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

Fascioliasis in Llama, Lama glama, in Andean Endemic Areas: Experimental Transmission Capacity by the High Altitude Snail Vector Galba truncatula and Epidemiological Analysis of Its Reservoir Role

South American camelids are definitive hosts of Fasciola hepatica. However, their capacity to participate in the transmission and epidemiology of fascioliasis has never been appropriately studied. Therefore, an F. hepatica isolate from Argentine llama is for the first time analyzed using Galba truncatula lymnaeids from Bolivia. Experimental follow-up studies included egg embryogenesis, miracidial infection of lymnaeid snails, intramolluscan larval development, cercarial production, chronobiology of cercarial shedding, vector survival to infection, and metacercarial infectivity of mammal host. Shorter prepatent and patent periods were leading to markedly lower cercarial production, shorter cercarial shedding, and a higher negative impact on snail survival. The usually low liver fluke prevalences and intensities and low daily fecal outputs indicate that llamas do not substantially contribute to fascioliasis transmission. The defecating behavior in dung piles far from freshwater collections prevents lymnaeid infection by eggs shed by this camelid. All results suggest the reservoir role of the llama to be negligible and, therefore, no priority within control measures in endemic areas. However, llamas may play a disease-spreading role if used as pack animals in rural areas. In the Northern Bolivian Altiplano human hyperendemic area, neither llamas nor alpacas should be considered for control measures within a One Health action.EEA SaltaFil: Mas-Coma, Santiago. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; EspañaFil: Cafrune Wierna, Marí­a Mercedes. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Salta; ArgentinaFil: Funatsu, Ilra Renata. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; EspañaFil: Mangold, Atilio Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina.Fil: Angles, Rene. Universidad Mayor de San Andrés. Facultad de Medicina. Cátedra de Parasitología; BoliviaFil: Buchon, Paola. Universidad Mayor de San Andrés. Instituto de Ecología. Unidad de Limnología; BoliviaFil: Fantozzi, Maria Cecilia. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; EspañaFil: Artigas, Patricio. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; EspañaFil: Valero, Maria Adela. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; EspañaFil: Bargues, Maria Dolores. Universidad de Valencia. Facultad de Farmacia. Departamento de Parasitologia; Españ

DNA multigene sequencing of topotypic specimens of the fascioliasis vector Lymnaea diaphana and phylogenetic analysis of the genus Pectinidens (Gastropoda)

Freshwater lymnaeid snails are crucial in defining transmission and epidemiology of fascioliasis. In South America, human endemic areas are related to high altitudes in Andean regions. The species Lymnaea diaphana has, however, been involved in low altitude areas of Chile, Argentina and Peru where human infection also occurs. Complete nuclear ribosomal DNA 18S, internal transcribed spacer (ITS)-2 and ITS-1 and fragments of mitochondrial DNA 16S and cytochrome c oxidase (cox)1 genes of L. diaphana specimens from its type locality offered 1,848, 495, 520, 424 and 672 bp long sequences. Comparisons with New and Old World Galba/Fossaria, Palaearctic stagnicolines, Nearctic stagnicolines, Old World Radix and Pseudosuccinea allowed to conclude that (i) L. diaphana shows sequences very different from all other lymnaeids, (ii) each marker allows its differentiation, except cox1 amino acid sequence, and (iii) L. diaphana is not a fossarine lymnaeid, but rather an archaic relict form derived from the oldest North American stagnicoline ancestors. Phylogeny and large genetic distances support the genus Pectinidens as the first stagnicoline representative in the southern hemisphere, including colonization of extreme world regions, as most southern Patagonia, long time ago. The phylogenetic link of L. diaphana with the stagnicoline group may give light to the aforementioned peculiar low altitude epidemiological scenario of fascioliasis

Molecular characterization of Trypanosoma cruzi and infection rate of the vector Triatoma dimidiate in Costa Rica

According to the genetic characterization by the analysis of the miniexon gene, strains of Trypanosoma cruzi can be classified into six discrete typing units (DTUs), and the DTU 1 into four distinct genotypes associated with different life cycles. While Chagas disease is endemic in Costa Rica, T. cruzi isolates from this region have never been genetically characterized. An analysis of 16 isolates from Costa Rica, based on miniexon gene analysis, showed the existence of two different haplotypes in the country, closely related to the Colombian haplotype group TcIa and to sequences from several Mexican isolates, with eight variable positions in the alignment and a variability of 2.6 % between the compared sequences. No relationship between the habitat, vector or host, and the haplotypes was found, suggesting an active flow of T. cruzi in the country. The present study also reports a very high infection rate (47.3 %, 26 out of 55 specimens) in a Costa Rican population of Triatoma dimidiata, the main vector of Chagas disease in this country. The distribution and abundance of the parasite and its main vector suggest a high risk of Chagas disease emergence in Costa Rica.De acuerdo con la caracterización genética mediante el análisis del gen del miniexón, las cepas de Trypanosoma cruzi pueden clasificarse en seis unidades de tipificación discreta (DTUs), y la DTU 1 en cuatro genotipos distintos asociados a diferentes ciclos de vida. Si bien la enfermedad de Chagas es endémica en Costa Rica, los aislados de T. cruzi de esta región nunca se han caracterizado genéticamente. Un análisis de 16 aislados de Costa Rica, basado en el análisis del gen del miniexón, mostró la existencia de dos haplotipos diferentes en el país, estrechamente relacionados con el grupo de haplotipos colombianos TcIa y con secuencias de varios aislados mexicanos, con ocho posiciones variables en la alineación y una variabilidad del 2,6% entre las secuencias comparadas. No se encontró ninguna relación entre el hábitat, el vector o el huésped y los haplotipos, lo que sugiere un flujo activo de T. cruzi en el país. El presente estudio también informa de una tasa de infección muy elevada (47,3 %, 26 de 55 ejemplares) en una población costarricense de Triatoma dimidiata, el principal vector de la enfermedad de Chagas en este país. La distribución y abundancia del parásito y su principal vector sugieren un alto riesgo de aparición de la enfermedad de Chagas en Costa Rica.Escuela de Medicina Veterinari

Very high fascioliasis intensities in schoolchildren from nile delta governorates, egypt: The old world highest burdens found in lowlands

Quantitative coprological analyses of children were performed in Alexandria and Behera governorates, Egypt, to ascertain whether individual intensities in the Nile Delta lowlands reach high levels as those known in hyperendemic highland areas of Latin America. Analyses focused on subjects presenting intensities higher than 400 eggs per gram of faeces (epg), the high burden cut-off according to WHO classification. A total of 96 children were found to shed between 408 and 2304 epg, with arithmetic and geometric means of 699.5 and 629.07 epg, respectively. Intensities found are the highest hitherto recorded in Egypt, and also in the whole Old World. A total of 38 (39.6%) were males and 58 (60.4%) were females, with high intensities according to gender following a negative binomial distribution. The high burden distribution shows a peak in the 7–10 year-old children group, more precocious in females than males. Results showed high burdens in winter to be remarkably higher than those known in summer. The fascioliasis scenario in Egyptian lowlands shows similarities to highlands of Bolivia and Peru. Diagnostic methods, pathogenicity and morbidity in high burdens should be considered. The need for an appropriate quantitative assessment of heavy infected children to avoid post-treatment colic episodes is highlighted.Fil: Periago, Maria Victoria. Fundación Mundo Sano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Valencia; EspañaFil: Adela Valero, M.. Universidad de Valencia; EspañaFil: Artigas, Patricio. Universidad de Valencia; EspañaFil: Agramunt, Verónica H.. Universidad de Valencia; EspañaFil: Bargues, M. Dolores. Universidad de Valencia; EspañaFil: Curtale, Filippo. Istituto Nazionale Per la Promozione Della Salute; ItaliaFil: Mas-Coma, Santiago. Universidad de Valencia; Españ

Molecular phylogeny of Psychodopygina (Diptera, Psychodidae) supporting morphological systematics of this group of vectors of New World tegumentary leishmaniasis

International audienceNew World sandflies are vectors of leishmaniasis, bartonellosis, and some arboviruses. A classification based on 88 morphological characters was proposed 27 years ago when the New World phlebotomines were organized into two tribes Hertigiini and Phlebotomini. The latter was structured into four subtribes (Brumptomyiina, Sergentomyiina, Lutzomyiina, and Psychodopygina) and 20 genera. The subtribe Psychodopygina, including most of the American vectors of tegumentary Leishmania comprises seven genera from which no molecular work has been produced to support this classification. Here, we carried out a molecular phylogeny based on combined sequences (1,334 bp) of two genes: partial 28S rDNA and mtDNA cytochrome b from 47 taxa belonging to the Psychodopygina. The Bayesian phylogenetic reconstruction agreed with the classification based on morphological characters, supporting the monophyly of the genera Psychodopygus and Psathyromyia, whereas Nyssomyia and Trichophoromyia seemed to be paraphyletic. The paraphylies of the two latter groups were exclusively caused by the doubtful position of the species Ny. richardwardi. Our molecular analysis provides additional support to adopt the morphologic classification of Psychodopygina

Mating Interactions between Schistosoma bovis and S. mansoni and Compatibility of Their F1 Progeny with Biomphalaria glabrata and Bulinus truncatus

Contrary to the majority of other Trematoda, Schistosoma species are gonochoric. Consequently, in endemic areas where several schistosome species overlap and can co-infect the same definitive host, there may be frequent opportunities for interspecific pairing. Our experimental study provides novel insight on the pairing behavior between Schistosoma bovis and S. mansoni in mixed infections in mice. We used six mate choice experiments to assess mating interactions between the two schistosome species. We show that mating between the two Schistosoma species is not random and that S. mansoni exhibits greater mate recognition compared to S. bovis. We also performed reciprocal crosses (male S. mansoni × female S. bovis) and (female S. mansoni × male S. bovis) that produce active swimming miracidia. These miracidia were genotyped by ITS2 sequencing and proposed for mollusc infection. Molecular analyses show that all the miracidia are parthenogenetically produced (i.e., their harbor the mother ITS2 genotype) and as a consequence can only infect the mollusc of the maternal species. Offspring produced by male S. mansoni × female S. bovis pairing can only infect Bulinus truncatus whereas offspring produced by female S. mansoni × male S. bovis can only infect Biomphalaria glabrata snails. Evolutionary and epidemiological consequences are discussed