Turkey Flocks Research Articles

Seromolecular study of chicken infectious anemia in chickens, ostriches, and turkeys in Iran

SUMMARY Until recently, the chicken has been considered the only natural host and the main host for chicken anemia virus (CAV). However, CAV infection has now been reported in other avian species, including Japanese quail, jackdaws, rooks, and rare avian breeds. In this study, we examined chickens, ostriches, and turkeys for seromolecular detection of CAV in Iran. For the study, 375 serum and thymus samples from chickens, 84 serum and blood samples from ostriches, and 100 serum and blood samples from turkeys were collected from various locations in Iran. Serum samples were examined using ELISA. Deoxyribonucleic acid was extracted from the thymus, and blood samples were analyzed for detection of the VP2 genome of CAV by PCR. According to these results, 69.07 and 58.4% of chickens were positive for the antibody to CAV and the VP2 genome of CAV, respectively. In addition, in ostriches 27.38 and 34.52% were positive for the CAV antibody and the CAV VP2 genome, respectively. In turkey flocks, all turkeys (100%) were negative with respect to detection of the VP2 CAV genome and CAV antibody. It was concluded that CAV is distributed in broiler chickens and ostriches throughout Iran. Furthermore, ostriches may be considered a reservoir of CAV, and turkeys appear not to be susceptible to CAV infection.

Characterization and antimicrobial resistance analysis of avian pathogenic Escherichia coli isolated from Italian turkey flocks

This study investigated the occurrence of avian pathogenic Escherichia coli (APEC) in a finishing turkey commercial farm, carrying out longitudinal surveys involving 3 consecutive flocks. The diversity and the distribution of the E. coli strains detected during colisepticemia outbreaks were examined. The strains were isolated, serogrouped, assessed for the presence of virulence-associated genes, typed by random amplification of polymorphic DNA (RAPD), and antimicrobial resistance analysis was then carried out. Escherichia coli O78 and O2 were predominantly found. Moreover, based on the somatic antigens used in the study, strains were recovered that were nontypeable. On one occasion, an E. coli O111 strain was found in turkeys. The E. coli isolates differed in terms of antibiotic resistance and RAPD profile. All strains possessed the virulence genes that enabled them to be considered APEC. Strains not only differed between flocks, but also within the same flock. These findings point out the importance of addressing colibacillosis therapy on the basis of a sensitivity test.

The occurrence of enteric viruses in Light Turkey Syndrome

Two studies were conducted to determine the role of enteric viruses in Light Turkey Syndrome (LTS), which is characterized by lower weight in market age turkeys than their standard breed character. In the surveillance study, we selected four LTS and two non-LTS turkey flocks in Minnesota and collected faecal samples at 2, 3, 5 and 8-weeks of age. Astrovirus, rotavirus, and reovirus were detected alone or in various combinations in both LTS and non-LTS flocks. No coronavirus was detected in LTS flocks and no corona- or reovirus was detected in non-LTS flocks. In the second study, 2-week-old turkey poults were divided into two groups; Group A (challenged) was inoculated orally with 10% pooled faecal suspension from LTS flocks and group B (control) was inoculated with phosphate buffered saline (PBS). Clinical signs of depression, huddling, and lack of uniform size were observed in the challenged group but not in the control group. diarrhoea was observed in both groups but was more severe in the challenged group than in the control group. Birds in the challenged group shed astrovirus, rotavirus and reovirus, while the control group shed only astrovirus. Virus shedding in both groups was observed for up to nine weeks of age. Significantly lower body weights were seen in the challenged group starting at seven weeks of age and lasting until 20 weeks of age. These findings suggest that viral enteritis at an early age may set up conditions for the development of LTS in adult turkeys.

Salmonella Prevalence in Turkey Flocks before and after Implementation of the Control Program in Germany

The objective of the study was to describe the Salmonella prevalence in turkey flocks before and after the implementation of the Salmonella control program in Germany and to identify factors that are potentially associated with the presence of Salmonella in the flocks. To achieve this, all breeding flocks and a representative sample of the fattening flocks were tested for Salmonella. None of the 98 turkey breeding flocks but 31 (10.3%) of 300 turkey fattening flocks were positive for Salmonella spp. in the baseline study during 2006/2007. In 11 (3.7%) fattening flocks S. Enteritidis (1 flock; 0.3%) or S. Typhimurium (8 flocks; 2.7%) or monophasic S. Typhimurium (2 flocks; 0.3%), which are of special public health relevance in Germany, were detected. Logistic regression analysis confirmed that production type and season were significant risk factors for the presence of Salmonella spp. in fattening turkey flocks in Germany. Data from mandatory official testing within the Salmonella control program in 2010 and 2011 revealed that Salmonella prevalence in turkey fattening flocks has decreased significantly to 3.3% and 2.6%. In line with this result, prevalence of S. Enteritidis or S. Typhimurium had decreased to 2.6% and 1.5%. Results indicate that the prevalence of Salmonella in turkey fattening flocks has decreased significantly.

Effect of in-feed paromomycin supplementation on antimicrobial resistance of enteric bacteria in turkeys

Histomoniasis in turkeys can be prevented by administering paromomycin sulfate, an aminoglycoside antimicrobial agent, in feed. The aim of this study was to evaluate the impact of in-feed paromomycin sulfate supplementation on the antimicrobial resistance of intestinal bacteria in turkeys. Twelve flocks of breeder turkeys were administered 100ppm paromomycin sulfate from hatching to day 120; 12 flocks not supplemented with paromomycin were used as controls. Faecal samples were collected monthly from days 0 to 180. The resistance of Escherichia coli, Enterococcus faecium and Staphylococcus aureus to paramomycin and other antimicrobial agents was compared in paromomycin supplemented (PS) and unsupplemented (PNS) flocks.E. coli from PS birds had a significantly higher frequency of resistance to paromomycin, neomycin and kanamycin until 1month after the end of supplementation compared to PNS birds. Resistance to amoxicillin or trimethoprim–sulfamethoxazole was also more frequent in PS turkeys. Resistance was mainly due to the presence of aph genes, which could be transmitted by conjugation, sometimes with streptomycin, tetracycline, amoxicillin, trimethoprim or sulfonamide resistance genes. Resistance to kanamycin and streptomycin in E. faecium was significantly different in PS and PNS breeders on days 60 and 90. Significantly higher frequencies of resistance to paromomycin, kanamycin, neomycin and tobramycin were observed in S. aureus isolates from PS birds. Paromomycin supplementation resulted in resistance to aminoglycosides in bacteria of PS turkeys. Co-selection for resistance to other antimicrobial agents was observed in E. coli isolates.

Enteric viruses in Brazilian turkey flocks: Single and multiple virus infection frequency according to age and clinical signs of intestinal disease

Poult enteritis complex has been associated with enteritis and reduction in growth rates in commercial turkeys worldwide. Intestinal samples from 76 turkey flocks from different Brazilian states affected or not with intestinal disorders were evaluated for the presence of adenovirus groups 1 and 2 (TAV), astrovirus types 1 and 2 (TAstV-1 and TAstV-2), turkey coronavirus (TCoV), reovirus, rotavirus, and avian nephritis virus (ANV) using PCR. The percentage of positive samples was categorized according to the geographic origin, age of the flocks, and presence of clinical signs of intestinal disease. The percentage of samples that were positive for at least one virus was 93.4%, whereas the percentage of samples that were positive for more than one virus was 69.7%. An average of 3.20 viruses per sample was detected in turkeys in the growing phase of the production cycle (1 to 4 wk of age). The TAstV-1 and TCoV were the most frequently observed viruses in growing phase turkeys and occurred simultaneously in 85% of these samples. In turkeys in the finishing phase of development (5 to 18 wk), a lower average number of viruses was observed (2.41), and the most frequent viruses isolated in these turkeys were TAstV-1 (57.1%) and rotavirus (51.8%). Overall, every virus was detected more frequently in growing phase turkeys than in finishing phase turkeys with the exception of TAV. Samples from flocks exhibiting clinical signs of intestinal disease showed a higher rate of positivity, and TAstV-1, TAstV-2, and TCoV were the most frequently occurring viruses in this cohort. Birds without clinical signs most frequently harbored TAstV-1 and rotavirus. Future studies should focus on the description and elucidation of the role of each virus, as well as the pathogenic and immunological implications of the different combinations of viruses in turkeys.

Detection of Genetic Diversity in Campylobacter jejuni Isolated from a Commercial Turkey Flock Using flaA Typing, MLST Analysis and Microarray Assay

Campylobacter is genetically highly diverse and undergoes frequent intraspecific recombination. Turkeys have been identified as an important reservoir for Campylobacter jejuni which is of public health significance. The assessment of the genetic diversity among Campylobacter population is critical for our understanding of the epidemiology of this bacterium. The genetic profiles were different according to the molecular typing methods used. The performance of established flaA genotyping, multilocus sequencing typing (MLST) and DNA microarray assay based on the ArrayTube™ technology was evaluated using 14 Campylobacter jejuni isolated from a commercial turkey flock. The flaA typing was performed using PCR-RFLP with restriction enzymes Sau3AI, AluI, a ‘composite’ flaA analysis of AluI and Sau3AI and DdeI. The 14 isolates were differentiated into 3, 5, 7 and 9 genotypes, respectively. Entire flaA gene and short variable region (SVR) sequences were analysed. Sequencing of the entire flaA provided 11 different genotypes. flaA-SVR sequence analysis detected 8 flaA alleles and 4 flaA peptides. One new flaA allele type (528) was identified. MLST analysis represented 10 different sequence types (STs) and 5 clonal complexes (CCs). The microarray assay recognised 14 different genotypes. The discriminatory indices were 0.560, 0.802, 0.857, and 0.912 for flaA-RFLP depending on the used enzymes, 0.890 for flaA-SVR, 0.967 for entire flaA sequencing, 0.945 for MLST and 1.00 for the DNA microarray assay. The flaA gene was genetically stable over 20 passages on blood agar. In conclusion, the different typing tools demonstrated a high level of genetic heterogeneity of Campylobacter jejuni in a turkey flock, indicating that a single flock can be infected by multiple genotypes within one rearing cycle. DNA microarray-based assays had the highest discriminatory power when compared with other genotyping tools.

Occurrence of vancomycin-resistant enterococci in turkey flocks

In the present study, the prevalence of vancomycin-resistant enterococci (VRE) in turkeys in the southwest of Germany was investigated. For this purpose, 200 cloacal swab samples and 5 environmental dust samples (tested as a pooled sample) of each of the 20 flocks (10 female and 10 male flocks) included in this study were examined. The VRE could be isolated by means of a procedure combining bacterial cultivation in an enrichment broth and on a selective solid media. Enterococci were identified biochemically and subsequently tested on the presence of the vancomycin resistance genes vanA, vanB (B1/B2/B3), and vanC (C1/C2/C3) using real-time PCR assays. In 54 (27%) turkeys originating from 11 (55%) flocks and in 14 (70%) of the dust samples, exclusively vanA and vanC1 genes could be detected. Of the turkeys examined, 46 were colonized with VRE bearing the resistance gene vanC1 and 8 vanA, originating from 9 and 2 flocks, respectively. None of the birds carried vanB, vanC2, or vanC3 positive VRE. The results obtained from the birds are largely confirmed by the dust samples originating from 4 vanA and 10 vanC1 positive flocks. However, one flock housing animals colonized with vanC1 positive VRE could not be confirmed by the dust samples that revealed vanA bearing VRE. However, in one case vanA and in 3 cases vanC1 carrying VRE could be detected in dust samples of the turkey houses, but not in the turkeys of the associated flock. In 5 flocks the turkeys as well as the dust samples were free of VRE.

Prevalence of skin lesions in turkeys at slaughter

1. The aims of this study were (i) to evaluate the prevalence of welfare-related cutaneous lesions in turkeys at the end of the rearing period and (ii) to study the correlations between lesions. 2. The percentage of lesions in each flock was determined by observation at the slaughterhouse. Sixty flocks were investigated in 13 slaughterhouses between April and July 2006. 3. All flocks showed a high proportion of turkeys with footpad lesions, with 40·7% of turkey flocks having severe footpad dermatitis. A significant number of feet had swelling of the footpad and deviated toes (60·0% and 21·4% respectively). Arthritis was observed in 25·4% of the carcases and an average of 30·1% had breast buttons on the keel. 4. Positive correlations were found between evidence of feather pecking and arthritis, toe deviations and swelling of the footpad. Deviated toes, swelling of the feet and feather pecking were negatively linked to the most severe scratches (P < 0·001). 5. A method is proposed to assess turkey welfare at the slaughterhouse based on several criteria: footpad lesions, arthritis, severe scratches, deviated toes, swelling of the footpad and breast buttons.

Risk Factors and Characteristics of Low Pathogenic Avian Influenza Virus Isolated from Commercial Poultry in Tunisia

ObjectiveEstimate the seroprevalence of influenza A virus in various commercial poultry farms and evaluate specific risk factors as well as analyze their genetic nature using molecular assays.Materials and MethodsThis report summarizes the findings of a national survey realized from October 2010 to May 2011 on 800 flocks in 20 governorates. Serum samples were screened for the presence of specific influenza virus antibodies using cELISA test. Additionally, swab samples were tested by real time and conventional RT-PCR and compared with results obtained by others assays. Phylogenetic and genetic analyses of the glycoproteins were established for some strains.ResultsOut of the 800 chicken and turkey flocks tested by cELISA, 223 showed positive anti-NP antibodies (28.7%, 95% CI: 25.6–32.1). Significantly higher seroprevalence was found among the coastal areas compared to inland and during the autumn and winter. Broiler flocks showed significantly lower seroprevalence than layers and broiler breeders. The influenza virus infection prevalence increased after the laying phase among layer flocks. In addition, AIV seropositivity was significantly associated with low biosecurity measures. The Ag EIA and rRT-PCR tests revealed significantly higher numbers of AI positive samples as compared to cell cultures or egg inoculation. All new strains were subtyped as H9N2 by real time and conventional RT-PCR. Drift mutations, addition or deletion of glycosylation sites were likely to have occurred in the HA and NA glycoproteins of Tunisian strains resulting in multiple new amino acid substitutions. This fact may reflect different evolutionary pressures affecting these glycoproteins. The role of these newly detected substitutions should be tested.ConclusionOur findings highlight the potential risk of AIV to avian health. Strict enforcement of biosecurity measures and possible vaccination of all poultry flocks with continuous monitoring of poultry stations may ensure reduction of AIV prevalence and avoid emergence of more pathogenic strains.

Micromorphological changes on the embryonic membranes of turkey eggs infected with Aspergillus fumigatus and their importance for embryonic survival

Aspergillosis is a frequent fungal disease of young and adult poultry in our commercial flocks. Infection can occur after hatching by inhalation of Aspergillus conidia which can be present in contaminated hatcheries, or later, by spores from moldy litter, dust, faeces or feed. Spores from the surface of egg shell can penetrate inside of an egg. The main characteristic of aspergillosis is granulomatous inflammation of respiratory system, although generalized form is possible as well. Multiple yellow nodules can be seen as major patomorphological changes and they are usually localized in lungs, air sacs, and can also be found in spleen, brain, subcutis and eyes. Egg embryos are quite susceptible to infection by Aspergillus fumigatus during incubation. In this study, the history of a case on one local farm with mortality rate of 7.2% in the turkey flock is presented. At the same time, 28 day old 30 incubated hatching turkey eggs were sampled, that were unable to hatch. The aim of the present work was to determine the cause and to identify the agent of embryonic mortality. Total of the 30 eggs were opened, and 16 of them had thickened egg membranes in the area of air sac. Membrane thickening was visible and circumscript or diffuse presence of black-grey or grey-green fungal growth was observed. Only 3 samples air sacs were filled with developed stages of fungi. To evaluate histopathological lesions, changed egg membranes were processed by standard histological technique. Dominant microscopic finding was thickening of egg membranes as a consequence of fungal growth and many of them penetrated deep towards embryo. Most of the hyphae were growing vertically through membranes. On the outside surface of the membranes, the elements of fungi (conidial heads with phialids and spores on them), could be clearly observed. These changes were responsible for embryonic death, which on the basis of the size of dead embryos occurred between 7th and 10th day of incubation. Aspergillus fumigatus was isolated and identified from the content of air sacs.

Correlation between the limit values of laboratory and clinical mycotoxicosis

Analysis of feed for the presence of fungi and mycotoxins is a request necessary to meet in order to ensure a healthy and economical production in livestock. These tests are related to legal regulation which prescribes the maximum legislated content (MLC), both for the presence of mycotoxins and the total number of fungi in certain feeds. Health problems that can occur during the production of animals are sometimes caused by the presence of mycotoxins in the feed. Laboratory testing is a good practice to confirm a suspicion, and allows timely treatment of contaminated feed. Potential problems arise under circumstances when there is a clinical outcome of mycotoxicosis and animal and laboratory findings suggest that the obtained values are below the level that is within the MLC. For these reasons, the subject of our research was to investigate the occurrence of mycotoxins and mold in feed, as well as the clinical presentation for animals that were fed with the feed with allowed values of these agents according to the recommended levels. The aim of this paper was to highlight the problems associated with clinical correlation of sick animals and laboratory findings, and suggest their overcoming. In the period of one year, a total of 176 samples of feed (complete mixture for broilers, corn and soy products) were examined for the presence of fungi, 106 samples were examined for the presence of mycotoxins and 26 flocks of broilers and turkeys were clinically observed. Standard methods were used for isolation of molds and the ELISA test was used for the detection of mycotoxins. Clinical and pathomorphological observation of the flocks was done to determine the natural indicators of production. Studies indicated a problem because clinical and pathomorphological findings in some cases were not correlated with laboratory findings of molds and mycotoxins in the feed, and in some cases it did not necessarily mean that the animals were healthy. Synergism and cumulative effects of mycotoxins, on the one hand, and the characteristics of each species and product category on the other hand, can create specific circumstances that can lead to disease and can increase even though the values prescribed by legislation have been met.

Evaluation of different diagnostic tools for the detection and identification of Riemerella anatipestifer

Riemerella anatipestifer (RA) is an important avian pathogen with considerable impact on poultry production worldwide. However, the diagnosis of RA infections may be difficult, mainly due to problems with unequivocal differentiation of RA from other Flavobacteriaceae and a lack of standardized methods and reagents. The aim of the present study was therefore to complement the routine diagnostic strategies for RA by design and evaluation of alternative diagnostic tools. We designed and validated a new RA-specific polymerase chain reaction assay, which proved to be a valuable tool for the identification of RA isolates as well as for rapid and sensitive RA detection directly from diagnostic samples. Matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry fingerprinting of whole bacterial cells was also demonstrated to identify RA isolates efficiently. Furthermore, this method may also provide opportunities for RA subtyping. In our study, a stable subcluster was formed by the mass spectroscopy profiles of a group of RA isolates originating from turkey flocks in northern Germany, suggesting an epidemiological relationship of these isolates. Serotyping is a further important measure to characterize RA isolates. We tested a set of commercially available anti-RA sera with RA serotype reference strains and field isolates to allow comparison between these sera and reference sera. In summary, this report contributes to the improvement of present microbiological and molecular strategies for the diagnosis of RA infections by providing new tools as well as enhanced knowledge on existing methods.

A Longitudinal Study on Thermophilic Campylobacter spp. in Commercial Turkey Flocks in Northern Italy: Occurrence and Genetic Diversity

Poultry are recognized as a main reservoir of thermophilic campylobacters, but few studies have been carried out on commercial meat turkeys. This study was aimed at assessing the occurrence of thermophilic Campylobacter spp., their genetic diversity, and the trend of the infection during the whole production cycle of three turkey flocks from different farms in Northern Italy. Flocks were monitored from the time of housing 1-day-old poults to slaughter time by collecting samples (meconium and cloacal swabs) at weekly intervals up to the recovery of Campylobacter spp. and then twice a month. A conventional culture method and a multiplex PCR assay were used for Campylobacter detection and identification. A subset of isolates was genetically characterized by random amplified polymorphic DNA-PCR (RAPD-PCR) and flagellin gene A short variable region (flaA-SVR) sequencing. Although at different times, all flocks became colonized by Campylobacter jejuni or Campylobacter coli (or both) that persisted throughout the entire production cycle. Overall, nine RAPD types and 14 flaA-SVR types were detected with differences in their distribution among flocks and sampling times. Moreover, changes in the Campylobacter genotypes colonizing turkeys were observed over time within each flock. These findings suggest that Italian commercial turkeys might be widely colonized by different genotypes of C. jejuni and C. coli and also suggest that differences in the distribution and epidemiologic dynamics of these microorganisms might occur among flocks.

Prevalence of Parvoviruses in Commercial Turkey Flocks

Prevalence of Parvoviruses in Commercial Turkey Flocks

A Longitudinal Study on Thermophilic Campylobacter spp. in Commercial Turkey Flocks in Northern Italy: Occurrence and Genetic Diversity

A Longitudinal Study on Thermophilic Campylobacter spp. in Commercial Turkey Flocks in Northern Italy: Occurrence and Genetic Diversity

Molecular Epidemiology of Salmonella Enterica Serovar Saintpaul Isolated from Animals, Food, and Humans in 12 European Countries

Abstract The molecular epidemiological relationship among isolates of Salmonella enterica serovar (S.) Saintpaul, which was identified in animals, food, and humans in several EU countries, was investigated. Pulsed-field gel electrophoresis (PFGE) revealed a high degree of genetic diversity (82 XbaI PFGE profiles with 42.6% similarity) among 159 S. Saintpaul isolates from animals (n=91), food of animal origin (n=29), and humans (n=36) in 12 European countries during 2005 to 2009. Most frequent profiles (n=12) comprised almost 50% of the tested isolates. Profiles obtained in isolates from a single source within a particular geographical region or particular period of time were indistinguishable or closely related. Turkeys were confirmed as the major reservoir for S. Saintpaul. Indistinguishable PFGE profiles were identified in up to 19 isolates from turkey breeding and fattening flocks and food over the study period. Other animals, including food and pets, may also contribute to S. Saintpaul spread. International trade of animals and food, as well as travelling contributes to the spread of a specific clone to different geographical areas. Although control programmes in breeding turkey flocks, together with improved biosecurity, may interrupt the major transmission routes, it was concluded that S. Saintpaul will continue to represent a potential threat to human health.

Prevalence of Parvoviruses in Commercial Turkey Flocks

Turkey parvovirus belongs to the family Parvoviridae, subfamily Parvovirinae, Genus parvovirus. Since the initial report on turkey parvovirus in the United States appeared in 1983, there had been no further reports of parvovirus in turkeys until 2008. The aims of our study were to determine the prevalence of parvovirus in commercial turkey flocks using PCR; to determine their genetic relationship to previous strains identified in North America and Europe; and to test samples for enteric viruses by transmission electron microscopy (TEM). A total of 169 fecal samples collected from 42 turkey farms in four different states within the United States between 2000 and 2010 were examined. We found that the most frequently detected viruses by TEM were small round viruses, accounting for 52% of the examined samples; however, the PCR detected parvoviruses in 71% of the samples. The phylogenetic analysis of partial nonstructural gene sequences showed a certain degree of variability among the turkey samples tested in the study. Moreover, there was a clear dichotomy in the phylogenetic tree between chicken and turkey samples, with the exception of one turkey isolate from 2000, which clustered together with the chicken group.

Determination of Antimicrobial Sensitivities of Campylobacter jejuni Isolated from Commercial Turkey Farms in Germany

The emergence of antimicrobial resistance among Campylobacter isolates recovered from turkeys has increased dramatically. Monitoring the progress of this resistance becomes a growing public health issue. The aim of the present study was to provide information of the current status of antibiotic resistance patterns in Campylobacter jejuni from turkeys. Seventy-six C. jejuni isolates were recovered from 67 epidemiologically unrelated meat turkey flocks in different regions of Germany in 2010 and 2011. The isolates were typed by flaA genotyping and were investigated for antimicrobial susceptibility against 12 antibiotics by using a broth microdilution test as well as testing the genetic determination of ciprofloxacin, tetracycline, and erythromycin resistance. All isolates (n = 76) were sensitive to gentamicin and chloramphenicol. The numbers of isolates that were sensitive to streptomycin, erythromycin, neomycin, and amoxicillin were 69 (90.8%), 61 (80.2%), 58 (76.4%), and 44 (57.9%), respectively. Only one isolate was sensitive to all tested antibiotics. The emergence of a high resistance rate and multidrug resistance to three or more classes of antimicrobial agents were observed. The resistance against sulphamethoxazole/trimethoprim, metronidazole, ciprofloxacin, naladixic acid, and tetracycline was 58 (76.3%), 58 (76.3%), 53 (69.7%), 51 (67.1%), and 42 (55.3%), respectively. None of the isolates was resistant to all antibiotics. Multidrug resistance to three or more classes of antimicrobial agents was found and ranged from 3.9% to 40.8%. Replacement of the Thr-86-->Ile in gyrA gene and detection of the tet(O) gene were the main resistance mechanisms for fluoroquinolones and tetracycline, respectively, while the lack of mutation in position 2074 and 2075 on the 23S rRNA gene was responsible for macrolide resistance. The phenotypic and genotypic resistance profiles were compatible in the case of ciprofloxacin and tetracycline but were not completely congruent with respect to erythromycin.

A low-pathogenic avian influenza H6N1 outbreak in a turkey flock in France: a comprehensive case report

Based on a case observed and investigated on a commercial turkey farm in western France in 81-day-old birds, we report the pattern of H6N1 low-pathogenic avian influenza in this species. Diseased birds displayed an acute severe dyspnoea, leading to death by asphyxia of more than 5% of the flock. The most specific pathological feature was a constant diffuse infraorbital sinusitis, along with a focal necrotic exudate inside the lumen of the upper respiratory tract, characterized microscopically as a mixed fibrinous and leucocytic material. Influenza A immunohistochemistry revealed an intense staining of epithelial cells in tracheas, bronchi, air sacs and their luminal necrotic material. While no primary bacterial infection could be detected from diseased turkeys, influenza H6 reverse transcription-polymerase chain reaction analysis performed on tracheal swabs tested positive. Direct sequencing and phylogenetic analysis of the eight segments showed that this H6N1 virus clustered closely within West European mallards' (group 3) H6 genotypes. A thorough analysis of genetic databases suggests that a regional waterfowl reservoir is likely to play a central role in H6 introductions in poultry farms, whose pathways remain to be elucidated.