Akabane virus (AKAV) has been detected in a variety of host species in China, but there are only limited records of its occurrence in goats. However, more attention needs to be paid to understanding the diversity of viruses in this species. The aim of the study was to explore the genotype characteristics and variation trend of AKAV and their relationship with virulence in Yunnan, China.

In recent years, Shewanella putrefaciens, commonly known as a halophilic bacteria, has been associated with serious health disorders in freshwater fish. Therefore, it has been described as a new aetiological agent of the disease, named shewanellosis. S. putrefaciens is a heterogeneous group of microorganisms, belonging to the Alteromonadaceae family. Based on different criteria, three biovars and biogroups as well as four genomic groups have been distinguished. The first infections of S. putrefaciens in fish were reported in rabbitfish (Siganus rivulatus) and European sea bass (Dicentrarchus labrax L.). Outbreaks in farmed fish were reported in Poland for the first time in 2004. The disease causes skin disorders and haemorrhages in internal organs. It should be noted that S. putrefaciens could also be associated with different infections in humans, such as skin and tissue infections, bacteraemia, otitis. Investigations on pathogenic mechanisms of S. putrefaciens infections are very limited. Enzymatic activity, cytotoxin secretion, adhesion ability, lipopolysaccharide (LPS), and the presence of siderophores are potential virulence factors of S. putrefaciens. Antimicrobial resistance of S. putrefaciens is different and depends on the isolates. In general, these bacteria are sensitive to antimicrobial drugs commonly used in aquaculture.

Ornithobacterium rhinotracheale (ORT), is a bacterium that cause respiratory tract infection, has led to significant problems in the intensive poultry production. The current study aimed to isolate and identify ORT from broiler chickens, to detect antibacterial sensitivity and resistance of ORT isolates, and to test experimental infection of ORT in broiler chickens. One hundred eighty samples including tracheas, lungs and air sacs were subjected to isolation and phenotypic identification. Twelve suspected ORT isolates were used for molecular identification. Agar gel precipitation test was used to determine serotype of ORT isolates. Antibacterial sensitivity and resistance of ORT isolates were tested against 14 antibacterial drugs using standard disk diffusion technique. Pathogenicity of ORT was tested by experimental infection in broiler chickens. Results revealed that the incidence of ORT infection in broiler chickens in Assiut Governorate is 17.77% using isolation and phenotypic methods of identification, while it is 3.33% using molecular identification. Serological identification of ORT isolates indicated that all tested isolates, were belonged to serotype A. All ORT isolates were resistant to gentamycin, amoxycillin and cephradine with 100% incidence, where, 100% isolates were sensitive to colistin and doxycycline, 50% of isolates were sensitive to ampicillin and streptomycin, and 16.67% of isolates were sensitive to neomycin and trimethoprim. Living Newcastle attenuated vaccine, Lasota vaccine, exaggerates the clinical signs and lesions of ORT experimental infection.

The pathogenic effect of representative local isolates of Aeromonas organisms was studied on 1٠0 native breed chickens. At 2 weeks of age, one hundred chicks were grouped into four equal groups (1-4); 25 birds each; after collection of fecal from all groups, examined and proved to be free from Aeromonas species. All groups were subcutaneously (s.c) inoculated with 0.5 ml containing 9×105 cfu /bird. Group 1 of chickens was infected by A. hydrophila; while group 2 was infected with A. caviae. The third group was infected with A. sobria; while, chicks of Group 4 were kept as non infected control. Results were showed mild clinical signs in some birds in theform of alternative diarrhea. Post mortem lesions showed general congestion of all carcasses. In severely emaciated cases the lesions were confined to the intestine, which filled with watery fluid and distended with gas. Results of Aeromonas reisolation revealed that all collected weekly fecal swabs were positive. While, percentage of A. hydrophila and A. caviae was 100% out of all testedorgans, while isolation of A. sobria was 100%, 100% and 80% from liver, intestine and heart; respectively. Histopathological examination of infected chicken organs showing focal coaggulative necrosis in liver with mononuclear cells infiltration that varied in severity between groups as less severe in A. hydrophila (Gr.1) than A. caviae (Gr. 2), while A. sobria (Gr. 3) was markedly affected showing severe degenerated and dissociated hepatocytes. Intestinal changes were severe in group 3 than 2 while group 1 showing the mildest comparatively the changes was consist of necrosed mucosa, gland with leucocytic infiltration in lamina propria. Under thecondition of our study we can conclude that the used Aeromonas isolates from field diseased chickens were of mild pathogenicity to s.c. inoculated 12 days old Fayoumi chicks with long course affection.

This study was carried out to investigate the prevalence, molecular characterization and pathogenicity of field infectious bursal disease virus (IBDV) isolates. Nine isolates of IBDV were isolated from 13 naturally infected broiler flocks. Detection of IBDV antigen was carried out by agar gel precipitation test (AGPT), followed by virus isolation in specific pathogen free (SPF) embryonated chicken eggs (ECE) and finally molecularly characterized and identified using reverse transcriptase polymerase chain reaction (RT-PCR). The obtained nine strains of IBDV by RT-PCR were further classified by using restriction fragment length polymorphism (RFLP) technique into (4) classical, (3) variant and (2) very virulent (vv) IBDV serotype (I). The pathogenicity of the isolated IBDV strains was detected by three passages in SPF ECEs and by experimental infection of one hundred 14 days old maternally immune layer chicks. The results showed that the mortality rate of the embryos was increased by increase the number of passages till the third passage where it reached 100% for all IBDV strains and the embryos showed typical lesions of IBDV. Chicks inoculated with variant IBDV strains showed morbidity rates of 60-80 %, without mortalities. Sacrificed birds showed atrophied bursae and thymus glands and enlarged thickened proventriculus. Groups infected with classical IBDV strains showed morbidity rates 40- 60,% with mortality 0-20%. The detectable lesions were muscular hemorrhages with variable bursal lesions. Inoculated chicks with vvIBDV strains showed 50-70% morbidity and mortality of rate was 30% with lesions of muscular hemorrhages, severe nephrosis with ureates in the ureters, hemorrhagic bursitis and pin point hemorrhages on the proventricular glands. Control negative non-infected group showed neither clinical signs nor mortalities along the observation period. The histopathological effect (lesion score) of IBDV strains on the bursa, spleen and thymus glands confirmed the previously mentioned results and revealed that the highest severity (score) for these organs were induced by vv IBDV strains.

A disease characterized by papules, nodules, vesicles, pustules and ulcers on teats and udder as well as drastic drop in milk production was seen among a cattle farm in Fayoum Governorate, Egypt. A virus was isolated by inoculation of vesicle and scrap homogenate pool from infected cattle into the chorioallantoic membrane of specific pathogen free embryonated chicken eggs. The virus was identified by presence of pock lesions, intracytoplasmic inclusion bodies on the chorioallantoic membrane, polymerase chain reaction and immunohistochemistry of the inoculated membrane. A novel pathogenicity model was developed via ear pinna inoculation of Swiss mice. The virus produced vesicular and ulcerative lesions at the site of inoculation in inoculated mice. The virus identity was confirmed by the presence of intracytoplasmic viral antigens by immunohistochemistry

Coinfection of goose parvovirus (GPV) and duck circovirus (DuCV) occurs commonly in field cases of short beak and dwarfism syndrome (SBDS). However, whether there is synergism between the two viruses in replication and pathogenicity remains undetermined. We established a coinfection model of GPV and DuCV in Cherry Valley ducks. Tissue samples were examined histopathologically. The viral loads in tissues were detected by qPCR, and the distribution of the virus in tissues was detected by immunohistochemistry (IHC). Coinfection of GPV and DuCV significantly inhibited growth and development of ducks, and caused atrophy and pallor of the immune organs and necrosis of the liver. GPV and DuCV synergistically amplified pathogenicity in coinfected ducks. In the early stage of infection, viral loads of both pathogens in coinfected ducks were significantly lower than those in monoinfected ducks (P < 0.05). With the development of the infection process, GPV and DuCV loads in coinfected ducks were significantly higher than those in monoinfected ducks (P < 0.05). Extended viral distribution in the liver, kidney, duodenum, spleen, and bursa of Fabricius was consistent with the viral load increases in GPV and DuCV coinfected ducks. These results indicate that GPV and DuCV synergistically potentiate their replication and pathogenicity in coinfected ducks.

Introduction: Mycoplasma synoviae (MS) is a chicken pathogen of major economic importance. Material and Methods: Between 2010 and 2016, 906 commercial layer chicken flocks in Poland were examined for MS, and the phylogenetic relationship among the strains was established. Regionally dispersed samples were collected and tested with the use of real-time PCR to detect the 16S–23S intergenic spacer region. Positive samples were also tested with LAMP and conventional PCR to detect the vlhA gene. Results: MS genetic material was detected in 265 (29%) of the tested flocks by real-time PCR, in 227 by the LAMP method and in 202 (22%) by conventional PCR. The by-year percentage of positive samples began at 34% in 2010, rose to 44% in 2012, and declined to 29% in 2016. A phylogenetic analysis of Polish M. synoviae strains using a partial sequence of the vlhA gene showed nine genotypes (A–I), the most frequently occurring being F and C. Pathogenic Polish MS field isolates (n = 27) collected from chickens with clinical signs of infection were grouped for their characteristic symptoms: respiratory for genotypes C, E, F, and I (n = 13), EAA and a drop in laying for genotypes F, E, and C (n = 12), and synovitis for genotype A (n = 2). Conclusion: These data showed the country’s isolate diversity. The high prevalence suggests the need to introduce appropriate control programmes. This is the first report of molecular epidemiological data on M. synoviae infection in layer chickens in Poland.

Introduction: The aim of the study was to test the utility of Flinders Technology Associates filter paper (FTA® Cards) for molecular detection and storage of avian influenza virus (AIV). Material and Methods: There were two strains of AIV used in the study: low pathogenicity H7N1 and high pathogenicity H5N1 subtypes. Detection of viral material was conducted using molecular RT-PCR and rRT- PCR method. Results: The infectivity of LPAIV/H7N1 and HPAIV/H5N1 was completely inactivated within 1 h and 24 h after adsorption to FTA® Cards at room temperature, respectively. Viruses stored on FTA® Cards had detection limit approximately 1 log₁₀ lower than live viruses. Viral RNA of both strains were detectable on the cards by rRT-PCR for a minimum of 150 d, irrespectively of storage temperatures (room temperature, -20ºC). RNA was also detected in all samples obtained from SPF chickens experimentally infected with HPAI/H5N1 on 3ʳᵈ and 4ᵗʰ day post-infection (p.i.). Conclusion: FTA® Cards enable safe and effective alternative transport of samples for molecular diagnosis of AIV.