Pigeon circovirus infections occur in both young and adult racing and meat pigeons and have been reported worldwide. In the present study, the ORF C1 capsid gene of pigeon circovirus was expressed in insect cells and the expressed protein was used in an indirect immunofluorescence assay to determine antibody titres in naturally infected pigeons. The viral load of sera and the Bursa of Fabricius were also measured by real-time polymerase chain reaction. Twenty seven of the 28 serum samples tested were found positive for antibodies to pigeon circovirus capsid protein (titres from log 2 4 to log 2 8). The circovirus was detected in serum and Bursa of all young pigeons by real time polymerase chain reaction, but serum of all adult pigeons (1 year old or older) was negative. Viral loads in the serum (6.56 x 10 8 ± 8.18 x 10 8 copies genome/µl) and in the Bursa (4 x 10 10 ± 3.87 x 10 10 copies genome/milligram tissue) of sick young pigeons were significantly higher when compared to those in the serum (4.52 x 10 7 ± 1.35 x 10 8 copies genome/µl) and in the Bursa (6.64 x 10 9 ± 1.12 x 10 10 copies genome/milligram tissue) of clinically healthy pigeons. This suggests that the detection of high levels of virus may be associated with the clinical status of the birds.

Infections by pigeon circovirus occur in young pigeons and have been reported worldwide.This infection, most often subclinical is a crucial factor of the young pigeon disease syndrome characterized by a broad range of clinical signs including lethargy, weight loss, diarrhoea, respiratory distress. The rate mortality is variable. However the etiologic role of this circovirus remains to be determined, but for many authors the virus is responsible of immunosuppression. No vaccine has been developed against this infection. This review article focuses on the current knowledge about pigeon circovirus infection.

The development of a real-time polymerase chain reaction (PCR) based on SYBR Green chemistry is described for the quantification of pigeon circovirus (PiCV) DNA in various samples. Plasmid containing a fragment of the PiCV genome was used to create a standard curve and to estimate the viral DNA copies in analysed samples. Both primers were designed in highly conserved regions to avoid false negatives, and amplified a 139-base-pair amplicon. When the amplifications were performed in the presence of cellular DNA extracted from PCR-negative liver, bursa and spleen samples, the detection limits were respectively 20, 20 and 60 copies of genome per milligram of tissue. These limits were 10, 160 and 25 copies/microl for control blood, sera and semen, respectively. For cloacal swab, the detection limit was 200 copies. The assay showed a linear detection over a six-log range (R(2)>0.99) and displayed reliable inter-assay and intra-assay reproducibility. Application of the test to sera samples indicated the presence of the virus in Belgium in 1991, 6 years before PiCV infections were histologically diagnosed. Testing of samples from pigeons with "young pigeon sickness" showed that the viral loads were high in the bursa of Fabricius (up to 2.07 x 10(9) copies/mg), the liver (up to 2.88 x 10(8) copies/mg) and spleen (up to 5.57 x 10(8) copies/mg). For liver, the viral load was significantly higher in sick pigeons than in apparently healthy pigeons. Detection of high quantities of PiCV DNA (up to 1.6 x 10(9) copies/microl) in the sera or blood of some young healthy pigeons indicated that the viral load in this sample type would not be useful as predictive indicator of disease. This work also showed that PiCV DNA can be detected in relatively large amounts in semen (up to 1.0 x 10(7) copies/ejaculate) and cloacal swabs (up to 3.6 x 10(10) copies/swab), confirming that PiCV may be transmitted by vertical and horizontal routes.

The genome sequences of eight pigeon circoviruses (PiCV) were determined and compared with four previously published sequences. The viruses compared were from the USA, five European countries, China and Australia and included PiCVs from racing, feral, ornamental and meat pigeons and a Senegal dove (Streptopelia senegalensis). The 12 PiCV genomes, ranging from 2032 to 2040 nucleotides in length, displayed similar organizations. Pairwise comparisons showed that the genome nucleotide sequence identities ranged from 85.1% to 97.8% and that the amino acid identities of the putative replication associated (Rep) and putative capsid (Cap) proteins displayed ranges of 91.5–99.1% and 73.0–99.3%, respectively. Comparative analyses identified conserved nucleotide sequences within the Rep gene and 3′ intergenic regions, which would be suitable for diagnostic PCR primers, and variable amino acid sequences within the capsid proteins, which should be considered when selecting virus isolates for vaccine development.

Infections with pigeon circovirus (PiCV) occur in young racing pigeons and pigeons raised for meat production and have been reported worldwide, but relatively little is known about the disease induced by PiCV infection. The aim of this study was to investigate how PiCV is transmitted. Using a sensitive polymerase chain reaction (PCR) test, the presence of PiCV was investigated in a wide range of samples from adult pigeons, embryos, breeders and young birds, which were derived from a racing loft that had a clinical history of "young pigeon sickness" and in which PiCV had been previously been diagnosed. Using PCR, PiCV DNA was detected in tissues of 13/20 apparently healthy older birds, aged from 1 to 9 years. Viral DNA was most commonly detected in the respiratory organs, including the trachea, pharynx and lung, followed by tissues such as the spleen, kidney and liver. It was also detected in the ovary and/or testes of some birds. This finding, and the detection of viral DNA in tissues from 8/22 embryos, suggested that PiCV may be vertically transmitted. Testing of pharyngeal and cloacal swabs, and blood samples, collected immediately before the death of the adult pigeons, failed to detect all birds found to be infected at necropsy, suggesting that testing of potential breeding birds would not enable exclusion of infected birds from breeding programmes. Additional PCR testing of cloacal swab samples obtained sequentially from 19 young pigeons showed that while four were excreting virus when 15 days old, only one bird was excreting at the time of weaning (28 days old). The detection of viral DNA in cloacal swab samples from 15.8% of the birds when 37 days old and 100% of birds when 51 days old suggested that most young pigeons probably became infected in the rearing loft.

Pigeon circovirus (picv) was detected in cloacal swab samples by means of a newly-developed, sensitive pcr. An initial investigation of 17 Belgian racing pigeons aged up to eight months showed that rates of detection of 88 per cent and above were achieved using samples of cloacal swab, blood and bursa of Fabricius. The sampling of 15 caged pigeons six times when they were from three to 31 weeks of age indicated that picv infections were more readily detected in cloacal swabs than in blood, and that the virus could be detected in cloacal swabs for longer periods after infection than in blood. picv infections were detected in cloacal swabs from 38 of 47 young pigeons aged from two to 31 weeks, from 12 racing lofts, which had clinical signs including diarrhoea and weight loss, regurgitation and respiratory signs. Samples from birds from two infected lofts indicated that picv could be detected in some birds for at least 27 weeks. Although nine of 14 pigeons aged from 32 to 45 weeks were virus-positive, picv was detected in only one of 18 adult pigeons that originated from four infected lofts.

Nineteen racing pigeons aged from one to five years were examined postmortem. pcr tests showed that the spleens of 16 of them were positive for pigeon circovirus, the livers of six were positive, and blood from one of them was positive for the virus. Five of 44 embryos in embryonated eggs collected from three lofts were positive by pcr, but swabs taken from the crops of 64 adult birds which were feeding one- to 10-day-old squabs in these three lofts were negative for the viral dna.

Polymerase chain reaction (PCR) and dot blot hybridisation (DBH) tests for detecting pigeon circovirus (PiCV) DNA were developed and evaluated using tissue samples obtained from diseased and clinically normal pigeons, which originated in Belgium and Northern Ireland. When PCR product was visually detected, the limit of detection of the PCR test was 31 fg, while that of the DBH was 1.6p g. For evaluation purposes, the results of the PCR and DBH tests, performed with DNAs extracted from samples of bursa of Fabricius (BF), were compared with those of in situ hybridisation (ISH) and histology. In 32 samples tested by all four tests, 27 (84%) were positive by PCR, 24 (75%) were positive by ISH, 20 (63%) were positive by DBH, and 13 (41%) were positive by histology. Additional PCR testing showed that in some disease-affected birds, PiCV DNA could be detected in a range of tissues including thymus, spleen, liver, kidney and brain. The PCR detection of PiCV DNA in BF samples from clinically normal birds indicated that PCR can detect infections in the absence of disease, a finding that mitigates against its use as a disease diagnostic. In addition, nucleotide sequence determinations indicated that PCR test performance was adversely affected by the sequence diversity exhibited by selected PiCVs. The application of the DBH test to dilutions of test samples indicated that the BF from some diseased pigeons contained very large amounts of virus DNA, as much as 10(13)genome copies/g tissue, and suggested that this test may be a convenient method of providing a semi-quantitative estimate of virus load.

This present paper describes the isolation of a pure culture of potentially pathogenic Acinetobacter Iwoffii from a swollen elbow-joint of a female pigeon.The virulence of this bacteria is also discussed.

This paper describes the different clinical aspects of the adenovirus infections in pigeons. Etiology, epidemiology, pathogenesis, diagnosis and treatment are discussed. The two specific clinical syndromes of pigeons are mainly described: classical adenovirus and necrotizing-hepatitis.

This work determines the degree of protection after two subcutaneous vaccinations at 20 days of interval with an inactivated aqueous adjuvanted vaccine against a paramyxovirus serotype 3 infection in Bourke parakeets, performed 23 days after the second vaccination. As shown by the mortality/morbidity rate after challenge, the vaccine confers protection and inhibits the virus multiplication in birds and therefore helps to control the dissemination of the infection.

The authors compare the protection obtained after subcutaneously vaccination of pigeons with 3 inactivated aqueous vaccines against a severe Salmonella (S.) Typhimurium var. Copenhagen challenge, The vaccines were maked up with a strain Salmonella (S.) Typhimurium var. Copenhagen isolated from pigeon, at different doses of bacterial antigens. As shown by the seroconversion and mortality/morbidity rate after challenge, there was a dose response correlation between antigen contains of vaccine and protection. Only the vaccine containing the higher dose of bacterial antigens had confered an excellent protection and inhibited the Salmonella multiplication in animals and therefore could help to control dissemination of the infection.

The minimal cytocidal concentrations of ronidazole (CMT) were determined in vitro and the cytopathogenic effects on chicken fibroblast cell cultures were evaluated for 31 strains of T. gallinae isolated from pigeons of different lofts frequenting the Avian clinic. The level of resistance in vitro corresponding to the in vivo resistance has been determined and is equal to 80 mu g/ml. Forty-five percent of the strains have a CMT of 40 mu g/ml, very close to the resistance level, it is recommended to take care of the use of nitroimidazoles to control trichomoniasis in pigeons. The treatments should be reserved only to clinically affected pigeons and should be given during a minimal period of five to seven days at a therapeutic dose of 100 to 150 mg ronidazole in one liter of drinking water.

This paper reports the first cases of pigeon circovirus infection in Belgium, Five pigeons were necropsied and specific lesions with inclusions bodies were observed in cloacal bursae, In addition diagnostic was confirmed by electronic microscopy.

The authors compare the efficiency of three experimental inactivated aqueous vaccines against Salmonella typhimurium infection in pigeons. As shown by the sere-conversion and mortality/morbidity rate after challenge, the three vaccines confer an excellent protection and inhibit the Salmonella multiplication in animals and therefore help to control dissemination of the infection.

These last years, the attention paid to Streptococcus bovis infection in pigeons is considerably increasing. The authors present a review of the main biochemical caracteristics of this new potentially pathogen bacteria, its epidemiology, the clinical signs induce, the gross lesions, the diagnosis, the prevention and the treatment of this pathology. They also give their own experience about it.

This work determines the duration of protection after a single subcutaneous vaccination of Colombovac PMV(R) combined with a live attenuated strain of pigeon poxvirus. Antibodies against pigeon poxvirus and PMV-1 were measured monthly respectively during 9 and 12 months. These tests indicated a good titre development against these two viruses. After an intravenous challenge with a virulent pigeon poxvirus strain 9 months post vaccination, vaccinated pigeons were significantly more protected than control pigeons. Protection was determined by evaluating lesions scores. Vaccinated pigeons were also protected against a challenge with paramyxovirus-1 twelve months post vaccination, while control pigeons were severely affected. Shedding of virulent PMV-1 after challenge by vaccinated pigeons was greatly reduced, compared to non-vaccinated pigeons. Addition of the Poxvirus vaccine to Colombovac PMV(R) therefore offers protection against poxvirus and paramyxovirus diseases for at least 9 and 12 months post vaccination, respectively.

The potentially pathogen bacterial flora isolated from pigeons suffering from acute or chronic respiratory distress and its resistance to common anti- microbial agents have been determined. Staphylococcus intermedius and Pasteurella multocida were recorded in 72 and 17 % of all the isolated pathogen bacteria. Taking each antibiotics' spectrum into account, the sensitivity to anti-microbial agents was on average 59 +/- 34% (n = 7). The best scores were for gentamicin (100%) and furoxone (89%), the least ones were for erythromycin (17%) and oxytetracycline (9%). The scores for chloramphenicol, enrofloxacin and sulfadoxine/trimethoprim combination have been 70,57 and 68%.