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Acute HSV-1 infection is associated with mild symptoms, such as fever and lesions of the mouth, face and skin. This phase is followed by a latency period before reactivation, which is associated with symptoms ranging from ulcers to encephalitis. Despite available anti-HSV-1 drugs, the development of new antiviral agents is sought due to the presence of resistant viruses. Melatonin, a molecule secreted by the pineal gland, has been shown to be an antioxidant, inducer of antioxidant enzymes, and regulator of various biological processes. Clinical trials have explored its therapeutic utility in conditions including infections. This study focuses on melatonin's role in HSV-1 replication and the underlying mechanisms. Melatonin was found to decrease the synthesis of HSV-1 proteins in infected Vero cells measured by immunofluorescence, indicating an inhibition of HSV-1 replication. Additionally, it regulates the activities of antioxidant enzymes and affects proteasome activity. Melatonin activates the unfolded protein response (UPR) and autophagy and suppresses apoptosis in HSV-1-infected cells. In summary, melatonin demonstrates an inhibitory role in HSV-1 replication by modulating various cellular responses, suggesting its potential utility in the treatment of viral infections.

Untreated HCV mono and HCV/HIV coinfected women have lower degrees of liver fibrosis (LF) compared to men. Direct acting antiviral (DAA) therapy attains viral eradication in > 90% of patients with progressive LF decline in parallel. Gender-related differences in LF regression in the long term assessed by non-invasive liver fibrosis markers (NILFM) in HCV mono and HCV/HIV coinfected after DAA treatment have not been explored so far. 374 HCV-infected adult patients, 214 of them HCV/HIV coinfected, were followed-up for 24 months after starting DAA therapy. LF was assessed by NILFM: transient elastometry (TE) and several biochemical indexes (APRI, Forns, FIB-4). Men had significantly more advanced LF at baseline than women assessed by NILFM. No LF differences at baseline in age, HIV coinfection course (CD4, HIV viral load), and HCV features (HCV viral load, genotype) were detected. No significant gender differences in LF decline after comparing 24-month and baseline LF values were observed. LF changes after DAA therapy were similar in HCV mono and HCV/HIV coinfected patients and in both sexes. Gender did not influence the course of LF decline after DAA assessed by NILFM: TE (P = 0.8), APRI (P = 0.9), Forns (P = 0.4) and FIB-4 (P = 0.7) by multivariate analysis. No gender differences in the 24 month LF decline after DAA with independence of having HCV mono or HCV/HIV coinfection were found., (© 2024. The Author(s).)

The influenza virus has accompanied humans since time immemorial, in the form of annual epidemics and occasional pandemics. It is a respiratory infection with multiple repercussions on people's lives at an individual and social level, as well as representing a significant burden on the health system. This Consensus Document arises from the collaboration of various Spanish scientific societies involved in influenza virus infection. The conclusions drawn are based on the highest quality evidence available in the scientific literature and, failing that, on the opinion of the experts convened. The Consensus Document addresses the clinical, microbiological, therapeutic, and preventive aspects (with respect to the prevention of transmission and in relation to vaccination) of influenza, for both adult and pediatric populations. This Consensus Document aims to help facilitate the clinical, microbiological, and preventive approach to influenza virus infection and, consequently, to reduce its important consequences on the morbidity and mortality of the population., (Copyright © 2023 The Authors. Publicado por Elsevier España, S.L.U. All rights reserved.)

Millions of SARS-CoV-2 whole genome sequences have been generated to date. However, good quality data and adequate surveillance systems are required to contribute to meaningful surveillance in public health. In this context, the network of Spanish laboratories for coronavirus (RELECOV) was created with the main goal of promoting actions to speed up the detection, analyses, and evaluation of SARS-CoV-2 at a national level, partially structured and financed by an ECDC-HERA-Incubator action (ECDC/GRANT/2021/024). A SARS-CoV-2 sequencing quality control assessment (QCA) was developed to evaluate the network's technical capacity. QCA full panel results showed a lower hit rate for lineage assignment compared to that obtained for variants. Genomic data comprising 48,578 viral genomes were studied and evaluated to monitor SARS-CoV-2. The developed network actions showed a 36% increase in sharing viral sequences. In addition, analysis of lineage/sublineage-defining mutations to track the virus showed characteristic mutation profiles for the Delta and Omicron variants. Further, phylogenetic analyses strongly correlated with different variant clusters, obtaining a robust reference tree. The RELECOV network has made it possible to improve and enhance the genomic surveillance of SARS-CoV-2 in Spain. It has provided and evaluated genomic tools for viral genome monitoring and characterization that make it possible to increase knowledge efficiently and quickly, promoting the genomic surveillance of SARS-CoV-2 in Spain.

Background: The clinical and epidemiological implications of abnormal immune responses in COVID-19 for latent tuberculosis infection (LTBI) screening are unclear., Methods: We reviewed QuantiFERON TB Gold Plus (QFT-Plus) results (36,709 patients) from July 2016 until October 2021 in Asturias (Spain). We also studied a cohort of ninety hospitalized patients with suspected/confirmed COVID-19 pneumonia and a group of elderly hospitalized patients with COVID-19 who underwent serial QFT-Plus and immune profiling testing., Results: The indeterminate QFT-Plus results rate went from 1.4% (July 2016 to November 2019) to 4.2% during the COVID-19 pandemic. The evolution of the number of cases with low/very low interferon-gamma (IFN-gamma) response in the mitogen tube paralleled the disease activity and number of deaths during the pandemic waves in our region (from March 2020 to October 2021). The percentages of positive QFT-plus patients did not significantly change before and during the pandemic (13.9% vs . 12.2%). Forty-nine patients from the suspected/confirmed COVID-19 pneumonia cohort (54.4%) had low/very low IFN-gamma response to mitogen, 22 of them (24.4%) had severe and critical pneumonia. None received immunosuppressants prior to testing. Abnormal radiological findings (P = 0.01) but not COVID-19 severity was associated with low mitogen response. Immune profiling showed a reduction of CD8 + T cells and a direct correlation between the number of EMRA CD8 + T-cells and IFN-gamma response to mitogen (P = 0.03)., Conclusion: Low IFN-gamma responses in mitogen tube of QFT-Plus often occur in COVID-19 pneumonia, which is associated with a low number of an effector CD8 + T-cell subset and does not seem to affect LTBI screening; however, this abnormality seems to parallel the dynamics of COVID-19 at the population level and its mortality., (© 2022 SEPAR. Published by Elsevier España, S.L.U. All rights reserved.)

Long term liver fibrosis (LF) changes and their best -monitoring non-invasive markers (NILFM) after effective anti-HCV DAA therapy are little- known. Matrix-metalloproteases (MMPs) and their tissue-inhibitors (TIMPs) are pivotal in liver inflammation repair. Their plasma levels might assess long-term LF changes after therapy. Overall 374 HCV-infected adult patients, 214 HCV-HIV coinfected, were followed-up for 24 months after starting DAA. LF was assessed by transient elastometry (TE), biochemical indexes (APRI, Forns, FIB-4) and, in 61 individuals, by MMPs and TIMP-1 plasma levels. Several MMPs and TIMP-1 SNPs were genotyped in 319 patients. TE was better than biochemical indexes for early and long-term LF monitoring. MMPs-2,-8,-9 and-TIMP-1 levels and TE displayed parallel declining curves although only TIMP-1 correlated with TE (P = 0.006) and biochemical indexes (P < 0.02). HCV monoinfected had significantly higher baseline NILFM and TIMP-1 plasma values, but lower MMPs levels than coinfected patients. No differences in NILFM course were observed between mono-and coinfected or between different DAA regimens. Only the MMP-2 (-1306 C/T) variant TT genotype associated with higher values of NILFM NILFM decline extends 24 months after therapy. TE and TIMP1 are reliable LF-monitoring tools. NILFM courses were similar in mono-and coinfected patients, DAA regimens type did not influence NILFM course., (© 2022. The Author(s).)

Background: Analyze possible relationships between HAdV and markers for inflammation, specifically the C-reactive protein (CRP) and procalcitonin (PCT) tests, along with other haematological markers., Methods: Retrospective study of 487 children presenting with fever and/or acute respiratory symptoms in the Paediatric Emergency Department. Analyses included viral presence/absence (both HAdV and other respiratory viruses) in respiratory exudates, CRP and PCT alterations in plasma, and haematological markers in whole blood., Results: Viral load was >500 copies/10 3 cells of HAdV in 127 cases (26.1%), of which 66 (52%, P<0.0001) had alterations in PCT, and 112 (88.1%, P<0.0001) in CRP. Haematological markers were similar either HAdV was present or not, although many HAdV positive patients demonstrated leukocytosis (66%). Bacterial cultures from 141 samples showed altered PCT in 27 (60%) with HAdV infection, in 3 (18.7%) with bacterial infection, and 13 (26.5%) without either viral or bacterial infection (P<0.05). CRP was altered in 88.9% of HAdV infected children and in 87% infected with bacteria, although the percentage was greater than in cases where other respiratory viruses were present (61.3% P<0.05)., Conclusions: Results demonstrate a clear relationship between HAdV infection and alterations in PCT and CRP which should be taken into account in paediatric patient management., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/tp-20-333). The authors have no conflicts of interest to declare., (2021 Translational Pediatrics. All rights reserved.)

The interferon induced transmembrane-protein 3 (IFITM3) plays an important role in the defence against viral infection. IFITM3 gene variants have been linked to differences in expression and associated with the risk of severe influenza by some authors. More recently, these variants have been associated with the risk of COVID-19 after SARS-CoV-2 infection. We determined the effect of two common IFITM3 polymorphisms (rs34481144 ​C/T and rs12252 A/G) on the risk of hospitalization due to COVID-19 by comparing 484 patients (152 required support in thr intensive care unit, ICU) and 182 age and sex matched controls (no disease symptoms). We found significantly higher frequencies of rs34481144 ​T and rs12252 ​G carriers among the patients (OR ​= ​2.02 and OR ​= ​1.51, respectively). None of the two variants were associated with ICU-admission or death. We found a significantly higher frequency of rs34481144 CC ​+ ​rs12252 AA genotype carriers among the controls, suggesting a protective effect ( p = 0.001, OR = 0.56, 95%CI = 0.40 - 0.80). Moreover, haplotype rs34481144 ​C - rs12252 A was significantly increased in the controls (p ​= ​0.008, OR ​= ​0.71, 95%CI ​= ​0.55-0.91). Our results showed a significant effect of the IFITM3 variants in the risk for hospitalization after SARS-CoV-2 infection., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Author(s).)

Background and Aims: The interferon-induced transmembrane proteins play an important antiviral role by preventing viruses from traversing the cellular lipid bilayer. IFITM3 gene variants have been associated with the clinical response to influenza and other viruses. Our aim was to determine whether the IFITM3 rs12252 polymorphism was associated with the risk of developing severe symptoms of COVID-19 in our population., Methods: A total of 288 COVID-19 patients who required hospitalization (81 in the intensive care unit) and 440 age matched controls were genotyped with a Taqman assay. Linear regression models were used to compare allele and genotype frequencies between the groups, correcting for age and sex., Results: Carriers of the minor allele frequency (rs12252 C) were significantly more frequent in the patients compared to controls after correcting by age and sex (p = 0.01, OR = 2.02, 95%CI = 1.19-3.42). This genotype was non-significantly more common among patients who required ICU., Conclusions: The IFITM3 rs12252 C allele was a risk factor for COVID-19 hospitalization in our Caucasian population. The extent of the association was lower than the reported among Chinese, a population with a much higher frequency of the risk allele., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The Angiotensin system is implicated in the pathogenesis of COVID-19. First, ACE2 is the cellular receptor for SARS-CoV-2, and expression of the ACE2 gene could regulate the individuaĺs susceptibility to infection. In addition, the balance between ACE1 and ACE2 activity has been implicated in the pathogenesis of respiratory diseases and could play a role in the severity of COVID-19. Functional ACE1/ACE2 gene polymorphisms have been associated with the risk of cardiovascular and pulmonary diseases, and could thus also contribute to the outcome of COVID-19. We studied 204 COVID-19 patients (137 non-severe and 67 severe-ICU cases) and 536 age-matched controls. The ACE1 insertion/deletion and ACE2 rs2285666 polymorphism were determined. Variables frequencies were compared between the groups by logistic regression. We also sequenced the ACE2 coding nucleotides in a group of patients. Severe COVID-19 was associated with hypertension male gender (p < 0.001), hypertension (p = 0.006), hypercholesterolaemia (p = 0.046), and the ACE1-DD genotype (p = 0.049). In the multiple logistic regression hypertension (p = 0.02, OR = 2.26, 95%CI = 1.12-4.63) and male gender (p = 0.002; OR = 3.15, 95%CI = 1.56-6.66) remained as independent significant predictors of severity. The ACE2 polymorphism was not associated with the disease outcome. The ACE2 sequencing showed no coding sequence variants that could explain an increased risk of developing COVID-19. In conclusion, an adverse outcome of COVID-19 was associated with male gender, hypertension, hypercholesterolemia and the ACE1 genotype. Our work suggested that the ACE1-I/D might influence COVID-19 severity, but the effect was dependent on the hypertensive status. This result requires further validation in other large cohorts., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Dialysis is the first procedure to partially replace renal function in end-stage renal diseases, despite several adverse side effects, such as infections. The primary aim of this study was to evaluate the levels of immune CMV-specific CD8+ T cells in a representative cohort of pre-transplant patients receiving hemodialysis (HD) or peritoneal dialysis (PD). The secondary aim was to monitor the CMV-specific CD8+ T cells in kidney transplant recipients undergoing different types of dialysis during the first year following their transplant. Methods: Sixty-nine patients were enrolled and examined with respect to the type of dialysis they received. HLA class I dextramers for CMV were used to determine the quantity of CMV-specific CD8+ T cells. The CMV DNA viral load was also determined. Forty-two of the patients enrolled in the study underwent solid organ transplantation and were analyzed during their first year post-transplantation. Results: Patients receiving HD had fewer CMV-specific CD8+ T cells than those in PD ( p < 0.05). We also observed that patients in PD had more CMV-specific CD8+ T cells during the follow-up period than those in HD ( p < 0.05), independently of the CMV DNA. Finally, PD patients had a higher frequency of CD8+ Effector-Memory RA T cells (TEMRA) and a lower frequency of central memory T cells (TCM) than did HD patients. Conclusions: These results indicate the better status of CMV-specific T cell immunity in PD patients. The use of CMV T cell dextramers would be advantageous for monitoring the CD8+ T-specific response, enabling the use of prophylactic treatment to be optimized.

Acute necrotizing encephalopathy (ANE) is a severe neurologic complication caused by influenza virus that has been infrequently reported in adult population. The diagnosis is made on epidemiological, clinical, and neuroimaging suspicion, but is rarely confirmed by microbiological findings in samples from the central nervous system (CNS), thus making it difficult to define the mechanism of pathogenesis of influenza-associated encephalitis/encephalopathies (IAE). We report a microbiologically documented case of ANE caused by influenza A/H3N2, in a previously healthy adult patient infected during a flu epidemic in Asturias (Spain). Direct viral invasion of the CNS was demonstrated with the isolation of the virus in a brain biopsy.

Traditional diagnostic assays for Helicobacter pylori detection have their limitations. Molecular methods can improve both diagnosis and understanding of gastric diseases. Here we describe an in-house quantitative real-time polymerase chain reaction (q-rt-PCR) for the detection of H. pylori in gastric biopsies which has been developed and has a detection limit of 10 copies, the specificity of which was tested against other gastric colonizer bacteria. In this study, 199 gastric biopsies from adults with different clinical gastric symptoms were examined. Biopsies were obtained during endoscopy and the following tests performed: rapid urease testing (RUT), culture and q-rt-PCR. H. pylori bacterial load expressed as bacterial load per 105 cells was calculated using a standard curve. H. pylori was isolated in 41% of patients, RUT was positive in 32% and bacterial genome was detected in 45% (p = 0.010). Concordance between traditional invasive microbiological methods used together and q-rt-PCR was almost 100%. Bacterial load in patients with positive RUT was significantly higher than those where it was negative (p<0.0001). There were also significant differences between bacterial load in patients with more than one positive assay versus those where only one method was positive (p = 0.006). The in-house q-PCR developed here is quick and inexpensive, and allows accurate diagnosis of H. pylori infection. It also permits normalized bacterial load quantification, which is important to differentiate between asymptomatic colonisation and infection.

Genetic variants of human papillomavirus types 16 and 18 (HPV16/18) could differ in their cancer risk. We studied the prevalence and association with high-grade cervical lesions of different HPV16/18 variant lineages in a case-control study including 217 cases (cervical intraepithelial neoplasia grade 2 or grade 3 or worse: CIN2 or CIN3+) and 116 controls (no CIN2 or CIN3+ in two-year follow-up). HPV lineages were determined by sequencing the long control region (LCR) and the E6 gene. Phylogenetic analysis of HPV16 confirmed that isolates clustered into previously described lineages: A (260, 87.5%), B (4, 1.3%), C (8, 2.7%), and D (25, 8.4%). Lineage D/lineage A strains were, respectively, detected in 4/82 control patients, 19/126 CIN3+ cases (OR = 3.1, 95%CI: 1.0-12.9, p = 0.04), 6/1 glandular high-grade lesions (OR = 123, 95%CI: 9.7-5713.6, p<0.0001), and 4/5 invasive lesions (OR = 16.4, 95%CI: 2.2-113.7, p = 0.002). HPV18 clustered in lineages A (32, 88.9%) and B (4, 11.1%). Lineage B/lineage A strains were respectively detected in 1/23 control patients and 2/5 CIN3+ cases (OR = 9.2, 95%CI: 0.4-565.4, p = 0.12). In conclusion, lineages A of HPV16/18 were predominant in Spain. Lineage D of HPV16 was associated with increased risk for CIN3+, glandular high-grade lesions, and invasive lesions compared with lineage A. Lineage B of HPV18 may be associated with increased risk for CIN3+ compared with lineage A, but the association was not significant. Large well-designed studies are needed before the application of HPV lineage detection in clinical settings.

Sinonasal squamous cell carcinomas (SCC) are rare tumors, etiologically related to occupational exposure to wood and leather dust. In spite of surgical and radiotherapeutic advances, the 5 year survival is still 30-50%. Therefore, alternative treatment options are needed. We report the establishment and characterization of six unique human sinonasal SCC cell lines, named SCCNC1, 2, 4, 5, 6 and 7. In vitro growth and invasion characteristics were evaluated and genetic profiles were compared to those of the original primary tumors. The population doubling times ranged from 21 to 34 hours. Cell lines SCCNC2 and 7 were highly invasive in matrigel. Five cell lines carried a high number of copy number alterations, including amplifications and homozygous deletions, while one showed only three abnormalities. Sequence analysis revealed three cell lines with TP53 mutation and none with KRAS or BRAF. Overexpression of p53 was observed in five, and of EGFR in four cell lines. None of the cell lines showed strong immunopositivity of p16 or presence of human papilloma virus. In conclusion, we have created six new cell lines that are clinically and genetically representative of sinonasal SCC and that will be a useful tool for the preclinical testing of new therapeutic agents.

Objective: Human Papillomavirus (HPV) infection in men may produce cancer and other major disorders. Men play an important role in the transmission of the virus and act as a reservoir. The aim of this study was to determine the HPV-genotypes and their prevalence in a group of men attending a Sexually Transmitted Infection service. PATIENTS AND SAMPLES: Between July 2002 and June 2011, 1392 balanopreputial, 435 urethral, 123 anal, and 67 condyloma lesions from 1551 men with a mean age of 35.8±11.3 years old (range: 17-87) were collected for HPV-DNA testing., Methods: A fragment of the L1-gene and a fragment of the E6/E7-genes were amplified by PCR. Positive samples were typed by hybridization., Results: The HPV genome was detected in 36.9% (486/1318) balanopreputial and in 24.9% (101/405) urethral (p<0.0001) swabs from 38.1% (538) of 1469 men. Co-infections were present in 5.4% (80/1469) of cases. HPV was found in 43.9% (373/850) of men younger than 35 vs. 31.7% (187/589) of men aged >35. HPV was found in 59.4% (104) of 165 men with lesions (macroscopic or positive peniscopy), and in 22.8% (61/267) without clinical alterations. HPV was also detected in 71.4% (40/56) men with condylomata and in 58.7% (64/109) of men with positive peniscopy., Conclusions: HPV prevalence in men was high and decreased with age. HPV was found more frequently in balanopreputial than in urethral swabs. There was a low rate of co-infections. Low-risk HPV vaccine genotypes were the most recurrent especially in younger. Although HPV has been associated with clinical alterations, it was also found in men without any clinical presentation. Inclusion of men in the national HPV vaccination program may reduce their burden of HPV-related disease and reduce transmission of the virus to non-vaccinated women.

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.

The contribution of human metapneumovirus (hMPV) relative to that of other respiratory viruses as a cause of respiratory infections in children less than 1 year old has been evaluated. From October 2003 to April 2004, nasopharyngeal samples from 211 children less than 1 year old were analyzed to detect respiratory viruses. Respiratory syncytial virus (RSV) was the predominant virus isolated (96 children [45.5%]), followed by influenza A virus, parainfluenza virus, adenovirus, cytomegalovirus, and herpes simplex virus type 1, which were only occasionally detected. From January 2004 to April 2004, a nested retrotranscription-PCR, using in-house primers directed to the matrix protein gene of hMPV, was carried out on samples in which no other viruses were detected. hMPV was detected in 18 (16.2%) children, indicating that this virus was the second-most-frequent cause of viral respiratory infections in children less than 1 year old. The rate of hospitalization for RSV- and hMPV-infected children was higher than 75%. While RSV had a peak from December to February, hMPV was increasingly detected from January to April. The mean age of hMPV-infected children (6.44 +/- 3.64 [mean +/- standard deviation] months) was significantly higher than that of RSV-infected children (3.99 +/- 2.96 [mean +/- standard deviation] months). On the other hand, 64.3% of the RSV-infected children and 12.5% of the hMPV-infected children showed high levels of C-reactive protein. Although several authors have reported that clinical symptoms of hMPV-positive patients mirrored those of RSV-positive patients, differences between the two viruses can be found.

The relationship between quantitative antigenemia and plasma DNAemia was studied for monitoring cytomegalovirus (CMV) viremia in CMV infection (CMVI) or disease (CMVD), in 20 transplant recipients (13 CMD, seven CMVI). A total of 142 samples of blood were assayed for CMV-DNA and pp-65 antigenemia (CMV-Ag). A quantitative correlation between both markers was found (P < 0.0001). First CMV antigenemia as well as first plasma DNA viral load was similar in CMVI and CMVD (29 vs. 24 CMV-Ag+ cells/10(5) PMN; and 7445 vs. 12407 CMV-DNA copies/ml). The maximum antigenemia was higher in CMVD than in CMVI (146 +/- 87 vs. 61 +/- 54 +cells/10(5) PMN, P < 0.05), but the highest CMV plasma viral load was similar in both groups (62592 +/- 33000 vs. 42055 +/- 38600 copies/ml). In nine patients, maximum antigenemia coincided with highest plasma DNA viral load, but in 10 highest DNAemia occurred 6 days later. On the contrary, antigenemia declined faster than CMV-DNAnemia, after treatment.

From November 2000 to October 2001, a reverse transcription-PCR using primers directed to the norovirus RNA polymerase coding region was included in a viral and bacterial routine screening to diagnose sporadic cases of acute gastroenteritis among children in Asturias, Spain. The role of noroviruses (8.6% of the positively diagnosed cases) as the cause of sporadic pediatric gastroenteritis was evaluated with respect to the detection rates of other gastroenteritis-associated viruses and bacteria. The results indicated that noroviruses were less common than rotaviruses (36.9%), Campylobacter spp. (28.8%), and Salmonella spp. (18.4%) but more frequent than astroviruses (4.3%), adenoviruses (3.8%), and Yersinia spp. (2.2%). Mixed infections involving noroviruses were rarely observed (0.5%). The presence of a norovirus-associated pediatric gastroenteritis peak in summer, as well as the complete absence of norovirus-associated cases in colder months, challenges the view that norovirus infections exclusively have wintertime seasonality. On the other hand, phylogenetic analysis of the amplified fragments showed that the norovirus strains responsible were closely related. A further study using the full-length capsid region showed that these strains could be included into genogroup II, Bristol/Lorsdale cluster, and were closely related to the 1995 and 1996 U.S. subset of strains associated with outbreaks recorded worldwide between 1995 and 1996.

Ganciclovir (GCV) prophylaxis or pre-emptive therapy significantly reduce the rate of cytomegalovirus (CMV) disease and viremia, but increase the potential for emergence of ganciclovir-resistant CMV strains. The inhibitor concentration at 50% (IC(50)) of GCV from 156 CMV isolates from 59 renal or heart transplant recipients was calculated by means of a rapid phenotypic susceptibility assay. Twenty-seven strains were from 14 patients undergoing GCV therapy. The IC(50) was higher in patients under the prophylaxis regimen. One CMV strain, from a heart transplant recipient, became GCV-resistant after 1 month of therapy (IC(50)=13.7 micromol/l). These data, together with clinical and virological markers, suggested that a switch to foscarnet was necessary, and good evolution was observed. Thus, assay of CMV susceptibility to GCV could be helpful in clinical management.

The susceptibility of human herpes simplex virus (HSV) to acyclovir (ACV) was determined with the use of a single dose of the drug (1 and 2 micrograms of ACV per ml for HSV-1 and HSV-2, respectively) in two rapid assays: a rapid cytopathic effect inhibitory assay (Rapid CIA) and a rapid dye uptake assay (Rapid DUA). These tests allow the simultaneous determination of virus titer and susceptibility to ACV at a determined viral concentration (100 50% tissue culture infective doses and 100 50% dye uptake units). These tests were compared with a conventional susceptibility assay (dye uptake assay) and showed similar results. Indeterminate results with the Rapid CIA appeared in 3 of 30 samples. With the use of both Rapid CIA and Rapid DUA, we were able to determine the susceptibility of 100% of the isolates. The rapid tests, unlike conventional assays, are able to provide susceptibility results within 3 days after the virus has been isolated from a clinical specimen and could thus play a direct role in therapeutic decisions.