Coinfection with porcine circovirus type 2 and Glaesserella parasuis serotype 4 enhances pathogenicity in piglets.

Coinfection of Porcine circovirus type 2 (PCV2) and Glaesserella parasuis type 4 (GPS4) is widespread clinically, resulting in high morbidity and mortality, however, interactions between the two pathogens during coinfection and the coinfection pathogenesis are poorly understood. In this study, a piglet model coinfected with PCV2 and GPS4 was established; coinfection of the piglets' group showed more obvious symptoms, such as high fever and emaciation, and more severe histological lesions appeared in various organs. Importantly, piglets in the coinfection group produced lower levels of PCV2 and GPS4 antibodies, and showed high levels of inflammatory cytokines, TLR2, and TLR4, while the levels of CD4, CD8, MHC II, costimulatory molecules, and IL-12p40 were decreased. In addition, a model of macrophage 3D4/21 cells coinfection with PCV2 and GPS4 was established, coinfected cells exhibited increased expression of the cytokines IL-6, IL-8, TNF-α, IL-1ß, and the receptors TLR2, TLR4, while decreased MHC II. We further demonstrate that cytokine production is associated with the activation of NF-κB and NLRP3 inflammasome signaling pathways, and TLR4 is also involved. Altogether, our findings suggest that coinfection with PCV2 and GPS4 exacerbates the inflammatory response, resulting in severe tissue damage, and probably impaired macrophage antigen presentation and T cell activation, resulting in immune dysregulation, aggravating host infection.

Effects of duck circovirus on immune function and secondary infection of Avian Pathogenic Escherichia coli.

Duck circovirus (DuCV) infection occurs frequently in ducks in China and is generally believed to lead to immunosuppression and secondary infection, though there has been a lack of detailed research and direct evidence. In this study, one-day-old Cherry Valley ducklings were artificially infected with DuCV alone and co-infected with DuCV and Avian Pathogenic Escherichia coli (APEC). The immune indexes at 32 d old were systematically monitored, including immune organ weight, lymphocyte transformation rate, IL-10, IL-12, soluble CD4 (sCD4), soluble CD8 (sCD8), IFN-γ, viral loads in each organ, APEC colonization, and so on. The results showed the development of immune organs in ducklings was affected, resulting in a decrease in the lymphocyte transformation rate (LTR), IL-12, sCD4, sCD8, IFN-γ and an increase in IL-10 content at 8 to 32 d postinfection (dpi). In the detection of virus loads in some organs, it was found that 8 dpi, DuCV existed stably in various organs, suggesting the importance of preventing and controlling the virus in the early stage of culture. The results of exploring the DuCV infection that shows some influence on secondary infection by APEC. The results showed that DuCV infection could significantly enhance the pathogenicity of APEC and the colonization ability of APEC in vivo. DuCV can induce more serious APEC infection in 24 dpi than in 14 dpi. Based on the above results, it can be concluded that DuCV infection will affect the immune system, cause immunosuppression, and lead to more serious secondary infection.

First detection and phylogenetic analysis of porcine circovirus 3 in female donkeys with reproductive disorders.

BACKGROUND: PCV3 is a pathogen associated with porcine dermatitis and nephropathy syndrome (PDNS)-like clinical signs, reproductive failure, and cardiac and multiorgan inflammation, which was newly identified in 2016 in sows in USA. Recently, PCV3 has also been identified from several non-porcine species like (cattle, dog, wild boar, deer, mice and ticks). However, PCV3 infection in donkey is not well established. Since 2019, 300 blood samples were collected from female donkey, which was characterized by abortion and sterility, in Liaocheng city of China. RESULTS: In the present study, an investigation of PCV3 in donkey blood samples was undertaken employing by real time PCR. Positive rates of PCV3 in donkeys reach to 21.0 %. In addition, one full-length PCV3 genome sequence was obtained, and it had a highest identity with porcine circovirus 3 PCV3/CN/Nanjing2017 strain and is clustered to PCV3a genotype based on ORF2 sequences. CONCLUSIONS: This is the first report of detection of PCV3 from female donkeys presenting reproductive failure in large-scale donkey farms, China. In addition, the PCV3 strain identified in this study shared the closest relationship with those from porcine, suggesting that PCV3 may be transmitted from pigs to donkeys. Totally, PCV3 infection in donkey should be concerned although the association between it and reproductive failure are not better understood.

Cross-species pathogenicity of gyrovirus 3 in experimentally infected chickens and mice.

Gyrovirus 3 (GyV3) has been identified in humans and other hosts, suggesting its cross-species pathogenicity, which poses an increased public health risk. In the current study, we established chicken and mouse models of GyV3 infection. We found that GyV3 induced persistent infections, characterized by viremia, aplastic anemia, immunosuppression, and systematic lymphocytic inflammation, in both species. Kinetic viral loads and antigen expression demonstrated rapid viral replication and broad tissue tropism of GyV3 in both models. The highest viral loads and the strongest antigen immunostaining were present in bone marrow and cerebrum in both chickens and mice, indicating that these are target tissues for GyV3. Genetic diversity analysis of VP1 in infected chickens and mice showed that GyV3 adapts to new hosts via rapid evolution of the hypervariable region of the gene encoding the structural protein VP1. Overall, our results indicate that GyV3 is a cross-species pathogenic virus; therefore, more attention needs to be paid to high levels of GyV3-induced neurotropism and aplastic anemia as a public health risk.

Co-infection status of novel parvovirus's (PPV2 to 4) with porcine circovirus 2 in porcine respiratory disease complex and porcine circovirus-associated disease from 1997 to 2012.

As global pig health diseases, porcine respiratory disease complex (PRDC) and porcine circovirus-associated disease (PCVAD) generate substantial economic losses despite pigs been vaccinated against the primary causative virus, highlighting the importance of understanding virome interactions and specifically co-factor infections. Established primary endemic pathogens for PRDC include porcine circovirus 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSv) and swine influenza virus (SIV), and PCV2 aetiology in interaction with other co-infecting viruses can result in PCVAD. Porcine parvovirus (PPV) 1 is a well-characterized virus with an available vaccine preventing reproductive failure in sows. However, whilst novel PPV 2 to 7 viruses have been identified since 2001, their viral pathogenic potential in clinical and subclinical disease remains to be determined. Therefore, this study has sought to develop a better understanding of their potential role as associated co-infections in PRDC and PCVAD by examining archival samples for the presence of PCV2 and the novel parvoviruses PPV2-4 from clinically diseased pigs across production age stages. Epidemiologically, the novel PPV2 was found to be the most prevalent within the fattener age group with PPV2-4 statistically associated with pig respiratory disease and enteric ulcers. Additionally, statistical modelling by latent class analysis (LCA) on veterinary pathology scored pigs found a clustering co-factor association between PPV2 and PCV2, suggesting the novel PPV may be involved in PRDC and PCVAD. Phylogenetic analysis of novel PPVs revealed the PPV2 capsid evolution to be diverged from the original strains with a low nucleotide homology of 88%-96% between two distinct clades. These findings determine that novel PPV 2-4 viruses are statistically associated as co-infectors in a diseased pig population, and significantly detected PPV2 clustering co-infection frequency with PCV2 in PRDC and PCVAD diseased pigs through LCA analysis.

Coinfection of novel goose parvovirus-associated virus and duck circovirus in feather sacs of Cherry Valley ducks with feather shedding syndrome.

Since 2017, an infectious disease, named feather shedding syndrome (FSS), has consistently broken out in Cherry Valley ducks in East China. The sick ducks showed the new clinical symptoms of feather shedding and being plucked off with difficulty after slaughter. The high incidence rate of 20 to 70% predominantly happened in ducks of 4 to 5 wk of age, and nearly 40% mortality rate was observed in infected ducks. To explore the possible role of novel goose parvovirus-associated virus (NGPV) and duck circovirus (DuCV) in this disease, a total of 540 feather sac samples were collected from sick ducks with FSS. The infection rates of NGPV and DuCV in samples were 82.78 and 78.89%, respectively, and the coinfection rate of the 2 viruses was 70.00%. Notably, ducks of 4 to 5 wk of age usually presented obvious and severe FSS in the flocks with high codetection rate of NGPV and DuCV. Furthermore, 9 NGPV strains were isolated from feather sacs and 5 synchronous amino acid mutations were demonstrated in VP3 protein. These results indicated that coinfection of NGPV and DuCV might play an important role in duck FSS disease.

Porcine circovirus type 3 (PCV3) infection in grower pigs from a Thai farm suffering from porcine respiratory disease complex (PRDC).

Porcine circovirus type 3 (PCV3) is a newly emerging virus with unknown pathogenesis. The major objective of this study was to investigate the presence of PCV3 in pigs from a farm in Thailand suffering from porcine respiratory disease complex (PRDC). Initially, a Thai PCV3 strain (PCV3/Thailand/PB01/17) was identified from a pig originated from a farm with PRDC problem during grower period and whole genome analysis showed that the Thai PCV3 shared highest nucleotide identity of 99.60% with the South Korean strain PCV3/KU-1602. The presence of PCV3 infection in PRDC-affected pigs was then investigated in this farm. Serum samples from clinically healthy pigs and pigs showing PRDC-related clinical signs during 5-18 weeks were used in PCV3 detection by PCR. The results showed that the PRDC-affected pigs exhibited higher prevalence of PCV3 infection and higher PCV3 titers comparing with the clinically healthy pigs. These results confirmed the presence of PCV3 in a Thai farm with PRDC problem. The pathogenesis of PCV3 on PRDC should be clarified in further studies.

Granulomatous Necrotizing Myositis in Swine Affected by Porcine Circovirus Disease.

Porcine circovirus type 2 (PCV2) is associated with multiple clinical syndromes in pigs, known as porcine circovirus diseases. This work describes an outbreak of porcine circovirus diseases with severe lesions affecting the skeletal muscle. Ninety-two pigs had apathy, weight loss, and diarrhea over a clinical course of 7 to 10 days. Approximately 30 of the pigs had stiff gait, muscle weakness, hind limb paresis, and recumbency. Twelve of the 92 pigs were necropsied, and 4 had pale discoloration of skeletal muscles with microscopic lesions of granulomatous necrotizing myositis. Immunohistochemistry of skeletal muscle showed that PCV2 antigen was located primarily in the cytoplasm and nuclei of macrophages, lymphocytes, and multinucleated giant cells, with a lower amount in the cytoplasm of endothelial cells, necrotic fibers, and satellite cells. Affected muscle samples were polymerase chain reaction-positive for PCV2 and the amplicon exhibited 99% identity with sequences belonging to the PCV2b genotype. Locomotor clinical signs and granulomatous necrotizing myositis should be considered as another expression of PCV2 infection in pigs.

Comparative epidemiology of porcine circovirus type 3 in pigs with different clinical presentations.

BACKGROUND: Porcine circovirus type 3 (PCV3), as an emerging circovirus species, was reported to be widely circulating in the United States, China, South Korea and Poland. Previous studies revealed that PCV3 was mainly concentrated in sick animals with respiratory disease, skin disease, reproductive disorders and so on. However, the circulating status of PCV3 in pigs with other clinical presentations (especilly asymptomatic or diarrhea) was not well established. FINDINGS: In this study, to conduct a comparative epidemiological survey of PCV3, 80 weaned pig serum samples with severe respiratory disease (SRD), 175 weaned pig serum samples with mild respiratory disease (MRD), 216 asymptomatic weaned pig serum samples, 35 diarrheal weaned pig samples and 35 non-diarrheal weaned pig samples were collected from eight provinces of China. Via qPCR testing, PCV3 was circulating in all sampling provinces, with total positive rates varying from 1.04% to 100%. Interestingly, the PCV3-positive rate was significantly higher in weaned pigs with SRD (63.75%, 51/80) than in those weaned pigs with MRD (13.14%, 23/175) and asymptomatic pigs (1.85%, 4/216) (P < 0.01). Similarly, the PCV3-positive rate was significantly higher in diarrheal weaned pigs (17.14%, 6/35) than in non-diarrheal weaned pigs (2.86%, 1/35) (P < 0.05). Moreover, the lower Ct values of qPCR were frequently found in those weaned pigs or fattening pigs with respiratory disease and diarrhea rather than that in asymptomatic pigs. Sequence analysis showed that low genetic diversity existed among those PCV3 sequences collected from pigs with different clinical presentations. CONCLUSIONS: The present study further extends evidence that newly described PCV3 widely circulates in six additional provinces of Southern and Northern China and has high similarity to previously reported isolates. As an emerging virus of swine, although the present case-control study reveals that PCV3 has a potential association with swine respiratory disease and diarrhea, further investigations into the pathogenesis are needed to ascertain the role of PCV3 in swine health.

Effect of a major quantitative trait locus for porcine reproductive and respiratory syndrome (PRRS) resistance on response to coinfection with PRRS virus and porcine circovirus type 2b (PCV2b) in commercial pigs, with or without prior vaccination for PRRS.

A major QTL for host response to porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) infection was identified in a previous study. Single nucleotide polymorphism WUR10000125 (WUR), which is in complete linkage disequilibrium with the putative causative mutation, can be used as a tag SNP for the QTL. However, the effect of WUR following PRRS vaccination and/or coinfection with other pathogens is not known. Therefore, objectives of this study were to estimate the effect of WUR on host response following PRRS vaccination and coinfection of PRRSV with porcine circovirus type 2b (PCV2b), to estimate genetic parameters for host response to vaccination and coinfection, and to estimate the effect of previously identified candidate SNP under PRRSV-only or PCV2b-only infection on host response to coinfection. Data from 2 trials, comprising a total of 396 commercial crossbred nursery pigs from a single genetic source, were used for all analyses. Pigs were preselected based on WUR genotype: approximately half AA and half AB, where B is the favorable and dominant allele. At weaning, pigs were shipped to Kansas State University, where half of the pigs were vaccinated with a PRRS modified live virus vaccine. Four weeks later, all pigs were coinfected with field strains of PRRSV and PCV2b and followed for 42 d. Body weight and serum viremia measurements were collected following vaccination and coinfection to calculate ADG and viral load (VL), respectively. Average heritability estimates for PRRS VL, PCV2b VL, and ADG were 0.29, 0.09, and 0.40, respectively. After vaccination, AB pigs had lower vaccination VL ( = 0.03) and faster gain ( = 0.004) than AA pigs, as expected. After coinfection, AB pigs had lower PRRSV VL ( < 0.001) but did not significantly differ from AA pigs in growth rate ( = 0.86). For PCV2b VL, suggestive evidence of an interaction between vaccination and WUR genotype ( = 0.11) was detected, where AB pigs had significantly lower PCV2b VL when vaccinated ( = 0.007) but not when they were not vaccinated ( = 0.87). In addition to WUR, several PRRS-associated SNP and a PCV2b-associated SNP had significant effects on host response to coinfection. In conclusion, marker-assisted selection based on WUR genotype alone, or along with other candidate SNP for PRRSV and PCV2b infection, is a promising strategy to select for improved host response to not just PRRS but also coinfection of PRRSV with PCV2b and perhaps other pathogens.

High detection rate of dog circovirus in diarrheal dogs.

BACKGROUND: Diarrhea is one of the most common clinical symptoms reported in companion animal clinics. Dog circovirus (DogCV) is a new mammalian circovirus that is considered to be a cause of alimentary syndromes such as diarrhea, vomiting and hemorrhagic enteritis. DogCV has previously only been identified in the United States, Italy, Germany (GeneBank accession number: KF887949) and China (GeneBank accession number: KT946839). Therefore, the aims of this study were to determine the prevalence of DogCV in Taiwan and to explore the correlation between diarrhea and DogCV infection. Clinical specimens were collected between 2012 and 2014 from 207 dogs suffering from diarrhea and 160 healthy dogs. RESULTS: In this study, we developed a sensitive and specific SYBR Green-based real-time PCR assays to detected DogCV in naturally infected animals. Of the analyzed fecal samples from diarrheal dogs and health dogs, 58 (28.0 %) and 19 (11.9 %), respectively, were DogCV positive. The difference in DogCV prevalence was highly significant (P = 0.0002755) in diarrheal dogs. CONCLUSIONS: This is the first study to reveal that DogCV is currently circulating in domestic dogs in Taiwan and to demonstrate its high detection rate in dogs with diarrhea.

Cyclovirus Vietnam DNA in immunodeficient patients.

BACKGROUND: Cyclovirus Vietnam (CyCV-VN) is a CyCV detected in 2013 from cerebrospinal fluid (CSF) samples of patients with neurological disorders. Information on prevalence, pathogenesis and disease association of CyCV-VN is still very patchy. OBJECTIVES AND STUDY DESIGN: In this study, we have used a PCR assay targeting the Rep gene to investigate the prevalence of CyCV-VN infection in blood and CSF samples of 346 Italian subjects. RESULTS: Overall, 7% of blood samples were positive for CyCV-VN while the virus was not detected in any of the CSF samples. The prevalence of CyCV-VN was relatively high in HIV positive patients (21%), modest in patients with HBV or HCV infection (6%), and low in transplant recipient patients (2%). Positive patients showed low levels of CyCV-VN viremia. The virus was not detected in serum samples from healthy individuals. Longitudinal analysis of serum samples obtained from selected patients showed a stable or transient presence of circulating CyCV-VN. CONCLUSIONS: The present study is the first to demonstrate CyCV-VN DNA circulation in Italy and to cast light on some biological aspects of this novel virus of men.

Canine Circovirus 1 (CaCV-1) and Canine Parvovirus 2 (CPV-2): Recurrent Dual Infections in a Papillon Breeding Colony.

Recurrent outbreaks of sudden death and bloody diarrhea were reported in March 2013 and February 2014 in a breeding colony of Papillon dogs. During the first outbreak, 1 adult dog and 2 eight-month-old puppies died. During the second outbreak, 2 ten-week-old puppies died. One puppy from the first outbreak and 2 puppies from the second outbreak were examined at necropsy. Histologically, all 3 puppies had severe segmental crypt necrosis of the small intestine and marked lymphoid follicle depletion in the spleen and Peyer's patches. Real-time (RT) polymerase chain reaction (PCR) demonstrated abundant canine parvovirus (CPV-2) DNA (Ct<15) in the affected small intestine, and immunohistochemistry detected large amounts of CPV-2 antigen in intestinal crypt epithelium and Kupffer cells but few positive macrophages in lymphoid organs. All puppies had marked sinusoidal histiocytosis and multifocal granulomatous inflammation in mesenteric lymph nodes and spleen, prompting additional RT-PCR testing for canine circovirus 1 (CaCV-1). Very high levels of CaCV-1 DNA (Ct<13) were detected in small intestine, lymph nodes, and spleen. In situ hybridization for CaCV-1 detected rare positive nuclei of regenerating crypt epithelium but abundant amounts of CaCV-1 nucleic acid in the cytoplasm and nuclei of histiocytes in all lymphoid tissues, including granulomatous inflammatory foci and hepatic Kupffer cells. Significant levels of CaCV-1 DNA were detected in blood and serum (Ct as low as 13) but not feces from 3 surviving dogs at 2 months or 1 year after the outbreak, respectively. We hypothesize that CPV-2 infection predisposed dogs to CaCV-1 infection and ultimately resulted in more severe clinical disease.

Synergistic pathogenicity in sequential coinfection with Mycoplasma hyorhinis and porcine circovirus type 2.

To investigate the synergistic pathogenicity of Mycoplasma hyorhinis (Mhr) with porcine circovirus type 2 (PCV2), thirty 35-day-old piglets were randomly distributed to six groups (n=5 each): Mhr/PCV2 (group 1, inoculated with Mhr and PCV2 1 week later), PCV2/Mhr (group 2, inoculated with PCV2 and Mhr 1 week later), Mhr-PCV2 (group 3, inoculated with PCV2 and Mhr concurrently), singular PCV2 group (group 4), singular Mhr group (group 5), and a uninfected control group (group 6). Mild transient lethargy, fever, coughing, inappetence, and decreased daily weight gain were observed in all dual-infected groups and the singular Mhr-infected group. There were significantly higher levels of PCV2 and Mhr antibodies, larger amounts and wider range of tissue distribution of PCV2 antigens and nucleic acids in the dual-infected groups compared to the single-infected and control groups. PCV2 and Mhr dual-infection resulted in significantly more severe macroscopic and microscopic lung lesions and wider PCV2 DNA distribution compared with piglets infected with PCV2 alone. Cytokine detection showed a significant change in tumor necrosis factor-α, interleukin-2, and interleukin-6 levels in the infected groups, especially in the Mhr-PCV2 group, compared with the control group. Hence, Mhr potentiated the severity of PCV2-associated lung lesions, increased the amount and distribution of PCV2 DNA in tissues, and increased the incidence of porcine respiratory disease.

Association of increased rate of condemnation of broiler carcasses due to hepatic abnormalities with immunosuppressive diseases in the broiler chicken industry in Saskatchewan.

The objective of this study was to identify the causative agents of hepatitis observed in broiler chickens at processing. Livers of chickens from 16 broiler farms in Saskatchewan with gross lesions of hepatitis were collected at processing. In addition to routine bacterial isolation and histopathological examination, serologic studies for infectious bursal disease virus (IBDV) and Chicken anaemia virus (CAV), calculation of the ratio of the weight of the bursa of Fabricius (BF) to body weight (BBW), and histopathological examination of the BF were done. Of the 264 livers with gross lesions, 83% had multifocal to coalescing necrotizing hepatitis, 16% had perihepatitis, and 1% had hemorrhages. No definitive causative microorganisms were isolated from the hepatic lesions; however, no significant bacterial isolations were made. Bursal atrophy, low BBW ratio, and high titer of antibody against IBDV each correlated with the rate of total condemnations (P = 0.0188, P = 0.0001, and P = 0.0073, respectively). Nucleotide sequencing of IBDV isolated from the BF identified the variant strains Delaware-E and 586. Condemnation because of hepatic lesions was correlated with titer of antibody against IBDV and BBW (P = 0.016 and P = 0.027). The results of this study demonstrate that hepatic lesions in Saskatchewan chickens are not currently caused by a primary bacterial pathogen but are associated with indicators of immunosuppression that is likely due to variant IBDV.

L'objectif de la présente étude était d'identifier les agents causals de l'hépatite observée chez des poulets à griller au moment de la transformation. Les foies de poulets provenant de 16 fermes de poulets à griller en Saskatchewan avec des lésions macroscopiques d'hépatite furent prélevés. En plus de l'isolement bactérien de routine et de l'examen histopathologique, on effectua des analyses sérologiques pour le virus de la bursite infectieuse aviaire (VBIA) et le virus de l'anémie du poulet (VAP), le calcul du ratio du poids de la bourse de Fabricius (BF) sur le poids corporel (BPC), et l'examen histopathologique de la BF. Sur les 264 foies ayant des lésions macroscopiques, 83 % avaient des lésions multifocales à coalescentes d'hépatite nécrosante, 16 % de la péri-hépatite et 1 % des hémorragies. Aucun agent causal définitif ne fut isolé des lésions hépatiques; toutefois, aucun agent bactérien significatif ne fut isolé. Une atrophie de la bourse, un faible ratio BPC, et un titre élevé d'anticorps dirigé contre VBIA corrélaient tous avec le taux de condamnation totale (P = 0,0188, P = 0,0001, et P = 0,0073, respectivement). Le séquençage nucléotidique des VBIA isolés des BF identifia les souches variantes Delaware-E et 586. La condamnation due aux lésions hépatiques était corrélée avec le titre d'anticorps contre VBIA et le BPC (P = 0,016 et P = 0,027, respectivement). Les résultats de la présente étude démontrent que les lésions hépatiques chez les poulets de la Saskatchewan ne sont pas actuellement causées par un agent bactérien pathogène primaire mais sont associées à des indicateurs d'immunosuppression qui est probablement causée par un variant de VBIA.(Traduit par Docteur Serge Messier).

Fatal disease associated with Swine Hepatitis E virus and Porcine circovirus 2 co-infection in four weaned pigs in China.

BACKGROUND: In recent decades, Porcine circovirus 2 (PCV2) infection has been recognized as the causative agent of postweaning multisystemic wasting syndrome, and has become a threat to the swine industry. Hepatitis E virus (HEV) is another high prevalent pathogen in swine in many regions of the world. PCV2 and HEV are both highly prevalent in pig farms in China. CASE PRESENTATION: In this study, we characterized the HEV and PCV2 co-infection in 2-3 month-old piglets, based on pathogen identification and the pathological changes observed, in Hebei Province, China. The pathological changes were severe, and general hyperemia, hemorrhage, inflammatory cell infiltration, and necrosis were evident in the tissues of dead swine. PCR was used to identify the pathogen and we tested for eight viruses (HEV, Porcine reproductive and respiratory syndrome virus, PCV2, Classical swine fever virus, Porcine epidemic diarrhea virus, Transmissible gastroenteritis coronavirus, Porcine parvovirus and Pseudorabies virus) that are prevalent in Chinese pig farms. The livers, kidneys, spleens, and other organs of the necropsied swine were positive for HEV and/or PCV2. Immunohistochemical staining showed HEV- and PCV2-antigen-positive signals in the livers, kidneys, lungs, lymph nodes, and intestine. CONCLUSION: HEV and PCV2 co-infection in piglets was detected in four out of seven dead pigs from two pig farms in Hebei, China, producing severe pathological changes. The natural co-infection of HEV and PCV2 in pigs in China has rarely been reported. We speculate that co-infection with PCV2 and HEV may bring some negative effect on pig production and recommend that more attention should be paid to this phenomenon.

A novel vaccine against Porcine circovirus type 2 (PCV2) and Streptococcus equi ssp. zooepidemicus (SEZ) co-infection.

To develop a vaccine against Porcine circovirus type 2 (PCV2) and Streptococcus equi ssp. zooepidemicus (SEZ) co-infection, the genes of porcine IL-18, capsid protein (Cap) of PCV2 and M-like protein (SzP) of SEZ were inserted into the swinepox virus (SPV) genome by homologous recombination. The recombinant swinepox virus rSPV-ICS was verified by PCR and indirect immunofluorescence assays. To evaluate the immunogenicity of rSPV-ICS, 28 PCV2 and SEZ seronegative Bama minipigs were immunized with rSPV-ICS (n=8), commercial PCV2 vaccine and SEZ vaccine (n=8) or wild type SPV (n=8). The results showed that SzP-specific antibody and PCV2 neutralizing antibody of the rSPV-ICS immunized group increased significantly compared to the wild type SPV treated group after vaccination and increased continuously over time. The levels of IL-4 and IFN-γ in the rSPV-ICS immunized group were significantly higher than the other three groups, respectively. After been co-challenged with PCV2 and SEZ, 87.5% piglets in rSPV-ICS immunized group were survived. Significant reductions in gross lung lesion score, histopathological lung lesion score, and lymph node lesion score were noticed in the rSPV-ICS immunized group compared with the wtSPV treated group. The results suggested that the recombinant rSPV-ICS provided piglets with significant protection against PCV2-SEZ co-infection; thus, it offers proof-of-principle for the development of a vaccine for the prevention of these swine diseases.

Síndrome «humpy-backed» en cerdos en España / «Humpy-backed» pigs’ syndrome in Spain

El síndrome «humpy-backed» fue descrito en cerdos por primera vez en el Reino Unido en 1984. El síndrome ha sido observado en algunos países pero la etiología y la patogenia son todavía desconocidas. Este caso describe la aparición de cerdos con «humpy-backed» en la lechonera de una granja de 3.800 cerdas situada en el noreste de España. El problema afectó aproximadamente al 3% de la progenie semanal de una línea genética particular de la granja compuesta por 450 cerdas. La incidencia alcanzó picos del 9-11% en algunas semanas. Los lechones aparecían deprimidos, con pelaje hirsuto y deterioro físico progresivo. En la necropsia, a pesar de la apariencia de lordosis, no se detectaron alteraciones en los huesos y articulaciones de la columna vertebral. Microscópicamente se observó periarteritis linfoplasmocítica en corazón, bazo, intestino, hígado, riñón, músculo esquelético, pulmón y meninges. También se observó miocarditis y miositis linfoplasmocítica con degeneración de fibras musculares esqueléticas. La apariencia macroscópica de lordosis se relacionó con infiltrado celular inflamatorio multiorgánico. Se asoció a un problema de tipo genético de los animales afectados, aunque podría haber una posible implicación de circovirus porcino tipo 2 (PCV2) y el virus del síndrome reproductivo y respiratorio porcino (PRRS) en la patogenia del síndrome, debido a la seropositividad frente a los mismos detectada en la granja (AU)

«Humpy-backed» pigs’ syndrome was firstly described in the United Kingdom in 1984. The syndrome has been reported in a few countries, but the ethiology and pathogenesis remains unclear. This report describes the appearance of «humpy-backed» piglets aetiology in the nursery of a 3800-sow farm in Northeast Spain. The problem affected around 3% of the weekly offspring from one particular genetic line present on the farm composed of 450 sows. The incidence reached peaks of 9-11% in some weeks. The piglets appeared depressed, with rough hair coat and progressive clinical deterioration. In the necropsy, despite the appearance of lordosis, no defect in the bones and joint of the vertebral spine were detected. Lympho-plasmacytic periarteritis was observed in heart, spleen, gut, liver, kidney, skeletal muscle, lung and meninges. Lympho-plasmacytic myocarditis and skeletal myositis with muscular fibre degeneration was also observed. The macroscopic appearance of lordosis was associated with a multiorganic inflammatory cell infiltration. There was an association with the genetic background of the affected animals although seropositivity to porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) was also found in the farm, pointing to a possible implication of viral infection in the pathogenesis of the syndrome (AU)

Interactions of Plasmodium juxtanucleare and chicken anaemia virus: establishing a model.

The pathogens Plasmodium juxtanucleare and chicken anaemia virus (CAV) are easily transmitted and potentially harmful to chickens. In this study, we established an experimental model to investigate the effects of avian malaria caused by P. juxtanucleare in white leghorn specific-pathogen-free (SPF) chicks previously immunosuppressed with CAV. Parasitaemia, haematological variables and clinical and pathological parameters were determined in four different experimental groups: chicks coinfected by CAV and P. juxtanucleare strain (Coinfected group), chicks exclusively infected by CAV (CAV group) or P. juxtanucleare (Malaria group) and uninfected chicks (Control group). Our data demonstrated that P. juxtanucleare parasitaemia was significantly higher in the Coinfected group. Furthermore, haematological parameters, including the RBC, haematocrit and haemoglobin concentration were significantly reduced in coinfected chicks. In agreement with the changes observed in haematological features, the mortality among coinfected chicks was higher compared with animals with single infections. Clinical analysis indicated moderate changes related to different organs size (bursa of Fabricius, heart and liver) in coinfected birds. The experimental coinfection of SPF chickens with P. juxtanucleare and CAV may represent a research tool for the study of avian malaria after CAV immunosuppression, enabling measurement of the impacts caused by different pathogens during malarial infection.