Vaccine effectiveness in preventing laboratory-confirmed influenza in Navarre, Spain: 2013/14 mid-season analysis

We estimate mid-2013/14 season vaccine effectiveness (VE) of the influenza trivalent vaccine in Navarre, Spain. Influenza-like illness cases attended in hospital (n=431) and primary healthcare (n=344) were included. The overall adjusted VE in preventing laboratory-confirmed influenza was 24% (95% CI: -14 to 50). The VE was 40% (95% CI: -12 to 68) against influenza A(H1)pdm09 and 13% (95% CI: -36 to 45) against influenza A(H3). These results suggest a moderate preventive effect against influenza A(H1)pdm09 and low protection against influenza A(H3).

Early estimates of influenza vaccine effectiveness in Navarre, Spain: 2012/13 mid-season analysis

We present estimates of influenza vaccine effectiveness (VE) in Navarre, Spain, in the early 2012/13 season, which was dominated by influenza B. In a population-based cohort using electronic records from physicians, the adjusted VE in preventing influenzalike illness was 32% (95% confidence interval (CI): 15 to 46). In a nested test-negative case-control analysis the adjusted VE in preventing laboratory-confirmed influenza was 86% (95% CI: 45 to 96). These results suggest a high protective effect of the vaccine.

Early estimates of influenza vaccine effectiveness in Navarre, Spain: 2012/13 mid-season analysis

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Antibody response to a fragment of the protein G of VHS rhabdovirus in immunised trout

A fragment (called frg#11, amino acids, aa 56-110) of the protein G (pG) of viral haemorrhagic septicaemia virus (VHSV) was designed after previous results showed it to be recognised by approximately 40% of the trout immunised to VHSV [Dis. Aquat. Organ. 34 (1999) 167]. frg#11 was then cloned, expressed, purified and used to study the production of antibodies to its epitopes in trout immunised to VHSV. Anti-frg#11 trout antibodies could be detected in serum from individual trout surviving VHSV exposure, immunised by injection with purified VHSV or DNA-immunised with its pG gene whereas it was not detected in non-infected and non-immunised trout. The trout serum antibodies which reacted more strongly by ELISA using solid-phase frg#11 (continuous or linear epitopes on the sequence of the pG) had the lowest VHSV-neutralising activity (epitopes which are pG conformation-dependent). Because antibodies recognising continuous as well as conformation-dependent epitopes of the pG seem to be involved in protective trout immunological responses to VHSV, the estimation of anti-frg#11 antibodies could help to the dissection of the complex trout antibody response to VHSV infections. In addition, these preliminary results suggest that the determination of anti-frg#11 antibodies might also be used to complement in vitro viral neutralising assays which seem to be restricted to pG conformation-dependent epitopes.

DNA vaccination by immersion and ultrasound to trout viral haemorrhagic septicaemia virus

This work reports preliminary data on the application of a novel method, ultrasound, for the DNA vaccination of rainbow trout. First, the best formulations were selected that increased the transfer by immersion of a plasmid coding for the green fluorescent protein (GFP) gene into trout fry. Quantification of GFP expression by fluorescence in the fin cells was used to study time course, DNA concentration dependence and comparison of different formulations. The best GFP expression results were obtained with short pulses of ultrasound, DOTAP liposomes and recombinant bacteria or bactofection. Other liposomes or microencapsulation formulations resulted in a GFP fluorescence similar to background values. Second, DNA immersion-vaccination of immunocompetent fingerling trout with the selected formulations was performed by using a plasmid coding for the glycoprotein G gene of the viral haemorrhagic septicaemia virus (VHSV). The immunization of fingerling trout was estimated by measuring humoral antibody, lymphoproliferation and VHSV challenge responses. Short pulses of low intensity ultrasound were the only method by which both humoral antibody responses and survival after VHSV challenge were obtained. Immersion DNA-vaccination using short pulses of ultrasound could eventually lead to a practical way to vaccinate small fish.

In vitro inhibition of the replication of haemorrhagic septicaemia virus (VHSV) and African swine fever virus (ASFV) by extracts from marine microalgae

We have screened for in vitro inhibition of viral replication with extracts from the following marine microalgae: Porphyridium cruentum, Phaeodactylum tricornutum, Tetraselmis suecica, Chlorella autotrophica, Dunaliella tertiolecta, Dunaliella bardawil, Isochrysis galbana, Isochrysis galbana var Tiso, Ellipsoidon sp. and Tetraselmis tetrathele. We have used as viral models two enveloped viruses of significant economic importance, the viral hemorrhagic septicemia virus (VHSV) of salmonid fish and the African swine fever virus (ASFV). The aqueous extracts from P. cruentum, C. autotrophica and Ellipsoidon sp., produced a significant inhibition of the in vitro replication of both viruses in a dose-dependent manner. That this inhibition could be due to sulfated polysaccharides was suggested because the same pattern of viral inhibition was obtained by using exocellular extracts from microalgae enriched in these compounds and/or dextran sulfate of high molecular weight. However, the inhibition of viral replication did not correlate with the percentage of sulfatation of the exocellular polysaccharides. Extracts from marine microalgae may have prophylactic utility against fish and mammalian viral diseases.

Structure, binding and neutralization of VHSV with synthetic peptides

The phosphatidylserine binding region p2 of VHSV was characterized and was shown to be involved with fusion. Synthetic peptides corresponding to this region interact with phospholipids by penetrating into the membrane and changing to a beta sheet configuration. Computer modeling of this region shows the possible ways by which the interaction with the membranes can succeed. Inhibitory peptides are presently being sought by studying possible interactions within heptad repeats located in other regions of the G protein of VHSV. The heptad repeat region that includes the phosphatidylserine binding domain p2 has been cloned and preliminary experiments show that under certain conditions, peptides from this region can inhibit VHSV infectivity.

Mapping of linear antibody epitopes of the glycoprotein of VHSV, a salmonid rhabdovirus

Antibody linear epitopes of the glycoprotein G (gpG) of the viral haemorrhagic septicaemia virus (VHSV), a rhabdovirus of salmonids, were mapped by pepscan using overlapping 15-mer peptides covering the entire gpG sequence and ELISA with polyclonal and monoclonal murine and polyclonal trout antibodies. Among the regions recognized in the pepscan by the polyclonal antibodies (PAbs) were the previously identified phosphatidylserine binding heptad-repeats (Estepa & Coll 1996; Virology 216:60-70) and leucocyte stimulating peptides (Lorenzo et al. 1995; Virology 212:348-355). Among 17 monoclonal antibodies (MAbs), only 2 non-neutralizing MAbs, 110 (aa 139-153) and IP1H3 (aa 399-413), could be mapped to specific peptides in the pepscan of the gpG. Mapping of these MAbs was confirmed by immunoblotting with recombinant proteins and/or other synthetic peptides covering those sequences. None of the neutralizing MAbs tested reacted with any of the gpG peptides. Previously mapped MAb resistant mutants in the gpG did not coincide with any of the linear epitopes defined by the pepscan strategy, suggesting the complementarity of the 2 methods for the identification of antibody recognition sites.