Search

Avian gastric yeast (Macrorhabdus ornithogaster) is an anamorphic ascomycetous yeast which colonises the junction between proventriculus and ventriculus in many species of birds. Although a normal flora, sometimes it causes a subclinical infection and at times lead to gastric infections. The present study confirmed the presence of Macrorhabdus ornithogaster from faecal samples of budgerigar with symptoms like regurgitation and chronic wasting. Gram's staining of the direct smear demonstrates large number of pleomorphic Gram positive organisms. The organism could be cultured on blood agar, Sabouraud's dextrose agar and De Man Rogosa and Sharpe agar but not on MacConkey agar. The organisms were found to be negative for catalase and oxidase and did not reduce nitrate. It produced acid from maltose, sucrose, glucose, galactose and trehalose and not from raffinose and lactose. The cultural and biochemical characters of the isolate along with clinical symptoms confirmed the case as avian gastric yeast infection. [ABSTRACT FROM AUTHOR]

Background: Macrorhabdus ornithogaster, a yeast-like fungus, has the potential to infect various bird species, including companion birds. Although birds infected with M. ornithogaster may often remain asymptomatic, the infection can develop into chronic wasting gastritis and even progress to gastric cancer, highlighting the importance of early detection of M. ornithogaster infection. Despite direct fecal examination being a commonly used diagnostic method, the polymerase chain reaction (PCR) is anticipated to offer a higher detection rate. However, the actual diagnostic accuracy of the PCR for M. ornithogaster remains unknown. Case Description: Ninety fecal samples collected from companion birds that visited or were admitted to a hospital, regardless of their stage of Macrorhabdus diagnosis or treatment, were subjected to PCR testing. An accuracy analysis was then performed, considering symptomatology, direct fecal testing, and sequencing. The PCR test had a sensitivity of 83.33 %, specificity of 95.00 %, false negative rate of 16.67%, false positive rate of 5.00%, positive predictive value of 89.29%, negative predictive value of 91.94%, prevalence of 33.33 %, positive likelihood ratio of 16.67, negative likelihood ratio of 0.18, and diagnostic odds ratio of 95.00. Conclusion: The findings suggest that the PCR for Macrorhabdus possesses high diagnostic accuracy, with the ability to accurately identify uninfected individuals as negative. While the direct fecal examination is appropriate for routine primary screening, in cases where M. ornithogaster is not detected by fecal testing, the PCR may provide a more accurate and definitive diagnosis due to its high specificity. [Open Vet J 2023; 13(12.000): 1769-1775]

Background: Macrorhabdus ornithogaster (MO) is an infectious yeast which can cause acute gastric disturbances in birds. It has a worldwide distribution with a broad host-range of bird species. Aims: Molecular identification and phylogenetic analysis of MO based on the 18S rRNA gene in companion birds of Iran. Methods: A total of 54 stool samples were taken from birds (10 species) suspected of being infected. The presence of MO in collected stool samples was investigated using direct wet mount microscopy. Specific primers were designed to identify the MO 18S rRNA gene by using PCR. PCR products were sequenced and phylogenetic analysis was performed to determine the molecular diversity. Results: The obtained results demonstrated that 44.44% and 59.26% of the samples were diagnosed positive based on the first and second specific primers, respectively. MO was detected in the feces of canary, goldfinch, budgerigar, toucan, and English budge. Phylogenetic analysis revealed that MO sequence data from canaries, finches, and goldfinches had homology with an MO isolated from a German zebra finch. Moreover, MOs from cockatiels, rosy faced love birds, and budgerigars had a high phylogenetic similarity with multiple references, including American budgerigar, Japanese cockatiel, European goldfinch, and German budgerigar. Conclusion: MO exists in many species of Iranian birds, including goldfinches, budgerigars, toucans, and English budgies. As indicated by phylogenetic and polymorphism data analysis, the newly designed specific primers spanning a large portion of 18S rRNA gene of MO, provides additional tool to detect and study the molecular diversity of MO. [ABSTRACT FROM AUTHOR]

Twenty-four American white ibis (Eudocimus albus) nestlings were collected in Florida (USA) on 17 April 2017 to establish a captive flock. On 7 May 2017, three birds died suddenly, following severe lethargy, hemorrhaging from the mouth and nares, anorexia, and production of bright-green colored feces. An additional ibis with delayed growth and pathological fractures was euthanized 18 May 2017. Severe ventriculitis associated with Macrorhabdus ornithogaster was noted in all four birds, bacterial sepsis was confirmed in one bird by culture and histologic examination, and bacterial endotoxemia was suspected in two birds based on gross and histologic examination, but no bacteria were isolated from these birds. Birds also had vitamin E liver levels consistent with coagulopathy previously described in pelicans. We sampled feces from 91 adult, free-living, healthy ibis in Florida in July 2017 and found 71% were shedding organisms with morphologic characteristics consistent with Macrorhabdus sp. Molecular characterization of the ibis-origin M. ornithogaster showed it was phylogenetically related to numerous M. ornithogaster sequences. It is unknown if M. ornithogaster infection resulted in clinical disease as a result of dietary or stress-related dysbiosis, or other factors. Macrorhabdus-associated disease has not previously been confirmed in wading birds. We discuss potential associations of gastric M. ornithogaster infection with morbidity and mortality in these cases and highlight the need for additional studies on this pathogen in free-living birds. [ABSTRACT FROM AUTHOR]

Macrorhabdus ornithogaster is a microorganism that causes nonspecific and general clinical symptoms and to this day, diagnosis and also treatment have been yet hard. The present study was conducted to survey the prevalence of macrorhabdosis and to characterize M. ornithogaster phylogenetically in Psittaciformes suspected of macrorhabdosis from January 2018 to May 2019 in Ahvaz, Iran. For this purpose, fecal samples were collected from Psittaciformes with signs of the disease. Wet mounts were prepared from fecal samples and examined carefully using a light microscope. Samples from parrots with gastrointestinal symptoms of the disease were chosen for molecular diagnosis of the organism and DNA was extracted from these samples. For detection of M. ornithogaster, primer sets (BIG1, Sm4) and (AGY1, Sm4) which target the 18S rDNA gene were selected and Semi-nested polymerase chain reaction (Semi-nested PCR) was performed. The PCR method confirmed the presence of M. ornithogaster in 14.00% of the samples. Purified PCR products were sequenced for more accurate confirmation and according to the gene sequence all sequences were owned by M. ornithogaster. The results disclosed a 96.03% - 100% identity when compared to other sequences of M. ornithogaster which had previously been deposited in the GenBank® from Germany and the USA. The results of this study proved the circulation of M. ornithogaster between cockatiel, budgerigar and grey parrot. The prevalence of macrorhabdosis was higher in cockatiel compared to budgerigar and grey parrot. As far as the authors know, this was the first record of macrorhabdosis in African grey parrots. [ABSTRACT FROM AUTHOR]

A vast range of infectious and noninfectious diseases can affect avian patients. Practitioners should be familiar with common presenting signs of these diseases in order to steer diagnostic testing and treatment., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Macrorhabdus ornithogaster (MO) is an infectious fungus that causes gastric damage in birds. In this study, we established nested and seminested polymerase chain reaction (PCR) methods that specifically amplify the domain D1/D2 region (D1/D2) of 26S ribosomal DNA (rDNA), internal transcribed spacer (ITS) of rDNA, and intergenic spacer (IGS) 1 region from avian feces. Phylogenetic analysis of MO collected from Japanese pet birds showed little genetic variation; analysis based on these regions did not distinguish between host species order, differences in MO shape, or host gastrointestinal symptoms. These regions were found to be unsuitable for molecular epidemiological studies of MO and further investigation into other genetic regions is required. [ABSTRACT FROM AUTHOR]

In Austria, numerous deaths of wild birds of the order Passeriformes, family Fringillidae, occurred during the winter months of 2010 and 2012. The Eurasian Siskin (Carduelis spinus) was the species most often affected. The dead birds were mainly found in the immediate vicinity of feeding places. Vigilant citizens sent birds (n=34) for pathologic examination to the Institute of Pathology in Vienna, Austria. All birds were cachectic or in a very poor nutritional condition. At gross examination, the most striking findings were multifocal to confluent, yellow-white nodules in the crop or esophageal mucosa. In histologically examined birds (n=24), severe transmural fibrino-purulent to necrotizing ingluviitis or esophagitis with large amounts of intralesional bacteria was observed. Bacteriologic examination of crop, liver, or other organs from 14 birds revealed abundant growth of Salmonella serovar Typhimurium (antigenic formula 1,4,5,12:i:1,2; phage type U277) in all individuals. By means of immunohistochemistry, these bacteria were detected not only in crop mucosa but also in lung tissue. In 17 birds (71%), structures morphologically resembling Macrorhabdus ornithogaster were detected histologically on the surface of the proventricular epithelium. Thus, the cause of mass mortality of the passerine birds was identified as infection with Salmonella Typhimurium, which was associated with growth of presumed M. ornithogaster in many cases. [ABSTRACT FROM AUTHOR]

Macrorhabdus ornithogaster is an ascomycete yeast often found at the isthmus of the ventriculus and proventriculus of infected birds. Antemortem diagnosis has traditionally involved direct visualization of organisms on wet-mount or gram-stained fecal preparations, cloacal and crop swabs, or by both methods; however, different in-clinic diagnostic techniques have never been compared to establish an optimum test for the identification of M ornithogaster in an avian patient. We compared 5 microscopically evaluated diagnostic testing methods: fecal Gram's stain, direct fecal wet preparation, macro suspension technique, macro suspension with Gram's stain, and macro suspension stained with new methylene blue. Each technique was performed on 96 fecal samples collected during the treatment of M ornithogaster–infected budgerigars with water-soluble amphotericin B. The macro suspension technique produced statistically higher organism counts than the other 4 techniques and was always estimated to have the largest detection probability. We recommend that the macro suspension technique be implemented as the most efficacious diagnostic test for in-clinic assessment of avian patients possibly infected with M ornithogaster. [ABSTRACT FROM AUTHOR]

Objective: To assess the efficacy of a commercially available in‐water amphotericin B treatment for Macrorhabdus ornithogaster. Design Clinical treatment trial. Methods: Faecal shedding of 16 naturally infected budgerigars (Melopsittacus undulatus) was monitored while they were being treated using in‐water amphotericin B, as per the manufacturer's instructions, for 10 days. Any birds that remained positive after 10 days received a further 10 day course of treatment. All birds were rechecked 16 days after the end of the second treatment period. Results: At the conclusion of treatment, 11 birds had stopped shedding M. ornithogaster, and 5 birds were still shedding. Sixteen days after the conclusion of the second treatment period, four birds that were negative after 10 days of treatment were shedding again, and two of the birds that were treated for 20 days were shedding. In addition, one bird from each treatment group died after treatment and before follow‐up testing. Conclusion: These findings represent a 36% treatment failure, suggesting that treatment with the commercially available, water‐soluble amphotericin B has inconsistent efficacy against M. ornithogaster in some budgerigars in Australia and is not effective for eliminating it from budgerigar aviaries. [ABSTRACT FROM AUTHOR]

Avian gastric yeast (Macrorhabdus ornithogaster) is a microorganism that infects aviary birds worldwide, both captive and wild. A total number of 352 birds, belonging to 18 avian species, were examined from 2019 to 2022 for M. ornithogaster, using fecal smears of live birds or cytological samples of the proventriculus taken at necropsy. These cytological samples were taken from birds that died from different causes. Some of the birds exhibited symptoms such as lethargy, regurgitation, weight loss and anorexia. Faecal samples were collected from all the birds and analysed for gastric yeast using a direct smear and Gram-staining method. The microorganism was diagnosed most frequently in budgerigars (55.5%), the African gray parrot (33.3%), and nymphs (34.3%). The prevalence of M. ornithogaster in canaries was 10%. The infection was detected in 31% of the examined birds, which shows that the occurrence of M. ornithogaster in exotic birds is common. No clinical signs were observed in the vast majority of birds that tested positive for gastric yeast., (© 2024 The Authors. This is an open access article under the CC BY-NC-ND 4.0 license.)

Macrorhabdosis is a debilitating disease condition that affects budgerigars (Melopsittacus undulatus), cockatiels (Nymphicus hollandicus), and many other bird species worldwide. Macrorhabdus ornithogaster is a pathogen which leads to nonspecific clinical signs, and to date, diagnosis as well as therapy are still challenging. In this study, medical histories of 32 budgerigars and 7 cockatiels with macrorhabdosis diagnosed clinically and by polymerase chain reaction (PCR) within a period of 24 months (from January 2016 to January 2018) were retrospectively analyzed. Macrorhabdus ornithogaster was diagnosed through fecal samples collected over several days and analyzed by microscopic examination or PCR. The effectiveness of 2 different amphotericin B treatment regimens were investigated by PCR. In 23 cases, treatment was performed with amphotericin B via drinking water at 0.1 mg/mL for 28 days. For the remaining 16 birds, an alternative treatment regimen of amphotericin B at 100 mg/kg PO q12h for 10 days was combined with administration of amphotericin B via drinking water at 0.1 mg/mL for 28 days. Fecal samples of all treated flocks were reexamined by PCR 10–14 days post-amphotericin B treatment. More than half (56.4%) of the treated birds tested negative for M ornithogaster irrespective of the treatment regimen. In addition to clinical improvement and microscopic examination of droppings, PCR was used for the first time to evaluate treatment response in birds diagnosed with M ornithogaster. Administration of amphotericin B via drinking water proved to be effective in more than 50% of cases, indicating a less stressful alternative to the oral administration of amphotericin B twice daily. [ABSTRACT FROM AUTHOR]

Amphotericin B is widely used for the treatment of Macrorhabdus ornithogaster infections. To date, however, there have been no randomized controlled trials confirming its efficacy where cure was confirmed by postmortem examination. To determine the efficacy of amphotericin B against M. ornithogaster, a three-part study was undertaken. Treatment outcomes of M. ornithogaster infected birds treated amphotericin B were reviewed. A pilot treatment trial with two naturally infected birds (Melopsittacus undulatus and Agapornis roseicollis) was undertaken, administering amphotericin B at 100 mg/kg twice daily for 30 days. Finally, a randomized controlled trial using experimentally infected chickens treated with amphotericin B at 25 mg/kg and 100 mg/kg twice daily for 10 days was performed. Retrospective analysis indicated treatment failure in 80.4% of 36 cases that met the inclusion criteria. The pilot study showed that amphotericin B did not clear, but significantly decreased Macrorhabdus ornithogaster burden, followed by profound rebound effect of the number of organisms shed in the feces. Finally, the randomized controlled trial found that amphotericin B given at 100 mg/kg did not clear, but significantly decreased the burden of M. ornithogaster compared with both the 25 mg/kg group (P =.037) and the no treatment control group (P =.001). A strong curvilinear correlation between body weight and M. ornithogaster infection burden was present in the infected chickens. These findings represent treatment failure in three scenarios and indicate that treatment with amphotericin B has poor efficacy against Macrorhabdus ornithogaster. [ABSTRACT FROM AUTHOR]

Proventricular infection with the anamorphic, ascomycetous yeast Macrorhabdus ornithogaster and disease associated with infection (macrorhabdiosis) have been widely reported in budgerigars (Melopsittacus undulatus). Proventricular adenocarcinoma has also been previously reported in this species. In a retrospective archival search of clinical cases submitted to a zoo animal and exotic pet pathology service between 1998 and 2013, a total of 28 128 avian submissions were identified, which included 1006 budgerigars kept in zoos or aviaries or as pets. Of these budgerigars, 177 were identified histologically as infected with M. orthithogaster at the time of necropsy. Histologic examination of tissues from budgerigars infected with M. orthithogaster identified an apparent continuum in the development of proventricular isthmus lesions associated with M. ornithogaster that included inflammation, mucosal hyperplasia, glandular dysplasia, and adenocarcinoma. Proventricular adenocarcinoma was identified histologically in 21 budgerigars. Budgerigars with proventricular adenocarcinoma were significantly more likely to have macrorhabdiosis than budgerigars without proventricular adenocarcinoma. Based on odds ratios for archival data, budgerigars were 41 times (95% confidence interval [CI], 33–52) more likely to have macrorhabdiosis than other avian species and 19 times (95% CI, 11–33) more likely to have proventricular adenocarcinoma than other birds. Budgerigars were 323 times (95% CI, 42–2490) more likely to be affected by both diseases simultaneously compared with other avian species. These findings suggest that macrorhabdiosis may be an associated factor for proventricular adenocarcinoma, although the explanation for this statistically significant correlation remains unknown and further investigation is warranted. [ABSTRACT FROM AUTHOR]

Macrorhabdus ornithogaster is an opportunistic yeast that colonizes the gastric mucosa of many avian species. Until now, no studies have focused on the influence of a gastric infection on the balance of the intestinal microbiota of birds. In this study, 44 faecal samples from individual canaries, with and without M. ornithogaster infection, were analysed. The detection of the yeast was evaluated by 18S rRNA PCR. In order to evaluate the impact of the Macrorhabdus infection on the bacterial communities, culture-independent methods, by the use of amplicon-based sequencing as well as 16S rRNA-DGGE, were adopted. The different health status of animals affected the relative abundance of the main OTUs, with a greater diversification of the gut microbiota in healthy animals compared to the infected. In particular, Lactococcus, Pseudomonas, Acinetobacter, Lachnospiraceae, Propionibacterium and Weissella were found to be characteristic of uninfected animals (FDR < 0.05), while Lactobacillus and Candidatus Arthromitus were characteristic of infected animals (FDR < 0.05). Both these taxa have been reported as immunostimulatory, involved in immunological disorders. In infected animals the inferred metagenome assessed by PICRUST clearly showed a positive correlation between the presence of M. ornithogaster and KEGG genes related to ether lipid metabolism, already reported to be immunostimulatory by activation of macrophages and to play a pathophysiological role in several immunological disorders. Finally, our results show an interaction between infection of the digestive tract and intestinal microbiota of pet birds and provide insight into the changing of the complex enteric bacterial community. HIGHLIGHTS: Macrorabdus ornithogaster is a gastric yeast that colonizes a wide range of birds. Differences were found between infected and healthy animals in gut microbiota. Candidatus Arthromitus was closely associated with infected birds. M. ornithogaster can affect intestinal microbiota composition of canaries. [ABSTRACT FROM AUTHOR]

Infection by Macrorhabdus ornithogaster (MO) formerly called Megabacteriosis has been diagnosed as the cause of depression, wasting, regurgitation, fluffed feathers, lethargy, and soft watery bulky feces and also the cause of mortality in a flock of breeding canaries over a long period of time (3 months) in Mashhad, Iran. Large numbers of Macrorhabdus ornithogaster were detected in wetmount fecal preparations of the feces and direct smears from mucosal scrapings of proventrilculus of one bird under light microscopy. The diagnosis was confirmed by demonstrating a chronic proventriculitis histologically which was associated with MO organisms along with molecular tests.

Two dead birds from a flock of domestic canaries (Serinus canaria) were referred with a history of anorexia, weight loss, abdominal distension, and occasional mortality. A slightly enlarged liver and proventriculus were seen on the examination of the abdominal cavity. A large number of yeast resembling Macrorhabdus ornithogaster were observed on gram staining of the proventriculus mucosa. Pseudomonas aeruginosa was isolated on the microbial culture of the liver. The complete genomic sequence of the internal transcribed spacer 1 (ITS1) was determined in Macrorhabdus ornithogaster using panfungal primers. The alignment of the sequence obtained from this study with 6 GenBank deposited ITS1sequences of Macrorhabdus ornithogaster showed some repeated nucleotide substitutions. The complete ITS1 sequence of our study (MF993119) displayed a whole genetic similarity to ITS1 sequences of Macrorhabdus ornithogaster isolated from canaries and finches and clustered into a different group from ITS1 sequences of Macrorhabdus ornithogaster isolated from pssitacines. The ITS1 region is proposed as taxonomically informative for Macrorhabdus ornithogaster isolates from different hosts. [ABSTRACT FROM AUTHOR]

Macrorhabdus ornithogaster, avian gastric yeast, is a common cause of gastrointestinal disease in budgerigars ( Melopsittacus undulatus). To better understand the clinical disease in budgerigars presented in a practice population, we reviewed the occurrence, clinical signs, and treatment success of M ornithogaster disease in budgerigars during a 2.5-year period at the Clinic for Birds and Reptiles, University of Leipzig (Leipzig, Germany). The yeast was diagnosed by microscopic examination of fresh fecal samples. Male budgerigars of all ages were most affected. Most clinical signs in birds with confirmed positive results were nonspecific, except for the occurrence of undigested seeds in the feces. Although radiographic appearance of a dilated proventriculus is indicative of a M ornithogaster infection, it is difficult to recognize because of the small size of the budgerigars. Birds with positive results were treated with amphotericin B (100 mg/kg PO q12h) for 4 weeks. Treatment was stressful for the birds because of the handling required and the long treatment duration, and therapeutic results were unsatisfactory. Therefore, the indications for treatment with amphotericin B should be carefully considered in birds with positive M ornithogaster results. An increased occurrence of the infection in association with other pathogens was detected. [ABSTRACT FROM AUTHOR]

Macrorhabdus ornithogaster is a yeast organism that infects multiple species of captive and wild birds. Diagnosis of infection in vivo has proven difficult historically, as shedding can be intermittent, and not all positive animals are clinically ill. We compared polymerase chain reaction (PCR) of cloacal swab samples and fecal Gram's stain (FGS) for diagnosis of active shedding of M ornithogaster in a captive flock of budgerigars ( Melopsittacus undulatus). Of the 100 birds sampled, 57 (57%) were positive for M ornithogaster by PCR and 24 (24%) were positive for M ornithogaster by FGS. All FGS-tested birds also were positive on PCR. There was a significant association between the two methods, but the overall percent agreement for the two methods was only 67%. Based on these findings, cloacal swab PCR is more likely to diagnose the presence of M ornithogaster than FGS in budgerigars. [ABSTRACT FROM AUTHOR]

A recently identified circovirus (family Circoviridae) was detected in 14 zebra finches (Taeniopygia guttata) from seven aviaries and hobbyist breeders using polymerase chain reaction followed by sequencing. Full genome sequences of virus strains from six zebra finches consistently revealed characteristic circoviral genomic features such as a stem-loop structure and two major open reading frames (ORFs) encoding the replication-associated protein and the putative capsid protein. One further ORF encoding a protein of unknown function was additionally identified in all six genomes. Based on full genome nucleotide comparison, zebra finch circovirus was most similar to Finch circovirus originating from a Gouldian finch (Chloebia gouldiae) sharing 78% nucleotide identity. High genetic diversity was detected in the circoviruses from individual zebra finches. Comparison of the six full genome sequences revealed two genetic subgroups, which shared pairwise nucleotide identities between 91.4% and 92.7%. Analyses including partial sequences of the replication-associated protein gene of the zebra finch circovirus strains from all 14 birds supported the existence of two main clusters. Clinical diseases associated with circovirus infection were found in nestlings, fledglings and adult birds and varied from mild to severe with high mortality caused by secondary infections. Macrorhabdus ornithogaster was the most frequently detected opportunistic pathogen. Feathering disorders were seen in two birds. Lymphocytic depletion of the spleen and leukocytopaenia were detected in individual birds, suggesting immunosuppression and a pathogenesis common to circovirus infections in other birds. [ABSTRACT FROM AUTHOR]

Since 2000, Macrorhabdus ornithogaster "megabacteriosis" has been diagnosed in the avian diseases laboratory in a diversity of avian species and varied spectrum of disease. The disease in some species (chickens, turkeys, guinea fowls) was clinically characterized by emaciation, prostration, loss of appetite, cachexia and death, with a typically chronic course. A more acute disease was observed in finches (canary-Serinus and zebra-Taeniopygia) and budgerigars (Melopsittacus undulatus). The large rod shaped organism, visible from 100 times magnification, with and without staining, could be detected in sick and also in reasonably normal individuals of some species, such as chickens, turkeys, quails and pigeons. In rheas (Rhea americana), ostriches (Struthio camelus), canaries, zebra-finches, guinea-fowl (Numida meleagris) and budgerigars. The disease was severe, causing to up to 100% mortality. The infection could be detected in some species along with other infectious or disease problems, such as endoparasites (helminths, coccidia) and ectoparasitism (order Mallophaga or/and order Acarina). The cultivation of M. ornithogaster was successfully achieved in solid and liquid media, originated from chickens (four isolates), guinea fowl (1 isolate), chuckar partridge (1 isolate) and canary (1 isolate). A very interesting finding at microscopy was motility of M. ornithogaster, as detected both in cultures obtained on agar for pathogenic fungi and passaged into thioglycolate broth, as well as on samples observed in wet preparations from in vivo. Differences in colony aspects were noted among the isolates. Experimental infections were attempted in chicken and japanese quail, using a chicken isolate, allowing the detection of the organism in the proventriculus and liver in apparently normal birds. One chicken isolate was injected intraperitoneally in Balb/c mice and resulted in 100% mortality.Desde 2000, diversos casos de infecção e doença por Macrorhabdus ornithogaster (megabacteria) foram diagnosticados no Setor de Doenças das Aves (Escola de Veterinária da UFMG). A doença clínica foi caracterizada por emagrecimento, prostração, perda do apetite, caquexia e morte, em curso crônico, embora com forma mais aguda em canários e periquitos. O microrganismo grande, em forma de bastão, visível a partir de 100 aumentos sem e com coloração, pode também ser detectado em aves de aspecto clínico normal, principalmente galinhas, perus, codornas e pombos. Em emas (Rhea), avestruzes (Struthio camelus), canários, mandarins, galinhas da Angola (Numida meleagris) e periquitos Australianos (Melopsittacus undulatus), a severidade da doença foi sempre maior, ocasionando até 100% de mortalidade em alguns plantéis. Na maioria das espécies a doença foi detectada em aves com endo e/ou ectoparasitismo. O cultivo de M. ornithogaster foi obtido em meio sólido (ágar para fungos patogênicos) e subcultivado em meio líquido (thioglicolato), do proventriculo de galinha, galinha da Angola, perdiz de chuckar e canário. O resultado mais surpreendente na microscopia de M. ornithogaster foi a presença de motilidade, detectada tanto de cultivos in vitro quanto de preparações úmidas de in vivo. Diferenças nos aspectos das colônias foram notadas entre os isolados. Infecções experimentais em galinha (SPF) e codorna japonesa permitiram a detecção do organismo nos proventrículos das aves de aspecto normal. Nas codornas, à necropsia notaram-se hemorragias hepáticas. A infecção experimental em camundongos via intraperitoneal resultou em 100% de mortalidade, também com lesões hepáticas. Aspectos do cultivo, a importância da doença, as espécies de aves susceptíveis e seu papel na epidemiologia são discutidos.

The aim of this study was to describe the pathological findings in budgerigars simultaneously infected under field conditions with coccidiosis and megabacteriosis. Severe diarrhea and vomiting were observed in a budgerigar flock. Affected birds showed inappetence and loss of condition, with a flock mortality rate of 30%. At necropsy, the proventriculi and ventriculi were swollen and hyperemic, and viscous mucus and blood adhered to the mucosa. Cytological examination of Giemsa stained proventricular and ventricular tissue revealed clusters of yeast. Microscopically, mild to severe inflammatory reactions, ulcers and hemorrhage were observed in the proventriculi. Numerous large, rod shaped Macrorhabdus ornithogaster organisms had colonized the proventriculi, ventriculi and gut. The bright pink organism was easily detected in periodic acid Schiff stained sections. On microscopic examination of the feces, numerous Eimeria oocysts were observed. Histopathological examination of the gut revealed numerous coccidial organisms in epithelial cells. Eimeria dunsingi (Farr, 1960) was identified in the gut contents of the birds, based on morphological characteristics. Surviving birds were treated with amphotericin-B for megabacteriosis and with toltrazuril for coccidiosis, after which the mortalities ceased. These results demonstrated that simultaneous natural infections under field conditions can cause severe, gross histopathological lesions and high rates of mortality in birds. At the same time, this is the first report of M. ornithogaster infection in budgerigars in Turkey. [ABSTRACT FROM AUTHOR]

Macrorhabdus ornithogaster, often referred to as 'megabacterium', is an ascomycetous yeast usually found colonizing the mucosal surface of the isthmus existing between the glandular and grinding stomach of a wide diversity of bird species. However, this yeast can also behave as an avian pathogen, therefore representing a potential threat to bird breeding. The aim of this work was to assess the prevalence and patterns of fecal shedding of M. ornithogaster in a colony of healthy canary birds ( Serinus canaria) bred in captivity. Fresh fecal samples from 39 canaries (17 males and 22 females) were cultured in liquid media for M. ornithogaster enrichment. Only two clinically healthy females were fecal culture-positive for the yeast, which represents an overall prevalence of 5.13% in the sampled population. A close surveillance of the two culture-positive canaries, which included periodical microscopic examination of fresh stool samples, showed prolonged fecal shedding of M. ornithogaster. Nevertheless, both animals remained asymptomatic throughout the study period. To the best of our knowledge, this is the first study reporting the continuous shedding of M. ornithogaster by clinically healthy canaries. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine if Macrorhabdus ornithogaster, a yeast recovered from the junction of the proventriculus and ventriculus of the stomach of parrots and other birds, can infect mice. Fifteen healthy ARC (S) female mice (age 10 weeks) were incoculated with M. ornithogaster by gavage at (two different dosage rates [ n = 5]) or intraperitoneal injection ( n = 5) (one dosage rate). They were euthanized 5 days later and examined for gross and microscopic evidence of infection. Macrorhabdus ornithogaster was not found to colonize the stomach, peritoneum, or viscera of the challeneged mice. The results of this study show that M. ornithogaster is not able to infect mice by the oral and intraperitoneal routes of administration and suggest that infection in mammals is unlikely to occur. [ABSTRACT FROM AUTHOR]

This study was performed on a breeding colony (about 500 budgerigars) affected by chronic fatal wasting disease. Necropsy was undertaken on ten severely affected budgerigars, and fresh-impression smears of the ventricular and proventricular mucosa were prepared and observed unstained and stained by Giemsa and Gram's methods using light microscopy. Tissue samples for histopathology were taken from the proventriculus, gizzard, intestine, liver, spleen and lung, fixed in 10%-buffered formalin, and processed by standard paraffin wax technique. Sections were stained with H&E, Brown-Brenn and PAS methods. At necropsy, atrophy of the pectoral muscle, thickening of the proventricular and ventricular wall, covering of the proventricular mucosa by thick white mucus, ulceration and haemorrhage of the proventricular mucosa, and loosening of the koilin layer were observed. The most severe histopathological lesions were observed in the proventriculus and gizzard, especially at the proventricular-ventricular junction, including penetration of an organism to the lumen of the superficial proventricular crypts and occasionally to deeper parts of the glands; lymphocytic-plasmacytic proventriculitis, lymphocytic-plasmacytic ventriculitis and disruption of the koilin layer were also noted. The organism was gram-positive, PAS-positive and acidophilic in Gram's, PAS and Giemsa stained sections, respectively. Other birds in the colony were treated with nystatin after which, the rate of mortality decreased and reached zero. At necropsy of treated birds, no megabacteria were observed in smears and tissue sections. In conclusion, definitive diagnosis of megabacteriosis is most consistently demonstrated by histopathology and fresh smear of the proventricular mucus. An effective treatment is antifungal agents such as nystatin. [ABSTRACT FROM AUTHOR]

The article provides information on a study which examined ostrich gastric dysfunctions diagnosed at the Escola de Veterinária at the Universidade Federal de Minas Gerais from 1997 to 2009. The study analyzed clinical records with data of necropsies, clinical and laboratory results collected from 1997 to 2009. The analysis of the records showed that 46.2% of diagnosed dysfunctions in ostriches were gastroenteric diseases and 53.9% were dysfunctions of various origins.

A total of 312 post-mortem examinations of 178 canaries (Serinus canarius domesticus), 40 parakeets (Melopsittacus undulatus, Nymphicus hollandicus) and 94 parrots (Amazona aestiva, Psitaccus erithacus) were conducted at the Birds and Rabbits Service of the University of Liège, Belgium. After a detailed gross examination, tissue samples were collected for virological and/or bacteriological and/or parasitological examination to complete the diagnosis. In all cases, a microscopic examination of the proventricular mucus layer was undertaken for the detection of the anamorphic ascomycetous yeast Macrorhabdus ornithogaster, which causes the non-zoonotic but important disease in cage birds known as megabacteriosis. At the time of death, megabacteriosis was diagnosed respectively in 28% of canaries and 22.5% of budgerigars (P value for Fisher's exact test = 0.5576), but was not diagnosed in parrots (P value for Fisher's exact test <0.0001). The incidence of megabacteriosis significantly increases along the years (P value for χ² test <0.0001, Cramer's coefficient = 0.3405). The most common gross lesions seen at necropsy of the 59 megabacteriosis cases was proventricular dilatation (86.1%). All the birds diagnosed as typical megabacteriosis cases were free of Salmonella spp. infections and of any parasitic infections. Four megabacteriosis cases (three canaries, one parakeet) were not included in statistical analysis as salmonellosis, pseudotuberculosis, coccidiosis and chlamydophilosis were diagnosed concomitantly in these birds. With the exception of megabacteriosis, the most frequent causes of death were protozoan (coccidiosis, lankesterellosis) infections (18.4%) and salmonellosis (17.1%) in canaries, and psittacosis (31.5%) and viral hepatitis (26.3%) in parakeets. In parrots, the most common causes of death were psittacosis (28.6%) and aspergillosis (28.5%). [ABSTRACT FROM AUTHOR]

Macrorhabdus ornithogaster (MO) is an infectious fungus that causes gastric damage in birds. In this study, we established nested and seminested polymerase chain reaction (PCR) methods that specifically amplify the domain D1/D2 region (D1/D2) of 26S ribosomal DNA (rDNA), internal transcribed spacer (ITS) of rDNA, and intergenic spacer (IGS) 1 region from avian feces. Phylogenetic analysis of MO collected from Japanese pet birds showed little genetic variation; analysis based on these regions did not distinguish between host species order, differences in MO shape, or host gastrointestinal symptoms. These regions were found to be unsuitable for molecular epidemiological studies of MO and further investigation into other genetic regions is required.

Its report the first documented case of megabacteriosis occurred in a commercial of budgerigars (Melopsittacus undulatus) in the Municipality of Itaporanga D'Ajuda -- Sergipe -- Brazil. [ABSTRACT FROM AUTHOR]

Over a 4-mo period, a Michigan zoo had 32 budgerigars, Melopsittacus undulatus, from their flock die. Whole animals or formalin-fixed tissues were submitted to Michigan State University Veterinary Diagnostic Laboratory for diagnosis. Avian gastric yeast infection, Macrorhabdus ornithogaster, was diagnosed in seven birds. There was atrophy of breast musculature and no subcutaneous or coelomic fat stores in six necropsied birds. Only two birds had proventricular dilatation grossly. Histologic examination of the proventriculus of all seven birds revealed abundant 3 × 50-µm septate, parallel-walled, nonbranching yeast organisms morphologically consistent with Macrorhabdus ornithogaster. Mycobacteriosis was diagnosed in three budgerigars, two of which were necropsied. Both necropsied birds had hepatomegaly and one also had splenomegaly. No acid-fast bacilli were found in the livers of either bird but were found in splenic macrophages of the bird with splenomegaly and in the intestine of the other bird. Mycobacterium species were cultured from the enlarged spleen and identified by DNA sequence as Mycobacterium genavense. Pulmonary granulomas with acid-fast bacilli were found in the bird submitted as fixed tissues. None of the budgerigars had a dual infection. The remainder of the budgerigars died from hepatitis, nephrosis, oviductal prolapse, exclusion from food and water by flock mates, or tumors.