Biomphalaria snails are instrumental in transmission of the human blood fluke Schistosoma mansoni. With the World Health Organization's goal to eliminate schistosomiasis as a global health problem by 2025, there is now renewed emphasis on snail control. Here, we characterize the genome of Biomphalaria glabrata, a lophotrochozoan protostome, and provide timely and important information on snail biology. We describe aspects of phero-perception, stress responses, immune function and regulation of gene expression that support the persistence of B. glabrata in the field and may define this species as a suitable snail host for S. mansoni. We identify several potential targets for developing novel control measures aimed at reducing snail-mediated transmission of schistosomiasis.

Big cat genomes reveal a history of interspecies admixture and adaptive evolution of genes underlying development and sensory perception.

The purpose of the present study was to evaluate the immunohistochemistry (IMHC) and PCR (Polymerase Chain Reaction) tests for Canine Visceral Leishmaniasis (CVL) diagnosis and compare the results with serological tests such as the indirect fluorescence antibody test (IFAT), ELISA and a parasitological test (microscopic direct examination of the parasite stained with haematoxylin and eosin--HE). For this study, samples of healthy or lesion skin tissues were obtained from 34 CVL naturally infected dogs classified in three groups: asymptomatic, oligosymptomatic and polisymptomatic. Not only lesion (56.5%) but also healthy skins (31.8%) were positives by IMHC and confirmed by PCR in 97.8% of skin samples. In asymptomatic group, 87.5% dogs were negatives by serological tests, but positives by IMHC in 50% and by PCR in 100%. In oligosymptomatic group, 100%, 85.7% and 28.6% of dogs were positives, respectively by PCR, serological and IMHC tests. In addition, 91.7% of polisymptomatic dogs were serum positive and had intact parasites in the skin. In general, PCR showed higher positivity (100%). The efficiency of each test varied with the evolution of the disease. IMHC may be used to confirm the results of the serology and PCR in inconclusive cases after HE and IMHC. The association of techniques proposed in this study may increase the positivity and contributed to the control of this canine disease.

BackgroundThe parasite Echinococcus canadensis (G7) (phylum Platyhelminthes, class Cestoda) is one of the causative agents of echinococcosis. Echinococcosis is a worldwide chronic zoonosis affecting humans as well as domestic and wild mammals, which has been reported as a prioritized neglected disease by the World Health Organisation. No genomic data, comparative genomic analyses or efficient therapeutic and diagnostic tools are available for this severe disease. The information presented in this study will help to understand the peculiar biological characters and to design species-specific control tools.ResultsWe sequenced, assembled and annotated the 115-Mb genome of E. canadensis (G7). Comparative genomic analyses using whole genome data of three Echinococcus species not only confirmed the status of E. canadensis (G7) as a separate species but also demonstrated a high nucleotide sequences divergence in relation to E. granulosus (G1). The E. canadensis (G7) genome contains 11,449 genes with a core set of 881 orthologs shared among five cestode species. Comparative genomics revealed that there are more single nucleotide polymorphisms (SNPs) between E. canadensis (G7) and E. granulosus (G1) than between E. canadensis (G7) and E. multilocularis. This result was unexpected since E. canadensis (G7) and E. granulosus (G1) were considered to belong to the species complex E. granulosus sensu lato. We described SNPs in known drug targets and metabolism genes in the E. canadensis (G7) genome. Regarding gene regulation, we analysed three particular features: CpG island distribution along the three Echinococcus genomes, DNA methylation system and small RNA pathway. The results suggest the occurrence of yet unknown gene regulation mechanisms in Echinococcus.ConclusionsThis is the first work that addresses Echinococcus comparative genomics. The resources presented here will promote the study of mechanisms of parasite development as well as new tools for drug discovery. The availability of a high-quality genome assembly is critical for fully exploring the biology of a pathogenic organism. The E. canadensis (G7) genome presented in this study provides a unique opportunity to address the genetic diversity among the genus Echinococcus and its particular developmental features. At present, there is no unequivocal taxonomic classification of Echinococcus species; however, the genome-wide SNPs analysis performed here revealed the phylogenetic distance among these three Echinococcus species. Additional cestode genomes need to be sequenced to be able to resolve their phylogeny.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3574-0) contains supplementary material, which is available to authorized users.

The purpose of the present work was a comparative study of diagnostic methods for Canine Visceral Leishmaniasis (CVL) using serological methods, enzyme-linked immunosorbent assay (ELISA) and indirect fluorescent antibody test (IFAT), histochemical (HE) and immunohistochemical (IMHC) tests using spleen, lymph node and liver canine tissues. In addition, Polymerase Chain Reaction (PCR) was done in blood and in tissues in order to compare and confirm no conclusive and negative diagnosis by the methods above. For this study, 34 dogs were divided according to clinical signs in asymptomatic, oligosymptomatic and polisymptomatic Leishmania-infected dogs euthanized by Zoonotic Disease Control Center (CCZ) from Ilha Solteira, SP, Brazil. The positivism indexes of ELISA, IMHC, IFAT and HE were 65.0, 62.0, 56.0 and 56.0%, respectively with the highest numbers of positive dogs in polisymptomatic (92.0%) followed by oligosymptomatic (57.0%) and asymptomatic dogs (12.5%). Furthermore, PCR confirmed the positive results and detected DNA in tissues from 100% of negative dogs and 89.0% suspects raising the animal positivism index up to 97.0%. In conclusion, PCR was the most sensitive and a valuable method for a definitive CVL diagnosis.