Genomic analysis of two phlebotomine sand fly vectors of Leishmania from the New and Old World.

Phlebotomine sand flies are of global significance as important vectors of human disease, transmitting bacterial, viral, and protozoan pathogens, including the kinetoplastid parasites of the genus Leishmania, the causative agents of devastating diseases collectively termed leishmaniasis. More than 40 pathogenic Leishmania species are transmitted to humans by approximately 35 sand fly species in 98 countries with hundreds of millions of people at risk around the world. No approved efficacious vaccine exists for leishmaniasis and available therapeutic drugs are either toxic and/or expensive, or the parasites are becoming resistant to the more recently developed drugs. Therefore, sand fly and/or reservoir control are currently the most effective strategies to break transmission. To better understand the biology of sand flies, including the mechanisms involved in their vectorial capacity, insecticide resistance, and population structures we sequenced the genomes of two geographically widespread and important sand fly vector species: Phlebotomus papatasi, a vector of Leishmania parasites that cause cutaneous leishmaniasis, (distributed in Europe, the Middle East and North Africa) and Lutzomyia longipalpis, a vector of Leishmania parasites that cause visceral leishmaniasis (distributed across Central and South America). We categorized and curated genes involved in processes important to their roles as disease vectors, including chemosensation, blood feeding, circadian rhythm, immunity, and detoxification, as well as mobile genetic elements. We also defined gene orthology and observed micro-synteny among the genomes. Finally, we present the genetic diversity and population structure of these species in their respective geographical areas. These genomes will be a foundation on which to base future efforts to prevent vector-borne transmission of Leishmania parasites

Urban gully assessment in São Luis City (Maranhão State), Brazil, using penetrometer data and soil properties

This paper investigates soil erosion assessment in São Luis City, reporting an ongoing programme of field measurements (penetrometer measurements and gully monitoring), topsoil sampling and laboratory analyses. From the database, it is evident that the urban sector of São Luis is very prone to gully erosion, especially where land use promotes land degradation. This research work is part of the larger European Union Project ‘BORASSUS’, which investigates soil erosion assessment and rehabilitation in 10 different countries, including Brazil. In our case, we are the only country investigating urban gully erosion. Therefore, this paper presents some preliminary results, both in terms of penetrometer measurements and soil properties, and we make some initial conclusions regarding the four studied gullies, which are situated in São Luis City, Maranhão Island (2º19’9”- 2º51’S; 44º1’16”-44º19”37” W). In order to achieve the research objectives, we have carried out both field and laboratory work, so that penetrometer data could be related to laboratory data. On each one, we selected different parts, around each gully, to take three penetrometer measurements, to calculate the site mean. On completion, we calculated the mean for the whole gully, taking into account the mean for each site. We collected topsoil (0-10 cm) samples to determine selected soil properties in the laboratory (particle size distribution, particle density, bulk density and porosity), using EMBRAPA (1997) protocols. Although most penetrometer studies are related to agricultural situations, for this study we have used penetrometry to assist our understanding of gully evolution and behaviour. The whole study area shows a high sand content and low silt and clay contents; textures being sandy loams. In 60% of analysed soil samples, the silt content is higher than the clay content, confirming the higher detachability and transportability of fine sand and silt. Penetrometer measurements are related to soil compaction, due to people walking on tracks around the gullies. Those values showed direct association with parameters related to vegetation cover. We can conclude that this area presents high sensitivity to erosion, expressed by high bulk density values, high fine sand and silt contents, low clay content and low porosity