Clinical and histopathological study of inclusion body hepatitis in broilers in Basrah governorate

The poultry industry plays an important role in the food economics and the food industry in both their layer and broiler chicken. Poultry diseases on the other way impact in the poultry industry especially diseases from virus sources since it does not have a specific treatment except for vaccines with routine prevention and control. This study was designed for the assessment of histopathological changes, molecular diagnosis and phylogenetic analyses of the Infectious Bronchitis virus circulating in broilers in Basrah province in the south of Iraq. The tissue samples were (trachea, lung and kidney). One hundred samples were studied with clinical signs and lesions related to IB. The histopathological changes caused by the virus were studied with hematoxylin and eosin stain, and the causative agent Infectious Bronchitis Virus (IBV) was identified using a polymerase chain reaction combined with explaining the phylogenetic analysis. The results of molecular diagnosis and identification showed the twelve Iraqi field strains of IBV were closely related and shared a high identity of 98.44 %- 99.69 % of each other. Variant 2(IS/1494 like) was a predominant genotype of IBV in the present study, and has high similarity with the variant 2(IS/1494) like a strain of IBV circulating in Iran and in the Kurdistan region north of Iraq. The histopathological findings were desquamation of the cilia of the mucosa layer of the trachea, infiltration of inflammatory cells, hyperplasia of goblet cells with thickening of mucosal layer in some areas infiltration of inflammatory exudate within capillaries and Para bronchus, where the microscopic results in kidney were showed interstitial hemorrhage, necrosis of the renal tubular epithelium, infiltration of inflammatory cell. The present results provided useful information on target organs damaged by IBV and the genetic epidemiology of such virus strains circulating in Basrah governorate Iraq during this year that would be helpful to develop a local vaccine.

Inclusion body hepatitis (IBH) is a disease of chickens characterized by acute mortality with severe anemia caused by fowl adenoviruses (FAdV). IBH is one of the most important re-emerging diseases worldwide. In India earlier IBH/ Hydropericardium Syndrome (HPS) outbreaks were mainly due to (FAdV) type 4; however, in recent outbreaks, other serotypes are involved, despite regular vaccination in breeders and young chicks. The aim of the present study was isolation and molecular characterization of FAdV associated with IBH in India. A total of 193 liver samples of IBH suspected broiler chickens were collected from different regions of India. Liver samples were initially screened by histopathology and further, a total of 127 samples which microscopically showed basophilic, intra-nuclear inclusion bodies were processed for FAdV detection. A total of 69 samples were found to be positive for Hexon gene in PCR, of which 28 were sequenced. These samples showed more than 94% sequence homology with FAdV2 and 97% with FAdV11, which was confirmed by Restriction Enzyme Analysis (REA). Tissue Culture Infective Dose50 (TCID50) and Egg Infective Dose50 (EID50) titer of isolated FAdV was found to be 106.5/ml. Pathogenicity study in SPF chicks showed 100% mortality up to Post Infection Day (PID)-6. These findings conclude that the prevalence of FAdV-11 is currently causing IBH outbreaks India. However, further genetic and pathogenic analysis of FAdV is required, which would provide useful information for the development of the efficient commercial IBH vaccine.

Inclusion Body Hepatitis (IBH), is the main serotype caused by Fowl Adenovirus (FAdV), that affecting chickens leading to substantial economic losses in poultry industry worldwide. The virus mostly affects broiler chickens aged 3-6 weeks, resulting in mortality rates ranging from 10-30%. IBH is characterized by friable, enlarged livers with hepatic necrosis and ecchymotic hemorrhages, often accompanied by lesions in the kidney and spleen. This study was performed at the College of Veterinary Medicine, University of Diyala, aim to identifying the strains of this virus and detect the disease to confirm its presence in Diyala Governorate. This was achieved by conducting histopathological examinations on samples collected from post-mortem cases. Twenty-five tissue samples were collected from several organs, including the liver, spleen, and kidney, from five location farms in Baqubah, Al-Khalis, Al-Muqdadiyah, Al-Wajhiyah, and Kanaan. These sections were stained using routine hematoxylin and eosin (H&E) staining protocols. Histopathological examination of tissues infected broiler chickens with IBH- exposed significant pathological changes. Liver sections displayed coagulative necrosis, basophilic intranuclear inclusion bodies within hepatocytes, fatty infiltration, and subacute periportal hepatitis. In the spleen, vascular congestion, hemorrhage, and lymphocyte depletion were detected. Kidney segments exhibited sign of nephritis, tubular degeneration, and mild peritubular mononuclear infiltration. Additionally, the glomeruli displayed mesangial hyperplasia, proliferative glomerulonephritis, and thickening of Bowman’s capsule, while intranuclear inclusion bodies were rarely detected in renal tissues. These findings highlight the extensive tissue damage caused by IBH in affected organs. The results of the current study highlight the pathological effects of FAdV in broiler chickens emphasize the importance of timely detection and characterization of the virus to alleviate its economic effect on poultry rearing in Diyala Governorate

Inclusion body hepatitis (IBH) is an economically important disease of chickens, with a worldwide distribution, caused by Fowl Aviadenoviruses (FAdVs). Currently, the increased number of cases, the virulence of the isolate strains, as well as the lack of cross-species protection highlight that detailed in-field data are fundamental for the development of successful control strategies. This case report provides a detailed clinicopathological investigation of an unusual IBH outbreak in a commercial broiler farm in the region of Macedonia, Greece. The farm consisted of 64,000 birds, originated from the same breeder stock and placed in three different houses (Flock A–C). At 20 days of age, a sudden increase in daily mortality was recorded in Flock A. It is worth mentioning that, although all flocks were serologically (indirect ELISA) and molecularly (RT-PCR) positive for FAdV, the mortality rate, attributed to IBH, was much higher in Flock A compared to others. The clinical manifestation included non-specific symptoms such as depression, inappetence, yellowish mucoid diarrhea, and lack of uniformity. At necropsy, typically, enlarged, pale, and friable livers were dominant, while sporadically lesions were recorded in the pancreas, kidneys, skeletal muscles, and lymphoid organs. The histopathological examination of liver samples showed multifocal inflammation, necrosis, and the presence of basophilic/ eosinophilic inclusion bodies in hepatocytes. In addition, the loss of the architecture of pancreatic lobules and the presence of fibrosis and foci of mononuclear cell aggregates were suggestive of chronic pancreatic inflammation. PCR analysis confirmed the presence of FAdV, belonging to species E, serotype FAdV-8b. Performance and financial calculations revealed that IBH increased Feed Conversion Ratio (FCR), feed cost/chick as well as feed cost/kg live weight, whereas the Livability (%) and the European Production Efficiency Factor (EPEF) were decreased in the most severely affected flocks (Flock A). This study is the first report of the detection and identification of FAdV serotypes associated with IBH in commercial broiler flocks in Greece. However, there is still a lack of information about the circulating FAdV serotypes in the country, and therefore epidemiological studies are needed to establish control strategies for IBH.

Inclusion body hepatitis (IBH) has been reported in many countries in the world. The IBH or similar cases characterized by hepatitis and presence of intra-nuclear inclusion bodies in hepatocytes have not been reported in broiler chickens in Iran. This is the first report on outbreak of adenovirus-like inclusion body hepatitis in Iran. On October 2012, an onset of high acute mortality in a flock of 2 day-old broiler chickens was reported to the Veterinary Clinic, Faculty of Veterinary Medicine, Razi University, Kermanshah, Iran. The birds showed lethargy, huddling, ruffled feathers, and inappetence. At necropsy the livers were the primary organ affected which were enlarged, pale yellow with necrotic foci and multiple petechial hemorrhages. Tissue samples of liver, kidneys and heart were fixed in 10% buffered formalin. They were processed and stained with hematoxylin and eosin for histopathological studies. Significant microscopic lesions were seen in the livers. Large eosinophilic intra-nuclear inclusion bodies were seen in hepatocytes. Based on the acute high mortality, age of the broilers, gross lesions and histopathological findings (especially intra-nuclear inclusion bodies), the condition was diagnosed as adenovirus-like inclusion body hepatitis.

Viruses belong to the Family Adenoviridae can infect a wide range of vertebrates. These viruses are classified into different genera based on phylogenetic distance, genome organization, and host range. From those genera, Aviadenovirus only infect birds and are serologically different from other adenovirus genera. Fowl Adenoviruses (FAdVs) fall under the Aviadenovirus genus and have a considerably large genome. The FAdV genome comprises non-segmented, linear double-stranded DNA (dsDNA) of 43-46 kbp. The capsid of FAdVs is composed of hexons, penton bases, and fiber proteins, which are vital for cellular interaction and immune responses. Inclusion Body Hepatitis (IBH) is a significant disease caused by FAdVs, impacting broiler chickens primarily. Inclusion Body Hepatitis results in sudden mortality, poor growth, and other clinical signs, contributing to economic losses in the poultry industry, and is transmitted horizontally through contaminated excretions and vertically via embryonated eggs from infected parent flocks. The disease pathogenesis involves replication in the alimentary and respiratory tract epithelium, leading to viremia and dissemination to organs. Gross pathological findings mainly include swollen liver with necrotic foci and multifocal petechial hemorrhages. Histopathologically, degeneration, necrosis, and the presence of intranuclear/intracytoplasmic, basophilic/eosinophilic inclusion bodies are observed mainly in hepatocytes. Diagnosis of IBH involves detecting intranuclear inclusion bodies in hepatocytes, virus isolation, and molecular techniques like PCR for serotyping. Control strategies include strict biosecurity measures, continuous disease surveillance, breeder monitoring, and vaccination. Inactivated and live vaccines are commonly used, with autogenous inactivated vaccines prepared from prevalent serotypes for prevention in endemic regions. Since 2021, IBH outbreaks have been reported in Sri Lanka. The objective of this review is to provide a quick overview of the members and viral structure of the Family Adenoviridae as well as an in-depth review of IBH, one of the main diseases caused by FAdV in poultry.

Inclusion body hepatitis (IBH) virus primarily affects the broiler birds between the ages of 3 and 5 weeks under field conditions. This investigation was planned to study the pathogenicity of IBH virus by infecting broilers through intramuscular route using liver homogenate of IBH affected birds. Total 20 birds of two age groups were selected for the in vivo study, which included day-old broiler chicks (n=10, Group A) and twenty days old chickens (n=10, Group B). In both Group A and B, five birds each were inoculated with 0.2 ml infected liver homogenate suspension by i/m route, i.e. treatment groups (T) and remaining five birds injected i/m with 0.2 ml normal saline served as control groups (C). All birds were kept under observation for five days to record morbidity and mortality. In infected/treated chicks of Group A, 100% mortality was observed on third day, while in infected/treated chickens of Group B only 40% mortality was recorded within five days of observation period. Clinical signs like reduced feed intake and depressed appearance were observed in both the in vivo infected groups. However, hydropericardium syndrome was observed in infected birds of only Group B. Eosinophilic intranuclear inclusion bodies were observed in the hepatic cells of both the infected groups, which confirmed the disease as inclusion body hepatitis. The results indicated that the 0.2 ml liver homogenate of IBH affected birds was more pathogenic in day-old chicks than the older ones due to age factor.

Over the last decade, the emergence of aviadenovirus infections, namely inclusion body hepatitis (IBH) and gizzard erosion and ulceration syndrome (GEUS) has occurred in Morocco with significant losses to the poultry industry. In this work, 255 suspected flock cases of IBH and GEUS were assessed among various poultry production types in the country from 2012–2024. Macroscopic pathological changes in affected chickens included an enlarged, discoloured liver or a distended gizzard with haemorrhagic content and erosion/ulceration on the koilin layer. Microscopic findings revealed severe necrotic hepatitis, consistent with IBH, and/or necrotizing ventriculitis, which is characteristic of GEUS, with intranuclear viral inclusion bodies (INIB) in the hepatocytes or epithelial cells of the gizzard, which are attributable to fowl adenovirus (FAdV). The real-time PCR results revealed that 71% (182/255) of the suspected FAdV cases tested positive. The prevalence varied by poultry production type, with broiler farms being the most affected at 79% (144/194), followed by layer farms at 15% (28/42), breeder farms at 5% (9/13), and turkey farms at 1% (1/6). Sequencing of the isolates identified FAdV serotype 11 (species D) and serotype 8b (species E) in 22 and six cases of IBH, respectively. Additionally, FAdV serotype 1 (species A) and serotypes 8a and 8b (species E) were detected in nine and two cases of GEUS, respectively. These findings underscore the significant impact of fowl adenoviruses on the Moroccan poultry industry and highlight the need for continuous surveillance and targeted control interventions. RESEARCH HIGHLIGHTS Increase in FAdV infections (IBH and GEUS) in Morocco over past decade. FAdV-positive cases were mainly found in broiler farms (79%). Identification of FAdV-11 and 8b serotypes for IBH, and FAdV-1, 8a and 8b for GEUS.

In 2007, an inclusion body hepatitis (IBH) outbreak affected several broiler farms in Mississippi. Results of logistic regression analyses showed significant associations between IBH occurrence and high enzyme-linked immunosorbent assay geometric mean titers for infectious bursal disease virus. However, there was no association between IBH occurrence and chicken infectious anemia virus status. Results of linear regression model analyses showed significant associations between IBH occurrence with average weight and with cost deviation. Broiler meat production cost was $0.0058/kg more expensive to produce when IBH occurred. Although feed conversion was higher with IBH occurrence, the association was not significant. IBH onset in the first farms affected occurred between 19 and 30 days of age, whereas in the last farms affected, IBH onset occurred as early as 10 days.

A red belly macaw (Orthopsittaca manilata) bird was brought for necropsy from a farm comprising of about 200 pet birds including love birds with a history of sudden death. Gross lesions recorded were severe congestion of the liver, spleen and meningeal vessels. Impression smears from the liver and spleen revealed numerous bipolar organisms. Histopathologically, congestion of liver and lungs and basophilic intranuclear inclusion bodies of IBH (inclusion body hepatitis) in the hepatocytes were observed. Heart blood swab subjected for biological test, biochemical characterization studies and pathogenicity test revealed Pasteurella multocida. The PCR assay with species specific primers for Pasteurella multocida (KMT1T7 & KMT1SP6) yielded a product of 460 bp size. The case was diagnosed as concurrent occurrence of avian cholera and inclusion body hepatitis.

The occurrence of inclusion body hepatitis (IBH) on 11 properties in Australia is described. The 6 Victorian cases occurred between 1967 and 1973 and were identified as incidental findings accompanying other diseases or occurred as ill-defined, minor economic disease episodes. In well-managed flocks the extra mortality attributable to IBH was as low as 1.8% which represented a 50% increase in total mortality. The 1973 epidemic in New South Wales on 5 related farms resulted in flock mortality of 8.4% to 32.3% and an average mortality of 19.5% of 814,000 birds. For uninfected flocks of 307,000 birds the average mortality was 8.5%. Higher mortality in male flocks was statistically highly significant as was lowered efficiency of feed conversion. Growth rate in both sexes was depressed by about 0.15 kg in 70 days and heavy downgrading at processing occurred. Secondary infections were important. The cardinal features of IBH were fatal necrotising hepatitis with Cowdry type-A intranuclear inclusion body formation; secondary bacterial infections were also important causes of loss.

Inclusion Body Hepatitis (IBH) is an emerging acute viral disease in Sri Lanka caused by Fowl Adenoviruses (FAdVs) of the genus Aviadenovirus, family Adenoviridae. It primarily affects broilers aged 3–7 weeks, leading to liver damage and significant economic losses. Histopathological diagnosis of IBH is based on the presence of pathognomonic intranuclear basophilic inclusion bodies in degenerating hepatocytes. Molecular diagnosis of IBH involves the detection of the hexon gene of the FAdV using conventional PCR. The serotyping, based on the hexon gene L1 loop variable region, is important for developing effective vaccination strategies. This study aimed to identify circulating FAdV serotypes responsible for IBH in broilers in the Western, North Western, and Central provinces of Sri Lanka. A total of 76 dead broilers were collected/ received; Western (n = 23), North Western (n = 38), and Central (n = 15). Clinical history, vaccination data, and performance records were documented. The liver was the primary organ examined. Gross and histopathological evaluations were performed, and histopathological confirmation of IBH was based on intranuclear basophilic inclusion body detection. The gross lesions observed in all the examined livers had hepatomegaly, petechial haemorrhages and multifocalcoalescing necrotic patches. PCR was conducted on histopathologically confirmed IBH-positive samples (n = 28/76), of which 19 were PCR-positive (n = 19/28). Three PCR-positive samples from each province were selected for hexon gene sequencing using the Sanger method. Sequencing revealed serotype FAdV-8b in both the North Western and Central provinces and FAdV-11 only in the North Western province. No sequence data could be obtained from the Western province. These findings highlight the presence of different FAdV serotypes contributing to IBH in Sri Lanka and emphasise the need for region-specific surveillance and vaccination strategies.

Numerous reports and epidemiologic investigations in recent years identify adenoviral infection as an ongoing to increasing, international disease in commercially raised chickens. Impression smear cytopathology was evaluated as a tool for the diagnosis of adenoviral inclusion body hepatitis (IBH). In this study, 92, paired, Romanowsky-stained cytopathologic preparations and hematoxylin-and-eosin-stained histopathologic liver sections were evaluated from 54 chickens with experimentally induced or naturally occurring IBH. Large intranuclear inclusion bodies typical of adenoviruses were visible within hepatocytes on both cytopathology and histopathology. Cytopathologic to histopathologic percent positive agreement and percent negative agreement were 94% and 90%, respectively, with Π= 0.81 (0.61-1.01, 95% confidence, P < 0.001). A subset of 20 cytopathologic samples evaluated by eight veterinary professionals as consistent or inconsistent with IBH yielded an average of 66% positive agreement and 98% negative agreement to the histopathologic diagnosis, across all observers, with Π= 0.61 (0.53-0.68, 95% confidence, P < 0.001), resulting in a positive predictive value of 99% and a negative predictive value of 67%. Interobserver agreement was slightly higher (76% positive agreement, 94% negative agreement, Π= 0.68 [0.65-0.71], 95% confidence, P < 0.001) within the 12 of these samples that originated from natural disease, with stable positive and negative predictive values. A rapid, cost-effective, tentative diagnosis of IBH via impression smear cytopathology at the time of necropsy can streamline further confirmatory laboratory testing and facilitate timely communication in the interim to affected parties, especially in locations with delayed access to a diagnostic laboratory.

Molecular and pathological characterization of fowl adenovirus serotype 2 linked to inclusion body hepatitis in broiler chickens.

The fine structure of intranuclear inclusion bodies in the hepatic cells of chickens naturally affected with inclusion body hepatitis was studied comparing them with the inclusions seen with light microscopy. Ultra-structurally the inclusions were classified into two types depending on whether they contained virus particles or not. The first type consisted of virus particles, granular material and loose granular material, and sometimes concentric-circular lamellae enclosing the virus core. It is suggested that the virus particles are adenoviruses. This type corresponded to the basophilic inclusions seen with light microscopy. The second type was without virus particles and was subdivided into two forms, one consisting of fibrillar-granular material and the other of crystals composed of filaments. These corresponded to the eosinophilic inclusions seen with light microscopy. Eosinophilic inclusions were present in all 20 cases of inclusion body hepatitis, whereas the basophilic inclusions were present in only six. The presence of adenovirus particles might suggest that they are the aetiology of this condition, although they were present in only six of the 20 cases examined. The significance of the inclusions without viral particles was not adequately elucidated, but it was suggested they are degenerating material present in cells dying from the effects of the viral infection.