Intraspecific variation inSchistosoma haematobiumfrom Algeria

1997 ◽  
Vol 71 (1) ◽  
pp. 29-34 ◽  
Author(s):  
N. Kechemir ◽  
A. Théron
Keyword(s):  
Growth Rate ◽  
Comparative Analysis ◽  
Intermediate Host ◽  
Schistosoma Haematobium ◽  
Snail Host ◽  
Intraspecific Polymorphism ◽  
Bulinus Truncatus ◽  
Bioclimatic Zone ◽  
Two Populations ◽  
Cercarial Emergence

AbstractA comparative analysis has been carried out between two populations ofSchistosoma haematobiumusing the same intermediate snail host,Bulinus truncatus, but originating from two distinct ecological areas of Algeria: Khemis-El-Khechna in a sub-humid mediterranean zone and Djanet in a saharan bioclimatic zone. Four parameters have been studied: the growth rate of adult worms, size and shape of the eggs, chronobiology of cercarial emergence and the compatibility with the intermediate host. Results showing divergences for all the characters studied are discussed for the origin of this intraspecific polymorphism ofS. haematobiumin Algeria.

Dynamics of the intramolluscan larval development of Schistosoma haematobium: replication of daughter sporocysts and cercarial production

1989 ◽  
Vol 63 (1) ◽  
pp. 1-5 ◽  
Author(s):  
N. Kechemir ◽  
A. Théron
Keyword(s):  
Larval Development ◽  
Schistosoma Haematobium ◽  
Snail Host ◽  
Bulinus Truncatus ◽  
Cercarial Production

ABSTRACTDuring the intramolluscan larval development of Schistosoma haematobium (Algerian strain) in Bulinus truncatus, two replication processes of daughter sporocysts occur. Replication by direct sporocystogenesis appears more important than sporocystogenesis post cercariogenesis. These mechanisms assure a periodic renewal of the sporocyst stock in the snail host and seem to be synchronized with the development of cercarial generations. The succession of several generations of cercariae is responsible for the alternation of high and low periods of productivity.The scheme proposed for the intramolluscan development of S. haematobium is compared with those described for S. mansoni and S. bovis and interpreted in terms of demographic strategies adapted to a better exploitation of the snail host.

scholarly journals New location for Bulinus truncatus (Audouin, 1827) (Gastropoda: Planorbidae) intermediate host of Schistosoma haematobium and its distribution in the Iberian Peninsula

Graellsia ◽  
2015 ◽  
Vol 71 (2) ◽  
pp. e030 ◽  
Author(s):  
Elías D. Dana ◽  
Juan García-de-Lomas ◽  
José L. Juan Bañón ◽  
Encarnación Esteban ◽  
María A. A. Grácio ◽  
...  
Keyword(s):  
Intermediate Host ◽  
Iberian Peninsula ◽  
Schistosoma Haematobium ◽  
Bulinus Truncatus ◽  
New Location

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

Parasitology ◽  
1994 ◽  
Vol 108 (1) ◽  
pp. 27-34 ◽  
Author(s):  
S. J. Schrag ◽  
D. Rollinson
Keyword(s):  
Schistosoma Haematobium ◽  
Egg Production ◽  
Snail Host ◽  
Egg Mass ◽  
Simultaneous Hermaphrodite ◽  
Bulinus Truncatus ◽  
Egg Masses ◽  
Susceptibility To Infection ◽  
Fitness Consequences ◽  
Fecundity Compensation

SUMMARYThe 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. truncatus. Snails which developed patent infections produced 26% fewer eggs than controls and 35% fewer eggs than exposed snails which did not develop infections. This reduction was due to a lower lifetime production of egg masses and a smaller mean number of eggs/mass in infected snails relative to control or exposed snails. However, there was no evidence of increased mortality in infected snails. Contrary to reports of fecundity compensation in other intermediate host snails, egg production post-exposure during the pre-patent period did not increase relative to that of controls in either infected or exposed snails. Phally did not influence susceptibility to infection or length of the prepatent period. Furthermore, lifetime egg, egg mass and hatchling production, as well as mean eggs/mass and number of hatchlings reaching maturity, did not differ significantly between aphallics and euphallics within control or exposed experimental groups. However, within the infected group euphallics produced 38% fewer eggs, smaller egg masses, and fewer hatchlings reaching maturity than aphallics, supporting the prediction of a cost to the growth and maintenance of a full male tract. This cost was detectable only when snails were under the stress of infection. The proportion of euphallic offspring produced did not differ across experimental groups. We discuss these results in light of alternative host strategies to minimize fitness costs of infection.

Cercarial shedding patterns of Schistosoma bovis and S. haematobium from single and mixed infections of Bulinus truncatus

1991 ◽  
Vol 65 (1) ◽  
pp. 8-14 ◽  
Author(s):  
A. Mouahid ◽  
H. Moné ◽  
A. Chaib ◽  
A. Théron
Keyword(s):  
Snail Host ◽  
New Method ◽  
Mixed Infections ◽  
Intermediate Hosts ◽  
Bulinus Truncatus ◽  
Emergence Pattern ◽  
Schistosoma Bovis ◽  
Cercarial Emergence

ABSTRACTThe cercarial shedding of Schistosoma bovis and S. haematobium were studied in single and mixed infections in the snail host Bulinus truncatus. The two species displayed a distinctive diurnal cercarial emergence with an earlier shedding pattern for S. bovis than S. haematobium (the average emergence peaks were respectively at 0800 h and 1200 h). In mixed infections, each species kept its own cercarial shedding rhythm with no marked alterations. The cercarial emergence pattern is proposed as a new method to identify natural mixed infections in the snail intermediate hosts. The interactions between the two parasites are discussed.

scholarly journals Pilot Malacology Surveys for the Intermediate Hosts of Schistosomiasis in Rural and Semi-Urban Areas of the Moyen-Ogooué Province, Gabon

2021 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Jean Claude Dejon Agobé ◽  
Henry Curtis Kariuki ◽  
Jeannot Fréjus Zinsou ◽  
Yabo Josiane Honkpehedji ◽  
Martin Peter Grobusch ◽  
...  
Keyword(s):  
Species Diversity ◽  
Light Microscopy ◽  
Low Power ◽  
Intermediate Host ◽  
Urban Areas ◽  
Schistosoma Haematobium ◽  
Transmission Dynamics ◽  
Intermediate Hosts ◽  
Bulinus Truncatus ◽  
Predominant Species

The objective of this pilot malacological survey was to identify the snail intermediate hosts for Schistosoma haematobium in endemic rural and semi-urban areas of Gabon. Snails were collected, morphologically identified, and tested for infection by cercarial shedding. Released cercariae were morphologically identified using low-power light microscopy. A total of six species of snails were collected throughout the study area, with Bulinus truncatus, B. forskalii, and Potadoma spp. being the most predominant species collected. Only the Bulinus species were tested for infection by cercarial shedding, of which only B. truncatus shed cercariae. Some B. truncatus shed mammalian schistosome cercariae, while others shed Gymnocephalus cercariae. Our results indicate that B. truncatus appears to be a potential intermediate host of schistosomiasis in Gabon, where cases of S. haematobium, S. guineensis, and S. intercalatum infection are reported. However, it will be important to further understand the species diversity and transmission dynamics of schistosomes.

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