Outbreak of Avian Tuberculosis in Commercial Domestic Pekin Ducks ( Anas platyrhynchos domestica)

Identification and Phylogenetic Analysis of Mycobacterium avium subsp. avium Strain Isolated from Cow

Mycobacterium avium subsp. avium (MAA) is the main tuberculosis pathogen of poultry and wild birds. MAA can also infect mammals such as pigs, cattle, and horses and can pose a threat to people with low immunity. Here, we describe the first identification of MAA strain HJW isolated from a cow in Jilin Province, China. The isolate was completely sequenced and a phylogenetic analysis of its relationship to members of the Mycobacterium avium complex (MAC) was performed. The results revealed that strain HJW was type MAA based on the analysis of insertion sequence amplification and whole genome sequencing. The HJW genome size was 4,961,843 bp with a GC content of 69.28%. The strain was genetically most closely related to the Mycobacterium avium subsp. avium strain DSM 44156. This study suggests that MAA may pose an infection risk to cattle and provides data support for the phylogeny of Mycobacterium avium.

Mycobacterial Airsacculitis Caused by Mycobacterium fortuitum in a Southern Rockhopper Penguin (Eudyptes chrysocome)

A 21-year-old male southern rockhopper penguin (Eudyptes chrysocome) was presented with a chronic history of intermittently decreased appetite, lethargy, and regurgitation. On the external physical examination, the bird was determined to be in fair-to-thin body condition with the complete blood count and plasma chemistry panel being largely unremarkable. Full-body radiographic images were considered normal, and gastroscopy showed only mild gastritis and duodenitis. The penguin was euthanatized shortly thereafter due to acute onset of respiratory distress. During the gross necropsy examination, the bird had severe airsacculitis with thick, yellow-to-tan, moist granular plaques adhering to the surface of many air sacs, as well as regional contiguous pneumonia. Intralesional acid-fast bacilli were observed in histologic sections of air sac tissue, and polymerase chain reaction of the affected air sacs was positive for Mycobacterium fortuitum. This clinical case study describes mycobacteriosis in a sub-Antarctic penguin and to the best of the authors' knowledge, the first reported isolation of M fortuitum from a penguin.

Isolation of Mycobacterium avium and other nontuberculous mycobacteria in chickens and captive birds in peninsular Malaysia

Background

Mycobacterium avium complex (MAC) causes a chronic infectious in the birds known as avian mycobacteriosis. Almost all species of the birds are susceptible to MAC which consists of two closely related species of mycobacteria, that is, M. avium and M. intracellulare. This study aimed to determine the occurrence of Mycobacterium avium subsp. avium (MAA) in chickens and captive birds in selected states of Peninsular Malaysia.

Results

A 300 fecal samples were collected from village chickens (n = 100), layer chickens (n = 100) and captive birds (n = 100). Fecal samples were split into two aliquots for microbiological and molecular detection of MAA. Microbiology detection consisted of microscopy (Ziehl-Neelsen staining) and culture of samples decontaminated with 1% Cetylperidinium chloride and vancomycin, nalidixic acid and amphotericin B (VNA) antibiotic cocktail [vancomycin (VAN) 100 μg/ml, nalidixic acid (NAL) 100 μg/ml and amphotericin B (AMB) 50 μg/ml] onto Löwenstein-Jensen (L-J). Molecular detection (PCR-IS901) was performed to detect MAA DNA from the feces and PCR-16S rRNA and IS901 for identification of genus Mycobacterium and Mycobacterium avium sub species avium isolated onto L-J. All samples (296) were AFB negative smear. M. avium was isolated in 0.3% (1/296) samples by culture and detected in 2.5% (6/242) samples by PCR (IS901). Other mycobacteria were found in 1.7% (5/296) chickens. Of five isolates, two were identified as Mycobacterium terrae and M. engbaekii and remaining isolates were not sequenced. Birds positive for M. avium included White Pelican (n = 1) Black Hornbill (n = 1), Macaw (n = 2), Cockatoo (n = 2) and village chicken (n = 1).

Conclusion

It is concluded that chickens and birds were infected with M. avium in selected areas of Peninsular Malaysia. Although, PCR is rapid, reliable and cost effective method for detection of M. avium in a subclinical stage, the culture of the avian feces should still be used as a reference test for the diagnosis of avian tuberculosis.

Outbreak of avian mycobacteriosis in a commercial turkey breeder flock

Avian mycobacteriosis (AM) is a chronic and contagious disease of pet birds, captive exotic, wild and domestic fowl, and mammals. Mycobacterium avium subsp. avium is the most common cause of AM in poultry. For the first time, we report a chronic outbreak of AM in an Iranian breeder flock of 250 45-week-old turkeys (Meleagris gallopavo) with a morbidity and mortality rate of 91.6% and 80%, respectively. A well-defined clinical feature of the outbreak included a progressive weight loss, decreased egg production, listlessness, and lameness. Tuberculous nodules were seen on liver, spleen, ovary, and ribs. Granulomatous inflammation and acid-fast bacilli were confirmed by using Ziehl-Neelsen method on hepatic lesions. M. avium subsp. avium was identified by polymerase chain reaction techniques based on the presence of 16S ribosomal RNA gene and insertion elements IS1245 and IS901. In this report, we not only describe the epidemiological, pathological, and molecular characteristics of the outbreak in detail, but we also discuss multiple factors influencing the introduction and development of AM critically. In this case, wild feral pigeons might have been the source of infection, but further molecular-epidemiology studies are needed to understand the role of wild birds in the persistence and transmission of Mycobacterium.RESEARCH HIGHLIGHTS First report of avian mycobacteriosis in an Iranian commercial turkey flock is described in detail.Risk factors intrinsic to the bird and mycobacteria, as well as extrinsic factors influencing the introduction and development of avian mycobacteriosis in birds, are critically discussed.

Comparison of immunohistochemistry and Ziehl-Neelsen staining for detecting the distribution of Mycobacterium avium subsp avium in naturally infected domestic Pekin ducks (Anas platyrhynchos domestica)

In order to detect the distribution of Mycobacterium avium subsp avium (MAA) in naturally infected domestic Pekin ducks, immunohistochemistry (IHC) and Ziehl-Neelsen (ZN) staining were used and compared. Six organs, the liver, spleen, lung, kidney, duodenum and pectoralis muscle, were collected from naturally infected Pekin ducks. Paraffin embedded tissues were examined, and the results were compared. Statistical analysis was performed using Chi-Square test. The results showed that the detection rates by IHC were similar with ZN staining in liver, lung, spleen and pectoralis muscle, but the detection rates by IHC were much higher than ZN staining in kidney and duodenum (p = .013, p = .0044). The liver (87.5%) and lung (81.3%) had the highest detection rates. Acid-fast bacilli (AFB) were primarily found intracellularly in six organs using ZN staining. Similarly, the MAA antigens in those selected organs were also detected in the cytoplasm with different cell types. Specifically, MAA antigen was distributed in epithelioid macrophages and necrotic centres within the liver, lung, spleen and kidney, while they were observed in macrophages of the lamina propria and duodenal glands and degenerative myocytes in the pectoralis muscle. This comparative study provides an important insight into the distribution of MAA in infected domestic ducks and indicates that the detection rate by IHC was higher than that of ZN staining.

Amyloid A amyloidosis secondary to avian tuberculosis in naturally infected domestic pekin ducks (Anas platyrhynchos domestica)

To investigate the correlation between avian tuberculosis and duck amyloidosis, the liver, lung, spleen, kidney, duodenum and pectoralis muscle of ducks naturally infected with Mycobacterium avium subsp. avium were used to detect amyloidosis by Congo red staining and potassium permanganate-Congo red staining. The expression level of IL-1β, IL-6, IL-10, TNF-α and SAA2 were detected by quantitative real-time RT-PCR (qRT-PCR). The results showed that the liver, lung, spleen, kidney, duodenum and pectoralis muscle of the infected ducks exhibited amyloid proteins under ordinary light microscopy and the polarization light under polarized light microscopy. However, no amyloid deposition in potassium permanganate-Congo red staining sections indicated that the amyloidosis was AA amyloidosis. In addition, the expression level of IL-1β, IL-6, IL-10, TNF-α and SAA2 increased from 4 to 43. This study showed that avian tuberculosis could induce secondary amyloidosis in naturally infected ducks.

Complete Genome Sequence of Mycobacterium avium, Isolated from Commercial Domestic Pekin Ducks (Anas platyrhynchos domestica), Determined Using PacBio Single-Molecule Real-Time Technology

Mycobacterium avium is an important pathogenic bacterium in birds and has never, to our knowledge, reported to be isolated from domestic ducks. We present here the complete genome sequence of a virulent strain of Mycobacterium avium, isolated from domestic Pekin ducks for the first time, which was determined by PacBio single-molecule real-time technology.