Genetic structure of Aedes aegypti in the city of Córdoba (Argentina), a recently reinfested area

To understand the transmission of a vector-borne disease, knowledge of the magnitude of dispersal among vector populations is essential because of its influence on pathogen transfer. The principal vector of dengue, the most common arboviral disease in the world, is the mosquito Aedes aegypti (L.). This tropical and subtropical species is native to Africa but has dispersed worldwide since the XV century. In Argentina, the species was declared eradicated in 1963, but has reinfested the country in recent years. In the present work, we used RAPD-PCR markers to assess the levels of genetic variability and differentiation among populations of Ae. aegypti (the vector of dengue and yellow fever) in Córdoba, the second largest city in Argentina. We detected similar levels of genetic variability (He between 0.351-0.404) across samples and significant genetic differentiation between most population pairs within the city (F ST between 0.0013-0.0253). Genetic distances indicate that there are three distinct groups, formed predominantly by populations that are connected by, or near, main roads. This suggests that, in addition to other factors such as availability of oviposition sites or step-by-step migration, passive transport plays an important role in gene flow within the city.

L'Ordenació urbanística en paísos del sud: el cas del pla de desenvolupament integral de Quilalí (Nicaragua)

Article que té com objectiu l'elaboració d'un Pla de Desenvolupament Integral per el municipi de Quilalí, situat al nord de Nicaragua, fent frontera amb Hondures. Primers'exposen les fases per a l'elaboració del Pla i en segon terme es destaquen, a partir de la propia experiència dels autors, les fases del Pla que els autors creuen méssignificatives, i s'exposen alguns dels resultats obtinguts

Visceral leishmaniasis in border areas: clustered distribution of phlebotomine sand flies in Clorinda, Argentina

Three years after the first report of Lutzomyia longipalpis in Clorinda, Argentina, a border city near Asunción, Paraguay, the city was surveyed again. Lu. longipalpis was found clustered in the same neighbourhoods in 2007 as in 2004, even though the scattered distribution of canine visceral leishmaniasis was more related to the traffic of dogs through the border.

Therapy, diagnosis and prognosis of chronic Chagas disease: insight gained in Argentina

The purpose of this review is to describe research findings regarding chronic Chagas disease in Argentina that have changed the standards of care for patients with Trypanosoma cruzi infection. Indirect techniques (serological tests) are still the main tools for the primary diagnosis of infection in the chronic phase, but polymerase chain reaction has been shown to be promising. The prognosis of patients with heart failure or advanced stages of chagasic cardiomyopathy is poor, but a timely diagnosis during the initial stages of the disease would allow for prescription of appropriate therapies to offer a better quality of life. Treatment of T. cruzi infection is beneficial as secondary prevention to successfully cure the infection or to delay, reduce or prevent the progression to disease and as primary disease prevention by breaking the chain of transmission. Current recommendations have placed the bulk of the diagnostic and treatment responsibility on the Primary Health Care System. Overall, the current research priorities with respect to Chagas disease should be targeted towards (i) the production of new drugs that would provide a shorter treatment course with fewer side effects; (ii) the development of new tools to confirm cure after a full course of treatment during the chronic phase and (iii) biomarkers to identify patients with a high risk of developing diseases.

Paleoparasitological results for rodent coprolites from Santa Cruz Province, Argentina

The aim of this study was to examine the parasite remains present in rodent coprolites collected from the archaeological site Alero Destacamento Guardaparque (ADG) located in the Perito Moreno National Park (Santa Cruz Province, 47º57'S 72º05'W). Forty-eight coprolites were obtained from the layers 7, 6 and 5 of ADG, dated at 6,700 ± 70, 4,900 ± 70 and 3,440 ± 70 years BP, respectively. The faecal samples were processed and examined using paleoparasitological procedures. A total of 582 eggs of parasites were found in 47 coprolites. Samples were positive for eggs of Trichuris sp. (Nematoda: Trichuridae), Calodium sp., Eucoleus sp., Echinocoleus sp. and an unidentified capillariid (Nematoda: Capillariidae) and for eggs of Monoecocestus (Cestoda: Anoplocephalidae). Quantitative differences among layer for both coprolites and parasites were recorded. In this study, the specific filiations of parasites, their zoonotic importance, the rodent identity, on the basis of previous zooarchaeological knowledge, and the environmental conditions during the Holocene in the area are discussed.

Current resistance status to temephos in Aedes aegypti from different regions of Argentina

In Argentina, more than 25,000 cases of dengue were reported in the summer of 2009, even in provinces where the disease was formerly absent. We analysed the susceptibility levels to the larvicide temephos in seven populations of Aedes aegypti, the primary vector of dengue, collected during summer 2007/2008, using the susceptible Rockefeller strain as a control. Although no control failures were observed during the experiment, a majority of the lethal concentration and resistance ratio values indicate an incipient resistance. An integrative program to monitor the resistance of Ae. aegypti to insecticides is needed in the country.

The risk of acquiring the new influenza A(H1N1) for Brazilian travelers to Chile, Argentina and the USA

We estimate the risk of acquiring the new influenza A(H1N1) for Brazilian travelers to Chile, Argentina and the USA. This is done by a mathematical model that quantifies the intensity of transmission of the new virus in those countries and the probability that one individual has of acquiring the influenza depending on the date of arrival and time spent in the area. The maximum estimated risk reached 7.5 cases per 10,000 visitors to Chile, 17 cases per 10,000 travelers to Argentina and 23 cases per 10,000 travelers to the USA. The estimated number of imported cases until 27 July is 57 ± 9 from Chile, 136 ± 27 from the USA and 301 ± 21 from Argentina, which are in accord with the official figures. Estimating the number of imported cases was particularly important for the moment of the disease introduction into this country, but it will certainly be important again as a tool to calculate the number of future imported cases from northern countries in our next inter-epidemic season, were imported cases can constitute again the majority of the new influenza burden to the Brazilian health services.

Chagas disease: serological and electrocardiographic studies in Wichi and Creole communities of Misión Nueva Pompeya, Chaco, Argentina

Chagas disease, which is caused by Trypanosoma cruzi, affects nearly 16 million people in Latin America and causes 75-90 million people to be at risk of infection. The disease is urbanizing and globalizing due to frequent migrations. There are regions of high prevalence of infection, including the north-eastern provinces of Argentina and the entire phytogeographic region known as the Gran Chaco. In the province of Chaco, Argentina, there are places inhabited by native populations such as the Wichi and Toba communities, among others. Many Creole populations resulting from miscegenation with European colonists and immigrants coexist within these communities. It has been widely accepted that in the chronic phase of the disease, between 25-30% of individuals develop some form of cardiac disease, with the right bundle-branch block being the most typical condition described so far. The aim of this work was to study the prevalence of Chagas infection and its electrocardiographic profile in the Wichi and Creole populations of Misión Nueva Pompeya, in the area known as Monte Impenetrable in Chaco, to determine the prevalence and the pattern of heart diseases produced by Chagas disease in this region.

Genetic-morphometric variation in Culex quinquefasciatus from Brazil and La Plata, Argentina

Variation among natural populations of Culex (Culex) quinquefasciatus Say is associated with different vectorial capacities. The species Cx. quinquefasciatus is present in the equatorial, tropical and subtropical zones in the Brazilian territory, with intermediate forms between Cx. quinquefasciatus and Culex pipiens occurring in regions of latitudes around 33°-35°S. Herein, we studied geographically distinct populations of Cx. quinquefasciatus by genetic characterization and analysis of intra-specific wing morphometrics. After morphological analysis, molecular characterization of Cx. quinquefasciatus and intermediate forms was performed by polymerase chain reaction of the polymorphic nuclear region of the second intron of the acetylcholinesterase locus. Additionally, the morphology of adult female wings collected from six locations was analyzed. Wing centroid sizes were significantly different between some geographical pairs. Mean values of R2/R2+3 differed significantly after pairwise comparisons. The overall wing shape represented by morphometric characters could be divided into two main groupings. Our data suggest that Brazilian samples are morphologically and genetically distinct from the Argentinean samples and also indicated a morphological distinction between northern and southern populations of Brazilian Cx. quinquefasciatus. We suggest that wing morphology may be used for preliminary assessment of population structure of Cx. quinquefasciatusin Brazil.

Tren d’alta velocitat i desenvolupament local urbà. Aportacions a una nova base teòrica

Una de les finalitats principals del tren d’alta velocitat és la d’aportar desenvolupament local en aquelles ciutats i territoris on se’n construeixi una estació. Per aquesta raó, calen reflexions teòriques que ajudin els agents i les institucions a planificar correctament l’arribada de la nova gran infraestructura de transport, especialment en els aspectes relacionats amb la capacitat d’organització dels actors territorials. La teoria reticular pot ser una base teòrica útil per evitar concepcions deterministes de la relació entre infraestructura i territori, per explicar com es produeix el procés de desenvolupament local i per demostrar la importància dels agents territorials en aquest procés

Detection of Leishmania infantum in naturally infected Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae) and Canis familiaris in Misiones, Argentina: the first report of a PCR-RFLP and sequencing-based confirmation assay

In this study, a genotypification of Leishmaniawas performed using polimerase chain reaction-restriction fragment length polymorfism (PCR-RFLP) and sequencing techniques to identify species of Leishmaniaparasites in phlebotomine sand flies and dogs naturally infected. Between January-February of 2009, CDC light traps were used to collect insect samples from 13 capture sites in the municipality of Posadas, which is located in the province of Misiones of Argentina. Sand flies identified as Lutzomyia longipalpiswere grouped into 28 separate pools for molecular biological analysis. Canine samples were taken from lymph node aspirates of two symptomatic stray animals that had been positively diagnosed with canine visceral leishmaniasis. One vector pool of 10 sand flies (1 out of the 28 pools tested) and both of the canine samples tested positively for Leishmania infantumby PCR and RFLP analysis. PCR products were confirmed by sequencing and showed a maximum identity with L. infantum. Given that infection was detected in one out of the 28 pools and that at least one infected insect was infected, it was possible to infer an infection rate at least of 0.47% for Lu. longipalpisamong the analyzed samples. These results contribute to incriminate Lu. longipalpis as the vector of L. infantumin the municipality of Posadas, where cases of the disease in humans and dogs have been reported since 2005.

Projecte de desenvolupament agroeconòmic i social del poblat d’ Atitsohoe, Togo, Àfrica

La motivació principal d’aquest treball ha estat la de conèixer una realitat agrícola isocial d’una àrea limitada però, representativa en un país en via de desenvolupament com és Togo. El protocol de treball ha permès recollir informació tant sobre l’organització social del poble d’Atitsohoe com les varies fases del maneig i ús de la terra, que proporciona la base per l’alimentació local. Mitjançant un sistema d’enquestes sobre l’organització de les pràctiques agrícoles i, un treball de camp i de laboratori per caracteritzar els sòls de l’àrea, hem pogut classificar els sòls i atribuir condicions de fertilitat com d’adequació per determinades espècies de cultius. Posteriorment als anàlisi s’han pogut plantejar un seguit de propostes de millora tant per les pràctiques agrícoles com per les condicions químiques i físiques dels sòls

Sex pheromone and period gene characterization of Lutzomyia longipalpis sensu lato (Lutz & Neiva) (Diptera: Psychodidae) from Posadas, Argentina

Lutzomyia longipalpis s.l. is the primary vector of Leishmania (L.) infantum in the New World. In this study, male Lutzomyia longipalpis specimens from Posadas, Argentina were characterized for two polymorphic markers: the male sex pheromone and the period (per) gene. The male sex pheromone was identified as (S)-9-methylgermacrene-B, the same compound produced by Lu. longipalpis from Paraguay and many populations from Brazil. The analysis of per gene sequences revealed that the population from Argentina is significantly differentiated from previously studied Brazilian populations. Marker studies could contribute to the understanding of the distribution and spread of urban American visceral leishmaniasis, thus aiding in the design of regional surveillance and control strategies.

Desenvolupament d’una metodologia de simulació mitjançant programari CFD per a la optimització d’agitadors

La dinàmica de fluids computacional (CFD) és una eina que serveix per analitzar mitjançantcomputadors diferents problemes que involucren fluxos de fluids. Els programes de CFD usen expressions matemàtiques no lineals que defineixen les equacions fonamentals de fluxos i transport de calor en fluids. Aquestes es resolen amb complexos algoritmes iteratius. Actualment aquesta eina és una part fonamental en els procés de disseny en moltes empreses relacionades amb la dinàmica de fluids. Les simulacions que es realitzen ambaquests programes s’ha demostrat que són fiables i que estalvien temps i diners, ja que eviten haver de realitzar els costosos processos d’assaig-error. En el projecte s’utilitza el programa de CFD Ansys CFX 11.0 per simular una agitació bifàsica composta per aigua i aire a temperatura ambient. Els objectius són determinar els paràmetres òptims de simulació que permetin recrear aquesta agitació, per posteriorment dissenyar un nou impulsor