Pathological and immunohistochemical study of chickens with co-infection of Marek's disease virus and chicken anaemia virus

Mobile Robot + IoT: Project of Sustainable Technology for Sanitizing Broiler Poultry Litter

The traditional aviary decontamination process involves farmers applying pesticides to the aviary's ground. These agricultural defenses are easily dispersed in the air, making the farmers susceptible to chronic diseases related to recurrent exposure. Industry 5.0 raises new pillars of research and innovation in transitioning to more sustainable, human-centric, and resilient companies. Based on these concepts, this paper presents a new aviary decontamination process that uses IoT and a robotic platform coupled with ozonizer (O3) and ultraviolet light (UVL). These clean technologies can successfully decontaminate poultry farms against pathogenic microorganisms, insects, and mites. Also, they can degrade toxic compounds used to control living organisms. This new decontamination process uses physicochemical information from the poultry litter through sensors installed in the environment, which allows accurate and safe disinfection. Different experimental tests were conducted to construct the system. First, tests related to measuring soil moisture, temperature, and pH were carried out, establishing the range of use and the confidence interval of the measurements. The robot's navigation uses a back-and-forth motion that parallels the aviary's longest side because it reduces the number of turns, reducing energy consumption. This task becomes more accessible because of the aviaries' standardized geometry. Furthermore, the prototype was tested in a real aviary to confirm the innovation, safety, and effectiveness of the proposal. Tests have shown that the UV + ozone combination is sufficient to disinfect this environment.

First report of co-infections of Marek's disease virus and chicken infectious anaemia virus in poultry flocks in Nigeria

Marek's disease (MD) and chicken infectious anaemia (CIA) are viral immunosuppressive diseases of poultry caused by the MD virus (MDV) and CIA virus (CIAV) respectively. Despite vaccination against MD, the incidence of the disease in vaccinated poultry flocks in Nigeria persists. However, underlying factors like co-infection with CIAV have not been investigated in the country. This study was designed to investigate possible co-infections of MDV and CIAV in poultry flocks in Nigeria. In 2016, tumorous tissue samples were collected from suspected cases of MD at necropsy in Jos, Plateau State, Nigeria. The samples collected were fixed in formalin for histopathological examination, genomic DNA was extracted from a second part and analysed by polymerase chain reaction (PCR), targeting the meq and VP1 genes of the MDV and CIAV, respectively. The histology results revealed that the cutaneous and proventricular lymphomas were characterized by large numbers of mononuclear cellular infiltrates admixed with heterophils. The PCR results revealed that MDV was detected in 66.7% (16/24), CIAV in 45.8% (11/24), and co-infections of MDV and CIAV were detected in 45.8% (11/24) of the samples analysed. In addition, co-infections of MD and CIA were recorded in 100% (6/6) and 27.7% (5/18) of broilers and layer/pullet' samples respectively. Phylogenetic analysis of the meq gene sequences revealed that the Nigerian MDV clusters with very virulent MDV from Egypt and Italy. While, CIAV sequences were genotype II and genotype III and clustered with CIAVs from Cameroon and China. This is the first report of co-infections of MD and CIA in Nigeria.

Differences in Pathogenicity and Vaccine Resistance Discovered between Two Epidemic Strains of Marek's Disease Virus in China

Despite highly effective vaccines, Marek's disease (MD) causes great economic loss to the poultry industry annually, largely due to the continuous emergence of new MD virus (MDV) strains. To explore the pathogenic characteristics of newly emerged MDV strains, we selected two strains (AH/1807 and DH/18) with clinically different pathotypes. We studied each strain's infection process and pathogenicity and observed differences in immunosuppression and vaccine resistance. Specific pathogen-free chickens, unvaccinated or vaccinated with CVI988, were challenged with AH/1807 or DH/18. Both infections induced MD damage; however, differences were observed in terms of mortality (AH/1807: 77.8%, DH/18: 50%) and tumor rates (AH/1807: 50%, DH/18: 33.3%). The immune protection indices of the vaccine also differed (AH/1807: 94.1, DH/18: 61.1). Additionally, while both strains caused interferon-β and interferon-γ expression to decline, DH/18 infection caused stronger immunosuppression than AH/1807. This inhibition persisted even after vaccination, leading to increased replication of DH/18 that ultimately broke through vaccine immune protection. These results indicate that both strains have different characteristics, and that strains such as DH/18, which cause weaker pathogenic damage but can break through vaccine immune protection, require further attention. Our findings increase the understanding of the differences between epidemic strains and factors underlying MD vaccination failure in China.

Retrospective Investigation and Genetic Variation Analysis of Chicken Infectious Anemia in Shandong Province, 2020-2022

Chicken infectious anemia (CIA) is a vertical transmission infectious chicken disease caused by the chicken infectious anemia virus (CAV). The disease can induce stunting and immunosuppression in chicks by infecting bone marrow-derived stem cells, causing huge economic losses for the poultry industry. To determine the prevalence of CIA in Shandong Province, China, 854 suspected CIA samples were collected and analyzed in 13 cities in Shandong from 2020 to 2022. The PCR results showed that a total of 115 CAV were isolated. The CAV-positive rates were 17.21% (26/151) in 2020, 12.23% (35/286) in 2021, and 12.94% (54/417) in 2022, with severe mixed infections. Among them, CAV and fowl adenovirus (FAdV) were the most common, accounting for 40.86%. VP1 gene homology analysis showed that isolated strains shared 96.1-100% homology with the previously reported CAV strains. Genetic variation analysis showed that most of the isolated CAV strains were located in genotype A. These results indicate that CIA infection in Shandong chickens in recent years has been prevalent and mixed infections are common, but there were no significant genetic variations. Our results extend the understanding of the prevalence and genetic evolution of CIA in Shandong Province. They will offer new references for further study of the epidemiology and virus variation and the prevention and control of this disease.

Molecular Epidemiology and Pathogenic Characterization of Novel Chicken Infectious Anemia Viruses in Henan Province of China

Chicken infectious anemia (CIA) is an immunosuppressive disease caused by the chicken infectious anemia virus (CIAV) resulting in heavy economic losses once an outbreak is established. This study conducted a systematic analysis of the epidemiology and pathology of CIA in Henan province, China. A total of 437 clinical tissue samples and 120 poultry disease-related live attenuated vaccines were collected during 2017–2020; of which 45 were positive for CIAV nucleic acid, with a positive rate of 8.08%. Our results showed that genome sequence similarity among a total of 12 CIAV isolates was high, and ranged from 97.1 to 99.3%, and their similarity to the vaccine strains Cux-1 and Del-Ros ranged from 97.8 to 98.6%. However, There were mutations in the locus of the major capsid proteins VP1, VP2, and VP3 among all isolates. The subsequent sequence analysis indicated that the isolates of HN-4 and HN-8 showed genetic recombination and follow up animal experiments revealed that HN-4 might be a pathogenic strain. Our results reveal that both field infection and non-CIAV vaccines contamination promote the epidemiology of CIAV in China and some dominant epidemic viruses have undergone recombination and evolution. This study provides important information to help with the prevention and control of CIAV in the poultry industry.

Effect of Goose Parvovirus and Duck Circovirus Coinfection in Ducks

Introduction

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.

Material and Methods

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).

Results

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.

Conclusion

These results indicate that GPV and DuCV synergistically potentiate their replication and pathogenicity in coinfected ducks.

The Role of Apoptin in Chicken Anemia Virus Replication

Apoptin is the Vp3 protein of chicken anemia virus (CAV), which infects the thymocytes and erythroblasts in young chickens, causing chicken infectious anemia and immunosuppression. Apoptin is highly studied for its ability to selectively induce apoptosis in human tumor cells and, thus, is a protein of interest in anti-tumor therapy. CAV apoptin is known to localize to different subcellular compartments in transformed and non-transformed cells, depending on the DNA damage response, and the phosphorylation of several identified threonine residues. In addition, apoptin interacts with molecular machinery such as the anaphase promoting complex/cyclosome (APC/C) to inhibit the cell cycle and induce arrest in G2/M phase. While these functions of apoptin contribute to the tumor-selective effect of the protein, they also provide an important fundamental framework to apoptin’s role in viral infection, pathogenesis, and propagation. Here, we reviewed how the regulation, localization, and functions of apoptin contribute to the viral life cycle and postulated its importance in efficient replication of CAV. A model of the molecular biology of infection is critical to informing our understanding of CAV and other related animal viruses that threaten the agricultural industry.

Virus-Induced Immunosuppression in Chickens

A healthy immune system is a cornerstone for poultry production. Any factor diminishing the immune responses will affect production parameters and increase cost. There are numerous factors, infectious and noninfectious, causing immunosuppression (IS) in chickens. This paper reviews the three viral diseases that most commonly induce IS or subclinical IS in chickens: Marek's disease virus (MDV), chicken infectious anemia virus (CIAV), and infectious bursal disease virus (IBDV), as well as the interactions among them. MDV-induced IS (MDV-IS) affects both humoral and cellular immune responses. It is very complex, poorly understood, and in many cases underdiagnosed. Vaccination protects against some but not all aspects of MDV-IS. CIAV induces apoptosis of the hemocytoblasts resulting in anemia, hemorrhages, and increased susceptibility to bacterial infections. It also causes apoptosis of thymocytes and dividing T lymphocytes, affecting T helper functions, which are essential for antibody production and cytotoxic T lymphocyte (CTL) functions. Control of CIAV is based on vaccination of breeders and maternal antibodies (MAbs). However, subclinical IS can occur after MAbs wane. IBDV infection affects the innate immune responses during virus replication and humoral immune responses as a consequence of the destruction of B-cell populations. Vaccines with various levels of attenuation are used to control IBDV. Interactions with MAbs and residual virulence of the vaccines need to be considered when designing vaccination plans. The interaction between IBDV, CIAV, and MDV is critical although underestimated in many cases. A proper control of IBDV is a must to have proper humoral immune responses needed to control CIAV. Equally, long-term control of MDV is not possible if chickens are coinfected with CIAV, as CIAV jeopardizes CTL functions critical for MDV control.

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.

Efficacy of CpG-ODN and Freund's immune adjuvants on antibody responses induced by chicken infectious anemia virus VP1, VP2, and VP3 subunit proteins

Chicken infectious anemia virus is an important pathogen that causes severe anemia and immunosuppression in chickens, leading to serious economic losses worldwide in the poultry industry. However, no commercialized inactivated vaccine, subunit vaccine, or genetically engineered vaccine that is effective for controlling this virus is available. In this study, 3 recombinant plasmids were constructed to produce corresponding viral proteins in an Escherichia coli system. The immune effects of the subunit proteins accompanied by CpG-ODN or Freund's immune adjuvants were evaluated and analyzed in systemic animal experiments. The results showed that VP1 induced the highest antibody titers with the participation of VP2 protein, indicating better protection under combined treatment, and the CpG-ODN adjuvant induced higher antibody titers and smaller dispersion of antibody titers than Freund's adjuvants. This is the first study to demonstrate that VP1 protein formulated with VP2 and CpG-ODN adjuvant can induce highest antibody titers and markedly enhance the immune response, indicating its promise as a vaccine candidate.

Molecular epidemiology of chicken anaemia virus in sick chickens in China from 2014 to 2015

Chicken anaemia virus (CAV), a member of the genus Gyrovirus, is the etiological agent of chicken infectious anaemia. CAV infects bone marrow-derived cells, resulting in severe anaemia and immunosuppression in young chickens and a compromised immune response in older birds. We investigated the molecular epidemiology of CAV in sick chickens in China from 2014 to 2015 and showed that the CAV-positive rate was 13.30%, in which mixed infection (55.56%) was the main type of infection. We isolated and identified 15 new CAV strains using different methods including indirect immunofluorescence assay and Western Blotting. We used overlapping polymerase chain reaction to map the whole genome of the strains. Phylogenetic analyses of the obtained sequences and related sequences available in GenBank generated four distinct groups (A-D). We built phylogenetic trees using predicted viral protein (VP) sequences. Unlike CAV VP2s and VP3s that were well conserved, the diversity of VP1s indicated that the new strains were virulent. Our epidemiological study provided new insights into the prevalence of CAV in clinical settings in recent years in China.

Molecular characterization of Marek's disease virus in a poultry layer farm from Colombia

Marek's disease (MD) is a lymphoproliferative disease caused by an Alphaherpesvirus, genus Mardivirus, serotype 1 (Gallid Herpesvirus 2, GaHV-2) that includes all known pathogenic strains. In addition to Marek's disease virus (MDV) serotype 1, the genus includes 2 distinct nonpathogenic serotypes: serotype 2 (GaHV-3) and serotype 3 (Meleagridis Herpesvirus 1, MeHV-1) which are used in commercially available vaccines against MD. As a result of vaccination, clinical signs are not commonly observed, and new cases are usually associated with emerging variant strains against which the vaccines are less effective. In this study, a commercial layer farm showing clinical signs compatible with MDV infection was evaluated. Histological lesions and positive immunohistochemistry in the sciatic nerve and thymus were compatible with cytolytic phase of MD. GaHV-2, GaHV-3 and MeHV-1 were identified by PCR and qPCR in blood samples from 17 birds with suspected MD. Analysis of the Meq gene of the Colombian GaHV-2 isolate revealed a 99% sequence identity with Asian strains, and in the phylogenetic analysis clustered with vv+ MDV. The analysis of amino acid alignments demonstrated an interruption of the proline rich region in P176A, P217A and P233L positions, which are generally associated with vv+ strains. Some of these changes, such as P233L and L258S positions have not been reported previously. In addition, primary cell cultures inoculated with lymphocytes isolated from the spleen showed typical cytopathic effect of GaHV-2 at 5 d post infection. Based on the molecular analysis, the results from this study indicate the presence of vv+ MDV infection in commercial birds for the first time in Colombia. It is recommended to perform further assays in order to demonstrate the pathotype characteristics in vivo.

Marek's disease virus oncoprotein Meq physically interacts with the chicken infectious anemia virus-encoded apoptotic protein apoptin

Marek's disease (MD) is a neoplastic disease of poultry caused by Marek's disease virus (MDV), a highly contagious alphaherpesvirus. Meq, the major MDV oncoprotein, induces neoplastic transformation of T-cells through several mechanisms, including inhibition of apoptosis. In contrast, the chicken anemia virus (CAV)-encoded protein apoptin (VP3) is a powerful inducer of apoptosis of tumor cells, a property that is exploited for anticancer therapeutics. Although the molecular mechanisms of selective induction of tumor cell apoptosis by apoptin are not fully understood, its tumor cell–restricted nuclear translocation is thought to be important. Co-infection with MDV and CAV is common in many countries, CAV antigens are readily detectable in MD lymphomas, and the MDV-transformed T-lymphoblastoid cell lines such as MSB-1 is widely used for propagating CAV for vaccine production. As MDV-transformed cell lines express high levels of Meq, we examined here whether CAV-encoded apoptin interacts with Meq in these cells. Using immunofluorescence microscopy, we found that apoptin and Meq co-localize to the nucleus, and biochemical analysis indicated that the two proteins do physically interact. Using a combination of Meq mutagenesis and co-immunoprecipitation, we demonstrate that apoptin interacts with Meq within a region between amino acids 130 and 140. Results from the IncuCyte assay suggested that Meq inhibits apoptin-induced apoptosis activity. In summary, our findings indicate that Meq interacts with and inhibits apoptin. Insights into this novel interaction between Meq and apoptin will relevance for pathogenesis of coinfections of the two viruses and in CAV vaccine production using MDV-transformed cell lines.

Characterization of full genome sequences of chicken anemia viruses circulating in Egypt reveals distinct genetic diversity and evidence of recombination

Chicken anemia virus (CAV) is one of the commercially important diseases of poultry worldwide. In Egypt, CAV has been reported to be a potential threat to the commercial poultry sectors. Hence, this study was aimed at isolation and full genomic analysis of CAVs circulating in chicken populations in different geographical location in Egypt. A total of 42 samples were collected from broiler chicken flocks in 9 governorates in Egypt from 12 to 42 days of age. The mortality rate observed among chickens was ranging from 3% to 22%. Nineteen out of 42 farms were found positive for the CAV genome by polymerase chain reaction (PCR). Full genome sequencing was conducted for 18 positive samples. Genetic analysis revealed a high similarity of >99% in 11 viruses with the vaccine strain Del-Ros; while the other seven samples shared close similarity to CAV field strains isolated from China, Taiwan, and Brazil. The data also indicated Q139 and Q144 amino acids substitutions among the VP1 of Egyptian field strains, which are known to be important in virus replication and spread. Phylogenetic analysis of the sequenced viruses (n = 18) based on either the full gene nucleotide sequence or VP1 coding sequence, suggested the circulation of four distinct genotypes in Egypt designated as group A, B, C and D. Moreover, evidence of recombination was detected among four Egyptian CAVs located within group A. The findings of this study succeeded to elucidate the epidemiological and genetic features of CAVs circulating in Egypt, and underscores the important of CAVs surveillance.

Chicken anaemia virus evades host immune responses in transformed lymphocytes

Chicken anaemia virus (CAV) is a lymphotropic virus that causes anaemia and immunosuppression in chickens. Previously, we proposed that CAV evades host antiviral responses in vivo by disrupting T-cell signalling, but the precise cellular targets and modes of action remain elusive. In this study, we examined gene expression in Marek's disease virus-transformed chicken T-cell line MSB-1 after infection with CAV using both a custom 5K immune-focused microarray and quantitative real-time PCR at 24, 48 and 72 h post-infection. The data demonstrate an intricate equilibrium between CAV and the host gene expression, displaying subtle but significant modulation of transcripts involved in the T-cell, inflammation and NF-κB signalling cascades. CAV efficiently blocked the induction of type-I interferons and interferon-stimulated genes at 72 h. The cell expression pattern implies that CAV subverts host antiviral responses and that the transformed environment of MSB-1 cells offers an opportunistic advantage for virus growth.

Effects of T-2 Toxin on Turkey Herpesvirus-Induced Vaccinal Immunity Against Marek's Disease

T-2 toxin, a very potent immunotoxic Type A trichothecene, is a secondary metabolite produced primarily by Fusarium spp., which grows on cereal grains and can lead to contaminated livestock feed. Repeated exposure to T-2 toxin has been shown to cause immunosuppression and decrease the resistance of exposed animals to a variety of infectious diseases; however, the effects of T-2 toxin on Marek's disease (MD) vaccinal immunity have not been reported. Four trials were conducted to determine the effects of T-2 toxin on vaccinal immunity against MD. Day-old, white leghorn chicks of Avian Disease and Oncology Laboratory line 15I5 × 71 were treated daily for 7 days via crop gavage with T-2 toxin at a sublethal dose of 1.25 mg/kg body weight. Treated and untreated chicks were also vaccinated with turkey herpesvirus (HVT) at hatch and were challenged with the JM strain of MD virus (MDV) at 8 days of age. Chickens were tested for HVT viremia at 1 wk postvaccination immediately before challenge, and for HVT and MDV viremia at 3 wk postchallenge. Chickens were observed for the development of MD lesions and mortality within 8 wk of age. T-2 toxin significantly reduced body weight and titers of HVT viremia within 7 days after hatch. T-2 toxin shortened the incubation period for the development of MD lesions and mortality, but only in unvaccinated chickens. The percent MD protection in T-2-toxin-treated, HVT-vaccinated chickens ranged from 82% to 96% and was comparable to that in HVT-vaccinated untreated control chickens (89%-100%). The data suggest that exposure of chickens to sublethal doses of T-2 toxin for 7 consecutive days after hatch may influence the development of 1) HVT viremia; and 2) MD lesions and mortality, but only in unvaccinated chickens.

Persistence of chicken anemia virus antigen and inclusions in spontaneous cases of Marek's disease visceral lymphomas in broiler chickens at slaughterhouses

The chicken anemia virus (CAV) and Marek’s disease virus (MDV) infect chickens worldwide; a single or dual infection by these viruses has a great impact on poultry production. In the present study, we examined the existence of CAV antigen and its inclusions in Marek’s disease (MD) lymphomas in chickens in the slaughterhouses of Iwate prefecture, Japan. Forty-nine spleens and 13 livers with different degrees of nodular lesions were histopathologically examined at our laboratory. Grossly, the tested organs showed various sizes and anatomical architectures. Based on the cellular morphology and the infiltrative nature of the neoplastic lymphocytes, MD was confirmed in 76% (37/49) of the spleens and 92% (12/13) of the livers. The lesions of MD, according to the pattern of lymphocytic accumulation in the affected organs, were divided into multifocal, coalesced and diffuse. CAV intranuclear inclusion bodies were detected within the small and the large bizarre lymphocytes of the MD lymphomas in 2 livers and 9 spleens, and the immunostaining test for CAV confirmed the persistence of CAV antigens and inclusions in the neoplastic cells. This study demonstrated the persistence of CAV infection within the neoplastic cells of naturally occurring MD lymphomas in chickens.

Respiratory viruses and torque teno virus in adults with acute respiratory infections

Objective

To define the molecular epidemiology of respiratory viral infections in adult patients.

Methods

Nasal and throat swabs were collected from all adult patients with influenza-like illness (ILI), acute respiratory infection (ARI), or severe ARI (SARI) admitted to a tertiary hospital in Surakarta, Indonesia, between March 2010 and April 2011 and analyzed for 19 respiratory viruses and for torque teno virus (TTV) and human gyrovirus (HGyV).

Results

Respiratory viruses were detected in 61.3% of the subjects, most of whom had ARI (90.8%, OR = 11.39), were hospitalized (96.9%, OR = 22.31), had asthma exacerbation (90.9%, OR = 8.67), and/or had pneumonia (80%, OR = 4.0). Human rhinovirus (HRV) A43 predominated. Influenza A H3N2, human metapneumovirus (HMPV) subtypes A1 and A2, the influenza B virus, human adenovirus B, and human coronavirus OC43 were also detected. All respiratory viruses were detected in the transition month between the rainy and dry seasons. No mixed respiratory virus infection was found. Coinfections of the influenza A H3N2 virus with TTV, HMPV with TTV, HRV with TTV, and human parainfluenza virus-3 with TTV were found in 4.7, 2.8, 19.8, and 0.9% of the samples, respectively.

Conclusions

This study highlights the need to perform routine detection of respiratory viruses in adults hospitalized with ARI, asthma exacerbation, and/or pneumonia.

Chicken anemia virus and avian gyrovirus 2 as contaminants in poultry vaccines

This study focuses on the detection of chicken anemia virus (CAV) and avian gyrovirus 2 (AGV2) genomes in commercially available poultry vaccines. A duplex quantitative real-time PCR (dqPCR), capable of identifying genomes of both viruses in a single assay, was employed to determine the viral loads of these agents in commercially available vaccines. Thirty five vaccines from eight manufacturers (32 prepared with live and 3 with inactivated microorganisms) were examined. Genomes of CAV were detected as contaminants in 6/32 live vaccines and in 1/3 inactivated vaccines. The CAV genome loads ranged from 6.4 to 173.4 per 50 ng of vaccine DNA (equivalent to 0.07 to 0.69 genome copies per dose of vaccine). Likewise, AGV2 genomes were detected in 9/32 live vaccines, with viral loads ranging from 93 to 156,187 per 50 ng of vaccine DNA (equivalent to 0.28-9176 genome copies per dose of vaccine). These findings provide evidence for the possibility of contamination of poultry vaccines with CAV and AGV2 and they also emphasize the need of searching for these agents in vaccines in order to ensure the absence of such potential contaminants.

New insight into the structure, development, functions and popular disorders of bursa Fabricii

Humoral immune responses in birds, contrary to mammals, depend on the normal functioning of bursa Fabricii. Recent studies have delivered new information about the structure, development and origin of cells that compose the bursa environment. Several viral infections affect bursa, causing lymphocyte depletion or excessive proliferation. This review summarizes data on the development and histology of healthy bursa and introduces some common disorders that affect this organ.

Human gyrovirus DNA in human blood, Italy

HGyV in blood suggests the infection might be systemic.

Human gyrovirus (HGyV) is a recent addition to the list of agents found in humans. Prevalence, biologic properties, and clinical associations of this novel virus are still incompletely understood. We used qualitative PCRs to detect HGyV in blood samples of 301 persons from Italy. HGyV genome was detected in 3 of 100 solid organ transplant recipients and in 1 HIV-infected person. The virus was not detected in plasma samples from healthy persons. Furthermore, during observation, persons for whom longitudinal plasma samples were obtained had transient and scattered presence of circulating HGyV. Sequencing of a 138-bp fragment showed nucleotide identity among all the HGyV isolates. These results show that HGyV can be present in the blood of infected persons. Additional studies are needed to investigate possible clinical implications.

Pathological and immunohistochemical studies of subclinical infection of chicken anemia virus in 4-week-old chickens

Subclinical infection of chicken anemia virus (CAV) at 4 to 6 weeks of age, after maternal antibodies have waned, is implicated in several field problems in broiler flocks. In order to understand the pathogenesis of subclinical infection with CAV, an immunopathological study of CAV-inoculated 4-week-old SPF chickens was performed. Sixty 4-week-old SPF chickens were equally divided into CAV and control groups. The CAV group was inoculated intramuscularly with the MSB1-TK5803 strain of CAV. Neither mortality nor anemia was detected in the CAV and control groups. In the CAV group, no signs were observed, except that some chickens were grossly smaller compared with the control group. Sporadic thymus lobes appeared to be reddening and atrophied. Within the first two weeks p.i. of CAV, there was a mild to moderate depletion of lymphocytes in the thymus cortex and spleen in some chickens. Moreover, lymphoid depletion of the bursa of Fabricius, proventriculus and cecal tonsils was observed. Hyperplastic lymphoid foci were observed in the liver, lungs, kidneys and heart at the 4th week p.i. of CAV. Immunohistochemically, a moderate lymphoid depletion of CD4(+)and CD8(+) T cells in the thymus cortex and spleen was observed in some chickens within two weeks p.i. of CAV. CAV inclusions and antigens were detected infrequently in the thymus cortex and spleen. It could be concluded that the immunosuppression in subclinical infection with CAV occurs as a result of reduction of cellular immunity.