Browsing by Author "Abarca, Katia"
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- ItemA Third Amblyomma Species and the First Tick-Borne Rickettsia in Chile(OXFORD UNIV PRESS INC, 2012) Abarca, Katia; Lopez, Javier; Acosta Jamett, Gerardo; Lepe, Paulina; Soares, Joao Fabio; Labruna, Marcelo B.During November 2010, three ticks were collected from three dogs living in the rural area of Arica, northern Chile. Morphological analyses of the ticks in the laboratory revealed that they were most similar to Amblyomma maculatum Koch and Amblyomma triste Koch. However, because of unique metatarsal spurs, neither of the Chilean specimens could be assigned with certainty to A. maculatum or A. triste, based on external morphology. The mitochondrial 16S rRNA gene partial sequences obtained from two Chilean specimens were 99.5% identical to A. triste from Uruguay, and 99.0% identical to A. maculatum from the United States. Through phylogenetic analysis inferred from partial 16S rRNA sequences, the Chilean specimens were classified as A. triste. Molecular analyses also showed that one of the three Chilean ticks was infected by Candidatus 'Rickettsia andeanae'. These findings extend the geographical distribution of A. triste to Chile, where no tick-associated rickettsia had been reported previously.
- ItemAnaplasma platys in dogs, Chile(CENTER DISEASE CONTROL, 2007) Abarca, Katia; Lopez, Javier; Perret, Cecilia; Guerrero, Javier; Godoy, Paula; Veloz, Ana; Valiente Echeverria, Fernando; Leon, Ursula; Gutjahr, Constanza; Azocar, TeresaWe conducted a 16S rRNA nested PCR for the genus Ehrlichia and Ehrlichia spp. with blood samples from 30 ill dogs in Chile. Phylogenetic analysis was performed by using groESL gene amplification. We identified Anaplasma platys as 1 of the etiologic agents of canine ehrlichiosis.
- ItemAsthma and the Risk of Invasive Pneumococcal Disease: A Meta-analysis(2020) Castro Rodríguez, Jose; Abarca, Katia; Forno, ErickInvasive pneumococcal disease (IPD) and pneumonia are a leading cause of morbidity and mortality throughout the world, and asthma is the most common chronic disease of childhood. To evaluate the risk of IPD or pneumonia among children with asthma after the introduction of pneumococcal conjugate vaccines (PCVs). Four electronic databases were searched. We selected all cohorts or case-control studies of IPD and pneumonia in populations who already received PCV (largely 7-valent pneumococcal conjugate vaccine), but not 23-valent pneumococcal polysaccharide, in which authors reported data for children with asthma and in which healthy controls were included, without language restriction. Two reviewers independently reviewed all studies. Primary outcomes were occurrence of IPD and pneumonia. Secondary outcomes included mortality, hospital admissions, hospital length of stay, ICU admission, respiratory support, costs, and additional medication use. Five studies met inclusion criteria; of those, 3 retrospective cohorts (∼26 million person-years) and 1 case-control study (N = 3294 children) qualified for the meta-analysis. Children with asthma had 90% higher odds of IPD than healthy controls (odds ratio = 1.90; 95% confidence interval = 1.63-2.11; I2 = 1.7%). Pneumonia was also more frequent among children with asthma than among controls, and 1 study reported that pneumonia-associated costs increased by asthma severity. None of the identified studies had information of asthma therapy or compliance. Despite PCV vaccination, children with asthma continue to have a higher risk of IPD than children without asthma. Further research is needed to assess the need for supplemental 23-valent pneumococcal polysaccharide vaccination in children with asthma, regardless of their use of oral steroids.
- ItemClinic and epidemiologic description of Clostridium difficile infection in a pediatric population(SOC CHILENA INFECTOLOGIA, 2015) Maccioni, Andrea; Cerda, Jaime; Terrazas, Claudia; Abarca, KatiaBackground: Clostridium difficile (CD)-associated disease (CDAD) and the role of the hypervirulent strain NAP1 have not been well characterized in Pediatrics. Aims: To describe clinical features of CDAD, and to estimate NAP1 frequency and association with disease severity in Pediatrics. Methods: Descriptive, transversal surveillance of diarrheal episodes in Chilean children, hospitalized between February 2012 and December 2013, positive for CD by molecular diagnosis. Results: A total of 66 episodes of diarrhea with identification of CD occurred thougout the study period in children between 1 month and 19 years of age of which 39% were younger than one year old. CD acquisition was predominantly nosocomial and the most common risk factors were: presence of comorbidities (98.6%), use of antibiotics (93.9%), proton pump inhibitors (84.8%), invasive mechanic ventilation (54.5%), feeding tube (48.5%) and immunosuppression (40.9%). Clinical course was mostly mild, but 12 cases presented an unfavorable course, of which 3/26 occurred in children less than one year. Only one case was positive for NAP1 and had a mild course. Conclusion: Diarrhea with identification of CD was present throughout all pediatric ages, including children less than one year old. Analytical and longitudinal studies are required to better characterize the pathogenic role of CD in this age group. CDAD occurred mostly in patients with risk factors, and the clinical course was predominantly mild.
- ItemDetection of Rickettsia andeanae in two regions of Chile(SOC CHILENA INFECTOLOGIA, 2013) Abarca, Katia; Lopez, Javier; Acosta Jamett, Gerardo; Martinez Valdebenito, ConstanzaIntroduction: Candidatus 'Rickettsia andeanae' is recently recognized specie, with no attributed pathogenic role so far. It has been reported in Amblyomma ticks from Peru, USA and Argentina, and recently in Chile, in one specimen of Amblyomma triste from a rural locality in Arica. Objective: To determine the presence of rickettsial agents in ticks from domestic dogs from two Chilean regions. Methods: A transversal descriptive study in Coquimbo and Araucania regions, Consisted in households sampling in the cities of Coquimbo and Angol and nearby rural localities, in spring-summer 2011-2012. One clog per house was examined and ticks Were collected when present; after taxonomic identification, gltA and ompA genes were amplified and sequenced. Results: 462 dogs were examined, 255 had ticks (55%). In the cities just Rhipicephalus sanguineus was found; in rural localities also Amblyomma tigrinum. Obtained sequences in 12 specimens from A. tigrinum corresponded to Candidatus 'Rickettsia andeanae'. Conclusions: We documented the presence of R. andeanae in two distant Chilean regions, which is added to its recently finding in the Northern extreme of the country. This new rickettsial agent limits to Amblyomma ticks and rural areas, as it was reported in other American countries and corresponds with this tick habitat.
- ItemEffectiveness of varicella vaccine as post exposure prophylaxis in Chilean children(SOC CHILENA INFECTOLOGIA, 2012) Pinochet, Constanza; Cerda, Jaime; Hirsch, Tamara; Mieres, Jocelyn; Inostroza, Carolina; Abarca, KatiaEffectiveness of varicella vaccine as post exposure prophylaxis in Chilean children Introduction: Efficacy and effectiveness of varicella vaccine (VV) as post exposure prophylaxis (PEP) strategy have shown discordant results for disease risk reduction, and more consistent results in their ability to attenuate the disease. Aim: To assess the effectiveness of VV as PEP among household contacts. Material and Methods: We followed up 33 children after household exposure to a varicella case, of which 15 received VV as PEP and 18 did not received VV. The presence and severity of the disease were clinically determined. Results: Secondary attack rate was 53% among vaccinated and 89% among non-vaccinated children. Overall effectiveness of VV as PEP was 40% (CI95% 1%-64%). The effectiveness for preventing moderate or severe disease was 63% (CI95% 8%-85%) in the entire group and 77% (CI95% 14%-94%) among children vaccinated during the first 3 days post exposure. Vaccine tolerance was acceptable, with a low number of adverse reactions, all of them mild. Conclusion: The results suggest that VV as PEP is effective among household contacts, especially for reducing the severity of the disease.
- ItemFuente de infección de Bordetella pertussis en lactantes hospitalizados por coqueluche(SOC MEDICA SANTIAGO, 2011) Perret, Cecilia; Viviani, Tamara; Pena, Anamaria; Abarca, Katia; Ferres, MarcelaBackground: Despite pertussis vaccination, very young infants have the highest rates of morbidity and mortality caused by the microorganism. Aim: To determine the source of Pertussis infection in infants aged six months or less in Chile. Material and Methods: Twenty six household contacts of 10 young infants hospitalized with confirmed Pertussis were studied for the presence of Bordetella Pertussis by polymerase chain reaction (PCR). Clinical and demographic data were analyzed. Results: Respiratory symptoms were present in 20 (77%) contacts, being cough the most common. Pertussis cases were identified in every household and in 18 (72%) of the household members. Four members with B.pertussis were asymptomatic. Source of infection was identified in 80% (8/10) of the infant cases with ages ranging from 6 to 62 years. Half of primary cases had positive PR and their cough duration was significantly shorter compared to primary cases with negative PER. Conclusions: B. pertussis transmission to young infants occurred mainly within the household where adults are generally the source of the infection. Risk factors for infant infection are the same as in developed countries. Therefore, the same strategies, such as routine vaccination in adolescents and adults or cocoon strategy, will help to prevent this disease in infants. (Rev Med Chile 2011; 139: 448-454).
- ItemImmunogenicity and tolerability of a paediatric presentation of a virosomal hepatitis A vaccine in Chilean children aged 1-16 years(ELSEVIER SCI LTD, 2011) Abarca, Katia; Ibanez, Isabel; de la Fuente, Pablo; Cerda, Leonardo; Bergeret, Jorge; Froesner, Gert; Ibarra, HumbertoWe assessed the immunogenicity of the paediatric dose of Epaxal (R) (0.25 mL) and the degrees of seroprotection achieved with the standard dose (0.5 mL) of Epaxal (R) or a dose of Havrix (R) Junior, in children in an open, randomised, controlled, multi-centre, parallel-group study conducted at 2 Chilean study centres. 360 healthy children and adolescents 12 months to <17 years of age not previously vaccinated against hepatitis A were enrolled. Subjects were randomised 2:2:1 to be vaccinated with either Epaxal (R) 0.25 mL [n = 146], Epaxal (R) 0.5 mL [n = 142] or Havrix (R) Junior In = 72] intramuscularly on Day 1 and after 6 months (26 weeks +/- 14 days). Primary end point was the proportion of subjects seroprotected (anti-HAV antibody concentration >= 10 mIU/mL) in the ATP population at Month 1. All vaccines elicited high seroprotection rates at Month 1: 95.7% with Epaxal (R) 0.25 mL, 99.3% with Epaxal (R) 0.5 mL and 94.0% with Havrix (R) Junior. After the booster vaccination, all subjects demonstrated 100% seroprotection with all vaccines. Antibody concentrations were similarly high in all age groups. The paediatric presentation achieved antibody concentrations similar to those achieved with the 0.5 mL dose across the entire age range, and there were no differences across the range of body weights from 9.0 kg to 82.7 kg. All study vaccines were well tolerated and there were no AEs leading to discontinuation. Thus, the paediatric 0.25 mL dose of Epaxal (R) fulfilled the primary objective of showing non-inferiority to the adult 0.5 mL dose and to Havrix (R) Junior, in terms of seroprotection rates achieved. The results show the paediatric dose of Epaxal (R) to be an attractive option when conducting childhood-vaccination programmes. (C) 2011 Elsevier Ltd. All rights reserved.
- ItemIRF8 Mutations and Human Dendritic-Cell Immunodeficiency(MASSACHUSETTS MEDICAL SOC, 2011) Hambleton, Sophie; Salem, Sandra; Bustamante, Jacinta; Bigley, Venetia; Boisson Dupuis, Stephanie; Azevedo, Joana; Fortin, Anny; Haniffa, Muzlifah; Ceron Gutierrez, Lourdes; Bacon, Chris M.; Menon, Geetha; Trouillet, Celine; McDonald, David; Carey, Peter; Ginhoux, Florent; Alsina, Laia; Zumwalt, Timothy J.; Kong, Xiao Fei; Kumararatne, Dinakantha; Butler, Karina; Hubeau, Marjorie; Feinberg, Jacqueline; Al Muhsen, Saleh; Cant, Andrew; Abel, Laurent; Chaussabel, Damien; Doffinger, Rainer; Talesnik, Eduardo; Grumach, Anete; Duarte, Alberto; Abarca, Katia; Moraes Vasconcelos, Dewton; Burk, David; Berghuis, Albert; Geissmann, Frederic; Collin, Matthew; Casanova, Jean Laurent; Gros, PhilippeBACKGROUND
- ItemMolecular identification of Ehrlichia canis in a dog from Arica, Chile(SOC CHILENA INFECTOLOGIA, 2012) Lopez, Javier; Abarca, Katia; Isabel Mundaca, M.; Caballero, Carla; Valiente Echeverria, FernandoWe report a molecular confirmed case of canine ehrlichiosis caused by Ehrlichia canis. A 10-year old female crossbred Siberian from the city of Arica, which was infested by ticks, presented hemorrhagic manifestations (hematomas and snout bleeding) and prostration. Blood cell count revealed thrombocytopenia (30,000 platelets/mm(3)). Immunochromatographic rapid testing for E. canis IgG was positive. Amplification and sequencing of a fragment of the 16S rRNA gen from a blood sample showed 100% homology with E. can is from Peril. This is the first report of E. canis in Chile, an agent with known zoonotic potential.
- ItemMorphological and molecular identification of canine filariae in a semi-rural district of the Metropolitan Region in Chile(SOC CHILENA INFECTOLOGIA, 2012) Lopez, Javier; Valiente Echeverria, Fernando; Carrasco, Marcela; Mercado, Ruben; Abarca, KatiaIntroduction: To date, there has been no definitive confirmation of the presence of zoonotic dirofilariasis in dogs in Chile. Objectives: To study the presence of dirofilarias in blood samples from dogs collected in a semi-rural district near Santiago and to compare their frequency in dogs with and without dermatological manifestations. Methods: We examined 100 blood samples for dog filariae infections using microscopic methods (modified Knott technique). 50 dogs presented dermatological symptoms or signs compatible with filarial infections and 50 were asymptomatic. ITS-2 and 12s rDNA gene amplification by PCR and sequencing were performed in samples microscopically positive for microfilariae. Results. We observed microfilariae in 22 dogs (22%). Of these, 16/50 (32%) were symptomatic and 6/50 (12%) were asymptomatic (p = 0.02). Morphologically, the majority of microfilariae were similar to Dirofilaria repens, although many had a bigger size than previously described. Nucleotide sequencing of the amplified genes showed no more than 95% homology with the D. repens sequences available for comparison. D. reconditum and D. dracunculoides infections were also identified. Conclusions: These features might indicate the presence of new species of Dirofilaria or a D. repens close related variant in Chile.
- ItemOral polio vaccine in infants does not interfere in detection of enterovirus in blood(SOC CHILENA INFECTOLOGIA, 2013) Gonzalez, Marcela; Sandoval, Carmen; Valenzuela, Patricia; Montecinos, Luisa; Martinez, Constanza; Godoy, Paula; Abarca, KatiaIntroduction: 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 prevaccination 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.
- ItemPartial recessive IFN-gamma R1 deficiency: genetic, immunological and clinical features of 14 patients from 11 kindreds(OXFORD UNIV PRESS, 2011) Sologuren, Ithaisa; Boisson Dupuis, Stephanie; Pestano, Jose; Vincent, Quentin Benoit; Fernandez Perez, Leandro; Chapgier, Ariane; Cardenes, Maria; Feinberg, Jacqueline; Isabel Garcia Laorden, M.; Picard, Capucine; Santiago, Esther; Kong, Xiaofei; Janniere, Lucile; Colino, Elena; Herrera Ramos, Estefania; Frances, Adela; Navarrete, Carmen; Blanche, Stephane; Faria, Emilia; Remiszewski, Pawel; Cordeiro, Ana; Freeman, Alexandra; Holland, Steven; Abarca, Katia; Valeron Lemaur, Monica; Goncalo Marques, Jose; Silveira, Luisa; Manuel Garcia Castellano, Jose; Caminero, Jose; Luis Perez Arellano, Jose; Bustamante, Jacinta; Abel, Laurent; Casanova, Jean Laurent; Rodriguez Gallego, CarlosWe report a series of 14 patients from 11 kindreds with recessive partial (RP)- interferon (IFN)-gamma R1 deficiency. The I87T mutation was found in nine homozygous patients from Chile, Portugal and Poland, and the V63G mutation was found in five homozygous patients from the Canary Islands. Founder effects accounted for the recurrence of both mutations. The most recent common ancestors of the patients with the I87T and V63G mutations probably lived 1600 (875-2950) and 500 (200-1275) years ago, respectively. The two alleles confer phenotypes that are similar but differ in terms of IFN-gamma R1 levels and residual response to IFN-gamma. The patients suffered from bacillus Calmette-Guerin-osis (n = 6), environmental mycobacteriosis (n = 6) or tuberculosis (n = 1). One patient did not suffer from mycobacterial infections but had disseminated salmonellosis, which was also present in two other patients. Age at onset of the first environmental mycobacterial disease differed widely between patients, with a mean value of 11.25 +/- 9.13 years. Thirteen patients survived until the age of 14.82 +/- 11.2 years, and one patient died at the age of 7 years, 9 days after the diagnosis of long-term Mycobacterium avium infection and the initiation of antimycobacterial treatment. Up to 10 patients are currently free of infection with no prophylaxis. The clinical heterogeneity of the 14 patients was not clearly related to either IFNGR1 genotype or the resulting cellular phenotype. RP-IFN-gamma R1 deficiency is, thus, more common than initially thought and should be considered in both children and adults with mild or severe mycobacterial diseases.
- ItemSafety, Tolerability, Pharmacokinetics, and Immunogenicity of Motavizumab, a Humanized, Enhanced-Potency Monoclonal Antibody for the Prevention of Respiratory Syncytial Virus Infection in At-Risk Children(LIPPINCOTT WILLIAMS & WILKINS, 2009) Abarca, Katia; Jung, Elizabeth; Fernandez, Pilar; Zhao, Liang; Harris, Brian; Connor, Edward M.; Losonsky, Genevieve A.; Motavizumab Study GrpBackground: Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection in young children. Motavizumab is an investigational humanized monoclonal antibody for RSV prophylaxis.
- ItemViral Hepatitis in Children(LIPPINCOTT WILLIAMS & WILKINS, 2012) Nel, Etienne; Sokol, Ronald J.; Comparcola, Donatella; Nobili, Valerio; Hardikar, Winita; Cristobal Gana, Juan; Abarca, Katia; Wu, Jia Feng; Chang, Mei Hwei; Renner, James Kweku
- ItemYellow fever vaccination for Chilean tourists visiting Brazil. Practical considerations(SOC CHILENA INFECTOLOGIA, 2018) Weitzel, Thomas; Perret, Cecilia; Valdivieso, Francisca; Abarca, Katia; Vial, PabloDue to the recent yellow fever outbreak affecting the costal region of Brazil, including main touristic destinations, there is a high demand of yellow fever vaccination. This publication addresses the most relevant practical issues regarding this vaccine for tourists visiting Brazil and aims to serve as a guideline for non-expert physicians in Chile and elsewhere.