Disease In Pigeons Research Articles

First experimental proof of Rotavirus A (RVA) genotype G18P[17] inducing the clinical presentation of 'young pigeon disease syndrome' (YPDS) in domestic pigeons (Columba livia).

Young pigeon disease syndrome (YPDS) is characterized as a seasonally occurring, acute and primarily enteric medical condition of mainly juvenile domestic pigeons (Columba livia) with highly variable mortality reaching more than 50%. Although the syndrome has been known in Europe for almost three decades, its aetiology remains largely obscure. Recently, a previously unknown pigeon-associated clade of Rotavirus A (RVA) genotype G18P[17] was detected in Europe and Australia in association with fatal diseases resembling YPDS. Here we show for the first time, that peroral inoculation of healthy juvenile homing pigeons with two genetically different cell culture isolates of RVA G18P[17] (106.3 foci-forming units per bird) induces an acute and self-limiting YPDS-like disease in all infected birds. Clinical signs included regurgitation, diarrhoea, congested crops, anorexia and weight loss, as described for naturally RVA-infected pigeons. In agreement with the original outbreaks, RVA isolate DR-7 induced more pronounced clinical signs as compared to isolate DR-5, indicating strain-dependent virulence factors to contribute to variable disease outcomes observed in the field. All inoculated birds developed rotavirus-reactive antibodies starting at seven days after inoculation. High levels of viral RNA and infectious virus were detectable in cloacal swabs and faecal samples already three days after inoculation. While shedding of infectious virus subsided within few days, moderate viral RNA levels were still detectable in cloacal swabs, faeces, and tissue samples at the end of the experiment three weeks after inoculation. Histopathological analysis at this time point revealed inflammatory lesions in spleens and livers of pigeons from both infected groups. In summary, we fulfilled Henle-Koch's postulates and confirmed RVA G18P[17] as a primary cause of YPDS-like diseases in domestic pigeons. By establishing an infection model, we provide a crucial tool for future research, such as identification of transmission routes and establishing vaccination regimes.

Influence of pigeon interferon alpha (PiIFN-α) on pigeon circovirus (PiCV) replication and cytokine expression in Columba livia

Pigeon circovirus (PiCV) is the most diagnosed virus in pigeons (Columba livia) and have been studied and reported globally. PiCV infections can lead to immunosuppression and pigeons infected with PiCV can result to lymphocyte apoptosis and atrophy of immune organs. Young pigeon disease syndrome (YPDS) is a complex disease and believed that PiCV could be one of the agents leading to this syndrome. An effective treatment regimen is needed to control the spread of PiCV in pigeons. In this study pigeon interferon alpha (PiIFN-α) was cloned and expressed and its antiviral effects were tested against fowl adenovirus type 4 (FAdV-4) in vitro and PiCV in vivo. No detectable levels of FAdV-4 viral genome in LMH cells stimulated with 300 μg/mL PiIFN-α were found. Additionally, PiIFN-α was stable at different temperature and pH for 4 h, and no reduction in antiviral activity was observed in untreated and treated cells. In pigeons naturally and experimentally infected by PiCV, no detectable levels of PiCV virus titers were found after treatment with PiIFN-α. Cytokine and ISG expression levels in liver and spleen samples were detected and IFN-γ and Mx1 genes were dominantly up-regulated following PiIFN-α treatment (p < 0.05). This study demonstrated that PiCV can be inhibited by administration of PiIFN-α and PiFN-α can be used as a therapeutic approach to prevent the spread of PiCV in pigeons.

Assembly of pigeon circovirus-like particles using baculovirus expression system

Pigeon circovirus (PiCV) is able to infect racing and meat pigeons of all ages and is a key factor that triggers young pigeon disease syndrome (YPDS). PiCV vaccine research has been impeded because PiCV cannot be grown or propagated in cell cultures. Virus-like particles (VLPs), which can be generated by a wide range of expression systems, have been shown to have outstanding immunogenicity and constitute promising vaccines against a wide range of pathogens. Cap protein, which contains neutralizing antibody epitopes, is the only capsid protein of PiCV. In this study, the baculovirus expression system was utilized to express the PiCV Cap protein, which was self-assembled into VLPs with a spherical morphology and diameters of 15–18 nm. Specific antibodies against the Cap protein were induced after BALB/c mice immunized intramuscularly (i.m.) with VLPs combined with adjuvant. Based on these findings, PiCV VLPs may be a promising candidate vaccine against PiCV.

Chemotherapy of gastrointestinal parasitic diseases in domestic pigeons (Columba livia) in Rajshahi division of Bangladesh

The present study was undertaken to find out the prevalence of gastrointestinal nematodes in pigeon (columba livia) at Rajshahi division from 01-01-2016 to 15-12-2016 and to evaluate the comparative efficacy piparazine citrate and levamisole HCL. Total 3 different species of parasites were recorded in this study and those were Ascaridia columbae, Capillilaria obsignata, Raillietina tetragona. Out of 263 pigeon, 109 pigeon having ascarid and capillaria positive were treatment with piparazine citrate and levamisole HCL. The pigeon were treated with recommended (10g mixed in 6 litre drinking water for 100 pigeon) dose of Ascarex® and recommended (1gm mixed in 1 litre drinking water) dose of Avinex® orally, respectively. The recovery rate of ascariasis at 7th days was 50.9% and capillariasis was 51.85%. After 21th days the recovery rate of ascariasis was 72.72% and capillariasis was 66.66%. The efficacy of drugs is more in case of young (77.27% at 7th days and 87.36% at 21th days) than adult (44.82% at 7th days and 65.51% at 21th days).In exotic breeds efficacy is good (60.41% at 7th days and 85.41% at 21th days) than indigenous breeds (44.26% at 7th days and 66.65% at 21th days). The recovery rate is more in traditional (65.3% at 7th days and 78.33% at 21th days) than commercial farming system (42.85% at 7th days and 58.33% at 21th days).&#x0D; Res. Agric., Livest. Fish.6(2): 323-328, August 2019

Occurrence and antimicrobial susceptibility of Salmonella spp. isolated from domestic pigeons Columba livia var. domestica in 2007-2017 in Poland

Salmonellosis is one of the most important bacterial diseases in pigeons. The disease occurs in birds of different ages, and long-term Salmonella spp. carrier status is a major problem. The study included 499 samples from live pigeons and internal organs from 265 necropsied birds. The samples were cultured on a standard and selective media. Their antimicrobial susceptibility was carried out by the Kirby-Bauer diffusion method. Thirty one Salmonella spp. isolates were cultured. Most isolates were obtained from the internal organs of dead or euthanised pigeons, and only single isolates were obtained from droppings and cloacal swabs. A total of 4% of the samples tested were positive. The greatest percentage of isolates was susceptible to enrofloxacin (96.3%) and florfenicol (95.7%). Sulfamethoxazole and trimethoprim combination was effective against 73.9% of the isolates. Despite the fact of increasing antibiotic resistance of the investigated bacteria, it is comforting that enrofloxacin remains highly effective despite its widespread use in birds.

Immunogenicity of Pigeon Circovirus Recombinant Capsid Protein in Pigeons

Pigeon circovirus (PiCV) is the most frequently diagnosed virus in pigeons and is thought to be one of the causative factors of a complex disease called the young pigeon disease syndrome (YPDS). The development of a vaccine against this virus could be a strategy for YPDS control. Since laboratory culture of PiCV is impossible, its recombinant capsid protein (rCP) can be considered as a potential antigen candidate in sub-unit vaccines. The aim of this basic research was to evaluate the immune response of pigeons to PiCV rCP. Sixty six-week-old carrier pigeons were divided into two groups (experimental immunized with PiCV rCP mixed with an adjuvant, and control immunized with an adjuvant only), and immunized twice in a 21-day interval. On the day of immunization and on two, 23, 39, and 46 days post first immunization (dpv), samples of blood, spleen, and bursa of Fabricius were collected from six birds from each group to examine anti-PiCV rCP IgY, anti-PiCV rCP IgY-secreting B cells (SBC), IFN-γ gene expression, and percentage of T CD3+, CD4+, CD8+, and B IgM+ lymphocytes. The results indicated a correct immune response to PiCV rCP both in humoral and cell-mediated immunity, which was manifested by seroconversion since 23 dpv, by a significantly higher anti-PiCV rCP IgY-SBC number on two and 23 dpv, and significantly higher IFN-γ gene expression since two dpv. There were no significant differences or trends noted between particular T and B lymphocyte subpopulations. To conclude, PiCV rCP may be deemed immunogenic and could be considered as an antigen candidate in sub-unit vaccines against PiCV infections in pigeons.

PREVALENCE OF COCCIDIA INFECTION AMONG DOMESTIC PIGEON (COLUMBA LIVIA DOMESTICA) AND QUAILS (COTURNIX YPSILOPHORA) IN QENA PROVINCE, SOUTHERN EGYPT

Coccidiosis, caused by species of the apicomplexan parasite Eimeria, is a major disease of pigeons and to quails. Therefore, the present study was conducted to detect the prevalence and identify the species of Eimeria causing coccidiosis in both pigeons and quails in Qena province, Southern Egypt. In the current study, three hundred and sixty fecal samples of each species were collected and screened for Eimeria infection by floatation technique from November 2017 to October 2018.The results of the current study revealed an overall prevalence of 56%, with a higher infection rate in pigeon (58.3%) in comparison to quails (53.9%). Additionally, squabs had the highest prevalence (72.8%) as compared to adults (37.3), whereas the higher prevalence of Eimeria was observed in male birds in both species. Peak prevalence was observed in Autumn and Winter for pigeon and quails respectively. The results also, showed that more than one Eimeria species existed in most fecal samples, and the infection rate of identified Eimeria spp. in these samples was Eimeria labbeana (37.2%), E. columbae (30.8%), E. columbarum (27.9%) and E. gourai (4%) respectively.On the other hand, common Eimeria spp. found in quails were E. tsunoda (51.3%), E. uzura (28%)and E. bateri (20.5%).This indicates that Eimeriatsunoda are the predominant species in Qena Province. Histopathology also revealed a developmental stage of the parasite in the intestinal tract and desquamation of the epithelial lining with areas of necrosis. In conclusion, this study provides basic information on the first detection of coccidiosis of pigeons and quails in Qena Province, Egypt, which has an implication on the sustainable birds’ production for human protein requirement.

The impact of Aloe vera and licorice extracts on selected mechanisms of humoral and cell-mediated immunity in pigeons experimentally infected with PPMV-1

BackgroundThe aim of the study was to evaluate the impact of herbal extracts on selected immunity mechanisms in clinically healthy pigeons and pigeons inoculated with the pigeon paramyxovirus type 1 (PPMV-1). For the first 7 days post-inoculation (dpi), an aqueous solution of Aloe vera or licorice extract was administered daily at 300 or 500 mg/kg body weight (BW). The birds were euthanized at 4, 7 and 14 dpi, and spleen samples were collected during necropsy. Mononuclear cells were isolated from spleen samples and divided into two parts: one part was used to determine the percentage of IgM+ B cells in a flow cytometric analysis, and the other was used to evaluate the expression of genes encoding IFN-γ and surface receptors on CD3+, CD4+ and CD8+ T cells.ResultsThe expression of the IFN-γ gene increased in all birds inoculated with PPMV-1 and receiving both herbal extracts. The expression of the CD3 gene was lowest at 14 dpi in healthy birds and at 7 dpi in inoculated pigeons. The expression of the CD4 gene was higher in uninoculated pigeons receiving both herbal extracts than in the control group throughout nearly the entire experiment with a peak at 7 dpi. A reverse trend was observed in pigeons inoculated with PPMV-1 and receiving both herbal extracts. In uninoculated birds, increased expression of the CD8 gene was noted in the pigeons receiving a lower dose of the Aloe vera extract and both doses of licorice extracts. No significant differences in the expression of this gene were found between inoculated pigeons receiving both herbal extracts. The percentage of IgM+ B cells did not differ between any of the evaluated groups.ConclusionsThis results indicate that Aloe vera and licorice extracts have immunomodulatory properties and can be used successfully to prevent viral diseases, enhance immunity and as supplementary treatment for viral diseases in pigeons.

Autoinducer2 affects trimethoprim‐sulfamethoxazole susceptibility in avian pathogenic Escherichia coli dependent on the folate synthesis‐associate pathway

Avian pathogenic Escherichia coli (APEC) causes airsacculitis, polyserositis, septicemia, and other mainly extraintestinal diseases in chickens, ducks, geese, pigeons, and other avian species, and is responsible for great economic losses in the avian industry. The autoinducer 2 (AI‐2) quorum sensing system is widely present in many species of gram‐negative and gram‐positive bacteria and has been proposed to be involved in interspecies communication. In clinical APEC strains, whether or not AI‐2 affects the expression of antibiotic‐related genes has not been reported. In this study, we have reported that exogenous AI‐2 increase the susceptibility of APEC strains to trimethoprim‐sulfamethoxazole (SXT) in a folate synthesis‐dependent pathway but not in the LsrR‐dependent manner. Our results further explained that exogenous AI‐2 can down regulate the transcription of the folate synthetase encoding genes folA and folC, and the folate synthesis‐related genes luxS, metE, and metH. Gel shift assays confirmed that LsrR, the AI‐2 receptor, did not bind to the promoters of folA and folC, suggesting that exogenous AI‐2 might influence folate metabolism by a feedback inhibition effect but not in the LsrR‐dependent pathway. This study might provide further information in the search for potential drug targets for prophylaxis of avian colibacillosis and for auxiliary antibiotics in the treatment of avian colibacillosis.

Phylogenetic, antigenic and biological characterization of pigeon paramyxovirus type 1 circulating in China

BackgroundFor many years, ND has been one of the most important infectious pigeon diseases in China. In recent years, a high mortality has been observed in ND-infected pigeons in China. Mortality is from 40% to 80% or 100% in some cases.MethodsThe full-length genomes of four pigeon paramyxovirus type 1 (PPMV-1) strains, which were isolated from infected pigeons in China in 2012 and 2013, were sequenced and analyzed to determine the phylogenetic characteristics of PPMV-1 circulating in pigeons of China in recent years. Furthermore, cross hemagglutination inhibition and cross virus neutralization assays, as well as animal experiments were conducted to determine the antigenicity and pathogenicity of those viruses. Proteolytic cleavage sites (residues 112–117) of the F proteins were identified as the typical virulence motif, 112RRQKR↓F117 for all four PPMV-1 strains investigated.ResultsPhylogenetic analysis based on sequences of complete genomes and F gene revealed that the four PPMV-1 isolates and most of recent isolates in China were highly homologous to European isolates from 1998 to 2011. All those isolates were clustered in one clade of genotype VI NDV, termed as subgroup 4bii f. The R value was calculated based on cross hemagglutination inhibition and cross virus neutralization results, and confirmed antigenic difference of the PPMV-1 strains isolated in 2013 from the LaSota vaccine strain. Several mutations were identified in the surface glycoproteins F and HN, which probably gave rise to those antigenic differences.ConclusionOur result suggested that the PPMV-1 strain prevailing in China in the last decade diverged from a common ancestor and was presumably transmitted from Europe. PPMV-1 isolates displayed obvious antigenic differences from vaccine strain LaSota. Even though PPMV-1 did not cause high mortality in experimental pigeons, the infected pigeons were exhibiting viral shedding for 3 weeks after infection, suggesting PPMV-1 is a potential threat to NDV control worldwide.

Characterization and Epidemiology of Pigeon Paramyxovirus Type-1 Viruses (PPMV-1) Isolated in Macedonia.

We have characterized in this study 10 PPMV-1 isolated from domestic pigeons and one PPMV-1 isolated from a feral pigeon in the period 2007-2012, using both classical methods (HI test and ICPI test) and molecular methods (RT-qPCR, RT-PCR, and nucleotide sequencing). Using phylogenetic analysis of partial fusion gene sequences, these viruses clustered with recent European PPMV-1 isolates (EU/re) within the genotype VIb/1. All isolates possessed virulent cleavage site motifs with variable morbidity and mortality in pigeons. The intracerebral pathogenecity indices of the five isolates ranged from 0.59 to 1.53. The repetitive isolation of PPMV-1 viruses for several consecutive years led toward establishing enzootic presence of the disease in pigeons. A high nucleotide sequence homology between the Macedonian isolates and EU/re isolates was shown. Co-circulation of different isolates in the same holdings was detected. This is the first study to extensively describe the molecular epidemiology of PPMV-1 isolated in Macedonia.

Identification of a novel aviadenovirus, designated pigeon adenovirus 2 in domestic pigeons (Columba livia)

The young pigeon disease syndrome (YPDS) affects mainly young pigeons of less than one year of age and leads to crop stasis, vomitus, diarrhea, anorexia and occasionally death. This disease is internationally a major health problem because of its seasonal appearance during competitions such as homing pigeon races or exhibitions of ornamental birds. While the etiology of YPDS is still unclear, adenoviruses are frequently discussed as potential causative agents.Electron microscopy of feces from a YPDS outbreak revealed massive shedding of adenovirus-like particles. Whole genome sequencing of this sample identified a novel adenovirus tentatively named pigeon adenovirus 2 (PiAdV-2). Phylogenetic and comparative genome analysis suggest PiAdV-2 to belong to a new species within the genus Aviadenovirus, for which we propose the name Pigeon aviadenovirus B. The PiAdV-2 genome shares 54.9% nucleotide sequence identity with pigeon adenovirus 1 (PiAdV-1). In a screening of further YPDS-affected flocks two variants of PiAdV-2 (variant A and B) were detected which shared 97.6% nucleotide identity of partial polymerase sequences, but only 79.7% nucleotide identity of partial hexon sequences.The distribution of both PiAdV-2 variants was further investigated in fecal samples collected between 2008 and 2015 from healthy or YPDS-affected racing pigeons of different lofts. Independent of their health status, approximately 20% of young and 13% of adult pigeon flocks harbored PiAdV-2 variants. Birds were free of PiAdV-1 or other aviadenoviruses as determined by PCRs targeting the aviadenovirus polymerase or the PiAdV-1 fiber gene, respectively.In conclusion, there is no indication of a correlation between YPDS outbreaks and the presence of PiAdV-2 or other aviadenoviruses, arguing against an causative role in this disease complex.

No evidence of Sarcocystis calchasi involvement in mammalian meningoencephalitis of unknown origin

Sarcocystis calchasi has recently been identified as the cause of pigeon protozoal encephalitis, PPE, a lethal brain disease in pigeons and parrots. While only avian species have been identified so far to be susceptible to this pathogen as definitive or intermediate hosts, we speculated whether mammals may be susceptible as well, as in Sarcocystis neurona and other related apicomplexan parasites. Specifically, we hypothesized its involvement in mammalian meningoencephalitis of unknown origin, MUO. A total of 143 archived formalin fixed, paraffin embedded brain samples with MUO from dogs, cats, pigs, cattle, sheep, guinea pigs, horses, goats, mice, raccoon, ferret, hamster, mink and maned wolf were examined pathohistologically and by PCR for parasitic stages or DNA, respectively, of Sarcocystis calchasi or other apicomplexan parasites. All samples had non-suppurative, lymphoplasmacytic and/or granulomatous encephalitis or meningoencephalitis typical of MUO with many similarities to PPE in pigeons. However, neither parasitic structures nor DNA of Sarcocystis calchasi or other apicomplexan parasites were detected. It thus appears that, despite histological similarities between mammalian MUO and pigeon PPE and despite seemingly high prevalence of PPE and a persistent threat by Sarcocystis calchasi in pigeons, based on histopathology and PCR there is no evidence for a role of this parasite in MUO in mammals as intermediate or aberrant hosts.

House Sparrows Do Not Constitute a Significant Salmonella Typhimurium Reservoir across Urban Gradients in Flanders, Belgium.

In recent decades major declines in urban house sparrow (Passer domesticus) populations have been observed in north-western European cities, whereas suburban and rural house sparrow populations have remained relatively stable or are recovering from previous declines. Differential exposure to avian pathogens known to cause epidemics in house sparrows may in part explain this spatial pattern of declines. Here we investigate the potential effect of urbanization on the development of a bacterial pathogen reservoir in free-ranging house sparrows. This was achieved by comparing the prevalence of Salmonella enterica subspecies enterica serotype Typhimurium in 364 apparently healthy house sparrows captured in urban, suburban and rural regions across Flanders, Belgium between September 2013 and March 2014. In addition 12 dead birds, received from bird rescue centers, were necropsied. The apparent absence of Salmonella Typhimurium in fecal samples of healthy birds, and the identification of only one house sparrow seropositive for Salmonella spp., suggests that during the winter of 2013–2014 these birds did not represent any considerable Salmonella Typhimurium reservoir in Belgium and thus may be considered naïve hosts, susceptible to clinical infection. This susceptibility is demonstrated by the isolation of two different Salmonella Typhimurium strains from two of the deceased house sparrows: one DT99, typically associated with disease in pigeons, and one DT195, previously associated with a passerine decline. The apparent absence (prevalence: <1.3%) of a reservoir in healthy house sparrows and the association of infection with clinical disease suggests that the impact of Salmonella Typhimurium on house sparrows is largely driven by the risk of exogenous exposure to pathogenic Salmonella Typhimurium strains. However, no inference could be made on a causal relationship between Salmonella infection and the observed house sparrow population declines.

OCCURRENCE OF PIGEON DISEASES AT KHULNA SADAR, BANGLADESH

A study on pigeon diseases at Khulna sadar and surrounding private farms was done to determine the occurrence of the common pigeon diseases. A total of 502 diseased pigeon were examined. According to age, they were classified into three categories squab (1-2 weeks), young (30-90 days) and adult (&gt;90days). Those diseases were identified clinically by postmortem examination and laboratory testing, were carried out in veterinary hospital at Khulna from March 2013 to February 2014. Out of 502, 20.32% were salmonellosis, 18. 92% were pigeon pox, 11.95% were canker. Pigeon pox found high level in June-July. Among other diseases parasitic infestation (31.67%) was more prevalent. Disease varies significantly (P&lt;0.01) with season, where summer (57.37%) is more prevalent. Rate of diseases (salmonellosis and pigeon pox) affection significantly (P&lt;0.01) varies with age. Young are more susceptible with salmonellosis and pigeon pox. This study was done first time at Khulna and right time to take necessary steps saving pigeon farming.

Toltrazuril does not show an effect against pigeon protozoal encephalitis.

The protozoan parasite Sarcocystis calchasi causes a severe neurologic disease in domestic pigeons (Columba livia f. dom.) named pigeon protozoal encephalitis. Recently, the parasite has also been reported in psittacines causing a virtually identical disease with fatal outcome. So far, an etiological treatment of S. calchasi infections in pigeons or psittacines is unknown. The present study evaluates the effectiveness of the anticoccidian drug toltrazuril against S. calchasi and the influence of the timepoint of treatment. Therefore, nine domestic pigeons were inoculated with 400 S. calchasi sporocysts and treated with toltrazuril (25 mg/kg) in groups of three pigeons each at dpi 10/11 and dpi 40/41 and on two consecutive days at the onset of neurologic signs. After euthanasia at dpi 73, tissue samples including brain and skeletal muscles were examined by histology and S. calchasi-specific real-time PCR. All pigeons independent of the group developed neurologic signs from dpi 49 onwards. Histology identified sarcocysts in the skeletal muscles and a granulomatous encephalitis in the brains. The relative amount of S. calchasi DNA was on a comparable level in all pigeons. Consequently, toltrazuril was demonstrated to be not effective against S. calchasi with the applied treatment regime. Longer treatment periods or agents other the toltrazuril may be considered for further investigations. So far, preventive measures like roofing of aviaries for prevention of infection and regular disinfection remain the most important factor in the control of S. calchasi infections.

Diseases of Pigeons Reared on Small-Holdings in Bangladesh

A cross-sectional survey was undertaken on dead pigeons to explore the diseases and conditions associated with the death of pigeons reared at smallholdings and sold at live-bird markets in Bangladesh. 108 dead pigeons were collected from 2 live-bird markets-one in Dhaka and other based at Chittagong districts, 38 smallholdings, of which 20, 3, 3, 5 and 7 were located in Jessore, Dhaka, Chittagong, Magura and Jhenaidah districts respectively. Initially the collected dead pigeons were preserved at the households’ refrigerators and then transferred to the department of Microbiology, Chittagong Veterinary and Animal Sciences University, where they were further frozen at -84°C until investigated. All the collected dead pigeons were thoroughly examined postmortem. From each of the dead pigeon (except decomposed carcasses) bacteriological examination done through taking samples from the liver with sterile cotton swabs, and inoculated onto at least two media- McConkey and Mueller-Hinton agar (supplemented with 5% defrinated sheep blood). To identify the organism for any bacterial growths on these two media were examined using the standard procedures. The 4 major disease/conditions associated with the deaths of the pigeons were cervical disruption & related haemorrhages (17.6%), colibacillosis (13.89%), external injuries (8.33%) and morbus cordis (10.18%).

Parasite distribution and early-stage encephalitis in Sarcocystis calchasi infections in domestic pigeons (Columba livia f. domestica)

Pigeon protozoal encephalitis is a biphasic, neurologic disease of domestic pigeons (Columba livia f. domestica) caused by the apicomplexan parasite Sarcocystis calchasi. Despite severe inflammatory lesions of the brain, associated parasitic stages have only rarely been identified and the cause of the lesions is still unclear. The aim of this study was therefore to characterize the tissue distribution of S. calchasi within pigeons between the two clinical phases and during the occurrence of neurological signs. For this purpose, a semi-quantitative real-time polymerase chain reaction (PCR) was developed. Forty-five domestic pigeons were infected orally (via a cannula into the crop) with 200 S. calchasi sporocysts and euthanized in groups of three pigeons at intervals of 2 to 10 days over a period of 61 days. Tissue samples including brain and skeletal muscle were examined by histology, immunohistochemistry, and PCR. Schizonts were detected in the liver of one pigeon at day 10 post infection. A mild encephalitis was detected at day 20 post infection, around 4 weeks before the onset of neurological signs. At the same time, immature sarcocysts were present in the skeletal muscle. In seven pigeons a few sarcocysts were identified in the brain, but not associated with any lesion. These results suggest that the encephalitis is induced at a very early stage of the S. calchasi lifecycle rather than in the chronic phase of pigeon protozoal encephalitis. Despite the increasing severity of lesions in the central nervous system, the amount of sarcocysts did not increase. This supports the hypothesis of a delayed-type hypersensitivity response as the cause of the encephalitis. The study also demonstrated that S. calchasi DNA is detectable in tissues negative by histological methods, indicating a higher sensitivity of the real-time PCR.

STREPTOCOCCUS GALLOLYTICUS INFECTION IN PIGEONS: PATHOGENICITY AND ANTIBIOTIC SUSCEPTABILITY

Streptococcus gallolyticus infection is considered an important septicemic disease in pigeons especially in squabs. In this study the pathogenicity and antimicrobial sensitivity of St. gallolyticus were searched. 141 samples of diseased and recently dead pigeons of different ages were collected and subjected to bacterial examination in order to isolate St. gallolyticus. Sixteen strains were isolated and identified at recovery rate of 11.35%. All isolated strains found following biotype I. The strains were tested In-Vitro for antimicrobial sensitivity to 9 types of antimicrobial drugs. All strains were found highly sensitive to enrofloxacin and flumequine, followed by streptomycin and florophenicol then doxycyclin and lincomycin. A half of strains were sensitive to trimethoprim / sulphmethoxazole, while most strains show high resistance to ampicillin and erythromycin. The test indicates that, most isolated strains (11/16) have multi-drug resistance. Experimental infection with a strain of St. gallolyticus was studied by 2 routs (Intravenous inoculation or crop inoculation) in clinically healthy pigeons. The inoculated microbe dose not cause deaths by any of the 2 routs used for inoculation. Clinical signs as well as post-mortem lesions of experimentally inoculated pigeons by both two routes were recorded and discussed. The inoculated organism was re-isolated from inoculated birds.

Occurrence and genetic diversity of pigeon circovirus strains in Poland

Pigeon circovirus (PiCV) is an immunosuppressive agent widespread throughout the world, which causes a disease in pigeons called Young Pigeon Disease Syndrome. The aim of the study was to evaluate the prevalence of PiCV in Poland and investigate the genetic diversity relative to other known PiCV isolates. Samples from 152 pigeon flocks (88 flocks of racing pigeons and 64 flocks of fancy pigeons) from various regions of Poland were tested by polymerase chain reaction and an approximately 326-base fragment of the capsid protein gene (Cap gene) of the virus was amplified. The average viral prevalence was found to be 70.3% (76.13% in racing pigeons and 62.5% in fancy pigeons). Among the obtained positive samples, 21 were selected for sequencing and a phylogenetic analysis was performed. It was found that the majority of Polish PiCV isolates, to varying degrees, are related to isolates occurring in Europe. It was also observed that the Cap gene is variable and mutations often occur in it, which impacts the amino acid sequences in the capsid protein (nucleotide similarity averaged 86.57%, amino acid similarity averaged 89.02%).