About 30 yr after malaria eradication, surveys to assess the presence and abundance of anopheline vectors were carried out in central and southern Italy and in the islands of Sardinia and Sicily from 1992 to 1994. Anopheles labranchiae Falleroni was present in scattered foci in all regions, except for Tuscany, where it breeds almost exclusively in rice fields (Grosseto Province). Most common breeding sites were rivers and streams, followed by ponds and ground pools. The highest adult density was found in Tuscany near rice fields and along the west coast of Calabria. Anophelines in Grosseto were abundant at human bait, with peaks of > 200 landings per human per night and vectorial capacity between 7.3 and 26 for Plasmodium falciparum and between 8.3 and 32.5 for Plasmodium vivax. Anopheles sacharovi Favre, a former malaria vector in Puglia and Sardinia, was not found in these regions. The other vector in southern Italy, Anopheles superpictus Grassi, was found at low densities on the western and eastern coasts of Calabria. All anopheline populations were fully susceptible to deltamethrin, malathion, and DDT but showed reduced susceptibility to permethrin and propoxur. These data are discussed in the light of a possible reintroduction of malaria into Italy.
Fluorescence in situ hybridization (FISH) was used to localize the 18S-28S ribosomal RNA gene clusters on the chromosomes of 15 mosquito species belonging to the Anophelinae and Culicinae subfamilies. In the genus Anopheles the rRNA genes are localized on the heterochromatic arm of both sex chromosomes. The association between rRNA genes and sex determining chromosomes also applies to the homomorphic karyotype of Culicinae mosquitoes, at least in those cases in which localization of the sex locus/loci has been determined. In these species ribosomal genes are often found within or adjacent to heterochromatic regions (C bands). Differences in the location of rRNA genes among and within genera suggest the occurrence of several chromosomal rearrangements during the evolution of mosquitoes.
Following the spread of Bluetongue virus (BTV) in many Mediterranean countries during the last 5 years, presence of the main BTV vector, Culicoides imicola Kieffer (Diptera: Ceratopogonidae), was recorded in the region, including the island of Sardinia where the first BT epidemic originally started in the year 2000. Several models were also designed based on climate variables and satellite imaging in order to predict the presence and abundance of BTV vectors across Europe. A 3 years entomological survey (2001-2003) was conducted in the southern part of Sardinia confirming the widespread presence of C. imicola. However, substantial differences in terms of relative abundance were observed between field data and prediction maps based on satellite-derived climate variables. Distribution of other potential BT vectors, belonging to Culicoides obsoletus Meigen and Culicoides pulicaris Linnaeus groups was also not congruent with model-based predictions. These results stress the need of taking into account additional environmental factors (such as soil type, land usage, etc.) and local microclimatic conditions, especially related to breeding site requirements of Culicoides species, in order to predict the presence and abundance of BT vectors and to design reliable prediction maps on a local scale.
Abstract. Culicoides species belonging to the Obsoletus complex (Diptera: Ceratopogonidae) have been indicated as primary bluetongue (BT) vectors in many European countries and their possible involvement in the maintenance and overwintering of BT viruses has been suggested, even in regions where Culicoides imicola Keiffer is the main vector. The Obsoletus complex includes two predominant taxa, Culicoides obsoletus (Meigen) and Culicoides scoticus Downes & Kettle. However, the role played by each species in the epidemiology of BT is still unknown. Taxonomic identification is mainly based on the morphology of male genitalia and the lack of other reliable diagnostic features makes the screening of trap-collected vector populations, mainly females, particularly difficult. Although molecular markers have facilitated species identification, little information is yet available on the biology, abundance and population dynamics of the two taxa. The aim of this work was to investigate the genetic profile and temporal distribution of C. obsoletus and C. scoticus by using isozyme electrophoresis applied to adult midges, collected weekly at two selected farms in southern Sardinia. A total of nine enzyme loci were analysed and five of them provided diagnostic allozyme markers (Hk, Mdh, Pgi, Idh-1 and Idh-2 ). Nei's genetic distance between the two taxa was in the range of other well-separated taxa (D = 1.792), supporting their status as true species. Culicoides scoticus represented almost 61% of the 562 specimens analysed; its genetic structure was characterized by a very low level of intra-population variation (mean heterozygosity H e = 0.019) and higher genetic divergence between populations (F ST = 0.0016) than in C. obsoletus. The latter species had significantly more heterozygotes (H e = 0.123), a higher percentage of polymorphic loci, and no inter-population differentiation (F ST ∼ = 0). We suggest that different biological and ecological constraints, such as breeding habitat requirements, may contribute to shaping the genetic profiles of C. scoticus and C. obsoletus. However, enough gene flow was maintained between populations of each species as no spatial and temporal structuring was sustained by Fisher's exact probability test (P > 0.5). The seasonal distributions of C. scoticus and C. obsoletus only partially overlapped: both species were mainly found early in the year, when the main vector, C. imicola, was present in low numbers, and peaked in abundance in April and May. Culicoides scoticus was predominant until May, decreased rapidly in the following months and increased again in winter, whereas C. obsoletus decreased more slowly and was still present in early summer. Consequently, C. scoticus may be a good candidate for playing a role in the transmission and maintenance of BT virus in Sardinia,
A 73-year-old never-smoker woman with chronic bronchitis, increasing dyspnoea, and airflow limitation with a FEV1 of 49% of predicted value had low serum level of alpha-1-antitrypsin (69 mg/dL, normal range 150-350). Isoelectric focusing showed an Mlike pattern. Direct sequencing showed, in the second exon, a particular DNA alteration localized between codon 41 and codon 51: a region of 30 base pairs (bp) was completely deleted and substituted by a 22-bp sequence. The resulting loss of 8 bp yields, in the second exon, a 70-71 stop codon. This new Mlike variant was denominated MVarallo from the site where it was discovered.
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