Genetic diversity whithin schistosoma haematobium populations in Cameroon

29 Sep
Published by luogbou

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ABSTRACT

One of the characteristics which makes the study of genetic variability of the schistosomes important is the existence of separate sexes contrary to other species from the same family which are hermaphrodites; this particular character makes essential the crossings between male and female for their reproduction, thus creating possibilities of choice or change of partner, distribution of genes and even of extinction of a species. The study of the implications of this characteristic passes by the characterization of the genetic diversity of the schistosomes at all stages of its life cycle. By admitting that the character separate sexes and the environment of the schistosomes would have an influence on their genetic structures, it seemed to us necessary to undertake the characterization of the populations of S. haematobium in Cameroon; indeed, the data on genetic diversity of Schistosoma haematobium in various hearths of transmission in Cameroon based on the molecular markers are rare except the case of the hearth of Loum whose isolate was studied by methods based on the DNA. In order to evaluate the level of genetic diversity of Schistosoma haematobium and to establish a chart representing the molecular epidemiology of urinary schistosomiasis in Cameroon, the urines of the pupils (or the patients) will be collected in 6 localities (Kekem, Kumba, Loum, Kinding Ndjabi, Bessoum and Djalingo) distributed on five provinces of Cameroon (Table1); as well as the intermediate snails hosts of Schistosoma haematobium (Bulinus truncatus, Bulinus globosus, Bulinus camerunensis, and Bulinus senegalensis). The snails will be elevated at the laboratory to obtain young snails that will be infested by miracidiums obtained following the blossoming of filtered eggs of the urines collected in each locality (cities or villages). S. haematobium cercariae sheded by various snails will be used to infest the rodents. Three innovative techniques; SSCP analysis (Single Stranded Confomational Polymorphism) and DNA Barcoding would allow us to analyze subunit one of the mitochondrial gene cytochrome oxydase c (COx1) which will be used as molecular marker to characterize the populations of S. haematobium in Cameroon; whereas the PCR-RFLP (Restriction Fragment Length Polymorphism) will allow us to re-assess the hearths of mixed transmission of schistosome.By the end of this work, the results obtained could enable us to improve comprehension of the hosts-parasites interactions (compatibility, pathogenicity, resistance, virulence, etc.), to better consider the evolution and the co evolution of the species of schistosomes, to optimize the quality of the control of this disease and especially to improve our knowledge on epidemiology of Schistosoma haematobium in Cameroon.KEY WORDS: Genetic diversity, Schistosoma haematobium, intermediate Hosts, hearths of transmission, molecular Markers, Cox1, SSCP, PCR-RFLP, DNA Barcoding, Cameroon.

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luogbou's picture

hello everyone
I am a PhD Student in Biochemistry at the University of Yaounde I in Cameroon. I am working on genetic diversity of Schistosoma haematobium from Cameroon. At this moment I already cultivated S.hamatobium strains  from more than 10 foci in Cameroon.(see table bellow). I seek the support and / or collaboration of any researcher for molecular analysis of these Samples. I note that the miracidium and cercariae are stored on FTA cards wheras adult worms are preserved in 70% ethanol. Thank you for your understanding.

Localities
N# of Schools
GPS Cordinates
N#of samples for Miracidia
N#of samples for cercarea
N# of samples for Adult Worms
Total N# of Adult Worms

LAGDO
13
Alt:194 m N09.13255° E013.71407°
56
21
25
504 Males 336 Females

NJOMBE
6
Alt 77 m                             N04.59442° E009.66626°
19
5
7
418 Males 277 Females

PENJA
4
Alt 171m                 N04.64106° E009.67806°
7
3
2
70 Males     33 Females

LOUM
2
Alt 242m                                  N04.70772° E009.74710° 
12
6
7
263 Males 215 Females

MBAFAM
1
Alt 734 m                                   N05.10744° E010.02252°
3
1
2
18 Males       113 Females

MAGA
1
 Alt 312 m                     N10.84389°E014.95823°
1
0
0
0

YOYO
1
Alt 13m                          N03.65774° E009.64459°
1
1
1
5 Females