Interès, avantatges i inconvenients dels ecosistemes aïllats en estudis parasitològics

In the studies on the ecology of the parasite fauna of free living small mammals in Formentera (Balearic Islands) notable differences as regards similar works in other islands or in the continent were found. The particular qualitative and quantitative composition of the ectofauna and endofauna can be explained by the special phisiography of the island and the uncommon ecology of the definitive hosts (domination of the garden dormouse). On the basis of these investigations and of the data of the short literature dealing with the topic «parasitology in isolated ecosystems», it can be deduced a number of advantages and disadvantages offered by insular ecosystems in respect to parasitological research and finally the general interest of them

COVID-19 and globalization

The world is experiencing a major pandemic caused by SARS-CoV-2, the Coronavirus causing COVID-19. This disease first entered the human population in Hubei province, China, in mid-November 2019 and manifested in Wuhan, the largest metropolitan area of Hubei, when a cluster of patients were admitted to hospital with a ‘severe pneumonia of unknown cause’ in early December. Although humanity has survived previous pandemics by infectious agents, the present one is unprecedented in its capacity to take advantage of modern globalization allowing for massive transborder spread at a surprising speed. When writing these lines, the pandemic affects 181 countries and territories, with around 1,084,000 infected subjects, more than 58,000 deaths and 225,000 recovered patients, according to the Johns Hopkins University

DNA sequence characterisation and phylogeography of Lymnaea cousini and related species, vectors of fascioliasis in northern Andean countries, with description of L. meridensis n. sp. (Gastropoda: Lymnaeidae)

<p>Abstract</p> <p>Background</p> <p>Livestock fascioliasis is a problem throughout Ecuador, Colombia and Venezuela, mainly in Andean areas where the disease also appears to affect humans. Transmission patterns and epidemiological scenarios of liver fluke infection have shown to differ according to the lymnaeid vector snail species involved. These Andean countries present the vectors <it>Lymnaea cousini</it>, <it>L. bogotensis </it>and <it>L. ubaquensis</it>, unknown in the rest of Latin America. An exhaustive combined haplotype study of these species is performed by means of DNA sequencing of the nuclear ribosomal 18S RNA gene, ITS-2 and ITS-1, and mitochondrial DNA <it>cox</it>1 gene.</p> <p>Results</p> <p>The conserved 5.8S rDNA sequence corroborated that no pseudogenes are involved in the numerous non-microsatellite/minisatellite-related indels appearing between the ITS-2 and ITS-1 sequences when comparing different <it>L. cousini </it>- <it>L. bogotensis </it>populations. Sequence analyses and phylogenetic reconstruction methods including other lymnaeid vector species show that (i) <it>L. bogotensis </it>is a synonym of <it>L. cousini</it>, (ii) <it>L. ubaquensis </it>is a synonym of <it>Pseudosuccinea columella</it>, and (iii) populations of <it>L. cousini </it>hitherto known from Venezuelan highlands indeed belong to a new species for which the name <it>L. meridensis </it>n. sp. is proposed. This new species is described and a complete phenotypic differentiation provided.</p> <p>Conclusions</p> <p>ITS-2, ITS-1 and <it>cox</it>1 prove to be good markers for specimen classification and haplotype characterisation of these morphologically similar lymnaeids in endemic areas. Analysis of the 18S gene and phylogenetic reconstructions indicate that <it>L. cousini </it>and <it>L. meridensis </it>n. sp. cluster in an evolutionary line different from the one of <it>P. columella</it>, despite their external resemblance. This suggests an evolutionary phenotypic convergence related to similar environments and which has given rise to frequent specimen misclassification. Body size and phylogenetic relationships of <it>L. meridensis </it>n. sp. with well-known vectors as <it>Lymnaea cousini </it>and <it>P. columella</it>, as well as with <it>Galba</it>/<it>Fossaria </it>species, suggest that the new species may participate in disease transmission to both animals and humans in altitude areas during the yearly window in which temperatures are higher than the <it>F. hepatica </it>minimum development threshold. The involvement of <it>L. cousini </it>and <it>P. columella </it>in the transmission and geographical/altitudinal distribution of fascioliasis in these Andean countries is analysed.</p

West Nile virus in Spain: Forecasting the geographical distribution of risky areas with an ecological niche modelling approach

West Nile virus (WNV), a well-known emerging vector-borne arbovirus with a zoonotic life cycle, represents a threat to both public and animal health. Transmitted by ornithophilic mosquitoes, its transmission is difficult to predict and even more difficult to prevent. The massive and unprecedented number of human cases and equid outbreaks in Spain during 2020 interpellates for new approaches. For the first time, we present an integrate analysis from a niche perspective to provide an insight to the situation of West Nile disease (WND) in Spain. Our modelling approach benefits from the combined use of global occurrence records of outbreaks of WND in equids and of its two alleged main vectors in Spain, Culex pipiens and Cx. perexiguus. Maps of the climatic suitability for the presence of the two vectors species and for the circulation of WNV are provided. The main outcome of our study is a map delineating the areas under certain climatic risk of transmission. Our analyses indicate that the climatic risk of transmission of WND is medium in areas nearby the south Atlantic coastal area of the Cadiz Gulf and the Mediterranean coast, and high in southwestern Spain. The higher risk of transmission in the basins of the rivers Guadiana and Guadalquivir cannot be attributed exclusively to the local abundance of Cx. pipiens, but could be ascribed to the presence and abundance of Cx. perexiguus. Furthermore, this integrated analysis suggests that the WNV presents an ecological niche of its own, not fully overlapping the ones of its hosts or vector, and thus requiring particular environmental conditions to succeed in its infection cycle.Fil: Cuervo Bustamante, Pablo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina. Universidad de Valencia; EspañaFil: Artigas, Patricio. Universidad de Valencia; EspañaFil: Mas-Coma, Santiago. Universidad de Valencia; EspañaFil: Bargues, María Dolores. Universidad de Valencia; Españ

Efficacy of an insecticide paint against insecticide-susceptible and resistant mosquitoes - Part 1: Laboratory evaluation

<p>Abstract</p> <p>Background</p> <p>The main malaria vector <it>Anopheles gambiae </it>and the urban pest nuisance <it>Culex quinquefasciatus </it>are increasingly resistant to pyrethroids in many African countries. There is a need for new products and strategies. Insecticide paint Inesfly 5A IGR™, containing two organophosphates (OPs), chlorpyrifos and diazinon, and insect growth regulator (IGR), pyriproxyfen, was tested under laboratory conditions for 12 months following WHOPES Phase I procedures.</p> <p>Methods</p> <p>Mosquitoes used were laboratory strains of <it>Cx. quinquefasciatus </it>susceptible and resistant to OPs. The paint was applied at two different doses (1 kg/6 m²and 1 kg/12 m²) on different commonly used surfaces: porous (cement and stucco) and non-porous (softwood and hard plastic). Insecticide efficacy was studied in terms of delayed mortality using 30-minute WHO bioassay cones. IGR efficacy on fecundity, fertility and larval development was studied on OP-resistant females exposed for 30 minutes to cement treated and control surfaces.</p> <p>Results</p> <p>After treatment, delayed mortality was high (87-100%) even against OP-resistant females on all surfaces except cement treated at 1 kg/12 m². Remarkably, one year after treatment delayed mortality was 93-100% against OP-resistant females on non-porous surfaces at both doses. On cement, death rates were low 12 months after treatment regardless of the dose and the resistance status. Fecundity, fertility and adult emergence were reduced after treatment even at the lower dose (p < 10^{^-3}). A reduction in fecundity was still observed nine months after treatment at both doses (p < 10^{^-3}) and adult emergence was reduced at the higher dose (p < 10^{^-3}).</p> <p>Conclusions</p> <p>High mortality rates were observed against laboratory strains of the pest mosquito <it>Cx. quinquefasciatus </it>susceptible and resistant to insecticides. Long-term killing remained equally important on non-porous surfaces regardless the resistance status for over 12 months. The paint's effect on fecundity, fertility and adult emergence may continue to provide an additional angle of attack in reducing overall population densities when the lethal effect of OPs diminishes over time. Some options on how to deal with porous materials are given. Implications in vector control are discussed.</p

Secuenciación del ITS-1 del ADN ribosomal de Galba truncatula (Gastropoda, Lymnaeidae) y su impacto potencial en la transmisión de la fascioliasis en Mendoza, Argentina

Sequencing of the rDNA ITS–1 proved that the lymnaeid snail species Galba truncatula is present in Argentina and that it belongs to the haplotype HC, the same as that responsible for the fascioliasis transmission in the human hyperendemic area with the highest human prevalences and intensities known, the Northern Bolivian Altiplano.La secuenciación del ITS–1 del ADNr demostró que la especie de gasterópodo lymnaeido Galba truncatula se encuentra en Argentina y que pertenece al haplotipo HC, el mismo responsable de la transmisión de la fascioliasis en el área de hiperendemia humana con las mayores prevalencias e intensidades de fascioliasis conocidas, el Altiplano Norte Boliviano

Dicrocoelium dendriticum found in a Bronze Age cemetery in western Iran in the pre-Persepolis period: The oldest Asian palaeofinding in the present human infection hottest spot region

Dicrocoeliasis of animals and humans is caused by trematode species of the genus Dicrocoelium, mainly Dicrocoelium dendriticum in ruminants of the Holarctic region. D. dendriticum may be considered an old parasite, probably related to the appearance and diversification of Eurasian ovicaprines, occurred 14.7-14.5 million years ago. The oldest palaeoparasitological findings of Dicrocoelium in domestic animals and humans date from more than 5000 years BC in Europe. Eggs of D. dendriticum have been found in a burial of a Bronze Age cemetery (2600-2200 BC) close to Yasuj city, southwestern Iran. This is the oldest finding of D. dendriticum in the Near East, where present human infection reports are more numerous than in other world regions where human dicrocoeliasis is rare and sporadic. This palaeofinding in the Zagros mountainous chain area is of interest by its location close to Persepolis, suggesting a narrow relationship between humans and herbivorous animals in these highlands. Domestic ruminant populations of these highlands were following a repeated contact with those of the western flat lowlands of the Fertile Crescent thanks to annual altitudinal transhumance migrations of the nomadic pastoral tribes with their herds living throughout Zagros Mountains in the several millennium period BC. It is concluded that D. dendriticum spread together with sheep and goats westward throughout Europe from the Fertile Crescent during the 8000-6000 year BC period and somewhat later southward into Africa, both spreads facilitated by the low specificity of that trematode species regarding the snail and ant intermediate hosts. (C) 2015 Elsevier Ireland Ltd. All rights reserved

Malaria resurgence risk in southern Europe: climate assessment in an historically endemic area of rice fields at the Mediterranean shore of Spain

<p>Abstract</p> <p>Background</p> <p>International travel and immigration have been related with an increase of imported malaria cases. This fact and climate change, prolonging the period favouring vector development, require an analysis of the malaria transmission resurgence risk in areas of southern Europe. Such a study is made for the first time in Spain. The Ebro Delta historically endemic area was selected due to its rice field landscape, the presence of only one vector, <it>Anopheles atroparvus</it>, with densities similar to those it presented when malaria was present, in a situation which pronouncedly differs from already assessed potential resurgence areas in other Mediterranean countries, such as France and Italy, where many different <it>Anopheles </it>species coexist and a different vector species dominates.</p> <p>Methods</p> <p>The transmission risk was assessed analysing: 1) climate diagrams including the minimum temperature for <it>Plasmodium falciparum </it>and <it>Plasmodium vivax </it>development; 2) monthly evolution of the Gradient Model Risk (GMR) index, specifying transmission risk period and number of potential <it>Plasmodium </it>generations; 3) ecological characteristics using remote sensing images with the Eurasia Land Cover characteristics database and the monthly evolution of the Normalized Difference Vegetation Index (NDVI); 4) evaluation of <it>A. atroparvus </it>population dynamics.</p> <p>Results</p> <p>Climatological analyses and GMR index show that a transmission risk presently exists, lasting from May until September for <it>P. falciparum</it>, and from May until October for <it>P. vivax</it>. The GMR index shows that the temperature increase does not actually mean a transmission risk increase if accompanied by a precipitation decrease reducing the number of parasite generations and transmission period. Nevertheless, this limitation is offset by the artificial flooding of the rice fields. Maximum NDVI values and <it>A. atroparvus </it>maximum abundance correspond to months with maximum growth of the rice fields.</p> <p>Conclusions</p> <p>The Ebro Delta presents the ecological characteristics that favour transmission. The temperature increase has favoured a widening of the monthly potential transmission window with respect to when malaria was endemic. The combined application of modified climate diagrams and GMR index, together with spatial characterization conforms a useful tool for assessing potential areas at risk of malaria resurgence. NDVI is a good marker when dealing with a rice field area.</p