 6% were isolated from septicaemia. Strains expressing A and/or T1, however, were isolated form septicaemia in 57% of the cases. These observations may indicate that the A and/or T1 proteins are associated with virulence.

[Detection of chlamydia in the intestines and lungs in pigeons and humans]

Attempts were made to detect Chlamydia sp. by direct immunofluorescence (IF) in intestinal and lung tissues collected from wild town pigeons, young reared pigeons, and human corpses. Chlamydia in any organ were detected in 86.6% of the 427 adult pigeons and 27.3% of 16 young pigeons. Positive IF results were in intestinal and lung samples, collected from 427 adult pigeons, in 34.3% and 40.05% of the birds, respectively. Human (n = 100) intestinal and lung tissues were positive in 22% and 20% of the corpses, respectively. Titres 1:20 and higher were demonstrated by CF in 53.86% of the 427 adult pigeons. The highest titre found was 1:5 120.

Borrelia in pigeons: no serological evidence of Borrelia burgdorferi infection

In order to clarify the supposed involvement of urban pigeons (Columba livia livia) in the epidemiology of Lyme disease, the presence of antibodies against Borrelia burgdorferi and Borrelia anserina in pigeons' sera, collected in 12 areas of northern and central Italy, was evaluated. This evaluation was carried out using a classic immunofluorescence assay (IFA), a surface immunofluorescence assay (SIFA) and a standard Western Blot (WB) assay. A total of 104 out of 3,186 (3.26%) serum samples were positive for both spirochetes when tested by IFA, with titres ranging from 1/40 to 1/1280. All positive specimens showed the same or a higher reactivity against B. anserina than against B. burgdorferi. Of the IFA positive samples, 30 were tested by WB and SIFA to evaluate further the specificity of the antibody response, i.e. to try to clarify against which spirochete the antibodies were raised. The presence of antibodies against the 23 kDa protein exclusive to B. anserina, and against epitopes which are not surface-exposed and which are common to B. anserina and B. burgdorferi, was assessed by WB and SIFA. No serological evidence that B. burgdorferi can infect pigeons was found.

[Isolation of Cryptococcus neoformans from environments (pigeon excreta) in Nagasaki]

Cryptococcosis is one of the serious deep-seated mycoses in immunocompromised patients, especially those with AIDS. Cryptococcus neoformans ordinarily lives in natural environments such as soil and reproduces in pigeon excreta. It spreads in the air and infects human by inhalation. We isolated C. neoformans from pigeon excreta in hospitals, private houses, parks in Nagasaki from October to December in 1994. C. neoformans was isolated from 4 of 8 samples (50%) of pigeon excreta and the isolation rate increased to 80% (4/5) if they were weathered excreta. Two patients with pulmonary cryptococcosis occurred in the last two years in the area where C. neoformans was isolated during that period. Epidemiological studies of clinical isolates and environmental isolates are important to determine its origin of infection and the route of transmission.

Comparative ribotyping of Staphylococcus intermedius from dogs, pigeons, horses and mink

Strains of Staphylococcus (S.) intermedius from dogs, pigeons, horses and mink were typed by comparison of rRNA gene restriction fragment length polymorphisms (ribotyping) and the resulting ribotypes examined by cluster-analysis. Digestion of whole-cell DNA with HindIII resulted in 9 ribotypes with 3 to 4 bands. Separation of isolates from different host animal species was not possible. EcoRI yielded 11 different patterns with 4 to 9 fragments. The EcoRI-ribotypes of all canine strains grouped in one cluster encompassing four closely related ribotypes. Isolates were indistinguishable with respect to their origin from cases of canine pyoderma or from healthy carriers. In contrast, pigeon and equine strains expressed variety of ribotypes including some strains with patterns similar to canine isolates. However, for canine versus pigeon and equine strains the difference in distribution among ribotypes was significant (P < 0.001). The data might suggest that pigeons and horses carry S. intermedius transiently and might be able to spread these bacteria to other animal species.

[The occurrence of Listeria monocytogenes in fecal samples of pigeons]

Listeria spp. were isolated from faeces samples from 12 (3.4%) of 350 pigeons examined. Three isolates were identified as L. monocytogenes (1x serovar 1/2a, 1/2b, and 4ab), eight isolates were L. innocua (2x serovar 6a, 6x serovar 6b), and two isolates L. seeligeri (serovar 6b). One fecal sample yielded a mixed culture of L. monocytogenes and L. innocua. The results indicate that pigeons are not important in the epidemiology of listeriosis in man and animals.

Prevalence of thermotolerant species of Campylobacter and their biotypes in children and domestic birds and dogs in southern Chile

The prevalence of thermotolerant Campylobacter in diarrhoeic and healthy children as well as in dogs, hens, ducks and pigeons was determined in Southern Chile. Campylobacter were found in 34.5% of the faecal samples examined. The isolation rate of Campylobacter in diarrhoeic and healthy children was 16.3% and 6.4% respectively. Despite C. jejuni was always more frequent than C. coli, the latter was isolated with a high frequency (29%) from patients with diarrhoea. C. jejuni and C. coli biotypes I and II were found in healthy and diarrhoeic children and were predominant in all the animals species studied. This may point out towards the possible origin of strains infecting children.

Isolation of Cryptococcus neoformans from pigeon (Columba livia) droppings in Mexico City

To determine the ecological and epidemiological significance of pigeon excrement in cryptococcosis in Mexico City, 251 samples of pigeon droppings were studied. These were collected from houses, public buildings, churches, parks and pigeon nests. Each sample was suspended 1:10 in isotonic saline solution and then cultured in Staib medium. Identification of Cryptococcus neoformans was performed based on the development of brown-coloured colonies and the presence of encapsulated yeasts. Of 251 samples, 52 (20.7%) were positive for Cr. neoformans. The highest frequency was observed in droppings from public buildings (31.2%), followed by churches (22.0%) and houses (13.3%). No significant differences in isolation frequency were observed between fresh or dried excrement. All isolates obtained were Cr. neoformans var. neoformans. As in other studies on Cr. neoformans from pigeons, performed in other countries, these frequency data are considered 'normal'. The results, however, accentuate the potential risk of cryptococcosis acquisition, especially now that cryptococcosis frequency is increasing in Mexico, mainly in AIDS patients.

Streptococcus bovis infections in pigeons: virulence of different serotypes

In a first experiment, the relative virulence for pigeons of 5 strains of S. bovis was assessed by experimental inoculations. Two S. bovis serotype 1 strains, one serotype 2 strain and two serotype 3 strains were examined. One of the serotype 1 strains and the serotype 2 strain were isolated from pigeons that died from septicaemia. The other strains were isolated from cloaca samples of healthy pigeons. For each strain, 10-20 pigeons were intravenously inoculated with 1 x 10(9) CFU. Morbidity after infection with the serotype 1 and 2 strains varied between 75% and 90%. Disease signs included inability to fly, lameness, emaciation, production of slimy, green droppings, polyuria and sudden death. In groups of pigeons inoculated with the serotype 3 strains, morbidity was 0% and 6%, respectively. Results demonstrate that serotype 3 strains are less virulent for pigeons than serotype 1 and 2 strains. In a second experiment, bacteriological and histological examinations were performed on organs of pigeons serially killed between 1 and 10 days after experimental inoculation with an S. bovis serotype 3 strain of low virulence. Results were compared with results of studies carried out with a highly virulent serotype 1 strain. Notwithstanding bacterial spread and replication in various organs of inoculated pigeons, clinical disease was not observed and histological lesions were scarce and of limited extent.

Prevalence of Streptococcus bovis in racing pigeons

The prevalence of S. bovis in the intestinal tract of healthy racing pigeons was determined. Crop and cloaca swab samples obtained from 810 pigeons from 14 different lofts and from 122 pigeons that were presented for routine health control were examined for the presence of S. bovis. Pooled faecal samples were also obtained from pigeons in 82 different pigeon lofts. S. bovis was isolated from crop or cloaca samples of approximately 40% of pigeons of all ages by direct culture and from 80% of the pooled faecal samples by enrichment culture. In a longitudinal study, crop and cloaca samples were collected every 3 months from pigeons in seven different pigeon lofts. The prevalence of S. bovis in these pigeons ranged from 0 to 100%. The carriage rate was not related to the season or to the age of the pigeons. The prevalence of S. bovis in organ lesions of pigeons examined at necropsy was investigated over a 35-month period. S. bovis was isolated from 10% of the birds examined. The incidence of S. bovis septicaemia was significantly higher in January to August than in September to December. It was concluded that S. bovis is an opportunistic pathogenic agent in pigeons.

Purification and partial characterization of type 3 fimbriae from Salmonella typhimurium var. copenhagen

Aggregative thin fimbriae from a pigeon pathogen, Salmonella typhimurium var. copenhagen (STMVC) Mö 8 were isolated and purified. These fimbriae remained associated with the cells even after attempts to separate them from blended cells by centrifugation. After purification, fimbriae and little cell fractions were polymerized in formic acid and then analyzed by SDS-PAGE. This pretreatment resulted in the appearance of a main protein band of 17 kDa. The N-terminal amino acid sequence of 19 residues of purified 17 kDa protein showed considerable homology with the N-terminal sequence of thin fimbriae of S. enteritidis. Native fimbriae on whole cells were specifically labelled with immune serum raised to the purified fimbriae. This immune serum also reacted with the denatured 17 kDa protein in Western blots. The polyclonal immune serum did not cross-react with the type-1 fimbriae produced by STMVC.

Restriction fragment length polymorphism analysis of Cryptococcus neoformans isolates from environmental (pigeon excreta) and clinical sources in New York City

Restriction fragment length polymorphism analysis of environmental (pigeon excreta) and clinical Cryptococcus neoformans var. neoformans isolates in a limited geographic area distinguished 6 strains among 8 environmental isolates and 12 strains among 17 clinical isolates. Clusters of patients with three strains types accounted for 47% of clinical isolates. Despite this diversity, two strains were shared by environmental and clinical isolates.

A retrospective study of circovirus infection in pigeons: nine cases (1986-1993)

Circovirus infections were diagnosed in 12 pigeons from the United States 4 pigeons from Australia, and 1 pigeon from Canada (1986-1993). Circovirus was identified by electron microscopic examination of basophilic botryoid cytoplasmic inclusions that had a histologic appearance similar to that of psittacine beak and feather disease virus inclusions. Inclusions were seen in splenic, bursal, gut-associated, and bronchus-associated lymphoid tissue macrophages and in bursal epithelial cells. Inclusions were composed of paracrystalline arrays of tightly packed, nonenveloped icosahedral virions 14-17 nm in diameter. Histologic changes in the spleens ranged from lymphofollicular hyperplasia with mild discrete lymphocellular necrosis to lymphoid depletion and diffuse histiocytosis. Lesions in the bursa of Fabricius ranged from mild lymphocellular necrosis to severe cystic bursal atrophy. Remaining histologic findings coincided with concurrent bacterial, viral, fungal, and parasitic infections. Immunoperoxidase staining and DNA in situ hybridization demonstrated that pigeon circovirus is distinct from psittacine beak and feather disease virus; however both viruses apparently share some homologous DNA sequences. Clinical and diagnostic findings indicate that pigeon circovirus may be similar to psittacine beak and feather disease virus with respect to acquired immunodeficiency and subsequent multiple secondary infections.

An unusual outbreak of Streptococcus bovis septicaemia in racing pigeons (Columba livia)

In December 1991, an outbreak of Streptococcus bovis septicaemia occurred in a Belgian pigeon loft where 25 male and 25 female racing pigeons were housed. The main clinical signs included inability to fly and poor breeding results. None of the female pigeons and only one male pigeon was able to fly. Nine affected pigeons were necropsied. Histologically a tenosynovitis of the tendon of the deep pectoral muscle was observed in most of them and S bovis was isolated from the canalis triosseus or the shoulder joints of five of the nine pigeons. The pigeons were successfully treated with ampicillin administered in the drinking water for seven days.

A survey of birds in Denmark for the presence of Pneumocystis carinii

One hundred eighty-three toluidine blue O-stained necropsy lung imprint smears from different avian species were examined microscopically for Pneumocystis carinii. No cyst forms of the organism could be identified. Seventy-eight serum samples from a total of 155 chickens were examined by a competition enzyme-linked immunosorbent assay (ELISA) for antibodies to P. carinii; 53 serum samples were from individual chickens, and 25 samples were pools of sera from two to five chickens. Diluted 1:50, the 78 serum samples showed a specific ELISA-inhibition of 4% to 56% (the 95% confidence limit being 25% to 30% inhibition). Diluted 1:50, nine serum pools representing 34 chickens and 17 of the 53 individual serum samples (32.1%) showed an inhibition greater than 30%. No specific pneumocyst DNA could be detected in serum from 13 of the 53 chickens using polymerase chain reaction and dihydrofolate reductase gene as a specific probe. Specific antibodies to a 116,000-molecular-weight antigen of rat pneumocysts were shown in two (13.3%) of 15 individual chicken serum samples. The results indicate that P. carinii organisms do not commonly reside in the lungs of birds, although some birds may be exposed to external sources of organisms.

The isolation of Cryptococcus neoformans from pigeon droppings and serotyping of naturally and clinically sourced isolates in China

This is the first report on the isolation of Cryptococcus neoformans from pigeon droppings in China and their serotypes. C. neoformans colonies which produced brown colonies on caffeic acid-cornmeal agar were found in Twenty-five out of thirty-six samples of pigeon droppings. Fifty-one colonies randomly picked from the positive samples were identified as C. neoformans by a commercially available kit for carbon source assimilation test and Christensen's urea agar. Forty (78%) out of the 51 strains were serotyped as A and 11 (22%) as AD. At the same time, seventeen out of nineteen clinical isolates were serotyped as A and 2 as B. There are three findings in our results. One is that only C. neoformans var. neoformans strains could be isolated from pigeon droppings, although the variety gattii strains were found in the clinical isolates obtained in the same geographic site in China. The second is that serotype A strains were most frequently seen in natural and clinical materials in the southeast part of China, and serotype AD strains were isolated in pigeon droppings but not in clinical materials. The third is that the coexistence of serotype A and AD cells of C. neoformans strains in same samples of pigeon droppings were observed.