71 research outputs found
Lutzomyia longipalpis (Diptera: Psychodidae) Argentina-Bolivia border: new report and genetic diversity
American visceral leishmaniasis (AVL) has two main scenarios of transmission as follows: scattered cases in rural areas andurban outbreaks. Urban AVL is in active dispersion from the northeastern border of Argentina-Paraguay-Brazil to the South.The presence of Lutzomyia longipalpis was initially reported in urban environments in the northwestern border of the country.The presence of Lu. longipalpis, environmental variables associated with its distribution, and its genetic diversity were assessedin Salvador Mazza, Argentina, on the border with Bolivia. The genetic analysis showed high haplotype diversity, low nucleotidediversity, and low nucleotide polymorphism index. We discuss the hypothesis of an expanding urban population with introgressivehybridisation of older haplogroups found in their path in natural forest or rural environments, acquiring a new adaptability tourban environments, and the possibility of changes in vector capacity.Fil: Quintana, María Gabriela. Ministerio de Salud. Instituto Nacional de Medicina Tropical; Argentina. Red de Investigación de la Leishmaniasis en la Argentina; ArgentinaFil: Pech May, Angélica del Rosario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Red de Investigación de la Leishmaniasis en la Argentina; Argentina. Ministerio de Salud. Instituto Nacional de Medicina Tropical; ArgentinaFil: Fuenzalida, Ana Denise. Ministerio de Salud. Instituto Nacional de Medicina Tropical; Argentina. Red de Investigación de la Leishmaniasis en la Argentina; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; ArgentinaFil: Direni Mancini, José Manuel. Red de Investigación de la Leishmaniasis en la Argentina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; ArgentinaFil: Barroso, Paola Andrea. Ministerio de Salud. Instituto Nacional de Medicina Tropical; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Yadon, Zaida Estela. Ministerio de Salud. Instituto Nacional de Medicina Tropical; ArgentinaFil: Zaideneberg, Mario. Ministerio de Salud y Acción Social; ArgentinaFil: Salomón, Oscar Daniel. Ministerio de Salud. Instituto Nacional de Medicina Tropical; Argentina. Red de Investigación de la Leishmaniasis en la Argentina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentin
Prevalence of human cystic echinococcosis in the towns of Ñorquinco and Ramos Mexia in Rio Negro Province, Argentina, and direct risk factors for infection
Fil: Uchiumi, Leonardo. Ministerio de Salud de Rio Negro, Hospital Zatti,, Rio NegroFil: Mugica, Guillermo. Ministerio de Salud de Rio Negro, Salud Ambiental, Rio NegroFil: Araya, Daniel. Ministerio de Salud de Rio Negro, Ssluf Ambiental, Rio NegroFil: Salvitti, Juan. Ministerio de Salud de Rio Negro, Hospital Bariloche, Rio NegroFil: Sobrino, Mariano. Ministerio de Salud de Rio Negro, Hospital Bariloiche, Rio NegroFil: Moguilansky, Sergio. Universidad Nacional del Comahue, Catedra de Imagenes, Rio NegroFil: Solari, Santiago. Ministerio de Salud de Rio Negro, Hospital Valcheta, Rio NegroFil: Blanco, Patricia. Ministerio de Salud de Rio Negro, Salud Ambiental, Rio NedgroFil: Lamounier, Janette. Ministerio de Salud de Rio Negro, Hospital Ñorquinco, Rio NegroFil: Barrera, Federica. Ministerio de Salud de Rio Negro, Hospital Ramos Mexia, Rio NegroFil: Arezo, Marcos. Ministerio de Salud de Rio Negro, Salud Ambiental, Rio NegroFil: Seleiman, Marcos. Ministerio de Salud de Rio Negro, Salud Ambiental, Rio NegroFil: Yadon, Zaida. Academia Nacional de Medicina, Instituto investigaciones Epidemiologicas. Buenos AiresFil: Tamarozzi, Feamcesca. Universidad de La Sapienzia, Roma, ItaliaFil: Casulli, Adriano. Universidad de Las Sapienza, FRoma, ItaliaFil: Larrieu, Edmundo. Universidad Nacional de Rio Negro, Escuela de Veterinaria. Rio Negro. Argentina.Background: Cystic echinococcosis (CE) is a parasitic zoonosis caused by infection with the larval stage of Echinococcus granulosus (s.l.). This study investigated the prevalence and potential risk factors associated with human CE in the towns and rural areas of Ñorquinco and Ramos Mexia, Rio Negro province, Argentina.
Methods: To detect abdominal CE cysts, we screened 892 volunteers by ultrasound and investigated potential risk factors for CE using a standardized questionnaire. Prevalence ratio (PR) with 95% confidence intervals (CI) was used to measure the association between CE and the factors investigated, applying bivariate and multivariate analyses.
Results: Abdominal CE was detected in 42/892 screened volunteers (4.7%, 95% CI 3.2–6.1), only two of whom were under 15 years of age. Thirteen (30.9%) CE cases had 25 cysts in active stages (CE1, CE2, CE3a, according to the WHO Informal Working Group on Echinococcosis [WHO-IWGE] classification). The most relevant risk factors identified in the bivariate analysis included: living in rural areas (P = 0.003), age > 40 years (P = 0.000), always drinking water from natural sources (P = 0.007), residing in rural areas during the first 5 years of life (P = 0.000) and having lived more than 20 years at the current address (P = 0.013). In the multivariate final model, the statistically significant risk factors were: frequently touching dogs (P = 0.012), residing in rural areas during the first 5 years of life (P = 0.004), smoking (P = 0.000), age > 60 years (P = 0.002) and living in rural areas (P = 0.017).
Conclusions: Our results point toward infection with CE being acquired since childhood and with constant exposure throughout life, especially in rural areas with a general environmental contamination.
Keywords: Cystic echinococcosis, Echinococcus granulosus (s.l.), Ultrasound screening, Epidemiology, Risk factors
Improved tools and strategies for the prevention and control of arboviral diseases: A research-to-policy forum
Background
Research has been conducted on interventions to control dengue transmission and respond to outbreaks. A summary of the available evidence will help inform disease control policy decisions and research directions, both for dengue and, more broadly, for all Aedes-borne arboviral diseases.
Method
A research-to-policy forum was convened by TDR, the Special Programme for Research and Training in Tropical Diseases, with researchers and representatives from ministries of health, in order to review research findings and discuss their implications for policy and research.
Results
The participants reviewed findings of research supported by TDR and others. Surveillance and early outbreak warning. Systematic reviews and country studies identify the critical characteristics that an alert system should have to document trends reliably and trigger timely responses (i.e., early enough to prevent the epidemic spread of the virus) to dengue outbreaks. A range of variables that, according to the literature, either indicate risk of forthcoming dengue transmission or predict dengue outbreaks were tested and some of them could be successfully applied in an Early Warning and Response System (EWARS). Entomological surveillance and vector management. A summary of the published literature shows that controlling Aedes vectors requires complex interventions and points to the need for more rigorous, standardised study designs, with disease reduction as the primary outcome to be measured. House screening and targeted vector interventions are promising vector management approaches. Sampling vector populations, both for surveillance purposes and evaluation of control activities, is usually conducted in an unsystematic way, limiting the potentials of entomological surveillance for outbreak prediction. Combining outbreak alert and improved approaches of vector management will help to overcome the present uncertainties about major risk groups or areas where outbreak response should be initiated and where resources for vector management should be allocated during the interepidemic period.
Conclusions
The Forum concluded that the evidence collected can inform policy decisions, but also that important research gaps have yet to be filled
Analytical Performance of a Multiplex Real-Time PCR Assay Using TaqMan Probes for Quantification of Trypanosoma cruzi Satellite DNA in Blood Samples
Background: The analytical validation of sensitive, accurate and standardized Real-Time PCR methods for Trypanosoma cruzi quantification is crucial to provide a reliable laboratory tool for diagnosis of recent infections as well as for monitoring treatment efficacy. Methods/Principal Findings: We have standardized and validated a multiplex Real-Time quantitative PCR assay (qPCR) based on TaqMan technology, aiming to quantify T. cruzi satellite DNA as well as an internal amplification control (IAC) in a single-tube reaction. IAC amplification allows rule out false negative PCR results due to inhibitory substances or loss of DNA during sample processing. The assay has a limit of detection (LOD) of 0.70 parasite equivalents/mL and a limit of quantification (LOQ) of 1.53 parasite equivalents/mL starting from non-boiled Guanidine EDTA blood spiked with T. cruzi CLBrener stock. The method was evaluated with blood samples collected from Chagas disease patients experiencing different clinical stages and epidemiological scenarios: 1- Sixteen Venezuelan patients from an outbreak of oral transmission, 2- Sixty three Bolivian patients suffering chronic Chagas disease, 3- Thirty four Argentinean cases with chronic Chagas disease, 4- Twenty seven newborns to seropositive mothers, 5- A seronegative receptor who got infected after transplantation with a cadaveric kidney explanted from an infected subject. Conclusions/Significance: The performing parameters of this assay encourage its application to early assessment of T. cruzi infection in cases in which serological methods are not informative, such as recent infections by oral contamination or congenital transmission or after transplantation with organs from seropositive donors, as well as for monitoring Chagas disease patients under etiological treatment.Fil: Duffy, Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones En Ingeniería Genética y Biología Molecular; ArgentinaFil: Cura, Carolina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; ArgentinaFil: Ramírez, Juan C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; ArgentinaFil: Abate, Teresa. Universidad Central de Venezuela. Instituto de Medicina Tropical; VenezuelaFil: Cayo, Nelly M.. Universidad Nacional de Jujuy. Instituto de Biologia de la Altura; ArgentinaFil: Parrado, Rudy. Universidad San Simón; BoliviaFil: Diaz Bello, Zoraida. Universidad Central de Venezuela. Instituto de Medicina Tropical; VenezuelaFil: Velazquez, Elsa Beatriz. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Muñoz Calderón, Arturo. Universidad Central de Venezuela. Instituto de Medicina Tropical; VenezuelaFil: Juiz, Natalia Anahí. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; ArgentinaFil: Basile, Joaquín. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; ArgentinaFil: Garcia, Lineth. Universidad San Simón; BoliviaFil: Riarte, Adelina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Nasser, Julio Rubén. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Ocampo, Susana B.. Universidad Nacional de Jujuy. Instituto de Biologia de la Altura; ArgentinaFil: Yadon, Zaida E.. Pan-American Health Organization; Estados UnidosFil: Torrico, Faustino. Universidad San Simón; BoliviaFil: Alarcón de Noya, Belkisyole. Universidad Central de Venezuela. Instituto de Medicina Tropical; VenezuelaFil: Ribeiro, Isabela. Drugs and Neglected Diseases Initiative; SuizaFil: Schijman, Alejandro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; Argentin
Un brote inusual de Hantavirus en el sur de Argentina: ¿transmisión persona a persona?
El síndrome pulmonar por Hantavirus es una zoonosis sostenida por roedores reconocida primero en los Estados Unidos en 1993. La transmisión persona a persona no ha sido informada; sin embargo, en un brote de 20 casos informados aquí, la evidencia epidemiológica sugiere fuertemente esta ruta de transmisión.Facultad de Ciencias Veterinaria
Un brote inusual de Hantavirus en el sur de Argentina: ¿transmisión persona a persona?
El síndrome pulmonar por Hantavirus es una zoonosis sostenida por roedores reconocida primero en los Estados Unidos en 1993. La transmisión persona a persona no ha sido informada; sin embargo, en un brote de 20 casos informados aquí, la evidencia epidemiológica sugiere fuertemente esta ruta de transmisión.Facultad de Ciencias Veterinaria
Multiplex Real-Time PCR Assay Using TaqMan Probes for the Identification of Trypanosoma cruzi DTUs in Biological and Clinical Samples
Background:
Trypanosoma cruzi has been classified into six Discrete Typing Units (DTUs), designated as TcI–TcVI. In order to effectively use this standardized nomenclature, a reproducible genotyping strategy is imperative. Several typing schemes have been developed with variable levels of complexity, selectivity and analytical sensitivity. Most of them can be only applied to cultured stocks. In this context, we aimed to develop a multiplex Real-Time PCR method to identify the six T. cruzi DTUs using TaqMan probes (MTq-PCR).Methods/Principal Findings:
The MTq-PCR has been evaluated in 39 cultured stocks and 307 biological samples from vectors, reservoirs and patients from different geographical regions and transmission cycles in comparison with a multi-locus conventional PCR algorithm. The MTq-PCR was inclusive for laboratory stocks and natural isolates and sensitive for direct typing of different biological samples from vectors, reservoirs and patients with acute, congenital infection or Chagas reactivation. The first round SL-IR MTq-PCR detected 1 fg DNA/reaction tube of TcI, TcII and TcIII and 1 pg DNA/reaction tube of TcIV, TcV and TcVI reference strains. The MTq-PCR was able to characterize DTUs in 83% of triatomine and 96% of reservoir samples that had been typed by conventional PCR methods. Regarding clinical samples, 100% of those derived from acute infected patients, 62.5% from congenitally infected children and 50% from patients with clinical reactivation could be genotyped. Sensitivity for direct typing of blood samples from chronic Chagas disease patients (32.8% from asymptomatic and 22.2% from symptomatic patients) and mixed infections was lower than that of the conventional PCR algorithm.Conclusions/Significance:
Typing is resolved after a single or a second round of Real-Time PCR, depending on the DTU. This format reduces carryover contamination and is amenable to quantification, automation and kit production.This work received financial support from the Ministry of Science and Technology of Argentina [PICT 2011-0207 to AGS] and the National Scientific and Technical Research Council in Argentina (CONICET) [PIP 112 2011-010-0974 to AGS]. Work related to evaluation of biological samples was partially sponsored by the Pan-American Health Organization (PAHO) [Small Grants Program PAHO-TDR]; the Drugs and Neglected Diseases Initiative (DNDi, Geneva, Switzerland), Wellcome Trust (London, United Kingdom), SANOFI-AVENTIS (Buenos Aires, Argentina) and the National Council for Science and Technology in Mexico (CONACYT) [FONSEC 161405 to JMR]
Indoor and peridomestic transmission of American cutaneous leishmaniasis in northwestern Argentina: a retrospective case-control study.
A case-control study was carried out during 1990-1994 to identify risk factors associated with American cutaneous leishmaniasis (ACL) in Santiago del Estero, Argentina. The study subjects consisted of 171 cases and 308 controls matched by age, sex, and place of residence. The analysis was performed by conditional logistic regression. Risk factors found to be significantly associated with ACL were related to indoor transmission (few rooms in the house, dirt floor, and a permanent opening in lieu of a window); peridomestic transmission (presence of a pond or woodland within 150 m of the house and an agricultural area within 200 m of the house); and human behavior (sleeping in the backyard, collecting water, bathing, and performing agricultural activities). Most transmission appears to have occurred indoors and in the peridomicile. These environments should be included in further research and control policies
Implementation of the national tuberculosis guidelines on culture and drug sensitivity testing in Guatemala, 2013
ABSTRACT Objective To assess whether the National Tuberculosis Program (NTP) guidelines for culture and drug sensitivity testing (DST) in Guatemala were successfully implemented, particularly in cases of smear-negative pulmonary tuberculosis (TB) or previously treated TB, by documenting notification rates by department (geographic area), disease type and category, and culture and DST results. Methods This was a cross-sectional, operational research study that merged and linked all patients registered by the NTP and the National Reference Laboratory in 2013, eliminating duplicates. The proportions with culture (for new smear negative pulmonary cases) and culture combined with DST (for previously treated patients) were estimated and analyzed by department. Data were analyzed using EpiData Analysis version 2.2. Results There were 3 074 patients registered with TB (all forms), for a case notification rate of 20/100 000 population. Of these, 2 842 had new TB, of which 2 167 (76%) were smear-positive pulmonary TB (PTB), 385 (14%) were smear-negative PTB, and 290 (10%) were extrapulmonary TB. There were 232 (8%) previously treated cases. Case notification rates (all forms) varied by department from 2–68 per 100 000 population, with the highest rates seen in the southwest and northeast part of Guatemala. Of new TB patients, 136 had a culture performed and 55 had DST of which the results were 33 fully sensitive, 9 monoresistant, 3 polyresistant, and 10 multidrug resistant TB (MDR-TB). Only 21 (5%) of new smear-negative PTB patients had cultures. Of 232 previously treated patients, 54 (23%) had a culture and 47 (20%) had DST, of which 29 were fully sensitive, 7 monoresistant, 2 polyresistant, and 9 MDR-TB. Of 22 departments (including the capital), culture and DST was performed in new smear-negative PTB in 7 departments (32%) and in previously treated TB in 13 departments (59%). Conclusions Despite national guidelines, only 5% of smear-negative PTB cases had a culture and only 20% of previously treated TB had a culture and DST. Several departments did not perform culture or DST. These short comings must be improved if Guatemala is to curtail the spread of drug resistant forms of TB, while striving to eliminate all TB
Contrasting trends of tuberculosis in the cities of San Pedro Sula and Tegucigalpa, Honduras, 2005–2014
ABSTRACT Objective To 1) describe and compare the trends of tuberculosis (TB) case notification rates (CNRs) and treatment outcomes in the two largest cities in Honduras (San Pedro Sula and Tegucigalpa) for the period 2005–2014 and 2) identify possible related socioeconomic and health sector factors. Methods This retrospective ecological operational research study used aggregated data from the National TB Program (socioeconomic and health sector information and individual data from the 2014 TB case notification report). Results TB CNRs declined steadily over the study period in Tegucigalpa (from 46 to 28 per 100 000 inhabitants) but remained high in San Pedro Sula (decreasing from 89 to 78 per 100 000 inhabitants). Similar trends were observed for smear-positive TB. While presumptive TB cases examined were similar for both cities, in San Pedro Sula the proportions of presumptive cases with a positive smear; (7.7% versus 3.6%) relapses (8.9% versus 4.2%); and patients lost to follow-up (10.9% versus 2.7%) were significantly higher, and the treatment success lower (75.7% versus 87.0%). San Pedro Sula had lower annual income per capita, fewer public sector health workers and facilities, and a higher and increasing homicide index. The 2014 TB case data from San Pedro Sula showed a significantly lower median age and a higher proportion of assembly plant workers, prisoners, drug abusers, and diabetes. Conclusions The TB rate was higher and treatment success lower, and health care resources and socio-demographic indicators less favorable, in San Pedro Sula versus Tegucigalpa. City authorities, the NTP, and the health sector overall should strengthen early case detection, treatment, and infection control, involving both public and private health sectors
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