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Background: Several screening strategies for identifying congenital CMV (cCMV) have been proposed; however, the optimal solution has yet to be determined. We aimed to determine the prevalence of cCMV by universal screening with saliva pool testing and to identify the clinical variables associated with a higher risk of cCMV to optimize an expanded screening strategy. Methods: We carried out a prospective universal cCMV screening (September/2022 to August/2023) of 2186 newborns, analyzing saliva samples in pools of five (Alethia-LAMP-CMV®) and then performed confirmatory urine CMV RT-PCR. Infants with risk factors (small for gestational age, failed hearing screening, HIV-exposed, born to immunosuppressed mothers, or <1000 g birth weight) underwent expanded screening. Multivariate analyses were used to assess the association with maternal/neonatal variables. Results: We identified 10 infants with cCMV (prevalence: 0.46%, 95% CI 0.22–0.84), with significantly higher rates (2.1%, 95% CI 0.58–5.3) in the high-risk group (p = 0.04). False positives occurred in 0.09% of cases. No significant differences in maternal/neonatal characteristics were observed, except for a higher prevalence among infants born to non-Chilean mothers (p = 0.034), notably those born to Haitian mothers (1.5%, 95% CI 0.31–4.34), who had higher odds of cCMV (OR 6.82, 95% CI 1.23–37.9, p = 0.04). Incorporating maternal nationality improved predictive accuracy (AUC: 0.65 to 0.83). Conclusions: For low-prevalence diseases such as cCMV, universal screening with pool testing in saliva represents an optimal and cost-effective approach to enhance diagnosis in asymptomatic patients. An expanded screening strategy considering maternal nationality could be beneficial in resource-limited settings. [ABSTRACT FROM AUTHOR]

Background HIV in Chile has a notification rate of 0.01%. Coreceptor antagonists are a family of antiretroviral drugs that are used with the prior knowledge of patients HIV-1 tropism. Viral RNA-based tropism detection requires a plasma viral load ⩾1000 copies/mL, while proviral DNA-based detection can be performed regardless of plasma viral load. This test is useful in patients with low or undetectable viral loads and would benefit with a proper therapy. The aim of this study was to determine the correlation between HIV RNA and proviral genotypic DNA tropism tests. Findings Forty three Chilean patients were examined using population-based V3 sequencing, and a geno2pheno false-positive rate (FPR) cutoff values of 5, 5.75, 10 and 20%. With cutoff 5.75% a concordance of 88.4% in tropism prediction was found after a simultaneous comparison between HIV tropism assessment by RNA and DNA. In total, five discrepancies (11.6%) were found, 3 patients were RNA-R5/DNA-X4 and two were RNA-X4/DNA-R5. Proviral DNA enabled the prediction of tropism in patients with a low or undetectable viral load. For cutoff 5 and 5.75% genotypic testing using proviral DNA showed a similar sensitivity for X4 as RNA. We found that the highest sensitivity for detecting the X4 strain occurred with proviral DNA and cutoff of 10 and 20%. Viral loads were higher among X4 strain carriers than among R5 strain carriers (p < 0.05). Conclusions A high degree of concordance was found between tropism testing with RNA and testing with proviral DNA. Our results suggest that proviral DNA-based genotypic tropism testing is a useful option for patients with low or undetectable viral load who require a different therapy. [ABSTRACT FROM AUTHOR]

Acute respiratory infections (ARI) are an important cause of morbidity and mortality worldwide, affecting mainly children and the elderly. They are associated with a high economic burden, increased number of medical visits and hospitalizations. The surveillance of the circulation of respiratory viruses can reduce the health care associated costs, and to optimize the health response. A platform based on R and its package Shiny was designed, to create an interactive and friendly web interface for gathering, analysis and publication of the data. The data from the Chilean metropolitan respiratory viruses surveillance network, available since 2006, was uploaded into the platform. Using this platform, the researcher spends less than 1 minute to upload the data, and the analysis and publication is immediate, available to be seen by any user with a device connected to Internet, who can choose the variables to be displayed. With a very low cost, in a short time, and using the R programming language, it was possible to create a simple, and interactive platform, considerably decreasing the upload and analysis time, and increasing the impact and availability of this surveillance.

Introduction: Human parechovirus (HPeV) belongs to the Picornaviridae family and has been described in viral meningoencephalitis and sepsis like illness in infants. Until now, 16 genotypes have been recognized, the most common are HPEV 1, 2 and 3; type 3 is most severe., Aims: To estimate the frequency of HPEV etiology in viral meningoencephalitis and sepsis in infants and characterize clinical and molecular aspects of infection., Methods: Between October 2013 and March 2015 we collected CSF samples, plasma, nasopharyngeal swabs and/or stools of patients younger than two years with suspected sepsis and/or viral meningitis. Samples were obtained from laboratory storage sites and from hospitalized patients. HPeV was diagnosed by real-time polymerase chain reaction (PCR) assay against the 5'UTR region. Positive samples were genotyped by sequencing a 304pb segment in VP3/VP1 overlapping region obtained with a nested PCR., Results: Overall HPeV detection rate was 18,6% (11/59 patients), distributed in 8.7% (4/46) laboratory's samples and 53.8% (7/13) of samples from hospitalized patients; mean age was 49 days (18 days-6 months). Most common clinical signs (11/11 patients) were irritability, inappetence, and fever (magnitude 38-38.8°C). All six samples genotyped were HPeV 3 [CORRECTED]., Conclusions: HPeV should be considered as a relatively significant etiologic agent of viral meningoencephalitis and sepsis in infants.

Introduction: CMV pp65-antigenemia (antigenemia) has been used for monitoring CMV viremia in allogeneic hematopoietic stem cell transplant (aHSCT) recipients. Recently, real time quantitative PCR (RT-qPCR) has been used as a better approach than antigenemia for CMV diagnosis. The objective of this study was to assess the correlation of CMV viremia between RT-qPCR and antigenemia in aHSCT patients., Material and Methods: Observational prospective study of all aHSCT patients during 10 months in our center. CMV RT-qPCR in whole blood was performed weekly from day +7 to +100 after aHSCT. Simultaneous antigenemia was performed from engrafment to day +100. Concordance between both assays was evaluated., Results: Eighteen patients were included. In 120 simultaneous samples, 96 were concordant by both methods (80%). Kappa coefficient was 0.583. In 42% of cases without concordant results, patients were on antiviral therapy. Thirteen patients (72%) developed CMV infection (20 episodes). In 17 episodes, both the antigenemia and CMV RT-qPCR were positive. CMV RT-qPCR was detectable 1-2 weeks before antigenemia in 45% of the episodes., Conclusion: Both methods had a moderate concordance and CMV RT-qPCR detects CMV reactivations earlier than antigenemia, especially in neutropenic patients.

Introduction: There is not known if a viraemia post-oral polio vaccine (OPV) is detectable by modern molecular techniques. Such viraemia could affect the performance of the real time-polymerase chain reaction (PCR) for non polio enterovirus (EV) detection, technique of growing clinical use for the study of febrile infants., Objective: To determine viraemia post-first dose of OPV in healthy infants, by molecular techniques., Patients and Methods: 50 infants less than three months without previous VPO were randomized in 5 groups: a control group with pre-vaccination blood sample (BS), group 1 BS at day 2, group 2 BS at day 4, group 3, BS at day 6 and group 4, BS at day 8 post-vaccination. Conventional and specific PCR for poliovirus and real time PCR for non polio EV were performed in BS and in OPV samples., Results: No genetic material of poliovirus was detected in any infant, while in 9 of them (18%) non polio EV was identified. Real time PCR for EV did not amplify poliovirus from OPV samples., Discussion: Results suggest that no post VPO viraemia detectable by molecular methods exists. Considering that real time PCR for EV does not allow to identify polio virus, no false positives of the test are expected as a result of a recent VPO vaccination. We documented presence of non polio EV in blood of healthy asymptomatic infants.

Introduction: Viral respiratory infections (VRI) are a frequent cause of morbidity among adult population. Respiratory syncytial virus (RSV) produces 20%> of VRI, however diagnosis is limited for a low sensitivity of conventional (FDA and ELISA) tests., Aim: To assess the impact of real time reverse transcriptase-polymerase chain reaction (real time RT-PCR) technique in RSV diagnosis in adult hospitalized patients; to characterize RSV infection among these patients., Patients and Methods: All adults hospitalized in Hospital Clínico Universidad Católica during 8 weeks of winter season, with clinical picture of VRI, and with negative DFA for influenza A and B, parainfluenza 1, 2, 3 and adenovirus were included. Real time RT-PCR was performed from nasopharyngeal sample. Clinical information, general laboratory exams and chest X ray reports were collected., Results: Out of 114 patients with negative DFA, 17 (14.9%o) Debe decir: RSV cases were demonstrated using real time RT- PCR. Fever, pharyngeal congestion, cough and bronchial obstruction were present in 80%> of patients. Thirty percent of them had a baseline chronic disease and 47%> were immunocompromised. One out of 17 patients (6%) required mechanical ventilation. No mortality was observed., Conclusions: Use of RT-PCR allowed increasing detection of RSV infection over 100%> among adults with VRI without virological diagnosis with conventional techniques. It is necessary to consider RSV RT-PCR test among patients with clinical picture of VRI during RSV season, with negative virological screening tests.

Amantadine has been used for prevention and treatment of influenza A infection. It blocks the proton through the M2 ion channel. Drug-resistant viruses appear quickly when this therapy is used. Single amino acids changes in the H2 protein can confer resistance, being the most frequent one in position 31. Different methods to detect resistant strains have been described. The objectives were to determine the existence of amantadine resistance of influenza A strains isolated in a virologic laboratory in Santiago, Chile, between 2001-2002, and to validate a new molecular method to detect resistant strains. A PCR restriction fragment length polymorphism analysis was employed for the detection of resistant viruses. In 31 processed strains no mutation in the position 31 was found. This result supports that amantadine resistance is very low or absent in Chile. This could be explained by a limited use of this drug in the study population. This method could be used as a monitoring system to survey resistant viruses.