The interaction of Schistosoma haematobium and S. guineensis in Cameroon

2005 ◽  
Vol 79 (3) ◽  
pp. 193-197 ◽  
Author(s):  
B.L. Webster ◽  
L.A. Tchuem Tchuenté ◽  
J. Jourdane ◽  
V.R. Southgate
Keyword(s):  
Internal Transcribed Spacer ◽  
Schistosoma Haematobium ◽  
Introgressive Hybridization ◽  
Biological Data ◽  
Hybrid Zones ◽  
Hybridization Data ◽  
South West ◽  
Single Stranded Conformational Polymorphism ◽  
Second Internal Transcribed Spacer ◽  
Species Being

AbstractInteractions between schistosomes are complex with some different species being able to mate and hybridize. The epidemiology of schistosomiasis in specific areas of South West Cameroon has evolved remarkably over 30 years as a result of hybridization between Schistosoma guineensis and S. haematobium. Morphological and biological data suggest that S. haematobium replaced S. guineensis in areas of Cameroon through introgressive hybridization. Data are reported on the use of single stranded conformational polymorphism (SSCP) analysis of the nuclear ribosomal second internal transcribed spacer (ITS2) of individual schistosomes from hybrid zones of Cameroon. The data show that since 1990 S. haematobium has completely replaced S. guineensis in Loum, with S. haematobium and the recombinants still present in 2000. This study illustrates the complexities of the dynamics between S. haematobium and S. guineensis in South West Cameroon.

Differentiation of the Xiphinema americanum-group nematodes X. brevicollum, X. incognitum, X. diffusum and X. oxycaudatum in Taiwan by morphometrics and nuclear ribosomal DNA sequences

Nematology ◽  
2005 ◽  
Vol 7 (5) ◽  
pp. 713-725 ◽  
Author(s):  
Yung-Hsiung Cheng ◽  
Tung-Tsuan Tsay ◽  
Hui-Fang Ni ◽  
Diann-Yih Chen ◽  
Jyh-Herng Yen
Keyword(s):  
Ribosomal Dna ◽  
Dna Sequences ◽  
Internal Transcribed Spacer ◽  
Nuclear Ribosomal Dna ◽  
Pairwise Comparisons ◽  
Geographical Regions ◽  
Juvenile Stages ◽  
Stylet Length ◽  
Second Internal Transcribed Spacer ◽  
Species Being

AbstractMorphometrics and molecular variability of the X. americanum-group collected in Taiwan were studied. Morphometric data, derived from the females and their developing juveniles, revealed that the 27 populations comprised four taxa: X. brevicollum, X. incognitum, X. diffusum and X. oxycaudatum, the last species being found to have only three juvenile stages. Further identifications were conducted by analysing the nucleotide sequences of the first internal transcribed spacer (ITS-1), 5.8S gene and second internal transcribed spacer (ITS-2) of ribosomal DNA (rDNA). Pairwise comparisons revealed the sequence differences among these taxa ranging from 3.5 to 21.8% for the ITS-1, 2.9 to 28.6% for the ITS-2 and 0 to 3.1% for the 5.8S. Little or no intraspecific variation was detected in the four species for which multiple populations from different geographical regions or hosts were sequenced. Although X. incognitum is morphometrically closer to X. diffusum than it is to X. brevicollum in mean body length, total stylet length, and percentage position of vulva, there is a higher degree of genetic similarity between X. incognitum and X. brevicollum.

scholarly journals Mastomys natalensis (Smith, 1834) as a natural host for Schistosoma haematobium (Bilharz, 1852) Weinland, 1858 x Schistosoma bovis Sonsino, 1876 introgressive hybrids

2021 ◽  
Author(s):  
Boris A.E.S. Savassi ◽  
Gauthier Dobigny ◽  
Jonas R. Etougbétché ◽  
Thalasse T. Avocegan ◽  
François T. Quinsou ◽  
...  
Keyword(s):  
Definitive Host ◽  
Schistosoma Haematobium ◽  
Rattus Rattus ◽  
Introgressive Hybridization ◽  
Mastomys Natalensis ◽  
New Host ◽  
Time Period ◽  
Schistosoma Bovis ◽  
Bulinus Globosus ◽  
Internal Transcribed Spacer Rdna

AbstractCercarial emission of schistosomes is a determinant in the transmission to the definitive host and constitutes a good marker to identify which definitive host is responsible for transmission, mainly in introgressive hybridization situations. Our goal was to test the hypothesis that micro-mammals play a role in Schistosoma haematobium, S. bovis, and/or S. haematobium x S. bovis transmission. Small mammal sampling was conducted in seven semi-lacustrine villages of southern Benin. Among the 62 animals trapped, 50 individuals were investigated for Schistosoma adults and eggs: 37 Rattus rattus, 3 Rattus norvegicus, 9 Mastomys natalensis, and 1 Crocidura olivieri. Schistosoma adults were found in four R. rattus and two M. natalensis, with a local prevalence reaching 80% and 50%, respectively. Two cercarial chronotypes were found from Bulinus globosus experimentally infected with miracidia extracted from naturally infected M. natalensis: a late diurnal and nocturnal chronotype, and an early diurnal, late diurnal, and nocturnal chronotype. The cytochrome C oxidase subunit I mtDNA gene of the collected schistosomes (adults, miracidia, and cercariae) belonged to the S. bovis clade. Eleven internal transcribed spacer rDNA profiles were found; four belonged to S. bovis and seven to S. haematobium x S. bovis. These molecular results together with the observed multi-peak chronotypes add M. natalensis as a new host implicated in S. haematobium x S. bovis transmission. We discuss the origin of the new chronotypes which have become more complex with the appearance of several peaks in a 24-h day. We also discuss how the new populations of offspring may optimize intra-host ecological niche, host spectrum, and transmission time period.

Scanning electron microscope studies of miracidia suggest introgressive hybridization between Schistosoma haematobium and S. haematobium x S. mattheei in the Eastern Transvaal

1988 ◽  
Vol 62 (2) ◽  
pp. 141-147 ◽  
Author(s):  
F. J. Kruger ◽  
V. L. Hamilton-Attwell
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Schistosoma Haematobium ◽  
Introgressive Hybridization ◽  
Human Infection ◽  
Infection Rates ◽  
High Prevalence ◽  
Scanning Electron

ABSTRACTSchistosoma haematobium miracidia were collected from a locality with a high prevalence of human infection with the animal parasite, S. mattheei, which hybridizes with S. haematobium, and from 2 localities with negligible infection rates. The terebratoria of the miracidia from these localities were compared with each other, with laboratory maintained S. haematobium and with four populations of S. mattheei by means of scanning electron microscopy. It was found that the terebratorial membrane of certain of the S. haematobium miracidia from the locality with a high S. mattheei prevalence in humans, resembled the more intricate membrane of S. mattheei. This suggests introgressive hybridization between S. haematobium and S. haematobium x S. mattheei.

scholarly journals Intragenomic variation in the second internal transcribed spacer of the ribosomal DNA of species of the genera Culex and Lutzia (Diptera: Culicidae)

2011 ◽  
Vol 106 (1) ◽  
pp. 01-08 ◽  
Author(s):  
Fabiana Tavares Vesgueiro ◽  
Bruna Demari-Silva ◽  
Rosely dos Santos Malafronte ◽  
Maria Anice Mureb Sallum ◽  
Mauro Toledo Marrelli
Keyword(s):  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Intragenomic Variation ◽  
Second Internal Transcribed Spacer

scholarly journals Sequences of the second internal transcribed spacer of ribosomal DNA for three species of Trichostrongylus (Nematoda: Trichostrongylidae) from sheep in Russia

2007 ◽  
Vol 44 (2) ◽  
pp. 43-46 ◽  
Author(s):  
D. Kuznetsov ◽  
N. Kuznetsova
Keyword(s):  
Dna Sequence ◽  
Intraspecific Variation ◽  
Ribosomal Dna ◽  
Internal Transcribed Spacer ◽  
Sequence Data ◽  
Moscow Region ◽  
Dna Sequence Data ◽  
Interspecific Differences ◽  
Second Internal Transcribed Spacer ◽  
First Time

AbstractFor the first time, DNA sequence data were obtained for three species of Trichostrongylus from Russia. Internal transcribed spacer (ITS-2) of ribosomal DNA was sequenced for T. axei, T. colubriformis and T. probolurus from sheep from the Moscow region. ITS-2 rDNA length was estimated as 238 nucleotides for T. colubriformis and T. probolurus and 237 nucleotides for T. axei. The G+C content of the ITS-2 sequences of T. colubriformis, T. axei and T. probolurus were 31 %, 32 % and 34 % respectively. The level of interspecific differences in ITS-2 of rDNA of T. axei, T. probolurus and T. colubriformis ranged from 3 to 4 %. The ITS-2 sequences from the Russian specimens were compared with those of T. axei, T. probolurus and T. colubriformis from Australia and Germany. Intraspecific variation ranged from 0 % in T. colubriformis to 3.0 % in T. axei.

scholarly journals Optimization of the second internal transcribed spacer (ITS2) for characterizing land plants from soil

PLoS ONE ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. e0231436
Author(s):  
Emma K. Timpano ◽  
Melissa K. R. Scheible ◽  
Kelly A. Meiklejohn
Keyword(s):  
Internal Transcribed Spacer ◽  
Land Plants ◽  
Second Internal Transcribed Spacer
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