Proceedings of the schistosome genome project.

"The host-parasite relationship" is a vast and diverse research field which, despite huge human and financial input over many years, remains largely shrouded in mystery. Clearly, the adaptation of parasites to their different host species, and to the different environmental stresses that they represent, depends on interactions with, and responses to, various molecules of host and/or parasite origin. The schistosome genome project is a primary strategy to reach the goal; this systematic research project has successfully developed novel technologies for qualitative and quantitative characterization of schistosome genes and genome organization by extensive international collaboration between top quality laboratories.

Observations on compatibility between Bulinus truncatus and Schistosoma haematobium in the Senegal River Basin.

In experiments to determine the compatibility between isolates of Schistosoma haematobium and Bulinus truncatus from Mali and Senegal, the parasite isolates were shown to differ in their intermediate host specificity. Bulinus truncatus from the Lower and Middle Valleys (Senegal) and the Upper Valley (Mali) of the Senegal River Basin (SRB) were all susceptible to S. haematobium isolated from the urines of children living in Tenegue, Office du Niger, Mali.

Molecular characterization of Bulinus globosus and B. nasutus on Zanzibar, and an investigation of their roles in the epidemiology of Schistosoma haematobium.

The ribosomal internal transcribed spacer (ITS) regions of both Bulinus globosus and B. nasutus from Zanzibar were amplified and restricted with 6 enzymes. Restriction products were separated by polyacrylamide gel electrophoresis and visualized by ethidium bromide staining.

Some molecular insights into schistosome evolution.

Robust phylogenies based on molecular data for species within the genus Schistosoma have been generated in recent years. The considerable progress made in understanding the relationships between many of the 19 recognised species of Schistosoma is reviewed with particular attention being given to the detection and analysis of parasite variation as shown by studies on ribosomal RNA genes, mitochondrial DNA and RAPDs. For the most part, molecular phylogenies agree with observations based on morphological or life-history characteristics.

Royal Society of Tropical Medicine and Hygiene meeting at Manson House, London, 18 May 1995. The epidemiology of human schistosomiasis in the Senegal river basin.

Extensive water development has taken place in the north of Senegal over the last decade, resulting in a large increase in the amount of fresh water for irrigation. The objectives of the present study were to determine the prevalence and intensity of Schistosoma mansoni and S. haematobium in the Senegal river basin (SRB), and to ascertain the distribution of the snail species acting as intermediate hosts for both species of schistosomes.

Morphometric variability of Schistosoma intercalatum eggs: a diagnostic dilemma.

Variability of Schistosoma intercalatum eggs in shape and size, and their similarity to those of S. haematobium presented a problem of species identification when egg morphology was the diagnostic criterion used in a study of human schistosomiasis conducted on São Tomé and Principe. More than 2500 egg measurements were obtained by light micoscopy to gather data relating to size variability of S.

Variation within the internal transcribed spacer (ITS) of ribosomal DNA genes of intermediate snail hosts within the genus Bulinus (Gastropoda: Planorbidae).

Species within the genus Bulinus are responsible for transmission of schistosomes within the Schistosoma haematobium group. In order to provide a molecular insight into the species relationships within the genus, genetic variation between species representing the four species groups was assayed by Polymerase Chain Reaction (PCR) amplification of the ribosomal Internal Transcribed Spacer (ITS) region followed by Restriction Fragment Length Polymorphism (RFLP) analysis of this product with six restriction enzymes. This PCR-RFLP methodology detected considerable variation within the ITS region indicating that restriction profiles will be useful as genetic markers for identification purposes.

Transvaginal small-bowel evisceration: a case report.

Transvaginal small-bowel evisceration is rare. Only 47 case reports appear in the literature in English. Review of this literature shows that vaginal evisceration occurs mainly in women who are older, multiparous, and have undergone vaginal surgery.

Schistosoma mattheei infections in cattle: changes associated with season and age.

The Schistosoma mattheei egg output was monitored in 31 cattle over a 18-month period on a dairy farm near Lusaka (Zambia). The animals were kept on pasture with free access to two streams which were suitable for the intermediate host, Bulinus globosus. Individual faecal egg excretion reached an average peak of 130 eggs per gram, around 9 months after birth and decreased markedly before the age of 18 months.

Cattle schistosomiasis in Zambia.

A total of 358 cattle was examined for schistosome infection in Zambian slaughterhouses. A total of 542 worms collected from 104 infected individuals was examined for glucose-6-phosphate dehydrogenase and phosphoglucomutase using isoelectric focusing. The overall prevalence of infection was 51%.

Schistosomiasis in Dogon country, Mali: identification and prevalence of the species responsible for infection in the local community.

The prevalence of schistosomiasis amongst the Dogon people in 4 villages and one school of the Bankass district of Mali was determined during 2 surveys in 1992; 1398 urine and 1199 stool samples were examined. The most common schistosome was Schistosoma haematobium, with an overall prevalence of 51.3%; S.

Schistosomiasis in the Republic of São Tomé and Principe: characterization of Schistosoma intercalatum.

This paper reports the morphological and biochemical characterization of the species of Schistosoma infecting humans in the Republic of São Tomé and Principe. The eggs are typical in shape and size of S. intercalatum, measuring on average between 174.

Schistosomiasis in the Republic of São Tomé and Principe: human studies.

The only schistosome species found in stool specimens in the local population of the republic of São Tomé is Schistosoma intercalatum. An initial survey of schoolchildren showed an overall prevalence of 10.9%, with some schools reaching 29%.

The status and composition of the genus Steringophorus Odhner, 1905 (Digenea: Fellodistomidae), based on partial small subunit rRNA sequences.

Analysis of partial small subunit (18S) rRNA sequences shows the paraphyly of the genus Steringophorus as currently recognised. In consequence it is necessary to change the conception of the genus by the transfer of the species Steringophorus agnotus and S. sebastodis back to their original genus, Fellodistomum.

A phylogenetic analysis of Schistosoma haematobium group species based on randomly amplified polymorphic DNA.

Randomly amplified polymorphic DNA (RAPD) profiles were produced using four oligonucleotide primers with genomic DNA from 15 isolates of schistosome. Both inter- and intraspecific variation were noted. Intraspecific variation was greater for two species of the S.

Effects of Schistosoma haematobium infection on reproductive success and male outcrossing ability in the simultaneous hermaphrodite, Bulinus truncatus (Gastropoda: Planorbidae).

The schistosome intermediate snail host, Bulinus truncatus (Mollusca: Planorbidae), has two reproductive (phally) morphs. Both aphallics and euphallics can self-fertilize, but aphallics cannot donate sperm because they do not develop a functional penis and prostate. This study investigated the interactions between phally and fitness consequences of Schistosoma haematobium infection in B.

Cross-protection between species of the Schistosoma haematobium group induced by vaccination with irradiated parasites.

Mice vaccinated with irradiated cercariae of Schistosoma haematobium, S. bovis and S. margrebowiei showed good levels of resistance (38-62%) against an homologous challenge, and varying degrees of resistance (19-46%), against challenges with closely related species.

Studies on transmission and schistosome interactions in Senegal, Mali and Zambia.

The transmission and interaction of schistosomes in the Senegal River Basin in Mali and Zambia are reviewed and some preliminary field data are presented. In the Senegal River Basin four species of schistosomes are prevalent: Schistosoma mansoni, S. haematobium, S.

Opening the can of worms: molecular analysis of schistosome populations.

The Schistosomatidae are dioecious digenean parasites of the blood vascular system of vertebrates. Of the 13 genera within the family, only Sehistosoma is associated with humans and, of the mammalian blood flukes, this genus has achieved the greatest geographical distribution and diversification in terms of recognized species and definitive hosts parasitized. In this review, Dave Johnston, Emmanuel Dias Neto, Andy Simpson and David Rollinson consider some recent molecular research that either sheds light on the micro-evolutionary changes occurring within schistosome populations or provides insights into broader, macro-evolutionary questions.

Small subunit (18S) ribosomal RNA gene divergence in the genus Schistosoma.

An entire 18S rRNA gene sequence from Schistosoma spindale (1990 bases) and partial 18S rRNA gene sequences from S. haematobium (1950 bases) and S. japonicum (1648 bases) have been determined.

The random amplification of polymorphic DNA allows the identification of strains and species of schistosome.

The use of arbitrarily selected primers (10-24 nucleotides) and very low stringency annealing conditions (30 degrees C followed by 40 degrees C) for the polymerase chain reaction amplification of 1.0 ng of schistosome DNA resulted in relatively complex patterns of products. Amongst the primers tested some, for example 5'-TCGTAGCCAA, produced patterns that included bands that were polymorphic between strains of Schistosoma mansoni.

[Differentiation of schistosome species and strains by DNA hybridization].

Genomic DNA from Schistosoma mansoni and S. japonicum adult worms was hybridized to a 32p-labelled pSM 889 probe after cleavage by restriction endonuclease BglII, BamHI, XbaI and EcoRI, or to a 32p-labelled pSM 389 probe after cleavage by EcoRI. The resulting hybridization banding patterns were significantly different between the two species.