Pathogenicity of field strain of fowl aviadenovirus serotype 11 isolated from chickens with inclusion body hepatitis in Morocco.

Outbreaks of inclusion body hepatitis have emerged in Morocco since 2013 and has resulted in significant economic losses to poultry farms. Three isolates of the causative virus, Fowl adenonovirus (FAdV)were characterized from chickens with IBH, but their pathogenicity has never been investigated. In this work, the pathogenicity of an isolate FAdV 11 (MOR300315 strain) was evaluated by inoculating a group of 40 SPF chickens at 3 days of age by oral route. A group of 40 chicks injected with phosphate-buffered saline solution was used as a control group. The infected chickens showed decreased weight gain from 3dpi. Necropsy displayed pallor and enlargement in liver, swelling and slight hemorrhage in kidney and spleen at 6 dpi. Histopathological changes were mainly characterized by severe and extensive hepatic necrosis associated with the presence of basophilic intra-nuclear inclusion bodies within hepatocytes. The FAdV was reisolated in chicken embryo fibroblast cell culture from liver tissue homogenate of infected chicken from 3 to 6 dpi. Viral DNA was detected by PCR in liver, kidney, spleen and cloacal swabs from 3 to 13 dpi. Antibody response against inoculated FAdV was appeared from 9 dpi. These results confirmed that the FAdV 11 strain is pathogenic in chicken. This study is the first experimental infection of FAdV 11 in chicken in Morocco, which increase our understanding of its pathogenicity in chickens and indicate that preventive measures against FAdV infection in poultry farms should be implemented in Morocco.

Hepatic Perisinusoidal Myofibroblast Proliferation and Systemic Inflammatory Response Precedes Sep/Tox Hepatitis in Broilers.

Septicemia-toxemia (sep/tox) falls under U.S. Department of Agriculture (USDA) food safety Category 1 and is the most common and economically significant cause of broiler carcass condemnations. Hepatic lesions are considered a possible consequence of septicemia and associated bacterial contamination of the carcass. Thus, these lesions are considered an indicator of sep/tox (sep/tox hepatitis). This study was undertaken to analyze the histologic lesions preceding grossly visible liver lesions leading to condemnation because of sep/tox at the processing plant. Livers from carcasses of broilers condemned by USDA inspectors for sep/tox were used to establish microscopic and gross criteria of end-stage sep/tox hepatitis. Following the characterization of sep/tox hepatitis, broilers from a farm with a history of sep/tox condemnations were submitted for postmortem examination and bacteriologic investigation at four intervals during the final 20 days of production. Five healthy and five clinically ill chickens were submitted from four houses at 18, 25, 32, and 38 days of production (160 total). Microscopic lesions representing hepatic perisinusoidal myofibroblast proliferation (HPMP), periportal extramedullary granulopoiesis (PEMG), splenic follicular histiocytosis, and bone marrow cellularity (BMC) were graded subjectively for each bird, and subjective grading was evaluated with digital quantitative techniques. Perisinusoidal hepatic stellate cell morphology and progressive transformation of these cells into myofibroblasts was confirmed by immunohistochemistry for smooth muscle actin and desmin. Aerobic cultures of livers and gall bladders from sep/tox birds yielded no growth of bacteria associated with septicemia. Mild to severe HPMP was observed in all age groups, representing 28% of examined birds. Increases in inflammatory cells observed by PEMG and BMC were positively correlated with progressive HPMP and end-stage sep/tox hepatitis in broiler chickens.

Artículo regular­Proliferación de miofibroblastos perisinusoidales hepáticos y respuesta inflamatoria sistémica que precede a la hepatitis por septicemia y toxemia (sep/tox) en pollos de engorde. La septicemia-toxemia (sep/tox) se incluye en la Categoría 1 de seguridad alimentaria del Departamento de Agricultura de los Estados Unidos. (USDA) y es la causa más común y económicamente significativa de decomisos de canales de pollos de engorde. Las lesiones hepáticas se consideran una posible consecuencia de la septicemia y de la contaminación bacteriana asociada con la canal. Por lo tanto, estas lesiones se consideran un indicador de septicemia/toxemia (hepatitis sep/tox). Este estudio se llevó a cabo para analizar las lesiones histológicas que preceden a las lesiones hepáticas muy visibles que conducen a los decomisos debido a septicemia/toxemia en la planta de procesamiento. Se utilizaron hígados de canales de pollos de engorde decomisados por los inspectores del USDA por septicemia/toxemia para establecer criterios microscópicos y generales de hepatitis en etapa terminal de la septicemia/toxemia. Después de la caracterización de la hepatitis por septicemia/toxemia, los pollos de engorde de una granja con un historial de decomisos por septicemia/toxemia se sometieron a examen post mortem e investigación bacteriológica en cuatro intervalos durante los últimos 20 días de producción. Se enviaron cinco pollos sanos y cinco clínicamente enfermos de cuatro casetas a los 18, 25, 32 y 38 días de producción (160 en total). Las lesiones microscópicas que representan la proliferación de miofibroblastos perisinusoidales hepáticos (HPMP), la granulopoyesis extramedular periportal (PEMG), la histocitosis folicular esplénica y la celularidad de la médula ósea (BMC) se clasificaron subjetivamente para cada ave, y la clasificación subjetiva se evaluó con técnicas cuantitativas digitales. La morfología de las células estrelladas hepáticas perisinusoidales y la transformación progresiva de estas células en miofibroblastos se confirmó mediante inmunohistoquímica para actina y desmina del músculo liso. Los cultivos aeróbicos de hígados y vesícula biliar de aves con septicemia/toxemia no produjeron crecimiento de bacterias asociadas con la septicemia. Se observó proliferación de miofibroblastos perisinusoidales hepáticos de leve a severa en todos los grupos de edad, lo que representa el 28% de las aves examinadas. Los aumentos en las células inflamatorias observados por granulopoyesis extramedular periportal y celularidad de la médula ósea se correlacionaron positivamente con proliferación progresiva de miofibroblastos perisinusoidales hepáticos y con hepatitis por septicemia/toxemia en etapa terminal en pollos de engorde.

The first complete genome sequence and pathogenicity characterization of fowl adenovirus 11 from chickens with inclusion body hepatitis in Pakistan.

Inclusion body hepatitis (IBH), hydropericardium syndrome, and gizzard erosion associated with fowl adenovirus (FAdV) infections are reported globally and resulted in significant poultry industry economic losses. In 2018, severe IBH appeared in Pakistan in a 17-week-old layer flock. Subsequently, a FAdV-11 strain (designated as PKFAd18) was isolated from liver samples and identified based on phylogenetic analyses of the serotype-specific L1 region of the capsid hexon gene. There is no complete genome sequence of the Pakistani FAdV-11. This study successfully sequenced the complete genome of PKFAd18. The full genome of PKFAd18 contains 43 840 base pairs (bp) with a G + C content of 53.9 %, which is comparable to other FAdV serotypes. Similar to other FAdV-11 strains, PKFAd18 has only one fiber, while FAdV-1 and FAdV-4 have two fibers. Notably, PKFAd18 showed unique characteristics compared to other FAdV-11 strains. A natural large genomic deletion (1215 bp) appeared in tandem repeat region two, relative to the ON-NP2 strain. Phylogenetic analyses of the PKFAd18 penton gene showed higher homology with FAdV-9, highlighting potential natural recombination between FAdV-11 and FAdV-9. Moreover, the pathogenicity of PKFAd18 studied in specific-pathogen-free chickens showed that PKFAd18 is capable of inducing severe IBH and could be responsible for IBH in Pakistan. Thus, the first complete genome of FAdV-11 in Pakistan was sequenced in this study, which enriches the diversity of knowledge about FAdV-11 and is useful for developing diagnostics and vaccines for IBH induced by FAdV-11 in Pakistan.

Adenoviral hepatitis in two Nile crocodile (Crocodylus niloticus) hatchlings from South Africa.

Adenoviral infections may cause mild to severe morbidity or fatality in a large array of animal species. In crocodilians, hatchlings under 5 months of age are usually affected. However, there is a paucity of information on actual incidences in hatchlings originating from South Africa. Two cases of adenoviral hepatitis in crocodile hatchlings about 2 weeks old, bred on a commercial farm in South Africa, are described. Both hatchlings showed typical clinical signs of hepatitis. The identification of intranuclear inclusion bodies in the liver was used to differentiate between adenoviral hepatitis and chlamydial hepatitis. Although vertical transmission has never been proven in crocodiles, the young age of the affected hatchlings raises the possibility of vertical transmission. The lack of epidemiological information on adenoviral hepatitis in crocodiles highlights the need for further characterisation of the virus and targeted surveillance.

Prevalence of Fowl Adenovirus Serotype 4 and Co-Infection by Immunosuppressive Viruses in Fowl with Hydropericardium Hepatitis Syndrome in Shandong Province, China.

Fowl adenovirus serotype 4 (FAdV-4) is the pathogenic agent of hydropericardium hepatitis syndrome (HHS) in chickens and ducks, which has caused huge economic losses for the Chinese poultry industry since 2015. In order to objectively determine the prevalence and co-infection status of the virus in Shandong province in China, we analyzed a total of 679 clinical cases of chickens and ducks from 36 farms in the province. The results showed that the FAdV-4 infection rate was 65.2% (443/679), and the rate in breeder ducks was almost two-fold higher than that in breeder chickens (68.57% vs. 34.30%). Notably, co-infection by H9N2 avian influenza virus, infectious bursal disease virus, and/or chicken infectious anemia virus was very common in the 443 FAdV-4-positive cases. Furthermore, phylogenetic analysis of the hexon genes of four Shandong FAdV-4 isolates revealed that these strains clustered into Indian reference strains, indicating that the Shandong FAdV-4 strains might have originated in India. These findings provide the first data on the prevalence and co-infection status of FAdV-4 in Shandong province, which may serve as a foundation for the prevention of FAdV-4 in the field.

Inclusion Body Herpesvirus Hepatitis in Captive Falcons in the Middle East: A Review of Clinical and Pathologic Findings.

Inclusion body hepatitis in falcons is caused by a herpesvirus designated Falconid HV-1. This herpesvirus and other herpesviruses affecting birds of prey have not been assigned to a genus and include inclusion body herpesvirus hepatitis in eagles (Accipitrid HV-1) and inclusion body herpesvirus hepatitis in owls (Strigid HV-1). Herpesvirus infections have been diagnosed in both captive and free-living raptors across Europe, North America, and Asia in different species of the family Falconidae. Herpesviruses affecting owls and falcons have been found to be antigenically similar to pigeon herpesvirus (Columbid HV-1) and distinct from other avian herpesviruses. When the herpesvirus isolates from owls, falcons, and pigeons were compared by sequencing a fragment of the herpes viral DNA polymerase gene from those birds naturally infected with the virus, the sequences from these 3 sources were found to be nearly identical. The authors of this study concluded that the Falconid HV-1, Strigid HV-1, and Columbid HV-1 were the same virus. Furthermore, the authors also proposed that the virus therefore be referred to as Columbid HV-1 (CoHV-1), because pigeons may be responsible for the transmission of the virus to birds of prey. Pigeons are often carriers of the virus without showing any clinical signs. It has long been suspected that raptors may contract the infection by the ingestion of infected pigeons. Some studies have suggested that falcons may not contract the infection through the oral route by ingesting carrier pigeons, but through the ocular or nasal route. Inclusion body herpesvirus hepatitis is a frequently diagnosed disease in the captive falcon population used for falconry, racing, and breeding in the Middle East, and it seems to be associated with the extensive use of pigeons for training and as a food item. This paper reviews the clinical and pathological findings in falcons affected by inclusion body herpesvirus hepatitis in the Middle East.

Molecular detection and characterization of fowl adenovirus associated with inclusion body hepatitis from broiler chickens in Egypt.

A case-control study was performed to assess prescence of inclusion body hepatitis (IBH) caused by fowl adenoviruses (FAdVs) at Kafr EL-Shiekh Governorate, Egypt, during spring, 2017. The case group consisted of 100 liver and spleen samples collected from 10 broiler chickens flocks (10 samples from each flock) suspected to be infected with IBH depending on clinical manefestations and necropsy examination. Controls were randamly selected from chickens without clinical sings or evidence of the disease on postmortem examination. Molecular screening of the disease disease in collected samples based on the DNA polymerase gene of FAdVs was carried out. Furthermore, the DNA polymerase gene sequence was determined and analyzed with published reference sequences on GeneBank. Respectively, enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR) were used to confirm existence of co-infection with chicken infectious anemia virus (CIAV) and/or infectious bursal disease virus (IBDV in flocks involved in the study. Using PCR, FAdV genome was detected in seven flocks in the case group and one in the control group. FAdV identified in this study revealed close genetic relationship with FAdVs-D previously identified in UK and Canada, suggesting potential virus transmission from these countries. All tested serum samples from diseased chickens were positive for CIAV infection via ELISA while none of the collected bursa of Fabricius samples tested IBDV positive by RT-PCR. Therefore, results obtained from the current study highlighted the importance of implementation of control measures against FAdV and CIAV in Egyptian poultry flocks. This study opens the door for future work toward specific identification of FAdV serotypes circulating in Egyptian poultry farms and molecular characterization of the virus based on hexon gene or full genome sequencing for better understanding of genetic diversity among FAdVs in Egypt at higher reolution.

Evolutionary biology of human hepatitis viruses.

Hepatitis viruses are major threats to human health. During the last decade, highly diverse viruses related to human hepatitis viruses were found in animals other than primates. Herein, we describe both surprising conservation and striking differences of the unique biological properties and infection patterns of human hepatitis viruses and their animal homologues, including transmission routes, liver tropism, oncogenesis, chronicity, pathogenesis and envelopment. We discuss the potential for translation of newly discovered hepatitis viruses into preclinical animal models for drug testing, studies on pathogenesis and vaccine development. Finally, we re-evaluate the evolutionary origins of human hepatitis viruses and discuss the past and present zoonotic potential of their animal homologues.

Chicken infectious anemia virus helps fowl adenovirus break the protection of maternal antibody and cause inclusion body hepatitis-hydropericardium syndrome in layers after using co-contaminated Newcastle disease virus-attenuated vaccine.

Inclusion body hepatitis-hydropericardium syndrome (IBH-HPS) caused by fowl adenovirus type 4 (FAdV-4) has caused huge economic losses for China in the past five years. At present, this disease is controlled in many flocks with the inactivated FAdV vaccine, but the offspring chicks of a layer breeding flock that were vaccinated with this vaccine still became infected and developed IBH-HPS with a 20% mortality rate. Analysis revealed that the NDV-attenuated vaccine in use from the above-mentioned poultry farm was simultaneously contaminated with FAdV-4 and chicken infectious anemia virus (CIAV). The FAdV and CIAV isolated from the vaccine were purified for the artificial preparation of an NDV-attenuated vaccine singly contaminated with FAdV or CIAV, or simultaneously contaminated with both of them. Seven-day-old layers with maternal FAdV antibody were inoculated with the artificially prepared, contaminated vaccines and assessed for corresponding indices. The experiments showed that no obvious symptoms occurred after using the NDV-attenuated vaccine singly contaminated with FAdV or CIAV; however, common IBH and occasional HPS-related death was found in birds after administering the NDV-attenuated vaccine co-contaminated with FAdV and CIAV. In conclusion, this study illustrated that CIAV could assist FAdV in breaking maternal FAdV antibody protection, which then caused the IBH-HPS after vaccination with the co-contaminated NDV vaccine.

Identification and genetic characterization of a novel parvovirus associated with serum hepatitis in horses in China.

A novel equine parvovirus, equine parvovirus-hepatitis (EqPV-H), was first discovered in a horse that died of equine serum hepatitis in the USA in 2018. EqPV-H was shown to be a novel etiological agent associated with equine serum hepatitis. Following this initial report, no additional studies on EqPV-H have been published. In this study, a total of 143 serum samples were collected from racehorses at 5 separate farms in China and were analyzed to detect EqPV-H DNA via nested PCR. The results indicated a high prevalence of EqPV-H (11.9%, 17/143) in the studied animals. In addition, a remarkably high coinfection rate (58.8%, 10/17) with 2 equine flaviviruses (equine hepacivirus and equine pegivirus) was observed in the EqPV-H positive equines. However, all equines tested negative for Theiler's disease-associated virus, an etiological agent associated with equine serum hepatitis. The genomes of six field EqPV-H strains were sequenced and analyzed, with the results indicating that the Chinese EqPV-H strains have low genetic diversity and high genetic similarity with the USA EqPV-H strain BCT-01. A phylogenetic analysis demonstrated that the Chinese EqPV-H strains clustered with BCT-01 in the genus Copiparvovirus but were distantly related to another equine parvovirus identified in horse cerebrospinal fluid. In addition, liver enzyme levels were detected in the EqPV-H positive serum samples, and all the values were in the normal range, indicating that infection can occur without concurrent liver disease. This study will promote an understanding of the geographical distribution, genetic diversity, and pathogenicity of EqPV-H.

Newcastle disease virus-attenuated vaccine co-contaminated with fowl adenovirus and chicken infectious anemia virus results in inclusion body hepatitis-hydropericardium syndrome in poultry.

Inclusion body hepatitis-hydropericardium syndrome (IBH-HPS) induced by fowl adenovirus type 4 (FAdV-4) has caused huge economic losses to the poultry industry of China, but the source of infection for different flocks, especially flocks with high biological safety conditions, has remained unclear. This study tested the pathogenicity of Newcastle disease virus (NDV)-attenuated vaccine from a large-scale poultry farm in China where IBH-HPS had appeared with high mortality. Analysis revealed that the NDV-attenuated vaccine in use from the abovementioned poultry farm was simultaneously contaminated with FAdV-4 and chicken infectious anemia virus (CIAV). The FAdV and CIAV isolated from the vaccine were purified for the artificial preparation of an NDV-attenuated vaccine singly contaminated with FAdV or CIAV, or simultaneously contaminated with both of them. Seven-day-old specific pathogen-free chicks were inoculated with the artificially prepared contaminated vaccines and tested for corresponding indices. The experiments showed that no hydropericardium syndrome (HPS) and corresponding death occurred after administering the NDV-attenuated vaccine singly contaminated with FAdV or CIAV, but a mortality of 75% with IBH-HPS was commonly found in birds after administering the NDV-attenuated vaccine co-contaminated with FAdV and CIAV. In conclusion, this study found the co-contamination of FAdV-4 and CIAV in the same attenuated vaccine and confirmed that such a contaminated attenuated vaccine was a significant source of infection for outbreaks of IBH-HPS in some flocks.

Characterization of a hypervirulent fowl adenovirus 4 with the novel genotype newly prevalent in China and establishment of reproduction infection model of hydropericardium syndrome in chickens.

Severe hydropericardium syndrome (HPS) has been present in layers in the northeast of China since June 2015, with mortality rates varying from 30 to 90%. Dead layers had severe hydropericardium with pericardial volumes of 5 to 20 mL, as well as inclusion body hepatitis. Laboratory investigations led to the isolation of a fowl adenovirus strain, HLJFAd15, from the liver tissue of dead layers. Natural deletions of ORF19 and ORF27 were found in this clinical strain by complete genome sequencing, which was identified with the novel genotype recently prevalent in China. The pathogenicity characterization was conducted in 35-day-old SPF chickens using HLJFAd15 with novel genotype of fowl adenovirus serotype 4 (FAdV-4). The reproduction disease cases of HPS with mortality rates of 76.9% by oral administration and 100% by intramuscular injection were induced successfully by challenging SPF chickens, respectively. Non-enveloped viral particles with a mean diameter of approximately 80 nm were found in the livers of virus-infected SPF chickens. Our study revealed that HLJFAd15 was identified with the novel genotype strains recently emerging in China by complete genome sequencing, and the strain was capable of causing HPS by the pathogenicity analysis. However, although there is currently no commercial vaccine against the novel genotype FAdV-4, the animal infection model established in this study was valuable for vaccine evaluation and development.

Molecular characterisation of fowl adenovirus type 7 isolated from poultry associated with inclusion body hepatitis in Poland.

The fowl adenovirus field strain FAdV-JSN-5/10j (GenBank accession number KP879219) was isolated from the intestine of a 7-week-old chicken diagnosed with inclusion body hepatitis and simultaneously with Marek's disease, and for that reason, it was chosen for molecular study. It was identified as fowl adenovirus genotype 7 (species Fowl aviadenovirus E) based on nucleotide sequence analysis of the loop L1 region of the hexon gene. Nucleotide sequence alignment of this strain, FAdV-7 reference strains B-3A ATCC VR-832 (AF339922) and YR36 (AF508955), and eight additional FAdV-7 field strains confirmed its classification as FAdV-JS-5/10j and showed that these viruses are very similar to each other. Additionally, we described mutations and their influence on the amino acid sequence, nucleotide composition, and relative synonymous codon usage. Immunofluorescence of cell cultures infected with 104.5 TCID 50 per 0.1-ml dose of the FAdV-JSN-5/10j strain demonstrated the presence of a cytopathic effect. Infection of fowl with adenoviruses raises concerns for poultry production, and thus, the efficient detection of adenovirus infection is crucial. This is the first attempt to describe the molecular characteristics of FadV-7 strains isolated in Poland.

Treatment effect of a flavonoid prescription on duck virus hepatitis by its hepatoprotective and antioxidative ability.

CONTEXT: Duck virus hepatitis (DVH) caused by duck hepatitis A virus type 1 (DHAV-1) is an acute and lethal disease of young ducklings. However, there is still no effective drug to treat DVH. OBJECTIVE: This study assessed the curative effect on DVH of a flavonoid prescription baicalin-linarin-icariin-notoginsenoside R1 (BLIN) as well as the hepatoprotective and antioxidative effects of BLIN. MATERIALS AND METHODS: MTT method was used to test the anti-DHAV-1 ability of BLIN in vitro. We then treated ducklings by BLIN (3 mg per duckling, once a day for 5 days) to evaluate the in vivo efficacy. To study the hepatoprotective and antioxidative roles of BLIN in its curative effect on DVH, we investigated the hepatic injury evaluation biomarkers and the oxidative stress evaluation indices of the ducklings. RESULTS: On duck embryonic hepatocytes, DHAV-1 inhibitory rate of BLIN at 20 µg/mL was 69.3%. The survival rate of ducklings treated by BLIN was about 35.5%, which was significantly higher than that of virus control (0.0%). After the treatment of BLIN, both the hepatic injury and the oxidative stress of infected ducklings alleviated. At the same time, a significant positive correlation (p < 0.05) existed between the hepatic injury indices and the oxidative stress indices. CONCLUSIONS: BLIN showed a significant curative effect on DVH. The antioxidative and hepatoprotective effects of BLIN made great contributions to the treatment of DVH. Furthermore, BLIN is expected to be exploited as a new drug for the clinical treatment of DVH.

Serological and molecular epidemiology of canine adenovirus type 1 in red foxes (Vulpes vulpes) in the United Kingdom.

Canine adenovirus type 1 (CAV-1) causes infectious canine hepatitis (ICH), a frequently fatal disease which primarily affects canids. In this study, serology (ELISA) and molecular techniques (PCR/qPCR) were utilised to investigate the exposure of free-ranging red foxes (Vulpes vulpes) to CAV-1 in the United Kingdom (UK) and to examine their role as a wildlife reservoir of infection for susceptible species. The role of canine adenovirus type 2 (CAV-2), primarily a respiratory pathogen, was also explored. In foxes with no evidence of ICH on post-mortem examination, 29 of 154 (18.8%) red foxes had inapparent infections with CAV-1, as detected by a nested PCR, in a range of samples, including liver, kidney, spleen, brain, and lung. CAV-1 was detected in the urine of three red foxes with inapparent infections. It was estimated that 302 of 469 (64.4%) red foxes were seropositive for canine adenovirus (CAV) by ELISA. CAV-2 was not detected by PCR in any red foxes examined. Additional sequence data were obtained from CAV-1 positive samples, revealing regional variations in CAV-1 sequences. It is concluded that CAV-1 is endemic in free-ranging red foxes in the UK and that many foxes have inapparent infections in a range of tissues.

Genetic characterization of novel fowl aviadenovirus 4 isolates from outbreaks of hepatitis-hydropericardium syndrome in broiler chickens in China.

Since May 2015, severe outbreaks of hepatitis-hydropericardium syndrome (HHS) associated with infections of fowl aviadenovirus (FAdV) have emerged in broiler chickens in several Chinese provinces. To identify the genotype and gain a better understanding of the genetic properties of the FAdV strains responsible for the recent HHS outbreaks in China, the complete genome sequences of five isolates from outbreaks of HHS in broiler chickens in five provinces were determined. The results demonstrated that a novel fowl aviadenovirus 4 (FAdV-4) genotype was epidemic in China. To investigate the molecular characteristics of these Chinese FAdV-4 isolates, their genome contents were compared with those of reported pathogenic and non-pathogenic FAdV-4 strains. The comparative analysis revealed that the novel Chinese FAdV-4 isolates contain various genomic deletions and multiple distinct amino-acid mutations in their major structural genes. Two additional putative genetic virulence markers in the fiber 2 gene were identified. These findings confirmed some of the genetic differences between the pathogenic and non-pathogenic FAdV-4 isolates. The data presented in this report will enhance the current understanding of the molecular epidemiology and genetic diversity of FAdV-4 isolates in China and will provide additional insight into the critical factors that determine the pathogenicity of FAdV-4 strains. Finally, the emergence of this novel and highly pathogenic FAdV-4 genotype emphasizes that preventive measures against FAdV-4 infections on poultry farms should be implemented in China.

Fowl adenovirus species C serotype 4 is attributed to the emergence of hepatitis-hydropericardium syndrome in chickens in China.

Since July in 2015, an emerging infectious disease of Hepatitis-Hydropericardium syndrome (HHS) was prevalent in chicken flocks in China. To confirm the causative agent and investigate the epidemiology of the disease, a total of 38 chicken flocks including 187 samples from Jilin, Liaoning, Heilongjiang, Henan, Anhui, Hubei, Jiangxi, Xinjiang, Shandong and Hunan provinces in China were collected and determined by PCR detection, sequencing, phylogenetic analysis and virus isolation. 81 samples (positive rate of samples, 81/187, 43.3%) distributed in 33 chicken flocks (positive rate of chicken flocks, 33/38, 86.8%) were detected to be positive for fowl adenovirus (FAdV) by PCR method, of which 30 were determined as FAdV species C, 41 were species D, 9 were species E and 1 was uncertain for the viral species by phylogenetic analysis, implicating that at least three species (C, D and E) of FAdVs were prevalent in China and the species C and D were predominantly the prevalent viral strains. Interestingly, our results indicated that two types of FAdVs (C and D) co-existed in one flock, resulting in complex condition for the prevalence of the disease. In addition, 13 viral strains of FAdV-C were isolated from different geographic areas and one of the isolates from Henan province, designated HN/151025 strain, was inoculated into 40-day-old specific pathogen free chickens via intramuscular or oral route to evaluate the pathogenicity. It was found that 90% (9/10) chickens died in the intramuscular injection group and 30% (3/10) birds died in the oral route infection group after challenge. Histopathology examination displayed that the pathology confined to liver, kidney, spleen, and heart. These results indicated that the virus was a highly virulent strain.

Administration of Poly[di(sodium carboxylatoethylphenoxy)phosphazene] (PCEP) and Avian Beta Defensin as Adjuvants in Inactivated Inclusion Body Hepatitis Virus and its Hexon Protein-Based Experimental Vaccine Formulations in Chickens.

Inclusion body hepatitis (IBH) is one of the major infectious diseases adversely affecting the poultry industry of the United States and Canada. Currently, no effective and safe vaccine is available for the control of IBH virus (IBHV) infection in chickens. However, based on the excellent safety and immunogenic profiles of experimental veterinary vaccines developed with the use of new generation adjuvants, we hypothesized that characterization of vaccine formulations containing inactivated IBHV or its capsid protein hexon as antigens, along with poly[di(sodium carboxylatoethylphenoxy)phosphazene] (PCEP) and avian beta defensin 2 (ABD2) as vaccine adjuvants, will be helpful in development of an effective and safe vaccine formulation for IBH. Our data demonstrated that experimental administration of vaccine formulations containing inactivated IBHV and a mixture of PCEP with or without ABD2 as an adjuvant induced significantly higher antibody responses compared with other vaccine formulations, while hexon protein-based vaccine formulations showed relatively lower levels of antibody responses. Thus, a vaccine formulation containing inactivated IBHV with PCEP or a mixture of PCEP and ABD2 (with a reduced dosage of PCEP) as an adjuvant may serve as a potential vaccine candidate. However, in order to overcome the risks associated with whole virus inactivated vaccines, characterization of additional viral capsid proteins, including fiber protein and penton of IBHV along with hexon protein in combination with more new generation adjuvants, will be helpful in further improvements of vaccines against IBHV infection.

Pathogenicity and Complete Genome Characterization of Fowl Adenoviruses Isolated from Chickens Associated with Inclusion Body Hepatitis and Hydropericardium Syndrome in China.

In this study, we determined and genetically characterized three fowl adenoviruses isolated from chickens with inclusion body hepatitis (IBH) and hydropericardium syndrome (HPS) in China and assessed their pathogenicity. The full genome of HBQ12, BJH13 and JSJ13 was found to be 44,081, 43,966 and 43,756 nucleotides long, respectively. Sequence alignment and phylogenetic analysis revealed that strain HBQ12 and BJH13 were clustered together belonging to fowl adenoviruses D species and serotyped as FAdV-11, whereas strain JSJ13 was classified into fowl adenoviruses C species and serotyped as FAdV-4. To our knowledge, this is the first report of FAdV-4 strain circulating in China. The pathogenicity test showed that mortality for chickens infected with HBQ12 and JSJ13 within 21 days post infection (dpi) was 8.6% and 28.6%, respectively. Necropsy displayed mild or severe hepatitis and hydropericardium at 3 and 5 dpi as well as dead chickens. Viral DNA was detected in almost all tissues sampled from dead chickens. These results revealed that fowl adenovirus strains HBQ12 and JSJ13 are capable of causing IBH and HPS in chickens, indicating that preventive measures against FAdV infection on poultry farms should be implemented in China.

Rift Valley fever virus infection in golden Syrian hamsters.

Rift Valley fever virus (RVFV) is a formidable pathogen that causes severe disease and abortion in a variety of livestock species and a range of disease in humans that includes hemorrhagic fever, fulminant hepatitis, encephalitis and blindness. The natural transmission cycle involves mosquito vectors, but exposure can also occur through contact with infected fluids and tissues. The lack of approved antiviral therapies and vaccines for human use underlies the importance of small animal models for proof-of-concept efficacy studies. Several mouse and rat models of RVFV infection have been well characterized and provide useful systems for the study of certain aspects of pathogenesis, as well as antiviral drug and vaccine development. However, certain host-directed therapeutics may not act on mouse or rat pathways. Here, we describe the natural history of disease in golden Syrian hamsters challenged subcutaneously with the pathogenic ZH501 strain of RVFV. Peracute disease resulted in rapid lethality within 2 to 3 days of RVFV challenge. High titer viremia and substantial viral loads were observed in most tissues examined; however, histopathology and immunostaining for RVFV antigen were largely restricted to the liver. Acute hepatocellular necrosis associated with a strong presence of viral antigen in the hepatocytes indicates that fulminant hepatitis is the likely cause of mortality. Further studies to assess the susceptibility and disease progression following respiratory route exposure are warranted. The use of the hamsters to model RVFV infection is suitable for early stage antiviral drug and vaccine development studies.