Gil JF

Author: 
Date: 
01/06/2016
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Abstract

After more than eighty years dengue reemerged in Argentina in 1997. Since then, the largest epidemic in terms of geographical extent, magnitude and mortality, was recorded in 2009. In this report we analyzed the DEN-1 epidemic spread in Orán, a mid-size city in a non-endemic tropical area in Northern Argentina, and its correlation with demographic and socioeconomic factors. Cases were diagnosed by ELISA between January and June 2009. We applied a space-time and spatial scan statistic under a Poisson model. Possible association between dengue incidence and socio-economic variables was studied with the Spearman correlation test. The epidemic started from an imported case from Bolivia and space-time analysis detected two clusters: one on February and other in April (in the south and the northeast of the city respectively) with risk ratios of 25.24 and 4.07 (p<0.01). Subsequent cases spread widely around the city without significant space-temporal clustering. Maximum values of the entomological indices were observed in January, at the beginning of the epidemic (B=21.96; LH=8.39). No statistically significant association between socioeconomic variables and dengue incidence was found but positive correlation between population size and the number of cases (p<0.05) was detected. Two mechanisms may explain the observed pattern of epidemic spread in this non-endemic tropical city: a) Short range dispersal of mosquitoes and people generates clusters of cases and b) long-distance (within the city) human movement contributes to a quasi-random distribution of cases.

Date: 
01/01/2014
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Abstract

A systematic review of surveys performed between 1980 and 2011 (published in MEDLINE/Pubmed and/or LILACS indexed journals, available in the baseline data from a Mass Deworming National Program (MDNP, 2005) was used to identify the prevalence, distribution and detection of risk areas for soil transmitted helminth infections (STH) in Argentina. We found 310 publications in the database using the pre-defined key-words (medical subject headings) for research purposes. Only 24 articles with 26 surveillance sites in 8 provinces and a total of 5495 surveyed individuals fulfilled the inclusion criteria. Frequency rates for STH had a wide range: Ascaris lumbricoides: 0-67%, hookworms: 0-90%, Trichuris trichiura: 0-24.6 and Strongyloides stercoralis: 0-83%. The estimated combined incidence varied from 0.8% to 88.6%. Baseline surveys from the MDNP reporting on 1943 children from 12 provinces confirmed the heterogeneity, with combined STH frequency rates ranging from 0 to 42.7%. Surveys included in this review showed that the distribution of STH in Argentina is not homogeneous, with areas of high incidence (> 20%) in the northeastern and northwestern provinces where mass deworming activities would be highly beneficial. In several surveys, the high overall incidence was mostly due to hookworms and S. stercoralis, a situation to be considered when selecting diagnostic and therapeutic control strategies. The scarcity or absence of data from various provinces and the availability of less than 8000 surveyed individuals should be considered.

Date: 
01/09/2012
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Abstract

Many developing and threshold countries rely on shallow groundwater wells for their water supply whilst pit latrines are used for sanitation. We employed a unified strategy involving satellite images and environmental monitoring of 16 physico-chemical and microbiological water quality parameters to identify significant land uses that can lead to unacceptable deterioration of source water, in a region with a subtropical climate and seasonally restricted torrential rainfall in Northern Argentina. Agricultural and non-agricultural sources of nitrate were illustrated in satellite images and used to assess the organic load discharged. The estimated human organic load per year was 28.5 BOD(5) tons and the N load was 7.5 tons, while for poultry farms it was 9940-BOD(5) tons and 1037-N tons, respectively. Concentrations of nitrates and organics were significantly different between seasons in well water (p values of 0.026 and 0.039, respectively). The onset of the wet season had an extraordinarily negative impact on well water due in part to the high permeability of soils made up of fine gravels and coarse sand. Discriminant analysis showed that land uses had a pronounced seasonal influence on nitrates and introduced additional microbial contamination, causing nitrification and denitrification in shallow groundwater. P-well was highly impacted by a poultry farm while S-well was affected by anthropogenic pollution and background load, as revealed by Principal Component Analysis. The application of microbial source tracking techniques is recommended to corroborate local sources of human versus animal origin.

Author: 
Date: 
01/01/2011
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Abstract

It is important to know whether the variability of species of Leishmania parasites circulating in a region affects the performance of the ELISA test for the diagnosis of leishmaniasis. Therefore, the aim of this study was to analyze the reactivity of the ELISA using homogenates of promastigotes of Leishmania (V.) braziliensis (ELISAb), Leishmania (L) amazonensis (ELISAa) and Leishmania (V.) guyanensis (ELISAg) against different sera groups. Samples from individuals with cutaneous leishmaniasis (n = 37), mucocutaneous leishmaniasis (n = 8), healthy controls (n = 52), persons infected with Trypanosoma cruzi (n = 11) and mixed infections (n = 14) were included in the study. We calculated sensitivities, specificities, cut offs, and predictive values for the three tests and compared them using ANOVA, kappa index, ROC curves comparison, and confidence intervals calculated by the bootstrap method. Significant differences were found when comparing the OD levels of sera from patients with cutaneous leishmaniasis against healthy controls, but there were no differences when comparing the different ELISAs. The sensitivities calculated for ELISAb and ELISAa were 84.6 and of 88.5% for ELISAg, while the value of specificity for the three tests was 96.2. The kappa index (0.87) and comparison of ROC curves showed similar performance for the three ELISAs (p = 0.225). The high reactivity obtained for these ELISAs in sera of patients with mucocutaneous leishmaniasis indicates this test as an important complement in the diagnosis of the disease.

Author: 
Date: 
01/03/2010
Investigation Line: 

Abstract

We used kernel density and scan statistics to examine the spatial distribution of cases of pediatric and adult American cutaneous leishmaniasis in an urban disease-endemic area in Salta Province, Argentina. Spatial analysis was used for the whole population and stratified by women > 14 years of age (n = 159), men > 14 years of age (n = 667), and children < 15 years of age (n = 213). Although kernel density for adults encompassed nearly the entire city, distribution in children was most prevalent in the peripheral areas of the city. Scan statistic analysis for adult males, adult females, and children found 11, 2, and 8 clusters, respectively. Clusters for children had the highest odds ratios (P < 0.05) and were located in proximity of plantations and secondary vegetation. The data from this study provide further evidence of the potential urban transmission of American cutaneous leishmaniasis in northern Argentina.