Browsing by Autor "Jorge Vargas"

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Arboviral Etiologies of Acute Febrile Illnesses in Western South America, 2000–2007
(Public Library of Science, 2010) Brett M. Forshey; Carolina Guevara; V. Alberto Laguna-Torres; Manuel Céspedes; Jorge Vargas; Alberto Gianella; Efraín Vallejo; César Madrid; Nicolás Aguayo; Eduardo Gotuzzo
Our data provide a better understanding of the geographic range of arboviruses in South America and highlight the diversity of pathogens in circulation. These arboviruses are currently significant causes of human illness in endemic regions but also have potential for further expansion. Our data provide a basis for analyzing changes in their ecology and epidemiology.
Caracteristicas de las epidemias de dengue en la ciudad de Santa Cruz (2003-2007)
(2009) Yelin Roca; C Avila; Eva Fabbiana Bez Galarza; J. Pachuri; Jorge Vargas; Annie Walter; Jean-Pierre Hervé
International audience
Chapare Virus, a Newly Discovered Arenavirus Isolated from a Fatal Hemorrhagic Fever Case in Bolivia
(Public Library of Science, 2008) Simon Delgado; Bobbie R. Erickson; Roberto Agudo; Patrick J. Blair; Efraín Vallejo; César G. Albariño; Jorge Vargas; James A. Comer; Pierre E. Rollin; Thomas G. Ksiazek
A small focus of hemorrhagic fever (HF) cases occurred near Cochabamba, Bolivia, in December 2003 and January 2004. Specimens were available from only one fatal case, which had a clinical course that included fever, headache, arthralgia, myalgia, and vomiting with subsequent deterioration and multiple hemorrhagic signs. A non-cytopathic virus was isolated from two of the patient serum samples, and identified as an arenavirus by IFA staining with a rabbit polyvalent antiserum raised against South American arenaviruses known to be associated with HF (Guanarito, Machupo, and Sabiá). RT-PCR analysis and subsequent analysis of the complete virus S and L RNA segment sequences identified the virus as a member of the New World Clade B arenaviruses, which includes all the pathogenic South American arenaviruses. The virus was shown to be most closely related to Sabiá virus, but with 26% and 30% nucleotide difference in the S and L segments, and 26%, 28%, 15% and 22% amino acid differences for the L, Z, N, and GP proteins, respectively, indicating the virus represents a newly discovered arenavirus, for which we propose the name Chapare virus. In conclusion, two different arenaviruses, Machupo and Chapare, can be associated with severe HF cases in Bolivia.
Correlation of Serotype-Specific Dengue Virus Infection with Clinical Manifestations
(Public Library of Science, 2012) Eric S. Halsey; Morgan A. Marks; Eduardo Gotuzzo; Víctor Fiestas Solórzano; Luis Suárez; Jorge Vargas; Nicolás Aguayo; César Madrid; Carlos Vimos; Tadeusz J. Kochel
Specific clinical manifestations, as well as groups of clinical manifestations, are often overrepresented by an individual DENV serotype.
Epidemiological analysis of the influenza A(H1N1)v outbreak in Bolivia, May-August 2009
(European Centre for Disease Prevention and Control, 2009) Alberto Gianella; Azibadighi Walter; Roberto Jimmy Revollo; Roxana Loayza; Jorge Vargas; Yelin Roca
The outbreak of pandemic influenza (H1N1) began in Bolivia on 25 May 2009. Between May and August, the National Center of Tropical Disease (CENETROP) analysed by RT-PCR 7,060 samples of which 12.7% were positive. A preliminary analysis of the 895 confirmed cases identified between May and August 2009 describes epidemiological and clinical characteristics. After the first imported cases from the United States and Peru, the locally acquired infections predominated (90%). The number of cases was highest in the age group of 10 to 29 year-olds, and 89.6% of cases were observed in people under the age of 40 years. Fever, cough, nasal discharge and headache remained the main symptoms.
Evolution of Dengue Disease and Entomological Monitoring in Santa Cruz, Bolivia 2002 – 2008
(Public Library of Science, 2015) Philippe Brémond; Yelin Roca; Simone Frédérique Brénière; Annie Walter; Zaira Barja-Simon; Roberto Torres Fernández; Jorge Vargas
Over the years, the increasing trend of dengue cases has been highlighted as well as its widespread distribution over the entire city, but an underestimation of the number of cases is strongly suspected. Contrary to popular belief, the city center appears more affected than the periphery, and dengue is not particularly related to waste. Interestingly, the clinical diagnosis of dengue by physicians improved over the years, whatever the gender, age and residential area of suspected cases.
Genetic Characterization of Venezuelan Equine Encephalitis Virus from Bolivia, Ecuador and Peru: Identification of a New Subtype ID Lineage
(Public Library of Science, 2009) Patricia V. Aguilar; Alexandra Adams; Víctor Suárez; Luis Beingolea; Jorge Vargas; Stephen R. Manock; Juan Freire; Willan R. Espinoza; Vidal Felices; Ana María Díaz
Venezuelan equine encephalitis virus (VEEV) has been responsible for hundreds of thousands of human and equine cases of severe disease in the Americas. A passive surveillance study was conducted in Peru, Bolivia and Ecuador to determine the arboviral etiology of febrile illness. Patients with suspected viral-associated, acute, undifferentiated febrile illness of <7 days duration were enrolled in the study and blood samples were obtained from each patient and assayed by virus isolation. Demographic and clinical information from each patient was also obtained at the time of voluntary enrollment. In 2005-2007, cases of Venezuelan equine encephalitis (VEE) were diagnosed for the first time in residents of Bolivia; the patients did not report traveling, suggesting endemic circulation of VEEV in Bolivia. In 2001 and 2003, VEE cases were also identified in Ecuador. Since 1993, VEEV has been continuously isolated from patients in Loreto, Peru, and more recently (2005), in Madre de Dios, Peru. We performed phylogenetic analyses with VEEV from Bolivia, Ecuador and Peru and compared their relationships to strains from other parts of South America. We found that VEEV subtype ID Panama/Peru genotype is the predominant one circulating in Peru. We also demonstrated that VEEV subtype ID strains circulating in Ecuador belong to the Colombia/Venezuela genotype and VEEV from Madre de Dios, Peru and Cochabamba, Bolivia belong to a new ID genotype. In summary, we identified a new major lineage of enzootic VEEV subtype ID, information that could aid in the understanding of the emergence and evolution of VEEV in South America.
Genome-Scale Multilocus Microsatellite Typing of Trypanosoma cruzi Discrete Typing Unit I Reveals Phylogeographic Structure and Specific Genotypes Linked to Human Infection
(Public Library of Science, 2009) Martin Llewellyn; Michael A. Miles; H. Carrasco; Michael D. Lewis; Matthew Yeo; Jorge Vargas; Faustino Torrico; Patricio Diosque; Vera Valente; Sebastião Aldo da Silva Valente
Trypanosoma cruzi is the most important parasitic infection in Latin America and is also genetically highly diverse, with at least six discrete typing units (DTUs) reported: Tc I, IIa, IIb, IIc, IId, and IIe. However, the current six-genotype classification is likely to be a poor reflection of the total genetic diversity present in this undeniably ancient parasite. To determine whether epidemiologically important information is "hidden" at the sub-DTU level, we developed a 48-marker panel of polymorphic microsatellite loci to investigate population structure among 135 samples from across the geographic distribution of TcI. This DTU is the major cause of resurgent human disease in northern South America but also occurs in silvatic triatomine vectors and mammalian reservoir hosts throughout the continent. Based on a total dataset of 12,329 alleles, we demonstrate that silvatic TcI populations are extraordinarily genetically diverse, show spatial structuring on a continental scale, and have undergone recent biogeographic expansion into the southern United States of America. Conversely, the majority of human strains sampled are restricted to two distinct groups characterised by a considerable reduction in genetic diversity with respect to isolates from silvatic sources. In Venezuela, most human isolates showed little identity with known local silvatic strains, despite frequent invasion of the domestic setting by infected adult vectors. Multilocus linkage indices indicate predominantly clonal parasite propagation among all populations. However, excess homozygosity among silvatic strains and raised heterozygosity among domestic populations suggest that some level of genetic recombination cannot be ruled out. The epidemiological significance of these findings is discussed.
Guaroa Virus Infection among Humans in Bolivia and Peru
(American Society of Tropical Medicine and Hygiene, 2010) Patricia V. Aguilar; Amy C. Morrison; Claudio Rocha; Douglas M. Watts; Luis Beingolea; Víctor Suárez; Jorge Vargas; Cristhopher D. Cruz; Carolina Guevara; Joel M. Montgomery
Guaroa virus (GROV) was first isolated from humans in Colombia in 1959. Subsequent isolates of the virus have been recovered from febrile patients and mosquitoes in Brazil, Colombia, and Panama; however, association of the virus with human disease has been unclear. As part of a study on the etiology of febrile illnesses in Peru and Bolivia, 14 GROV strains were isolated from patients with febrile illnesses, and 3 additional cases were confirmed by IgM seroconversion. The prevalence rate of GROV antibodies among Iquitos residents was 13%; the highest rates were among persons with occupations such as woodcutters, fisherman, and oil-field workers. Genetic characterization of representative GROV isolates indicated that strains from Peru and Bolivia form a monophyletic group that can be distinguished from strains isolated earlier in Brazil and Colombia. This study confirms GROV as a cause of febrile illness in tropical regions of Central and South America.
Ilheus Virus Infection in Human, Bolivia
(Centers for Disease Control and Prevention, 2012) Erika A. Venegas; Patricia V. Aguilar; Cristhopher D. Cruz; Carolina Guevara; Tadeusz J. Kochel; Jorge Vargas; Eric S. Halsey
To the Editor: Ilheus virus (ILHV) was first isolated from mosquitoes of the genera Ochlerotatus and Psorophora near Ilheus, Bahia, Brazil, in 1944 (1). After its discovery, the virus was also isolated from other mosquito species, including the genera Culex, Sabethes, Haemagogus, and Trichoprosopon, and from a variety of birds in different countries in Latin America (2). Only a few reports describe isolation of this virus from humans in Central and South America with symptoms ranging from subclinical to severe febrile disease (2–6). In mild cases, patients often reported gastrointestinal or respiratory symptoms lasting ≈1 week. In severe cases, either the central nervous or cardiac system can be affected. However, long-term sequelae or deaths have not been described. No epidemics attributed to ILHV have been reported. In November 2005, a 15-year-old boy (farmer) sought medical attention in a health clinic in Magdalena, Bolivia, after having fever for 5 days. The patient’s symptoms included malaise, asthenia, conjunctival injection, vesicular rash, facial edema, arthralgia, myalgias, bone pain, abdominal pain, headache, and earache. Signs of cardiac, neurologic, or renal damage were not detected. A blood specimen was obtained during the clinic visit, and a convalescent-phase sample was obtained 24 days after onset of symptoms. At that follow-up visit, the patient reported a full recovery from his symptoms. Both samples were sent to the Naval Medical Research Unit No. 6 in Lima, Peru, for processing as part of a clinic-based study to determine the etiology of febrile illnesses in Bolivia (7). The study was approved by the Naval Medical Research Unit No. 6 Institutional Review Board (Navy Medical Research Center Detachment 2000.0008) and conducted in collaboration with the Bolivia Ministry of Health. Serologic analyses showed a 64-fold IgM seroconversion between the acute-phase (<100) and convalescent-phase samples (6,400) by using an IgM ELISA as described (8). Samples were also tested by ELISA for the following arboviruses: West Nile virus, dengue virus, Oropouche virus, Guaroa virus, Rocio virus, St. Louis encephalitis virus, yellow fever virus, Venezuelan equine encephalitis virus, and Mayaro virus. All test results were negative for these viruses. Virus isolation was attempted on the acute-phase serum sample by using Vero and C6/36 cells, but the culture did not yield any virus. Attempts to isolate virus by intracranial inoculation in suckling mice were also unsuccessful (University of Texas Medical Branch, Institutional Animal Care and Use Committee protocol 9505045). Viral RNA was extracted from the acute-phase sample and reverse transcription PCR specific for a portion of the nonstructural protein 5 gene was performed by using a described method (9). A 189-bp PCR product was obtained, purified, and sequenced by using flavivirus primers FU1 and cFD2 (9) and further analyzed by using BLAST (www.ncbi.nlm.nih.gov/blast), resulting in ≈95% homology to ILHV. Phylogenetic analysis with neighbor-joining and parsimony methods grouped the nucleotide sequence of the ILHV virus from Bolivia with ILHV strains from Ecuador and Peru (Figure). Figure Phylogenetic analysis of the nonstructural protein 5 (NS5) gene region of 7 Ilheus virus isolates and a 189-bp nt sequence (FMB 202 Bolivia). Alignments were analyzed by using the neighbor-joining method with the Kimura 2-parameter algorithm in MEGA5 ... Magdalena is a tropical city in northern Bolivia that borders Brazil. The city is surrounded by rivers and chestnut fields, and agriculture and fishing are the main sources of employment. Despite having ecoepidemiologic conditions similar to those in other locations with a history of ILHV transmission, the virus had not been detected in the area. The patient had no travel history in the 30 days preceding his illness, indicating that the virus is probably endemic to the area. Mild unspecific symptoms, a short viremic period, and lack of advanced confirmatory laboratory techniques in situ are some of the barriers impeding the diagnosis of ILHV in disease-endemic areas. High levels of antibody cross-reactivity among flaviviruses, which are also endemic to the area, might render diagnosis even more difficult. The presence of the main ILHV vector, Psorophora sp. mosquitoes, in the city suggests that much of the population that labors outdoors may be at risk for ILHV infection.
Ketoconazole in the Treatment of Paracoccidioidomycosis (South American Blastomycosis). Experience in 30 Cases in Bolivia/Ketoconazol in der Behandlung der Paracoccidioidomykose (Südamerikanische Blastomykose). Auswertung von 30 Fällen in Bolivien
(Wiley, 1988) Jorge Vargas; M. Recacoechea
Summary: The results for 30 patients suffering from paracoccidioidomycosis and treated orally with ketoconazole are reported. The patients (28 men and 2 women aged 5–70) presented a variety of pure and/or mixed clinical forms of this systemic mycosis. The process was primary in 25 cases and recurrent in 5. Nine patients had previously been treated with amphotericin B, miconazole, and sulphonamides. Ketoconazole was administered in doses of 200 mg/12 h (400 mg/day) for periods of 3 to 7 months. According to the established criteria, the results were classified as “very good” (clinical and laboratory cure) in 25 patients (83%) and as “good” (clinical improvement, variable laboratory response) in 3 patients (10%). No cases of a “poor” response to the treatment were recorded and 2 cases could not be assessed owing to a lack of examination data. No relapses were observed in the after‐treatment check‐ups carried out in 20 patients (up to 12 months after discontinuation of treatment). Adverse reactions and toxic effects were minimal. The overall results show that ketoconazole is the preferred choice of drug for the treatment of paracoccidioidomycosis. Zusammenfassung: Die Ergebnisse von 30 Patienten mit Paracoccidioidomykose nach oraler Behandlung mit Ketoconazol werden vorgelegt. Die Patienten (28 Männer, 2 Frauen, Altersgrenzen 5–70 Jahre) zeigten eine Vielzahl reiner und/oder gemischter klinischer Formen dieser Systemmykose. Die Erkrankung war bei 25 Patienten erstmalig, bei 5 rezidivierend. Neun Patienten waren vorher mit Amphoterizin B, Miconazol bzw. Sulfonamiden behandelt worden. Ketoconazol wurde in Dosen von 200 mg/12 h (400 mg/d) über Zeiträume von 3 bis 7 Monaten verabreicht Die Ergebnisse wurden nach festgesetzten Kriterien bei 25 Patienten (83%) als “sehr gut” (klinische Heilung mit mykologischer Sanierung) und bei 3 Patienten (10%) als “gut” (klinische Besserung, unterschiedliche Laborergebnisse) beurteilt. Kein Patient zeigte ein “schlechtes” Behandlungsergebnis, aber das Fehlen von Untersuchungsdaten bei 2 Patienten schloß deren Beurteilung aus. In den bis 12 Monate nach Behandlungsende durchgeführten Nachuntersuchungen an 20 Patienten wurden keine Rezidive beobachtet. Das Auftreten von toxischen und Nebenwirkungen war minimal. Aus den Gesamtergebnissen geht hervor, daß Ketoconazol bei der Behandlung der Paracoccidioidomykose das Arzneimittel der Wahl ist.
Molecular epidemiology of dengue virus type 3 in Northern South America: 2000–2005
(Elsevier BV, 2008) Tadeusz J. Kochel; Patricia Aguilar; Vidal Felices; Guillermo Comach; Cristhopher D. Cruz; Aracely Alava; Jorge Vargas; James G. Olson; Patrick J. Blair
Novel Strain of Andes Virus Associated with Fatal Human Infection, Central Bolivia
(Centers for Disease Control and Prevention, 2012) Cristhopher D. Cruz; Brett M. Forshey; Efraín Vallejo; Roberto Agudo; Jorge Vargas; David L. Blazes; Carolina Guevara; V. Alberto Laguna-Torres; Eric S. Halsey; Tadeusz J. Kochel
To better describe the genetic diversity of hantaviruses associated with human illness in South America, we screened blood samples from febrile patients in Chapare Province in central Bolivia during 2008-2009 for recent hantavirus infection. Hantavirus RNA was detected in 3 patients, including 1 who died. Partial RNA sequences of small and medium segments from the 3 patients were most closely related to Andes virus lineages but distinct (<90% nt identity) from reported strains. A survey for IgG against hantaviruses among residents of Chapare Province indicated that 12.2% of the population had past exposure to >1 hantaviruses; the highest prevalence was among agricultural workers. Because of the high level of human exposure to hantavirus strains and the severity of resulting disease, additional studies are warranted to determine the reservoirs, ecologic range, and public health effect of this novel strain of hantavirus.
Reemergence of Bolivian Hemorrhagic Fever, 2007–2008
(Centers for Disease Control and Prevention, 2009) Patricia V. Aguilar; Wilfredo Camargo; Jorge Vargas; Carolina Guevara; Yelin Roca; Vidal Felices; V. Alberto Laguna-Torres; Robert B. Tesh; Thomas G. Ksiazek; Tadeusz J. Kochel
age.In particular, suspected childhood TB patients without an identifiable TB contact and with normal immune status were subjected to further investigations.Multidisciplinary management, including enhanced laboratory diagnosis of atypical bony lesions in infants and children, is recommended for any suspected TB infection.Once BCGrelated infection is confirmed, medical treatment has to be consistent.
Trypanosoma cruzi IIc: Phylogenetic and Phylogeographic Insights from Sequence and Microsatellite Analysis and Potential Impact on Emergent Chagas Disease
(Public Library of Science, 2009) Martin Llewellyn; Michael D. Lewis; Nidia Acosta; Matthew Yeo; H. Carrasco; Maikell Segovia; Jorge Vargas; Faustino Torrico; Michael A. Miles; Michael W. Gaunt
Trypanosoma cruzi, the etiological agent of Chagas disease, is highly genetically diverse. Numerous lines of evidence point to the existence of six stable genetic lineages or DTUs: TcI, TcIIa, TcIIb, TcIIc, TcIId, and TcIIe. Molecular dating suggests that T. cruzi is likely to have been an endemic infection of neotropical mammalian fauna for many millions of years. Here we have applied a panel of 49 polymorphic microsatellite markers developed from the online T. cruzi genome to document genetic diversity among 53 isolates belonging to TcIIc, a lineage so far recorded almost exclusively in silvatic transmission cycles but increasingly a potential source of human infection. These data are complemented by parallel analysis of sequence variation in a fragment of the glucose-6-phosphate isomerase gene. New isolates confirm that TcIIc is associated with terrestrial transmission cycles and armadillo reservoir hosts, and demonstrate that TcIIc is far more widespread than previously thought, with a distribution at least from Western Venezuela to the Argentine Chaco. We show that TcIIc is truly a discrete T. cruzi lineage, that it could have an ancient origin and that diversity occurs within the terrestrial niche independently of the host species. We also show that spatial structure among TcIIc isolates from its principal host, the armadillo Dasypus novemcinctus, is greater than that among TcI from Didelphis spp. opossums and link this observation to differences in ecology of their respective niches. Homozygosity in TcIIc populations and some linkage indices indicate the possibility of recombination but cannot yet be effectively discriminated from a high genome-wide frequency of gene conversion. Finally, we suggest that the derived TcIIc population genetic data have a vital role in determining the origin of the epidemiologically important hybrid lineages TcIId and TcIIe.
Vitamin D supplementation: position Statement of the Iberoamerican Society of Osteoporosis and Mineral Metabolism (SIBOMM)
(Informa, 2020) Santiago Palacios; Sonia Cerdas; Ramiro Da Silva; Alejandro Paradas; Jorge Vargas; Desireé Mostajo; Konstantinos Tserotas; Luis Danckers; Mario Moreno; Maria Navas
The importance of VD has been widely documented and its deficiency is a pandemic. Many individuals have difficulty meeting daily VD requirements through food and the sun. The population of Latin America and the Caribbean has diverse ethnics, cultures, in addition to living in different latitudes and altitudes. Therefore, it is important to make a position on VD supplementation, given the different characteristics, ages and serum levels of 25(OH)D.