Evolutionary Dynamics of a Highly Pathogenic Type 2 Porcine Reproductive and Respiratory Syndrome Virus: Analyses of Envelope Protein-Coding Genes.

Porcine reproductive and respiratory syndrome virus (PRRSV) has long been an economically devastating swine viral disease. The recent emergence of a highly pathogenic type 2 PRRSV with high mobility and mortality in China, spreading in Vietnam, Laos, and Thailand has placed neighbouring countries at risk. This study applied a codon-based extension of the Bayesian relaxed clock model and the fixed effects maximum-likelihood method to investigate and compare the evolutionary dynamics of type 2 PRRSV for all of known structural envelope protein-coding genes. By comparing the highly pathogenic type 2 PRRSV clade against the typical type 2 PRRSV clade, this study demonstrated that the highly pathogenic clade evolved at high rates in all of the known structural genes but did not display rapid evolutionary dynamics compared with typical type 2 PRRSV. In contrast, the ORF3, ORF5 and ORF6 genes of the highly pathogenic clade evolved in a qualitatively different manner from the genes of the typical clade. At the population level, several codons of the sequence elements that were involved in viral neutralization, as well as codons that were associated with in vitro attenuation/over-attenuation, were predicted to be selected differentially between the typical clade and the highly pathogenic clade. The results of this study suggest that the multigenic factors of the envelope protein-coding genes contribute to diversifying the biological properties (virulence, antigenicity, etc.) of the highly pathogenic clade compared with the typical clade of type 2 PRRSV.

A Bayesian phylogeographical analysis of type 1 porcine reproductive and respiratory syndrome virus (PRRSV).

Understanding viral transmission is an important factor for the effective prevention one of the most devastating swine diseases, porcine reproductive and respiratory syndrome. Focusing on molecular epidemiology of type 1 PRRSV, this study analysed a large ORF5 dataset collected worldwide from 1991 to 2012 using a coalescent-based Bayesian Markov chain Monte Carlo approach. The results suggested that the virus diversified into unique subpopulations in Russia & Belarus and Italy approximately 100 years ago. Previously unreported consecutive diffusions of the virus were identified, which showed that some countries, such as Spain and Germany, acted as distribution sources to some extent. This study also provided statistical evidence for the existence of an ORF5-based phylogeographical structure of type 1 PRRSV, in which the virus tended to cluster by geographical locations more tightly than expected by chance. In contrast to this tight geographical structure, the evolution of the ORF5 gene, based on mapping of non-synonymous/synonymous substitutions, was best described by a non-homogeneous process that could be implicated as a mechanism for viral immune evasion.

Genomic sequence of infectious hypodermal and hematopoietic necrosis virus (IHHNV) KLV-2010-01 originating from the first Korean outbreak in cultured Litopenaeus vannamei.

Due to the need to track and monitor genetic diversity, the genome of the infectious hypodermal and hematopoietic necrosis virus (IHHNV) strain KLV-2010-01 in cultured Litopenaeus vannamei shrimp that originated from the first Korean outbreak in 2010 was sequenced and analyzed. The genome, with a length of 3914 nucleotides, was sequenced from the Korean IHHNV. The genome encoded three large and overlapping open reading frames: ORF1 (NS-1) of 2001 bp, ORF2 (NS-2) of 1092 bp and ORF3 (capsid protein) of 990 bp. The overall organization, size and predicted amino acid sequence of the three ORFs in Korean IHHNV were highly similar to those of members of the infectious IHHNV group, and the most closely related strains were IHHNVs described from Ecuador and Hawaii. Additionally, phylogenetic analysis showed that the Korean IHHNV was clustered with lineage III in the infectious IHHNV group and was most similar to IHHNV isolates from Ecuador, China and Taiwan.

[Halogenated inhalation anesthesia with a semiclosed circle system]. / Anesthésie halogénée utilisant un respirateur muni d'un circuit-filtre.

Thirty-six patients were anaesthetized for a maxillofacial surgical procedure. Ventilation was controlled by a ventilator (Kontron ABT 4100) with a semi-closed circle system. The flow of fresh gases was 1,200 ml.min-1. The vaporizer for the halogenated anaesthetic agent was placed out of the circle before the ventilator. Halothane was used for maintenance of anaesthesia and isoflurane for induced hypotension in orthognathic surgery. The inspired concentration of the halogenated agent was monitored by an analyser. A linear correlation between the delivered and the inhaled concentration of halogenated agent was established, the latter never reaching the delivered concentration. Monitoring the inspired oxygen concentration was required, so as to maintain a constant value. Carbon dioxide absorption by soda lime was also studied. The known advantages were: substantial economies in nitrous oxide and halogenated agents, prevention of contamination of the operating theatre, humidification and warning of the inspired gases. The use of such a system with the vaporizer out of the circle was safe, all the more so as the concentration of inhaled halogenated agents could be predicted.

Concentrations of lead, magnesium, calcium, zinc and cadmium in twenty rabbit tissues after exposure to low lead doses and atherogenic diet.

Four groups of 6 rabbits were subjected to the following diets for 25 weeks: I (controls), II (water with 9.66 mumol/l of lead), III (atherogenic) and IV (atherogenic + 9.66 mumol/l of lead). Lead, magnesium, calcium, zinc and cadmium were then analyzed in 20 dry tissues. At the level of the arteries, veins and skin a tendency was observed toward increased lead concentration in rabbits of groups II and IV, elevated calcium levels in groups III and IV (a tenfold increase of calcium in the aortas), and a higher concentration of cadmium in animals of group II. There was a significant reduction in lead and magnesium concentrations in the liver of animals in groups III and IV because of fibrosis and overabundance of fatty liver cells. The lead level in the liver of animals in group II had slightly increased. Lead concentrations were higher in the kidneys and spleen in groups II and IV. Cadmium levels were significantly lower in the liver, kidneys, adrenal glands and spleen of animals in groups III and IV, whereas in group II they were particularly increased in the liver and kidneys. Very little significant interaction between the two diets was noted. Rabbits in groups III and IV showed notable histopathological alterations in aorta, carotid and femoral arteries, left ventricle and liver. Extrapolation from rabbit to man would be inadvisable.