High Genetic Variability of Schistosoma haematobium in Mali and Nigeria

Schistosoma haematobium is one of the most prevalent parasitic flatworms, infecting over 112 million people in Africa. However, little is known about the genetic diversity of natural S. haematobium populations from the human host because of the inaccessible location of adult worms in the host. We used 4 microsatellite loci to genotype individually pooled S. haematobium eggs directly from each patient sampled at 4 endemic locations in Africa. We found that the average allele number of individuals from Mali was significantly higher than that from Nigeria. In addition, no significant difference in allelic composition was detected among the populations within Nigeria; however, the allelic composition was significantly different between Mali and Nigeria populations. This study demonstrated a high level of genetic variability of S. haematobium in the populations from Mali and Nigeria, the 2 major African endemic countries, suggesting that geographical population differentiation may occur in the regions.

High Genetic Variability of Schistosoma haematobium in Mali and Nigeria

Schistosoma haematobium is one of the most prevalent parasitic flatworms, infecting over 112 million people in Africa. However, little is known about the genetic diversity of natural S. haematobium populations from the human host because of the inaccessible location of adult worms in the host. We used 4 microsatellite loci to genotype individually pooled S. haematobium eggs directly from each patient sampled at 4 endemic locations in Africa. We found that the average allele number of individuals from Mali was significantly higher than that from Nigeria. In addition, no significant difference in allelic composition was detected among the populations within Nigeria; however, the allelic composition was significantly different between Mali and Nigeria populations. This study demonstrated a high level of genetic variability of S. haematobium in the populations from Mali and Nigeria, the 2 major African endemic countries, suggesting that geographical population differentiation may occur in the regions.

New Polymorphic Microsatellite Loci Identified Using Genomic Resource for Schistosoma japonicum / 中国寄生虫学与寄生虫病杂志

Objective To identify new microsatellite loci from genome sequence database for the study of poly-morphicsm of Schistosoma japonicum. Methods Schistosoma japonicum isolates were obtained from seven endemic sites in China: Tongling and Guichi counties of Anhui Province, Duchang county of Jiangxi Province, Changde and Yueyang Cities of Hunan Province, Shashi City of Hubei Province, Xichang City of Sichuan Province. In order to study the genetic variance, genomic DNAs of 96 individual adult worms were screened against 17 new Schistosoma japonicum microsatellites and the raw data were analyzed by GenMapper 4.0. Furthermore, the varieties of alleles were inverstigated using GenAlEx 6 and genetic distances within a subpopulation (GenClone) and among populations(UPGMA, MEGA 3.1) were analyzed. Results High levels of polymorphism were found between and within population samples, and significant genetic diversity was observed among the seven subpopulations.Within Jiangxi population, most genetic distances (17 loci) among samples range from 25 to 32, indicating a significant genetic diversity. There are three clusters among the seven populations: Jiangxi, Tonglin, Shashi and Changde population, with the genetics distances ranging from 0.017 8 to 0.036 3; Guichi and Yueyang population belong to another cluster, with the genetic distance of 0.024 7; However, Xichang population is an unique group. Its genetic distances to other populations are notable with a range from 0.019 2 to 0.069 3. Conclusion The 17 new polymorphic microsatellites identified may be used as suitable markers for the study on population genetics of Schistosoma japonicum and the genetic variance of the worms seems to be complicated.