Changing molecular epidemiology of Hepatitis A virus in Santiago, Chile from 2010 to 2021.

OBJECTIVES: Hepatitis A (HAV) virus causes asymptomatic to life-treating fulminant hepatitis. During infection, patients show large viral excretion in their stools. Resistance of HAV to environmental conditions, allows us to recover viral nucleotide sequences from wastewater and trace its evolutionary history. METHODS: We characterize twelve years of HAV circulation in wastewater from Santiago, Chile, and conducted phylogenetic analyses to decipher the dynamics of circulating lineages. RESULTS: We observed the exclusive circulation of the HAV IA genotype. The molecular epidemiologic analyses showed a steady circulation of a dominant lineage with low genetic diversity (d = 0,007) between 2010 and 2017. An outbreak of Hepatitis A associated with men who have sex with men, in 2017 was associated with the irruption of a new lineage. Remarkably, a dramatic change in the dynamic of HAV circulation was observed in the period post-outbreak; between 2017 and 2021 when 4 different lineages were transiently detected. Exhaustive phylogenetic analyses indicate that these lineages were introduced and possibly derived from isolates from other Latin American countries. CONCLUSION: The HAV circulation in recent years in Chile is rapidly changing and suggests that this phenomenon could be a consequence of massive population migrations in Latin America caused by political instability and natural disasters.

Short-term complications and post-acute sequelae in hospitalized paediatric patients with COVID-19 and obesity: A multicenter cohort study.

BACKGROUND: Obesity increases the severity of coronavirus disease 2019 illness in adults. The role of obesity in short-term complications and post-acute sequelae in children is not well defined. OBJECTIVE: To evaluate the relationship between obesity and short-term complications and post-acute sequelae of SARS-CoV-2 infection in hospitalized paediatric patients. METHODS: An observational study was conducted in three tertiary hospitals, including paediatric hospitalized patients with a confirmatory SARS-CoV-2 RT-PCR from March 2020 to December 2021. Obesity was defined according to WHO 2006 (0-2 years) and CDC 2000 (2-20 years) growth references. Short-term outcomes were intensive care unit admission, ventilatory support, superinfections, acute kidney injury, and mortality. Neurological, respiratory, and cardiological symptoms and/or delayed or long-term complications beyond 4 weeks from the onset of symptoms were considered as post-acute sequalae. Adjusted linear, logistic regression and generalized estimating equations models were performed. RESULTS: A total of 216 individuals were included, and 67 (31.02%) of them had obesity. Obesity was associated with intensive care unit admission (aOR = 5.63, CI95% 2.90-10.94), oxygen requirement (aOR = 2.77, CI95% 1.36-5.63), non-invasive ventilatory support (aOR = 6.81, CI95% 2.11-22.04), overall superinfections (aOR = 3.02 CI95% 1.45-6.31), and suspected bacterial pneumonia (aOR = 3.00 CI95% 1.44-6.23). For post-acute sequalae, obesity was associated with dyspnea (aOR = 9.91 CI95% 1.92-51.10) and muscle weakness (aOR = 20.04 CI95% 2.50-160.65). CONCLUSIONS: In paediatric hospitalized patients with COVID-19, severe short-term outcomes and post-acute sequelae are associated with obesity. Recognizing obesity as a key comorbidity is essential to develop targeted strategies for prevention of COVID-19 complications in children.

High prevalence of SARS-CoV-2 detection and prolonged viral shedding in stools: A systematic review and cohort study / Elevada detección de SARS-CoV-2 y prolongada excreción viral en deposiciones: Estudio de cohorte y revisión sistemática

Objectives: To: 1. Describe the frequency of viral RNA detection in stools in a cohort of patients infected with SARS-CoV-2, and 2. Perform a systematic review to assess the clearance time in stools of SARS-CoV-2. Methods: We conducted a prospective cohort study in two centers between March and May 2020. We included SARS-CoV-2 infected patients of any age and severity. We collected seriated nasopharyngeal swabs and stool samples to detect SARS-CoV-2. After, we performed a systematic review of the prevalence and clearance of SARS-CoV-2 in stools (PROSPERO-ID: CRD42020192490). We estimated prevalence using a random-effects model. We assessed clearance time by using Kaplan–Meier curves. Results: We included 32 patients; mean age was 43.7±17.7 years, 43.8% were female, and 40.6% reported gastrointestinal symptoms. Twenty-five percent (8/32) of patients had detectable viral RNA in stools. The median clearance time in stools of the cohort was 11[10–15] days. Systematic review included 30 studies (1392 patients) with stool samples. Six studies were performed in children and 55% were male. The pooled prevalence of viral detection in stools was 34.6% (twenty-four studies, 1393 patients; 95%CI:25.4–45.1); heterogeneity was high (I2:91.2%, Q:208.6; p≤0.001). A meta-regression demonstrates an association between female-gender and lower presence in stools (p=0.004). The median clearance time in stools was 22 days (nineteen studies, 140 patients; 95%CI:19–25). After 34 days, 19.9% (95%CI:11.3–29.7) of patients have a persistent detection in stools. Conclusions: Detection of SARS-CoV-2 in stools is a frequent finding. The clearance of SARS-CoV-2 in stools is prolonged and it takes longer than nasopharyngeal secretions.(AU)

Objetivos: 1. Evaluar la detección de ARN viral en deposiciones y su tiempo de excreción en una cohorte de pacientes con SARS-CoV-2; 2. Realizar una revisión sistemática para evaluar el tiempo de excreción en deposiciones del SARS-CoV-2. Métodos: Estudio de cohorte prospectiva en dos centros entre marzo-mayo del 2020. Incluimos pacientes infectados con SARS-CoV-2 de cualquier edad y gravedad. Recolectamos secreciones nasofaríngeas y deposiciones en forma seriada para detectar SARS-CoV-2. También realizamos una revisión sistemática de la prevalencia y excreción del SARS-CoV-2 en deposiciones (PROSPERO-ID: CRD42020192490). Estimamos la prevalencia usando un modelo de efectos aleatorios. Evaluamos el tiempo de excreción usando curvas Kaplan-Meier. Resultados: Incluimos 32 pacientes; edad media 43 ± 17,7 años, 43,8% eran mujeres y 40,6% reportaron síntomas gastrointestinales. Veinticinco por ciento (8/32) tenían ARN viral detectable en deposiciones. La mediana de excreción en deposiciones fue 11 [10-15] días. La revisión sistemática incluyó 30 estudios (1.392 pacientes) con muestras en deposiciones. Seis estudios fueron realizados en niños y 55% eran hombres. La prevalencia estimada de detección viral en deposiciones fue de 34,6% (24 estudios, 1.393 pacientes; IC 95%: 25,4-45,1); la heterogeneidad fue elevada (I2: 91,2%; Q: 208,6; p ≤ 0,001). Una metarregresión demostró una asociación entre el género femenino y menor prevalencia en deposiciones (p = 0,004). La mediana de tiempo de excreción fueron 22 días (19 estudios, 140 pacientes; IC 95%: 19-25). Tras 34 días, 19,9% (IC 95%: 11,3-29,7) de los pacientes tenían detección persistente en deposiciones. Conclusiones: La detección de SARS-CoV-2 en deposiciones es un hallazgo frecuente. La excreción del SARS-CoV-2 en deposiciones es prolongada y es más tardía que en secreciones nasofaríngeas.(AU)

Induction of SARS-CoV-2 neutralizing antibodies by CoronaVac and BNT162b2 vaccines in naïve and previously infected individuals.

BACKGROUND: A major challenge of the SARS-CoV-2 pandemic is to better define "protective thresholds" to guide the global response. We aimed to characterize the longitudinal dynamics of the antibody responses in naturally infected individuals in Chile and compared them to humoral responses induced after immunization with CoronaVac-based on an inactivated whole virus -or the BNT162b2- based on mRNA-vaccines. We also contrasted them with the respective effectiveness and efficacy data available for both vaccines. METHODS: We determined and compared the longitudinal neutralizing (nAb) and anti-nucleocapsid (anti-N) antibody responses of 74 COVID-19 individuals (37 outpatient and 37 hospitalized) during the acute disease and convalescence. We also assessed the antibody boosting of 36 of these individuals who were immunized after convalescence with either the CoronaVac (n = 30) or the BNT162b2 (n = 6) vaccines. Antibody titres were also measured for 50 naïve individuals immunized with two doses of CoronaVac (n = 35) or BNT162b2 (n = 15) vaccines. The neutralizing level after vaccination was compared to those of convalescent individuals and the predicted efficacy was estimated. FINDINGS: SARS-CoV-2 infection induced robust nAb and anti-N antibody responses lasting >9 months, but showing a rapid nAb decay. After convalescence, nAb titres were significantly boosted by vaccination with CoronaVac or BNT162b2. In naïve individuals, the calculated mean titre induced by two doses of CoronaVac or BNT162b2 was 0·2 times and 5.2 times, respectively, that of convalescent individuals, which has been proposed as threshold of protection. CoronaVac induced no or only modest anti-N antibody responses. Using two proposed logistic models, the predicted efficacy of BNT162b2 was estimated at 97%, in close agreement with phase 3 efficacy studies, while for CoronaVac it was ∼50% corresponding to the lowest range of clinical trials and below the real-life data from Chile (from February 2 through May 1, 2021 during the predominant circulation of the Gamma variant), where the estimated vaccine effectiveness to prevent COVID-19 was 62·8-64·6%. INTERPRETATION: The decay of nAbs titres in previously infected individuals over time indicates that vaccination is needed to boost humoral memory responses. Immunization of naïve individuals with two doses of CoronaVac induced nAbs titres that were significantly lower to that of convalescent patients, and similar to vaccination with one dose of BTN162b2. The real life effectiveness for CoronaVac in Chile was higher than estimated; indicating that lower titres and additional cellular immune responses induced by CoronaVac might afford protection in a highly immunized population. Nevertheless, the lower nAb titre induced by two doses of CoronaVac as compared to the BTN162b2 vaccine in naïve individuals, highlights the need of booster immunizations over time to maintain protective levels of antibody, particularly with the emergence of new SARS-CoV-2 variants. FUNDING: FONDECYT 1161971, 1212023, 1181799, FONDECYT Postdoctorado 3190706 and 3190648, ANID Becas/Doctorado Nacional 21212258, PIA ACT 1408, CONICYT REDES180170, Centro Ciencia & Vida, FB210008, Financiamiento Basal para Centros Científicos y Tecnológicos de Excelencia grants from the Agencia Nacional de Investigación y Desarrollo (ANID) of Chile; NIH-NIAD grants U19AI135972, R01AI132633 and contracts HHSN272201400008C and 75N93019C00051; the JPB Foundation, the Open Philanthropy Project grant 2020-215611 (5384); and by anonymous donors. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

High prevalence of SARS-CoV-2 detection and prolonged viral shedding in stools: A systematic review and cohort study.

OBJECTIVES: To: 1. Describe the frequency of viral RNA detection in stools in a cohort of patients infected with SARS-CoV-2, and 2. Perform a systematic review to assess the clearance time in stools of SARS-CoV-2. METHODS: We conducted a prospective cohort study in two centers between March and May 2020. We included SARS-CoV-2 infected patients of any age and severity. We collected seriated nasopharyngeal swabs and stool samples to detect SARS-CoV-2. After, we performed a systematic review of the prevalence and clearance of SARS-CoV-2 in stools (PROSPERO-ID: CRD42020192490). We estimated prevalence using a random-effects model. We assessed clearance time by using Kaplan-Meier curves. RESULTS: We included 32 patients; mean age was 43.7±17.7 years, 43.8% were female, and 40.6% reported gastrointestinal symptoms. Twenty-five percent (8/32) of patients had detectable viral RNA in stools. The median clearance time in stools of the cohort was 11[10-15] days. Systematic review included 30 studies (1392 patients) with stool samples. Six studies were performed in children and 55% were male. The pooled prevalence of viral detection in stools was 34.6% (twenty-four studies, 1393 patients; 95%CI:25.4-45.1); heterogeneity was high (I2:91.2%, Q:208.6; p≤0.001). A meta-regression demonstrates an association between female-gender and lower presence in stools (p=0.004). The median clearance time in stools was 22 days (nineteen studies, 140 patients; 95%CI:19-25). After 34 days, 19.9% (95%CI:11.3-29.7) of patients have a persistent detection in stools. CONCLUSIONS: Detection of SARS-CoV-2 in stools is a frequent finding. The clearance of SARS-CoV-2 in stools is prolonged and it takes longer than nasopharyngeal secretions.

Long-lasting neutralizing antibody responses in SARS-CoV-2 seropositive individuals are robustly boosted by immunization with the CoronaVac and BNT162b2 vaccines.

The durability of circulating neutralizing antibody (nAb) responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and their boosting by vaccination remains to be defined. We show that outpatient and hospitalized SARS-CoV-2 seropositive individuals mount a robust neutralizing antibody (nAb) response that peaks at days 23 and 27 post-symptom onset, respectively. Although nAb titers remained higher in hospitalized patients, both study groups showed long-lasting nAb responses that can persist for up to 12 months after natural infection. These nAb responses in previously seropositive individuals can be significantly boosted through immunization with two doses of the CoronaVac (Sinovac) or one dose of the BNT162b2 (BioNTech/Pfizer) vaccines, suggesting a substantial induction of B cell memory responses. Noteworthy, three obese previously seropositive individuals failed to mount a booster response upon vaccination, warranting further studies in this population. Immunization of naïve individuals with two doses of the CoronaVac vaccine or one dose of the BNT162b2 vaccine elicited similar levels of nAbs compared to seropositive individuals 4.2 to 13.3 months post-infection with SARS-CoV-2. Thus, this preliminary evidence suggests that both, seropositive and naïve individuals, require two doses of CoronaVac to ensure the induction of robust nAb titers.

A household case evidences shorter shedding of SARS-CoV-2 in naturally infected cats compared to their human owners.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been detected in domestic and wild cats. However, little is known about natural viral infections of domestic cats, although their importance for modelling disease spread, informing strategies for managing positive human-animal relationships and disease prevention. Here, we describe the SARS-CoV-2 infection in a household of two human adults and sibling cats (one male and two females) using real-time RT-PCR, an ELISA test, viral sequencing, and virus isolation. On May 5th, 2020, the cat-owners tested positive for SARS-CoV-2. Two days later, the male cat showed mild respiratory symptoms and tested positive. Four days after the male cat, the two female cats became positive, asymptomatically. Also, one human and one cat showed antibodies against SARS-CoV-2. All cats excreted detectable SARS-CoV-2 RNA for a shorter duration than humans and viral sequences analysis confirmed human-to-cat transmission. We could not determine if cat-to-cat transmission also occurred.

JC polyomavirus circulation in one-year surveillance in wastewater in Santiago, Chile.

Human polyomavirus JC (JCPyV) is a widely distributed viral agent and because it high resistance against environmental conditions it is frequently recovered from diverse sources of water and is considered a good marker for human pollution. Phylogenetic analysis of JCPyV isolated in different part of the world has revealed 7 genotypes, which have been associated with specific populations or ethnics groups. This feature has been used to trace pre-historic and historic human migration patterns across the world. Although there are many reports describing genotypes distribution around the world, data on JCPyV genotypes in the southernmost areas of South America are scarce. The goal of this study is to detect and characterize the JCPyV that circulates in Santiago, Chile using sewage samples from wastewater treatment plants (WWTP). Sewage samples were obtained monthly during 1 year from three WWTPs which together process about 80% of wastewater generated in the city of Santiago, Chile. Our results show that JCPyV profusely circulates in Santiago, Chile, because it was detected in 80.56% of the samples, reinforcing the use of JCPyV as a feasible marker to assess human environmental pollution. JCPyV was detected in high frequency in influents and effluents samples, with the largest WWTPs showing the highest percentage of detection and viral loads. In the phylogenetic analysis the Chilean sequences clustered mainly with genotype 2A (Asian genotype). This is similar to that previously reported from Buenos Aires, Argentina and divergent to data from Brazil, where the circulation of European subtypes 1 and 4 and African subtypes 3 and 6 has been described.

Role of BK human polyomavirus in cancer.

Human polyomaviruses (HPyV), which are small DNA viruses classified into the polyomaviridae family, are widely distributed in human populations. Thirteen distinct HPyVs have been described to date. Some of these viruses have been found in human tumors, suggesting an etiological relationship with cancer. In particular, convincing evidence of an oncogenic role has emerged for a specific HPyV, the Merkel cell polyomavirus (MCPyV). This HPyV has been linked to rare skin cancer, Merkel cell carcinoma (MCC). This finding may be just the tip of the iceberg, as HPyV infections are ubiquitous in humans. Many authors have conjectured that additional associations between HPyV infections and neoplastic diseases will likely be discovered. In 2012, the International Agency for Research on Cancer (IARC) evaluated the carcinogenicity of the BK virus (BKPyV), reporting that BKPyV is "possibly carcinogenic to humans." This review explores the BKPyV infection from a historical point of view, including biological aspects related to viral entry, tropism, epidemiology and mechanisms potentially involved in BKPyV-mediated human carcinogenesis. In order to clarify the role of this virus in human cancer, more epidemiological and basic research is strongly warranted.

Infectious pancreatic necrosis virus enters CHSE-214 cells via macropinocytosis.

Infectious pancreatic necrosis virus (IPNV) is a non-enveloped virus belonging to the Birnaviridae family. IPNV produces an acute disease in salmon fingerlings, with high mortality rates and persistent infection in survivors. Although there are reports of IPNV binding to various cells, the viral receptor and entry pathways remain unknown. The aim of this study was to determine the endocytic pathway that allows for IPNV entry. We observed that IPNV stimulated fluid uptake and virus particles co-localysed with the uptake marker dextran in intracellular compartments, suggesting a role for macropinocytosis in viral entry. Consistent with this idea, viral infection was significantly reduced when the Na+/H+ exchanger NHE1 was inhibited with 5-(N-Ethyl-N-isopropyl) amiloride (EIPA). Neither chlorpromazine nor filipin complex I affected IPNV infection. To examine the role of macropinocytosis regulators, additional inhibitors were tested. Inhibitors of the EGFR pathway and the effectors Pak1, Rac1 and PKC reduced viral infection. Together, our results indicate that IPNV is mainly internalized into CHSE-214 cells by macropinocytosis.

High genetic diversity of species A rotaviruses detected in swine farms in Chile.

Rotavirus A is one of the main causative agents of diarrhoea in lactating and weaned pigs worldwide. Its impact in the swine industry is well documented. However, in Chile, the current epidemiological status of rotavirus on porcine farms is unknown. This study evaluated the current epidemiologic status of rotavirus A infection in Chile using on-farm detection techniques, electrophoretic confirmation, genotyping and phylogenetic clustering by analysis of partial sequences of VP4 and VP7 genes. Rotavirus A was detected in four out of five farms with an overall prevalence of 17.7 % in diarrhoeic pigs. The average age of diarrhoea onset was at 32±6.2 days, corresponding to weaning pigs, and rotavirus was not detected in lactating piglets. Molecular characterization indicated that genotypes G5, G3, P[7] and P[13] are currently the most widely represented on these pigs farms. The phylogenetic analysis showed that farms shared similar G types (VP7), which might denote a common origin. Meanwhile, [P] types (VP4) showed considerable genetic diversity, and this might represent a high rate of reassortment of this genetic segment in rotavirus circulating in the researched area. These findings demonstrate the importance of considering both the geographical and production factors to accurately determine rotavirus prevalence status at the national level, and have relevant implications in determining effective strategies for rotavirus infection control on porcine farms.

[BK and JC polyomavirus detection in leukocyte extracts of peripheral blood samples of HIV+ patients from the north area of Santiago]. / Detección de polyomavirus BK y JC en extractos leucocitarios de sangre periférica de pacientes con infección por VIH del área norte de Santiago.

INTRODUCTION: Polyomavirus BK (BKPyV) and JC (JCPyV) are persistent pathogens able to reactivate in im-munocompromised patients, involving mostly urinary and central nervous system. There are no Chilean studies in HIV positive patients. OBJECTIVE: To detect BKPyV and JCPyV in blood of Chilean HIV positive adult patients and to correlate these results with clinical-related variables. MATERIALS AND METHODS: 96 stored blood samples from HIV patients belonging to the north area of Santiago were analyzed. Viral genomes of both viruses were detected by real-time PCR. For statistical analysis, chi-square (Pearson) and Mann-Whitney tests were used and p-values < 0.05 were considered significant. RESULTS: 33% of the samples were positive for BKPyV and a significant correlation was found between the presence of BKPyV genome and the absence of detectable HIV viral load. We demonstrated the need to consider more than one amplification target to detect the BKPyV genome. All the samples were negative for JCPyV genome. DISCUSSION: BKPyV prevalence in Chilean HIV patients is higher than most of international studies. New studies regarding the interaction between both viruses are required. These patients should undergo periodic evaluations by urologist and nephrologist.

Detección de polyomavirus BK y JC en extractos leucocitarios de sangre periférica de pacientes con infección por VIH del área norte de Santiago / BK and JC polyomavirus detection in leukocyte extracts of peripheral blood samples of HIV+ patients from the north area of Santiago

Introducción: Polyomavirus BK (BKPyV) y JC (JCPyV) son patógenos persistentes con capacidad de reactivación en inmunocomprometidos, afectando principalmente el sistema urinario y el sistema nervioso central, respectivamente. No existen estudios chilenos en población infectada por VIH. Objetivo: Detectar la presencia de BKPyV y JCPyV en muestras de sangre de pacientes adultos, chilenos, con infección por VIH y correlacionar los resultados con variables clínicas. Materiales y Métodos: Analizamos 96 muestras de extractos leucocitarios de pacientes del área norte de Santiago. El genoma viral se detectó mediante RPC en tiempo real. Para el análisis estadístico se utilizó las pruebas chi-cuadrado de Pearson y Mann-Whitney, considerando significativo un valor de p < 0,05. Resultados: 33% de las muestras resultaron positivas para BKPyV y se encontró una correlación significativa entre la presencia de genoma de BKPyV y la ausencia de carga viral de VIH. Se evidenció la necesidad de considerar más de un blanco de amplificación del genoma de BKPyV. Todas las muestras fueron negativas para JCPyV. Discusión: La prevalencia de BKPyV en pacientes chilenos con infección por VIH es superior a la informada en la mayoría de los reportes internacionales. Se requiere estudios que evalúen la interacción entre ambos virus. Estos pacientes deberían ser sometidos a controles urológicos y nefrológicos periódicos.

Introduction: Polyomavirus BK (BKPyV) and JC (JCPyV) are persistent pathogens able to reactivate in im-munocompromised patients, involving mostly urinary and central nervous system. There are no Chilean studies in HIV positive patients. Objective: To detect BKPyV and JCPyV in blood of Chilean HIV positive adult patients and to correlate these results with clinical-related variables. Materials and Methods: 96 stored blood samples from HIV patients belonging to the north area of Santiago were analyzed. Viral genomes of both viruses were detected by real-time PCR. For statistical analysis, chi-square (Pearson) and Mann-Whitney tests were used and p-values < 0.05 were considered significant. Results: 33% of the samples were positive for BKPyV and a significant correlation was found between the presence of BKPyV genome and the absence of detectable HIV viral load. We demonstrated the need to consider more than one amplification target to detect the BKPyV genome. All the samples were negative for JCPyV genome. Discussion: BKPyV prevalence in Chilean HIV patients is higher than most of international studies. New studies regarding the interaction between both viruses are required. These patients should undergo periodic evaluations by urologist and nephrologist.

Viral infections in prostate carcinomas in Chilean patients.

BACKGROUND: A few viruses have been detected in prostate cancer, however their role in the development of this malignancy has not been determined. The aim of this study was to analyze the presence and functionality of human papillomavirus (HPV) and polyomaviruses (BKPyV and JCPyV) in prostate carcinomas in Chilean patients. METHODS: Sixty-nine primary prostate carcinomas were analyzed for the presence of HPV, BKPyV and JCPyV using standard polymerase chain reaction protocols. In addition, when samples were positive for HPyV, large T antigen (TAg) transcripts were analyzed using reverse transcriptase PCR. RESULTS: HPV and JCPyV were not detected in any specimens (0/69, 0 %); whereas, BKPyV was detected in 6/69 PCas (8.7 %). We did not find a statistically significant association between the presence of BKPyV and age (p = 0.198) or Gleason score (p = 0.268). In addition, 2/6 (33 %) BKPyV positive specimens showed detectable levels of TAg transcripts. CONCLUSIONS: There was no association between HPV or JCPyV presence and prostate cancer development. The presence of BKPyV in a small subset of prostate carcinomas in Chilean patients could indicate that this virus plays a potential role in prostate cancer development and requires further investigation.

Comparison of virological profiles of respiratory syncytial virus and rhinovirus in acute lower tract respiratory infections in very young Chilean infants, according to their clinical outcome.

BACKGROUND: Respiratory syncytial virus (RSV) and rhinovirus (HRV) are the main cause of acute lower respiratory tract infections (ALRTIs) in infants. Viral and host-related risk factors for severe disease have also not been clearly established. OBJECTIVE: To assess whether certain viral features of RSV and, or HRV are associated with severe ALRTI. STUDY DESIGN: RSV and HRV were studied in nasopharyngeal samples of infants by immunofluorescence, Luminex(®) and/or real-time RT-PCR assays. Quantitation and genotyping of RSV and HRV by PCR were done. RESULTS: Of 124 virus positive specimens, 74 (59.7%) had RSV; 22 (17.7%) HRV and 28 (22.6%) RSV-HRV co-infection. Hospitalization was required in 57/74 RSV infants (77.0%); in 10/22 HRV cases (45.5%) (p=0.006) and in 15/28 co-infected by both viruses (53.6%) (p=0.003). Severe cases were 33/74 (44.6%) RSV infections, 2/22 HRV cases (9.1%), (p<0.002) and 6/28 (21.4%) patients co-infected by RSV-HRV (p<0.026). Three genotypes (NA1, B7, B9) of RSV circulated during the study. In 33 severe infants, NA1 was detected in 19 cases (57.6%); B7 in 13 (39.4%) and B9 in 1 (3.0%) (p<0.01; OR=10.0). RSV loads were similar between outpatients and hospitalized infants (p=0.7) and among different severities (p=0.7). NA1 loads were higher than other strains (p=0.049). Three geno-groups of HRV circulated homogeneously. CONCLUSION: In very young infants, RSV cause more severe disease than HRV. Co-infection does not increase the severity of illness. NA1 RSV genotype was associated with major frequency of hospitalization, severe respiratory disease and higher viral load.

Human bocavirus in children with acute gastroenteritis, Chile, 1985-2010.

We detected human bocavirus in 89 (19.3%) of 462 fecal samples collected during 3 periods from 1985 through 2010 from children <5 years of age in Chile who were hospitalized with acute gastroenteritis. Our findings confirm the long-term circulation of human bocavirus in Chile.

Merkel cell polyomavirus in non-small cell lung carcinomas from Chile.

Lung cancer is a leading pathology strongly associated with the smoking habit. However, a viral etiology for a subset of patients developing lung cancer has been suggested. Polyomaviruses (PyVs) are small double stranded DNA viruses associated with the development of some human diseases. However, a causal role of these viruses in human cancer has been difficult to demonstrate. In this study, eighty-six non-small cell lung carcinomas (NSCLCs), including adenocarcinomas (AdCs) and squamous cell lung carcinomas (SQCs) from Chile were analyzed for the presence of PyVs using polymerase chain reaction (PCR). All of the specimens were positive for a fragment of the betaglobin gene. We found that 4/86 (4.7%) of lung carcinomas were positive for PyVs. After sequencing and BlastN alignment, all four cases were identified as Merkel cell polyomaviruses (MCV) that corresponded to two AdCs and two SQCs. A non-significant statistical association was found between the presence of MCV and clinic-pathological features of the patients and tumors. In addition, 1/4 (25%) of the carcinomas were actively expressing large T antigen (LT) transcripts, as demonstrated by reverse-transcriptase PCR (RT-PCR). Thus a possible role of MCV in a very small subset of patients with lung cancer cannot be ruled out and warrants more investigation.

[Parvovirus B19 among blood donors from three hospitals in Santiago, Chile]. / Detección de ADN de parvovirus B19 en donantes de sangre de tres hospitales en Santiago, Chile.

BACKGROUND: Parvovirus B19 (B19) is associated with a wide range of diseases in humans, whose severity depends on the immunological and hematological status of the host. It is transmitted mainly through the airway but also by transfusions. AIM: To determine the B19 DNA carrier frequency in a population of volunteer blood donors from three hospitals blood banks in Santiago, Chile, and to determine the viral load in DNA positive cases. MATERIAL AND METHODS: A total of 477 serum samples were analyzed. The screening of B19 DNA was carried out by nested polymerase chain reaction (PCR) directed to the non-structural region of the virus (NS1). The viral load in positives cases was quantified by NS1 Real Time PCR. RESULTS: Parvovirus B19 was detected in four samples, rendering a frequency of 1:119. The viral loads ranged from less than 2000 to 5626 x 10(5) genome equivalents/ml. CONCLUSIONS: Parvovirus B19 was present in four of 477 blood bank blood donors from three hospitals in Santiago.

[Clinical, electrophysiological and molecular study of 26 chilean patients with spinal muscular atrophy]. / Atrofia muscular espinal: caracterización clínica, electrofisiológica y molecular de 26 pacientes.

BACKGROUND: Spinal Muscular Atrophy (SMA) is an autosomal recessive disorder affecting the anterior horn cells of the spinal cord resulting in muscle weakness and atrophy, linked to the homozygous disruption of the survival motor neuron 1 (SMN1) gene. It is the leading genetic cause of infant death. It has been classified into three types based on the severity of symptoms. Type I SMA is the most severe form with death within the first 2 years of life. Type II and III SMA patients show intermediate and mild forms of the disorder. AIM: To describe the clinical and electrophysiological findings of 26 Chilean patients with SMA with molecular confirmation. PATIENTS AND METHODS: Retrospective multicenter analysis of patients with SMA assessed between 2003 and 2010. The diagnosis was suspected on clinical and electrophysiological criteria. Since 2006 molecular genetics confirmation was implemented in one of our centers. RESULTS: Twenty-six patients between 2 months and 18 years of age at presentation were analyzed; 15 (58%) were males. SMA I, II and III clinical criteria were observed in 4 (15.4 %), 11 (42.3%) and 11 (42.3%)patients, respectively. All had proximal muscle weakness and atrophy. Electromyography showed features of acute denervation or re-innervation with normal motor and sensory nerve conduction. Nine patients required a muscle biopsy. The genetic confirmation of the disease by PCR technique followed by restriction fragment length polymorphism method disclosed the SMN1 gene deletion in all 26 cases. All patients died secondary to respiratory failure, between eight and 14 months of life. CONCLUSIONS: An adequate clinical and molecular diagnosis of spinal muscular atrophy will help for a better management of these patients.

Detección de ADN de parvovirus B19 en donantes de sangre de tres hospitales en Santiago, Chile / Parvovirus B19 among blood donors from three hospitals in Santiago, Chile

Background: Parvovirus B19 (B19) is associated with a wide range of diseases in humans, whose severity depends on the immunological and hematological status of the host. It is transmitted mainly through the airway but also by transfusions. Aim: To determine the B19 DNA carrier frequency in a population of volunteer blood donors from three hospitals blood banks in Santiago, Chile, and to determine the viral load in DNA positive cases. Material and Methods: A total of477 serum samples were analyzed. The screening of B19 DNA was carried out by nested polymerase chain reaction (PCR) directed to the non-structural region of the virus (NS1). The viral load in positives cases was quantified by NS1 Real Time PCR. Results: Parvovirus B19 was detected in four samples, rendering a frequency of 1:119. The viral loads ranged from less than 2000 to 5,626 x 10(5) genome equivalents/ml. Conclusions: Parvovirus B19 was present in four of 477 blood bank blood donors from three hospitals in Santiago.