Ángel L. Álvarez

Variant Rabbit Hemorrhagic Disease Virus in Young Rabbits, Spain

Outbreaks of rabbit hemorrhagic disease have occurred recently in young rabbits on farms on the Iberian Peninsula where rabbits were previously vaccinated. Investigation identified a rabbit hemorrhagic disease virus variant genetically related to apathogenic rabbit caliciviruses. Improved antivirus strategies are needed to slow the spread of this pathogen.

Neutralizing Antibodies after Infection with Dengue 1 Virus

Severity of disease is markedly increased when infection with dengue virus type 2 follows infection with dengue virus type 2 by an interval of 20 years.

Wild boar Sus scrofa mortality by hunting and wolf Canis lupus predation: an example in northern Spain

Abstract Over the last decades, wolf Canis lupus predation in northern Spain has focused on wild ungulates, even though livestock and other prey, such as other carnivores and small mammals, and garbage have been available. During 1994 and 1995, we studied the impact of wolf predation on wild boar Sus scrofa in four study areas in Asturias, Spain. The diet of the wolf was assessed by scat collection and analysis (N = 106, 329, 372 and 649, respectively). The mortality of wild boar was deduced from density estimates and hunting records from the Nature Reserve of Somiedo. Wild boar represented 3-31% of the biomass of food found in the wolf scats in the study areas. We estimated that 75% of wild boars eaten were piglets. The wild boar mortality rate was estimated at 38% (146 dead individuals out of 385). Wolf predation was estimated to cause 12% of the mortality of wild boar and to affect 4.5% of the wild boar population. Hunting had a higher importance as a mortality factor than wolf predation (31 and 12%, respectively). Even though, a two-year study is insufficient to come to a final conclusion, our results suggest that wolf predation may have a low impact on young wild boar and that a hunting pressure of the size we found is unlikely to control the wild boar population.

In vitro anti HSV-1 and HSV-2 activity of Tanacetum vulgare extracts and isolated compounds: An approach to their mechanisms of action

Herpes simplex viruses (HSV‐1 and HSV‐2) are responsible for long‐term latent infections in humans, with periods of recurring viral replication associated to lesions around the lips, eyes, mucous membrane of the oral cavity or the genitals. The lack of an effective vaccine, the moderate to high toxicity of the available synthetic antiherpes compounds and the appearance of resistant viral strains emphasize the need for new inhibitors. Tanacetum vulgare, commonly known as tansy, has been used for treating rheumatic pain, skin eruption and diuretic conditions as well as an anthelmintic, antihypertensive, stimulant, emmenagogue, carminative, antiseptic, antihypertensive, antispasmodic and antioxidant agent. The anti HSV‐1 activity of tansy aerial parts, ethyl acetate extract and the isolated compound parthenolide, has been reported recently. In this work, through a comprehensive mechanistic‐based antiherpetic activity study, it was revealed that constituents other than parthenolide are responsible for the antiviral activity of tansy. Copyright

In vitro anti-herpetic activity of an aqueous extract from the plant Phyllanthus orbicularis.

The Herpesviridae includes at least eight viral species pathogenic for humans, responsible for a wide variety of clinical symptoms. The lack of an effective vaccine and the moderate to high toxicity of the available synthetic anti-herpes compounds emphasises the need for new inhibitors. Several Phyllanthus genus (Euphorbiaceae) members have been widely used in traditional medicine and their biological properties have been intensely studied. In this study we investigated the in vitro antiviral activity of the Cuban-endemic plant Phyllanthus orbicularis H.B.K. against Herpes simplex virus type 1 (HSV-1) and 2 (HSV-2) reference strains and clinical isolates with different sensitivities to acyclovir. The inhibitory activity on Human cytomegalovirus (HCMV) replication was also investigated. The selectivity indexes (SI) found for Ph. orbicularis aqueous extract ranged from 8.7 to 37.6. Studies on the antiviral mechanisms involved revealed that the drug acted at early stages of herpesvirus replication, possibly by producing a virucidal effect, although further inhibition of intracellular replication events could not be ruled out.

Epidemiological studies on dengue virus type 3 in Playa municipality, Havana, Cuba, 2001-2002.

OBJECTIVES Recognizing the uniqueness of secondary dengue virus (DENV)-1/3 dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) cases at an interval of 24 years, we sought to estimate DENV infections as well as the ratios between mild disease and DHF/DSS by DENV infection sequence in Playa District (Havana, Cuba) during the 2001-2002 outbreak of dengue virus type 3 (DENV-3). METHODS A retrospective seroepidemiological study was conducted in 2003 in Playa District. Blood samples were collected from a 1% random sample of residents and were studied for the prevalence of dengue neutralizing antibodies. RESULTS DENV-3 was found to have infected 7.2% (95% confidence interval (95% CI) 6.0-8.4%) of susceptible individuals (the entire cohort), the majority of whom experienced silent infections. Virtually every individual who had a secondary infection in the sequence DENV-1 then DENV-3 became ill, with a ratio of severe to mild cases of 1:35 (95% CI 1:67-1:23). Secondary infections in the sequence DENV-2/3 were less pathogenic than DENV-1/3. Mild disease accompanying secondary DENV2/3 occurred at a ratio of 1:4.49 infections (95% CI 1:5.77-1:3.42) secondary infections. CONCLUSIONS The results obtained highlight the role of the infecting serotype and also the sequence of the viral infection in the clinical outcome of a dengue infection.

Bioactivity-guided Fractionation of Phyllanthus orbicularis and Identification of the Principal Anti HSV-2 Compounds

The antiherpes virus properties of Phyllanthus orbicularis Kunth, a Cuban‐endemic medicinal plant, have been reported previously but data on its phytochemical profile and identification of antiviral metabolites as well as their mechanisms of action are still lacking. In this work, a bioactivity‐guided phytochemical analysis was performed in order to isolate anti HSV‐2 compounds. P. orbicularis contained mainly phenolic acids derivatives and flavonoids. The antiviral effects were attributed to (−)‐epicatechin‐3‐O‐gallate (EC50 = 11.7 µg/mL), procyanidins B1 and B2 (EC50 = 32.8 µg/mL and 24.2 µg/mL, respectively) as well as oligomeric and polymeric procyanidins and their gallate derivatives. The antiviral mechanisms of the active P. orbicularis extracts and fractions were also investigated and the inhibition of several HSV‐2 early replication events and DNA synthesis were observed. This is the first study of extensive fractionation and phytochemical characterization of phenolic compounds from this species. Copyright

Apple Pomace, a By-Product from the Asturian Cider Industry, Inhibits Herpes Simplex Virus Types 1 and 2 In Vitro Replication: Study of Its Mechanisms of Action

The anti-herpes simplex virus type 1 and anti-herpes simplex virus type 2 effects of apple pomace, a by-product from the cider-processing industry, were investigated. The mechanisms of antiviral action were assessed using a battery of experiments targeting sequential steps in the viral replication cycle. The anti-herpetic mechanisms of apple pomaces included the inhibition of virus attachment to the cell surface and the arrest of virus entry and uncoating. Quercitrin and procyanidin B2 were found to play a crucial role in the antiviral activity.

Antiviral Activity of Myticin C Peptide from Mussel: an Ancient Defense against Herpesviruses

ABSTRACT Little is known about the antiviral response in mollusks. As in other invertebrates, the interferon signaling pathways have not been identified, and in fact, there is a debate about whether invertebrates possess antiviral immunity similar to that of vertebrates. In marine bivalves, due to their filtering activity, interaction with putative pathogens, including viruses, is very high, suggesting that they should have mechanisms to address these infections. In this study, we confirmed that constitutively expressed molecules in naive mussels confer resistance in oysters to ostreid herpesvirus 1 (OsHV-1) when oyster hemocytes are incubated with mussel hemolymph. Using a proteomic approach, myticin C peptides were identified in both mussel hemolymph and hemocytes. Myticins, antimicrobial peptides that have been previously characterized, were constitutively expressed in a fraction of mussel hemocytes and showed antiviral activity against OsHV-1, suggesting that these molecules could be responsible for the antiviral activity of mussel hemolymph. For the first time, a molecule from a bivalve has shown antiviral activity against a virus affecting mollusks. Moreover, myticin C peptides showed antiviral activity against human herpes simplex viruses 1 (HSV-1) and 2 (HSV-2). In summary, our work sheds light on the invertebrate antiviral immune response with the identification of a molecule with potential biotechnological applications. IMPORTANCE Several bioactive molecules that have potential pharmaceutical or industrial applications have been identified and isolated from marine invertebrates. Myticin C, an antimicrobial peptide from the Mediterranean mussel (Mytilus galloprovincialis) that was identified by proteomic techniques in both mussel hemolymph and hemocytes, showed potential as an antiviral agent against ostreid herpesvirus 1 (OsHV-1), which represents a major threat to the oyster-farming sector. Both hemolymph from mussels and a myticin C peptide inhibited OsHV-1 replication in oyster hemocytes. Additionally, a modified peptide derived from myticin C or the nanoencapsulated normal peptide also showed antiviral activity against the human herpesviruses HSV-1 and HSV-2. Therefore, myticin C is an example of the biotechnological and therapeutic potential of mollusks.

Inhibitory effects of lupene-derived pentacyclic triterpenoids from Bursera simaruba on HSV-1 and HSV-2 in vitro replication

The cytotoxicity and antiviral properties of Bursera simaruba against herpes simplex viruses (HSV-1 and HSV-2) were investigated through a bioactivity-guided isolation protocol. The plant material was fractionated using solvent-solvent partitioning, size-exclusion and thin-layer chromatography. The antiviral compounds present in the most active fractions were identified by means of LC-MS and NMR. Three different methods were compared during the evaluation of antiviral activity of samples. Four lupene-related pentacyclic triterpenes were found to be responsible for the anti-herpesvirus effects of B. simaruba and were isolated from this species for the first time. The selective indexes (SI) of B. simaruba-derived samples ranged from 7.7 to 201.9.