Publications (13)35.74 Total impact
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Article: Dynamics of Helicobacter pylori Detection in Stools during the First Five Years of Life in Chile, a Rapidly Developing Country.
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ABSTRACT: BACKGROUND:: Helicobacter pylori (H. pylori) colonization/infection can be transitory or persistent, conditions that have not been thoroughly evaluated in young children. We aimed to characterize the dynamics of H. pylori stool detection and determine host/environmental factors and symptoms associated with persistence. METHOD:: In a 5 year cohort study we followed infants from birth with clinic visits every three months. Symptoms/environmental risk factor survey and a stool sample for H. pylori antigen detection were requested in every visit. Secretor/ABH histo-blood group phenotype was determined in saliva. RESULTS:: Overall 218/1456 (15%) stool samples were H. pylori positive and 39/96 (41%) children had at least one positive sample. Stool detection was transitory in 16/39 (41%), persistent in 19 (49%) and undetermined in 4 (10%) children. Persistence was acquired largely during the first 24 months (17/19 cases), was associated with non-secretor phenotype (32% vs. 0% for transitory infection, p= .02) and day care attendance (67% vs. 26% for never infected, p=.019). Symptoms possibly associated with persistence were referred in only one child. CONCLUSIONS:: Near 20% of this Chilean cohort had persistent H. pylori stool sample detections during the first 5 years of life, acquired mostly during the first 24 months. Persistence was significantly associated with non-secretor phenotype and day care attendance and possibly associated gastrointestinal symptoms were rare. This relatively common group of young children with persistent H. pylori colonization/infection will require further study.The Pediatric Infectious Disease Journal 10/2012; · 3.58 Impact Factor -
Article: Enteric viruses in wastewaters: an interesting approach to evaluate the potential impact of rotavirus vaccination on viral circulation.
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ABSTRACT: Rotavirus and norovirus are the leading causes of acute gastroenteritis worldwide. Both viruses share features such as low infectious dose, high stool concentration and prolonged survival in the environment, including water. However, they differ in several aspects, reflecting potential differences in their interactive capacities with the environment and host. This work, which is a 13-month prospective study in a developing country with high rotavirus vaccine coverage demonstrated a high (44%) PCR detection of norovirus in 84 wastewater samples compared with a relatively low (11%) detection of rotavirus. These results suggest that rotavirus circulation may be positively affected by vaccination and support the use of enteric viral detection in wastewaters as a useful tool to measure the impact of specific interventions.Expert Review of Vaccines 04/2012; 11(4):419-22. · 4.25 Impact Factor -
Article: [Rotavirus genotypes in children with gastroenteritis assisted in two public hospitals from Chile: viral strains circulating in a country without a universal vaccination against rotavirus].
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ABSTRACT: Rotavirus is the main cause of severe gastroenteritis (GE) in children. Two vaccines currently available have proven efficacy against the predominant genotypes. Rotavirus genotypes vary both geographically and/or temporally. Genotype surveillance is important to monitor trends associated or not with vaccine use. Aim: To update information on rotavirus genotypes circulating in two main cities of Chile. Between May 2009-March 2010, children < 5y of age receiving medical care for GE in two large hospitals were recruited; none of these children had received rotavirus vaccine previously. Epidemiological information was recorded in an ad-hoc form and stool samples were collected for rotavirus detection by a commercial ELISA. Genotyping was performed by semi-nested RT-PCR. A total of 296/967 samples (31%) were positive for rotavirus, with a peak in November/ December mostly in children 7-24 months old (67%). G9P[8] was the predominant genotype (76%), followed for G1P[8] (6%) and G2P[4] (6%) in both cities. Rotavirus caused one third of GE requiring emergency room care and/or hospitalization, mostly in children within an age range susceptible to benefit from rotavirus vaccines. G9P[8], a genotype against which rotavirus vaccines have demonstrated high efficacy, was by far the most frequent rotavirus variant. Continued surveillance in Chile is crucial for providing background information on disease burden and strain diversity before the introduction of rotavirus vaccines.Revista chilena de infectologia: organo oficial de la Sociedad Chilena de Infectologia 04/2012; 29(2):142-8. · 0.45 Impact Factor -
Article: Rotarix®: vaccine performance 6 years postlicensure.
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ABSTRACT: Rotarix(®) was first licensed in 2004 and rapidly introduced into private and public markets worldwide. In a previous 2009 article, we reviewed the impact of rotavirus-associated disease, the rationale for different vaccines, prelicensure efficacy studies and cost-effectiveness studies for Rotarix. As of September 2011, Rotarix had been licensed in 123 countries in the Americas, Europe, Australia, Africa and Asia, of which 27 have incorporated the vaccine into national or regional immunization programs. The current review intends to provide the reader with further insight into this vaccine, focusing mainly on the new information obtained after a 6-year postlicensure period. This review will provide only a brief summary of prelicensure studies extensively discussed in the previous publication and refer, in more depth, to the worldwide experience with the vaccine, vaccine impact, and safety observed in effectiveness and observational studies, including a particular analysis on protection against rotavirus G2P[4].Expert Review of Vaccines 12/2011; 10(12):1645-59. · 4.25 Impact Factor -
Article: Development and validation of a microarray for the confirmation and typing of norovirus RT-PCR products.
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ABSTRACT: Noroviruses are implicated in many worldwide institutional, food and waterborne outbreaks each year. Genetic typing of isolates is valuable for monitoring outbreak spread as well as variation in circulating strains. Microarrays have the potential to provide rapid genotype information for norovirus samples. The NoroChip v3.0 provides an oligonucleotide hybridization platform to screen for over 600 potential interactions in each experiment. The NoroChip v3.0 was developed at Health Canada and validated in seven international partner laboratories. Each laboratory validated the NoroChip v3.0 using norovirus amplicons routinely characterized in their testing protocols. Fragments from the capsid region (region C) and a 2.4 kb amplicon spanning polymerase and capsid sequences (region AD) were validated in six of the partner laboratories and provided correct genogroup typing information (GI or GII) when hybridized to the NoroChip v3.0. Results indicate that the current limiting factor for implementing the NoroChip v3.0 as a strain typing tool is the difficulty obtaining a long, specific amplicon from all circulating norovirus strains. Data obtained with the longer region AD amplicon provided the best discrimination between norovirus strains.Journal of virological methods 02/2011; 173(2):233-50. · 2.13 Impact Factor -
Article: Prospective characterization of norovirus compared with rotavirus acute diarrhea episodes in chilean children.
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ABSTRACT: Rotavirus and more recently noroviruses are recognized as main causes of moderate to severe acute diarrhea episodes (ADE) in children < or =5 years of age. Comparing epidemiologic and clinical features of norovirus to rotavirus ADE will aid in the decision-making process required to develop norovirus vaccines. Surveillance for ADE occurring in children < or =5 years of age was implemented in the emergency department (ED) and ward of a large hospital in Santiago and Valparaiso, and in 4 outpatient clinics in Santiago. A stool sample was obtained within 48 hours of consultation for rotavirus detection by enzyme-linked immunosorbent assay and noroviruses by enzyme-linked immunosorbent assay or reverse transcription polymerase chain reaction. For ED and hospital rotavirus and norovirus ADE parents were instructed to monitor clinical findings associated with severity until the end of the episode. The 20-point Vesikari score was used to determine disease severity. Between July 2006 and October 2008 rotavirus and noroviruses were detected in 331 (26%) and 224 (18%) of 1913 ADE evaluated. The proportion of rotavirus-positive samples in hospital ward, ED, and outpatient clinic was 40%, 26% to 30%, and 13% compared with 18%, 17% to 19%, and 14% for noroviruses. Mean age and 25%-75% interquartile interval of children with rotavirus and norovirus ADE were remarkably similar, 15.6 months (9-20), and 15.5 months (9-19), respectively. Rotavirus cases displayed an autumn-winter peak followed 2 to 3 months later by the norovirus peak. The mean (interquartile) for the Vesikari score was 12.9 (11-15) and 11.9 (9-14.5) for rotavirus (N = 331) and norovirus (N = 224) ADE, respectively, P = 0.003. Compared with norovirus, rotavirus ADE were more common in the 11 to 16 severity score interval (P = 0.006), had a higher maximum stool output in a given day (P = 0.01) and more frequent fever (P < 0.0001). Duration of diarrhea, presence, duration and intensity of vomiting, and intensity of fever did not differ between viruses. Mixed rotavirus and norovirus infections were uncommon (<1%) and not clinically more severe. Clinical severity of ADE in young infants was similar for rotavirus and lower (P = 0.03) for noroviruses compared with older children. Noroviruses are a significant cause of moderate to severe endemic ADE in Chilean children. Although significantly less severe than rotavirus as a group, most norovirus episodes were moderate to severe clinically. An effective norovirus vaccine would be of significant additional benefit to the current rotavirus vaccine in decreasing disease burden associated with ADE.The Pediatric Infectious Disease Journal 09/2010; 29(9):855-9. · 3.58 Impact Factor -
Article: An update on management of severe acute infectious gastroenteritis in children.
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ABSTRACT: This article focuses on clinical and diagnostic aspects relevant to severe acute infectious gastroenteritis in children and will update treatment strategies focused on, although not limited to, anti-infective therapy. For the purposes of this article we will consider severe acute infectious gastroenteritis as follows: watery diarrhea accompanied by, or at high risk for, moderate to severe dehydration due to abrupt onset of vomiting that reduces oral intake, and/or frequent emission of liquid stools, or moderate to severe dysenteric/bloody diarrhea with moderate to high-grade fever. The article will not include food poisoning associated with bacterial toxins and will only briefly discuss oral rehydration strategies and intravenous solutions. The article will also briefly discuss current preventive measures against rotavirus gastroenteritis through vaccination, a topic that has been extensively discussed elsewhere.Expert Review of Anticancer Therapy 06/2010; 8(6):671-82. · 3.28 Impact Factor -
Article: Norovirus illness is a global problem: emergence and spread of norovirus GII.4 variants, 2001-2007.
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ABSTRACT: Noroviruses (NoVs) are the most common cause of viral gastroenteritis. Their high incidence and importance in health care facilities result in a great impact on public health. Studies from around the world describing increasing prevalence have been difficult to compare because of differing nomenclatures for variants of the dominant genotype, GII.4. We studied the global patterns of GII.4 epidemiology in relation to its genetic diversity. Data from NoV outbreaks with dates of onset from January 2001 through March 2007 were collected from 15 institutions on 5 continents. Partial genome sequences (n=775) were collected, allowing phylogenetic comparison of data from different countries. The 15 institutions reported 3098 GII.4 outbreaks, 62% of all reported NoV outbreaks. Eight GII.4 variants were identified. Four had a global distribution--the 1996, 2002, 2004, and 2006b variants. The 2003Asia and 2006a variants caused epidemics, but they were geographically limited. Finally, the 2001 Japan and 2001 Henry variants were found across the world but at low frequencies. NoV epidemics resulted from the global spread of GII.4 strains that evolved under the influence of population immunity. Lineages show notable (and currently unexplained) differences in geographic prevalence. Establishing a global NoV network by which data on strains with the potential to cause pandemics can be rapidly exchanged may lead to improved prevention and intervention strategies.The Journal of Infectious Diseases 10/2009; 200(5):802-12. · 6.41 Impact Factor -
Article: Symptomatic and asymptomatic rotavirus and norovirus infections during infancy in a Chilean birth cohort.
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ABSTRACT: Rotavirus and more recently norovirus have been recognized as 2 of the most common causes of acute diarrhea in children. Comparative analysis of these infections in a birth cohort has not been performed and can provide relevant insight on clinical and viral behaviors. Mother-infant pairs from middle-low socioeconomic background living in the Metropolitan Region of Chile are being followed for 18 months in 2 outpatient clinics. Infants are evaluated monthly for asymptomatic excretion of rotavirus and norovirus and during acute diarrhea episodes (ADE) for rotavirus, norovirus, and bacterial enteropathogens. Severity of ADE is evaluated using the Vesikari score. Between July 1, 2006 and September 1, 2008 a total of 198 children were followed for a mean of 15.7 months. Asymptomatic rotavirus and norovirus infections were detected in 1.3% and 8% of 2278 stool samples compromising 14% and 57% of infants, respectively. Incidence of ADE was approximately 0.8 for the first year of life and approximately 0.6 for the 13 to 18 month age group. Rotavirus and norovirus were detected in 15% and 18% of 145 ADE evaluated. Mean Vesikari score was 10.4 and 7.4 for rotavirus and norovirus respectively (P = 0.01) and severity was not associated with age of patients for either virus. Reinfections were more common for norovirus asymptomatic episodes: 44% versus 19% (P = 0.01) and borderline for symptomatic episodes: 40% versus 11% (P = 0.08). Rotavirus genotype G9P8 and norovirus genogroup II (GII) predominated although most asymptomatic episodes for both viruses were nontypable. None of 19 symptomatic GII norovirus infections had a previous documented GII infection compared with 10 of 31 asymptomatic GII infections (OR = 0. 95% CL = 0, 0.59; P = 0.008). Children had suffered a mean of approximately 1.4 ADE by 18 months of age of which 15% and 18% were caused by rotavirus and norovirus, respectively. In general rotavirus infections were more severe than norovirus infections and for both viruses severity was not related to age. Norovirus reinfections were significantly more common than rotavirus reinfections but for GII norovirus a primary infection seems to confer protection against clinically significant reinfections.The Pediatric Infectious Disease Journal 09/2009; 28(10):879-84. · 3.58 Impact Factor -
Article: [Clinical and epidemiological profile of intestinal intussusception among infants of Metropolitan Santiago].
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ABSTRACT: Intussusception (IS) is a potentially severe disease that affects an undetermined number of Chilean infants. The withdrawal of a rotavirus vaccine in 1999 due to its association with IS, highlighted the need for updated information on IS worldwide including Chile, before introduction of new vaccines. To estimate the incidence and to describe the epidemiology and clinical presentation of IS in the Metropolitan Area of Chile. IS cases occurring between 1996 and 2001 in the seven public pediatric hospitals and in six private clinics (during 2000 and 2001) were identified. Incidence rates were calculated using updated population estimates. A systematic review of the medical charts of IS cases occurring in the public hospitals for 2000-2001 was performed. IS incidence rates for the Public Sector ranged from 32 to 39 per 100,000 children < 2 years of age. These figures did not vary significantly among the different Health Care Services, nor after inclusion of the private clinics. IS was more common in males (66%) and infants younger than 12 months (83%), with 67% of cases occurring between 3 and 8 months of age. The most common presenting symptoms were abdominal pain (90%), vomiting (86%), and rectal bleeding (75%). Ileocolic IS predominated (83%) and surgical correction was the preferred treatment (81%). No death occurred in this series. IS incidence rates were intermediate compared to other series, stable over time, and similar between the public and private sector. Clinical characteristics were similar to those previously reported with a disproportionately high use of surgical correction over enema, currently considered the preferred treatment option.Revista medica de Chile 05/2004; 132(5):565-72. · 0.33 Impact Factor -
Article: Two year review of intestinal intussusception in six large public hospitals of Santiago, Chile.
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ABSTRACT: A need for updated information on different aspects of idiopathic intussusception resurged after the Rotashield experience. Variability of incidence rates worldwide and the possibility of a more severe outcome among infants that have intussusception at a younger age are two issues that remain unclear. We aimed to provide updated information on clinical aspects of intussusception in a large population of Chilean children <2 years of age, including a best estimate of incidence rate and a comparative analysis of the clinical evolution for children younger and older than 6 months of age. Several sources of information were used to recollect all intussusception cases 0 to 24 months of age treated in six public pediatric hospitals of the Metropolitan area during years 2000 and 2001 and to obtain updated estimates of the population covered by these hospitals. A thorough chart review of intussusception cases was performed using a standardized case report form. A total of 50 and 45 intussusception cases were detected for 2000 and 2001, respectively, and estimated intussusception rates for children 0 to 24 months and for the subgroup <12 months of age were 35 and 32 per 100 000, and 55 and 47 per 100 000. The monthly distribution of intussusception cases differed for both years without an identifiable reason, and no association between intussusception and rotavirus infection was observed. No intussusception-associated death was recorded. Overall complications occurred in 21% of children, and infants younger than 6 months of age did not have more complications or a more prolonged hospital stay than older children. Idiopathic intussusception is not uncommon among Chilean infants with incidence rates similar to those reported in the United States. There was no clear association with preexisting rotavirus infection and occurrence of complications was not related to young age.The Pediatric Infectious Disease Journal 08/2003; 22(8):717-21. · 3.58 Impact Factor -
Article: [Invasive fungal infections in children with cancer, neutropenia and fever, in Chile].
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ABSTRACT: Invasive fungal infections (IFI) cause prolonged hospitalizations and increase the possibility of death among patients with cancer and febrile neutropenia (FN). Up to 10% of febrile neutropenic episodes may be caused by IFI. To estimate the incidence of IFI among a large group of Chilean children with cancer and FN. Clinical and laboratory information was collected from a data base provided by the "Programa Infantil Nacional de Drogas Antineoplásicas" (PINDA) that included 445 FN episodes occurring in five hospitals in Santiago, Chile. This information was used to identify children that presented with signs and symptoms compatible with an IFI. According to predefined criteria based on a literature review, IFI episodes were categorized as "proven", "probable" or "possible". A total of 41/445 episodes (9.2%) were compatible with an IFI of which 4 (0.9%) were proven, 23 (5.2%) probable, and 14 (3.1%) possible. Hospitalization was longer (27 vs 8 days, p < .01), new infectious foci appeared with higher frequency (71 vs 38%, p < .01), and mortality was higher (10 vs 1.6%, p < .001) in children with IFI compatible episodes, when compared to children who did not have an IFI. The estimated incidence of IFI in Chilean children with cancer and FN ranged between 6-9% depending on the stringency of criteria selection used for classification. This estimate is similar to that reported by other studies. The low detection yield of clinically compatible IFI underscores the need of improved diagnosis of fungal infections in this population.Revista medica de Chile 11/2002; 130(10):1139-46. · 0.33 Impact Factor -
Article: Norovirus Illness Is a Global Problem: Emergence and Spread of Norovirus GII.4 Variants, 2001–2007
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ABSTRACT: Background. Noroviruses (NoVs) are the most common cause of viral gastroenteritis. Their high incidence and importance in health care facilities result in a great impact on public health. Studies from around the world describing increasing prevalence have been difficult to compare because of differing nomenclatures for variants of the dominant genotype, GII.4. We studied the global patterns of GII.4 epidemiology in relation to its genetic diversity. Methods. Data from NoV outbreaks with dates of onset from January 2001 through March 2007 were collected from 15 institutions on 5 continents. Partial genome sequences (np775) were collected, allowing phylogenetic comparison of data from different countries. Results. The 15 institutions reported 3098 GII.4 outbreaks, 62% of all reported NoV outbreaks. Eight GII.4 variants were identified. Four had a global distribution—the 1996, 2002, 2004, and 2006b variants. The 2003Asia and 2006a variants caused epidemics, but they were geographically limited. Finally, the 2001Japan and 2001Henry variants were found across the world but at low frequencies. Conclusions. NoV epidemics resulted from the global spread of GII.4 strains that evolved under the influence of population immunity. Lineages show notable (and currently unexplained) differences in geographic prevalence. Establishing a global NoV network by which data on strains with the potential to cause pandemics can be rapidly exchanged may lead to improved prevention and intervention strategies. Financial support: European Commission, Directorate General Research Quality of Life program (EVENT [Enteric Virus Emergence, New Tools] grant SP22-CT-2004- 502571 to J.J.S.); Indian Council of Medical Research, New Delhi, India (support to S.B. and A.C.); New Zealand Ministry of Health (funding for the New Zealand studies); Hungarian Scientific Research Fund (grant F048433 to G.R.); 973 National Key Basic Research Program of China (grant 2007CB310500 to the Chinese Center for Disease Control and Prevention); Chilean National Science and Technology Research Fund (grants 10210583 and 1061079 to Y.L. and M.O.); Alberta Health and Wellness (support to B.E.L. and X.-L.P.); Ministry of Science, Technology, and Innovation, Malaysia (grant 06-02-05-001 BTK/ER/002 to N.B.G.R.).
Top co-authors
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Institutions
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2002–2004
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University of Chile
- ICBM Instituto de Ciencias Biomédicas
Santiago, Region Metropolitana de Santiago, Chile
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