Detection and differentiation of re-emerging fowlpox virus (FWPV) strains carrying integrated reticuloendotheliosis virus (FWPV-REV) by real-time PCR

Current strains of fowlpox virus (FWPV) carrying circulating reticuloendotheliosis virus (FWPV-REV) sequence are becoming more pathogenic to poultry. This is evidenced by the fact that vaccination with current available FWPV vaccines provides limited protection against them. To characterize REV insertions in a collection of both older and more recent field isolates, we developed three different types of adjacent oligoprobes and primer sets from specific genomic locations of FWPV and REV: REV-ENV (accession no. K02537, 1382-2260), FWPV-REV integration site (accession no. AF006064, 86-1328), FWPV (accession no. AF198100, 232461-232670), and REV-LTR (accession no. V01204, 305-496). The data indicated that the primers from the REV-ENV region and the TaqMan probes specifically targeted REV-ENV sequences of FWPV-REV strains. Furthermore, the strains were differentiated based on quantitative melting temperature (T(m)) of their amplified products using FRET-based probes. The amplified products were further characterized by sequencing and multiple sequence alignment analysis. The results suggest that integrated REV-ENV sequences are both common and mostly conserved in field isolates. However, the minor variations found within the short-targeted ENV sequence from FWPV-REV strains suggest that these strains could have either undergone periodic point mutational changes or integration with different REV-ENV subtypes.     

Seroprevalence and associated risk factors of important pig viral diseases in Bhutan

A cross-sectional serological study was conducted in Bhutan between October 2011 and February 2012 to determine the prevalence of antibodies to classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), swine influenza virus (SIV) subtype H1N1 and Aujeszky's disease virus (ADV). Furthermore, risk factors for the seropositive status were investigated.     

Time-dependent infection probability of classical swine fever via excretions and secretions

Several routes contribute to the spread of classical swine fever (CSF) during outbreaks of this disease. However, for many infected herds in recent epidemics, no route of virus introduction could be indentified. To obtain more insight into the relative importance of secretions and excretions in transmission of CSF virus, a model was developed. This model quantified the daily transmission probabilities from one infectious pig to one susceptible pig, using quantitative data on: (a) virus excretion by infected pigs, (b) survival of virus in the environment and (c) virus dose needed to infect susceptible pigs. Furthermore, the model predicted the relative contribution of secretions and excretions to this daily probability of infection of a susceptible pig. Three virus strains that differed in virulence were evaluated with the model: the highly virulent strain Brescia, the moderately virulent strain Paderborn and the low virulent strain Zoelen. Results suggest that it is highly probable that susceptible pigs in contact with Brescia or Paderborn infected pigs will be infected. For a pig in contact with a Zoelen infected pig, infection is less likely. When contact with blood is excluded, the predicted overall probability of infection was only 0.08 over the entire infectious period. The three strains differed in the relative contribution of secretions and excretions to transmission, although blood had a high probability of causing infection of a susceptible pig when in contact with a pig infected with any strain. This supports the statement that during outbreaks, control measures should ideally be based on the characteristics of the specific virus strain involved, which implies the development of strain-specific measures.     

Influence of strain, dose of virus, and age at inoculation on subgroup J avian leukosis virus persistence, antibody response, and oncogenicity in commercial meat-type chickens

The effects of viral strain, viral dose, and age of bird at inoculation on subgroup J avian leukosis virus (ALV J) persistence, neutralizing antibody (VNAb) response, and tumors were studied in commercial meat-type chickens. Chickens were inoculated on the fifth day of embryonation (5 ED) or on day of hatch (DOH) with either 100 or 10,000 50% tissue-culture infective dose (TCID50) of one of three ALV J strains, namely ADOL Hcl, ADOL 6803, or ADOL 4817. At 1, 3, 7, 11, 15, 19, 23, 27, and 32 wk posthatch, chickens were examined for ALV J viremia and VNAb against the inoculated strain of ALV J. A high incidence (83%-100%) of ALV J persistence was observed in all treatment groups. Development of VNAb did not always lead to viremia-free status; even though 18% of the chickens developed VNAb, only 4% were able to clear viremia. The viral strain, dose, and age of bird at inoculation seemed to have an effect on the incidence of VNAb; however, the differences were statistically significant in only some treatment groups. Chickens infected with ADOL 6803 had higher incidence of VNAb than chickens infected with ADOL Hc1 and ADOL 4817 (P < 0.05 in groups 5 ED at 100 TCID50 and DOH at 10,000 TCID50). There was a trend in all groups inoculated with 100 TCID50 to have higher incidence of VNAb than that of groups inoculated with 10,000 TCID50 (ADOL 6803 at 5 ED and ADOL 4817 at DOH [P < 0.05]; ADOL Hc1 at DOH [P < 0.08]). In most treatment groups (ADOL Hc1 at 100 and 10,000 TCID50, ADOL 6803 at 10,000 TCID50, and ADOL 4817 at 100 TCID50), chickens inoculated at DOH had higher incidence of VNAb than that of chickens inoculated at 5 ED (ADOL 6803 at 10,000 TCID50 [P < 0.05], ADOL Hc1 at 100 TCID50 [P < 0.08]). Incidence of ALV J-induced tumors and tumor spectrum were influenced by viral strain, age at inoculation, and VNAb response.     

Colletotrichum gloeosporioides sensu lato associated with anthracnose in Bauhinia forficata

European Journal of Plant Pathology - Bauhinia forficata is an important plant commonly used in traditional medicine, and as an ornamental plant in parks and gardens. Its use as an ornamental plant...     

Survey of infectious agents involved in acute respiratory disease in finishing pigs.

Outbreaks of respiratory disease constitute a major health problem in herds of finishing pigs and their aetiology often remains unclear. In this study, 16 outbreaks of respiratory disease with acute clinical signs in finishing pigs were investigated to determine which infectious agents were involved. From each herd four diseased and two clinically healthy pigs were examined pathologically and for the presence of viruses, bacteria and mycoplasmas. In addition, paired blood samples from 10 groupmates of the diseased pigs were tested for antibodies against commonly known causal agents of respiratory disease. A clear diagnosis was possible in 12 of the 16 outbreaks. Seven were due to an infection with influenza virus and five were due to an infection with Actinobacillus pleuropneumoniae. A combination of influenza virus and A pleuropneumoniae may have caused one other outbreak, but no clear cause could be established for the other three outbreaks.     

Fatal yersiniosis in farmed deer caused by Yersinia pseudotuberculosis serotype O:3 encoding a mannosyltransferase-like protein WbyK.

Sudden death of 9 deer occurred in a large enclosed deer farm with approximately 400 heads of cervids. Fatal yersiniosis was diagnosed in 2 deer that were submitted for laboratory diagnosis. Histopathologically, the disease was characterized by multifocal pulmonary hemorrhage and mild interstitial pneumonia, marked diffuse cholangiohepatitis, minimal myocarditis with mild myocardial degeneration, and mild multifocal suppurative cystic colitis. Yersinia pseudotuberculosis was isolated from the lungs and colon of the affected animals. The isolates were PCR-positive for genes virF, inv, yopB, and yopH, which are essential for invasion and colonization of host intestine and lung. The isolates reacted with polyclonal antibodies against serotype O:3 antigen. The O-genotyping patterns of the isolates were identical with each other, but different from those of the 21 O-genotypes (or serotypes) reported previously. In addition to the O-antigen genes possessed by classical serotype O:3, a gene (wbyK) encoding a mannosyltransferase-like protein was detected in these isolates. The wbyK gene of the isolates showed 94% of DNA sequence homology with the wbyK gene harbored by Y. pseudotuberculosis O:1b. On the basis of pathology, bacteriology, and serology, the authors concluded that the acute deaths of these deer were caused by Y. pseudotuberculosis infection. Molecular characterization of the isolate revealed a genetic heterogeneity in the O-antigen gene cluster of Y. pseudotuberculosis serotype O:3.