Comparison of two diagnostic techniques to determine the prevalence of Schistosoma mansoni infections in Cameroonian school children

Background: The Kato-Katz technique is recommended for diagnosis of Schistosoma mansoni infection by the World Health Organization. However, egg counts are subject to variability. The aim of this study is to determine the prevalence of S. mansoni infection in school children using two different techniques and to recommend the technique that should be routinely used in the diagnosis of this infection. Methodology: Field investigations on faecal samples from 299 Cameroonian school children were carried out in 2016 to compare the effectiveness of the Kato-Katz and Formalin-ether techniques in diagnosis of S. mansoni infections. Results: Schistosome eggs were detected in 37 (12.3%) samples with the Kato-Katz technique and 61 (20.4%) samples with the Formalin-ether technique. The difference between the prevalence observed for the two techniques was significant in males and age group 10 - 12 years (p < 0.5). Conclusion: The Formalin-ether technique was more sensitive than the Kato-Katz method for detecting S. mansoni eggs in faecal matter. Despite its cost, the Formalin-ether technique can be routinely used in the laboratory for epidemiological studies of intestinal schistosomiasis

Egg excretion in the initial phase of experimental murine schistosomiasis mansoni: stability and association with worm burden

Atraves da analise de exames parasitologicos quantitativos seriados e da contagem de esquistossomos apos perfusao em dois grupos de camundongos infectados com diferentes cargas de cercarias de Schistosoma mansoni, verificou-se a existencia da estabilidade da eliminacao de ovos e sua correlacao com a carga parasitaria na fase inicial da esquistossomose mansoni...

Protein-DNA associations in a gender-specific gene of Schistosoma mansoni: characterization by UV cross-linking, DNase I footprinting and band shift assays

Protein extracts obtained from male and female shistosomes were incubated with a gender-specific gene, F-10, transcribed only in adult females and encoding a major egg-shell protein. The protein/DNA interaction was measured using the band shift, DNase-I-footprinting and UV cross-linking techniques. The results showed a clear band shift when a 302 bp restriction fragment containing the 3'end of the gene was incubated with either female or male proteins. This fragment also contained a putative steroid hormone regulatory element (HRE). In contrast, only the male proteins produced a shift with the 495 bp fragment corresponding to the middle region of the gene. DNase I footprinting showed that proteins from males and females interacted with the F-10 gene by binding to multiple adjacent sites along the DNA, thus generatingrelatively long protected fragments of approximately 100 bp. This result suggested that the adjacent binding of several moles of proteins occured at the 5'end of the gene. UV cross-linking between schistosome proteins and a 21 bp synthetic oligonucleotide the F-10 HRE, evidence proteins having MWS of 30,45 and 65 kDNA. These proteins are presumably involved in the regulation of transcription of the F-10 gene

Suscetibilidade de Biomphalaria tenagophila do estado de Säo Paulo à infecçäo por linhagens de Schistosoma mansoni da Baixada Maranhense (Maranhäo, Brasil) / Susceptibility of Biomphalaria tenagophila from the State of Sao Paulo to infecction by Schistosoma mansoni strains from the Baixada Maranhense (Maranhao, Brazil)

Exemplares de Biomphalaria tenagophila, provenientes do Vale do Rio Paraíba do Sul (Säo Paulo, Brasil), foram expostos às linhagens humana (H) e silvestre (S) de Schistosoma mansoni, oriundos da Regiäo da Baixada Maranhense, ao noroeste do Estado do Maranhäo. As linhagens H e S apresentaram comportamento distinto quando colocadas a infectar os moluscos paulistas. As B. tenagophila infectadas com a linhagem S apresentaram índice de mortalidade inferior ao observado nas infectadas com a linhagem H. No molusco paulista a linhagem silvestre maranhense completou seu desenvolvimento, fato que näo ocorreu com a linhagem humana. Estas observaçöes foram comparadas com os resultados anteriormente obtidos, quando estudou-se o comportamento dàs linhagens H e S do Vale do Rio Paraíba do Sul no molusco simpatrico. Foi verificado que às linhagens maranhenses e paulistas quando comparadas apresentavam comportamento similar frente a B. tenogophila do Vale do Rio Paraíba do Sul, SP