scholarly journals Population Dynamics of Intermediate-Host Snails in the White Nile River, Sudan: A Year-Round Observational Descriptive Study

2021 ◽  
Vol 59 (2) ◽  
pp. 121-129
Author(s):  
Hassan A. H. A. Ismail ◽  
Abed el Aziz A. el R. M. Ahmed ◽  
Young-Ha Lee ◽  
Mousab Siddig Elhag ◽  
Youngjin Kim ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Vegetation Coverage ◽  
Nile River ◽  
Snail Population ◽  
Infection Rates ◽  
Intermediate Hosts ◽  
Biomphalaria Pfeifferi ◽  
Bulinus Truncatus ◽  
Ecological Characteristics ◽  
White Nile

We aimed to explore the population dynamics of snail in 3 sites of the White Nile in Sudan. More specifically, we aimed to investigate the annual patterns of snail populations that act as intermediate hosts of schistosomes and monthly snail infection rates and ecological characteristics presumably related to snail populations. We collected snails for 1 year monthly at 3 different shore sites in the vicinity of El Shajara along the White Nile river in Khartoum State, Sudan. In addition, we measured air and water temperatures, water turbidities, vegetation coverages, and water depths and current speeds. Most of the collected snails were <i>Biomphalaria pfeifferi</i> and <i>Bulinus truncatus</i>. The population densities of snails and their infection rates varied across survey sites. The collected snails liberated <i>S. mansoni</i> and <i>S. haematobium</i> cercariae as well as Amphistome and Echinostome cercariae. Infected snails were found during March-June. The ecological characteristics found to be associated with the absence of snails population were: high turbidity, deep water, low vegetation coverage (near absence of vegetation), high water temperature, and high current speed. To our knowledge, this is the first longitudinal study of the snail population and ecological characteristics in the main basin of the White Nile river.

scholarly journals MALDI-TOF mass spectrometry for the identification of freshwater snails from Senegal, including intermediate hosts of schistosomes

2021 ◽  
Vol 15 (9) ◽  
pp. e0009725
Author(s):  
Fatima Zohra Hamlili ◽  
Fatou Thiam ◽  
Maureen Laroche ◽  
Adama Zan Diarra ◽  
Souleymane Doucouré ◽  
...  
Keyword(s):  
Neglected Diseases ◽  
Freshwater Snails ◽  
Snail Species ◽  
Correct Identification ◽  
Intermediate Hosts ◽  
Biomphalaria Pfeifferi ◽  
Bulinus Truncatus ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

Freshwater snails of the genera Biomphalaria, Bulinus, and Oncomelania are intermediate hosts of schistosomes that cause human schistosomiasis, one of the most significant infectious neglected diseases in the world. Identification of freshwater snails is usually based on morphology and, potentially, DNA-based methods, but these have many drawbacks that hamper their use. MALDI-TOF MS has revolutionised clinical microbiology and has emerged in the medical entomology field. This study aims to evaluate MALDI-TOF MS profiling for the identification of both frozen and ethanol-stored snail species using protein extracts from different body parts. A total of 530 field specimens belonging to nine species (Biomphalaria pfeifferi, Bulinus forskalii, Bulinus senegalensis, Bulinus truncatus, Bulinus globosus, Bellamya unicolor, Cleopatra bulimoides, Lymnaea natalensis, Melanoides tuberculata) and 89 laboratory-reared specimens, including three species (Bi. pfeifferi, Bu. forskalii, Bu. truncatus) were used for this study. For frozen snails, the feet of 127 field and 74 laboratory-reared specimens were used to validate the optimised MALDI-TOF MS protocol. The spectral analysis yielded intra-species reproducibility and inter-species specificity which resulted in the correct identification of all the specimens in blind queries, with log-score values greater than 1.7. In a second step, we demonstrated that MALDI-TOF MS could also be used to identify ethanol-stored snails using proteins extracted from the foot using a specific database including a large number of ethanol preserved specimens. This study shows for the first time that MALDI-TOF MS is a reliable tool for the rapid identification of frozen and ethanol-stored freshwater snails without any malacological expertise.

Studies of the relationships between Schistosoma and their intermediate hosts. IV. The genus Bulinus and Schistosoma bovis from Morocco

1979 ◽  
Vol 53 (4) ◽  
pp. 349-355 ◽  
Author(s):  
Flemming Frandsen
Keyword(s):  
Infection Rates ◽  
Intermediate Hosts ◽  
Bulinus Truncatus ◽  
Schistosoma Bovis ◽  
High Production ◽  
Very High ◽  
Infection Experiments

ABSTRACTSchistosoma bovis from Morocco was used in infection experiments with several populations of Bulinus truncatus. The snails from Libya, Malawi, Morocco and Senegal were very compatible with the schistosome since the infection rates were approximately 90%, the mortality was low, and a very high production of cercariae, approximately 1.2 million per 100 exposed snails, was observed. Only a very few B. truncatus (2n = 36) from Rhodesia became infected. B. permembranaceus and B. forskalii were refractory.

Studies of the relationship betweenSchistosomaand their intermediate hosts. III. The genusBiomphalariaandSchistosoma mansonifrom Egypt, Kenya, Sudan, Uganda, West Indies (St. Lucia) and Zaire (two different strains: Katanga and Kinshasa)

1979 ◽  
Vol 53 (4) ◽  
pp. 321-348 ◽  
Author(s):  
Flemming Frandsen
Keyword(s):  
West Indies ◽  
Prepatent Period ◽  
Snail Population ◽  
Intermediate Hosts ◽  
Biomphalaria Pfeifferi ◽  
The West ◽  
Cercarial Production ◽  
Long Duration ◽  
Duration Of Infection ◽  
Different Strains

ABSTRACTThe compatibility between strains ofSchistosoma mansonifrom Egypt, Kenya, Sudan, Uganda, the West Indies, and Zaire (two strains which came from Katanga and from Kinshasa), and various species and strains ofBiomphalaria, i.e.,Biomphalaria pfeifferi, B. alexandrina, B. glabrataandB. camerunensiswas investigated. Data as mortality, rate of infection of the surviving snails, duration of infection, cercarial production per day per positive snail, etc., were observed. The main emphasis was placed on determining the total cercarial production per 100 exposed snails for each snail population.It was possible to infect all the tested populations ofB. pfeifferiwith the various strains ofS. mansoni, but the observation as e.g. TCP/100 exposed snails varied greatly according to the population of snail and the strain ofS. mansoni. The results for the remaining species ofBiomphalariavaried greatly, depending on the combination, e.g.B. alexandrinawas only susceptible to the localS. mansonifrom Egypt.The highest TCP/100 exposed snails was more than 1 million for the strains ofS. mansonifrom Egypt, Kenya and the West Indies inB. alexandrina, B. pfeifferiandB. glabrata, respectively. The next group, with a TCP/100 exposed snails on 7 – 800 000 consists ofS. mansonifrom Sudan, Uganda and Zaire (Katanga) all inB. pfeifferi. The last tested strain ofS. mansoni, Zaire (Kinshasa) yielded a cercarial production on 500 000 per 100 exposed snails inB. pfeifferiandB. camerunensis.The shortest prepatent period, 19 days, was observed forS. mansonifrom Kinshasa, Zaire, inB. camerunensis, and the longest prepatent period, 25 days, was found for strains from Egypt and from the West Indies inB. alexandrinaandB. glabrata, respectively.In general, a very long duration of infection, lasting up to 200 days, was observed.

Population dynamics of Lymnaea columella and its natural infection by Fasciola hepatica in the State of Minas Gerais, Brazil

2003 ◽  
Vol 77 (1) ◽  
pp. 7-10 ◽  
Author(s):  
L.H.L. Coelho ◽  
W.S. Lima
Keyword(s):  
Population Dynamics ◽  
Aquatic Plants ◽  
Fasciola Hepatica ◽  
Natural Infection ◽  
Minas Gerais ◽  
The State ◽  
Snail Population ◽  
Infection Rates ◽  
Drastic Reduction ◽  
Brazilian State

AbstractStudies on the population dynamics and natural infection of Lymnaea columella by Fasciola hepatica were carried out from September 1999 to December 2000 in a low-lying area near Itajubá in the Brazilian State of Minas Gerais. A total of 626 snails were collected monthly at nine different sites, counted, and dissected to search for larvae of F. hepatica. The highest populations of L. columella were reached in October of 1999 and August of 2000, and the highest natural infection rates of snails by F. hepatica were reached in September 1999 (5.2%) and July 2000 (3.9%). The removal by farmers of aquatic plants from the drainage furrows caused a drastic reduction in this snail population.

The Application of Catalytic Models to Schistosomiasis in Snails

1971 ◽  
Vol 45 (2-3) ◽  
pp. 189-200 ◽  
Author(s):  
R. F. Sturrock ◽  
G. Webbe
Keyword(s):  
West Indies ◽  
Quantitative Data ◽  
Schistosoma Haematobium ◽  
Growth Curves ◽  
Biomphalaria Glabrata ◽  
The Other ◽  
Snail Population ◽  
Intermediate Hosts ◽  
Biomphalaria Pfeifferi ◽  
Independent Verification

1. With the aid of field growth curves, age-prevalence curves can be derived from field collections of snails, using cercarial shedding as proof of infection by schistosomes.2. Such curves were obtained from eight collections of field snails: one sample each of Bulinus (Physopsis) nasutus productus and Biomphalaria pfeifferi, intermediate hosts respectively of Schistosoma haematobium and S. mansoni in Tanzania, and six samples of Biomphalaria glabrata, intermediate host of S. mansoni on St. Lucia, West Indies.3. Catalytic curves were fitted to the data and in each case the two-stage curve gave the most satisfactory fit.4. This curve is the resultant of two opposing forces: one force being the rate of infection and the other the rate of loss of infection in a snail population.5. The rate of infection may be defined as the number of successful snail-miracidium contacts per 1,000 snails per week, while the rate of loss of infection is taken to represent the number of deaths per 1,000 infected snails per week.6. The underlying assumptions of this form of analysis are discussed and, in view of the independent verification of some of the calculated rates, the values are considered realistic.7. Besides providing quantitative data for inclusion in mathematical models of schistosome transmission, the technique offers an additional means of assessing the efficacy of certain methods of controlling transmission.

Effects of land use on intermediate snail host fauna, abundance, distribution and cercariae infection rate in Omo-Gibe river basin, Ethiopia

2020 ◽  
Author(s):  
Ketema Deribew ◽  
Etana Jaleta ◽  
Belayhun Mandefro ◽  
Zeleke Mekonnen ◽  
Delenasaw Yewhalaw ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Fresh Water ◽  
River Basin ◽  
Anthropogenic Activities ◽  
Freshwater Snail ◽  
Snail Host ◽  
Snail Species ◽  
Intermediate Hosts ◽  
Biomphalaria Pfeifferi

Abstract Background: Land use and land cover change significantly affects biodiversity, abundance and distribution of intermediate snail host fauna. In Omo-Gibe river basin the extent of land-use change is high due to anthropogenic activities leading to habitat change of freshwater snail intermediate hosts. Most intermediate snail hosts of human Schistosome parasites belong to two genera, Biomphalaria and Bulinus. In Addition, Lymnea spp. is another important host of Fasciola which causes fasciolasis in domestic animals and human. This study aims to assess the effects of land-use on the distribution and abundance of freshwater snail intermediate hosts and cercariae infection rates of fresh water intermediate snail hosts in Omo-Gibe River basin, Ethiopia.Methods: This study was conducted in Omo-Gibe river basin in 130 sampling sites which include rivers, lakes, dams, stream, wetlands and irrigation ditches. At each site data on land use, anthropogenic activities, freshwater snail abundance and species diversity, and water samples were collected. Snails were collected from each sampling sites using a scoop (20cm x 30cm) with a mesh size of 300µm. Snails were sorted by genus on Enamel pan using forceps and preserved in labeled vials containing 75% ethanol. Live snails collected from the same habitat were sorted carefully and put in clean plastic buckets half filled with water. Afterwards, snails were provided with fresh lettuce leaves and maintained in the laboratory. Snails were then identified morphologically to family, genus and to species level. Each snail was examined for cercaria shedding by placing in a petri dish containing water and exposed to the sun for 2 hours. Cercariae were morphologically identified by microscopy. ArcGIS software of version 10.3.1 was used to map snail distribution and data were analysed using SPSS version-20.Results: The results obtained in this study shows clearly that land use change affect the distribution and abundance of fresh water snails in Omo-Gibe river basin. Fresh water snails were more abundant in farmland and settlement areas. Of the total 2,559 freshwater snails collected from 130 surveyed sites in Omo-Gibe river basin, 1749 (68.34%) belongs to medically important snail species. Biomphalaria spp.914 (35.7%),, Lymnea spp.439 (17.1%),, Physa spp. 343(13.4%) and Bulinus spp 53 (2%)). Sphaeriidae group accounted for 810 (31.6%) of the collected specimens. Biomphalaria pfeifferi was the predominant species of the total snail sampled from lakes, wetlands, rivers and irrigation ditches. Biomphalaria pfeifferi was the most infected snail species by different cercariae. Bulinus globosus and L.natalensis were infected by more than one and same type of cercariae. However, none of B. sudanica and P. acuta specimens was infected by trematode.Conclusions: The results of this study revealed that land use change altered the abundance, distribution and diversity of medically important fresh water snails in the study area. In general medically important freshwater snails which include: Biomphalaria spp, Bulinus spp and Lymnaea spp were collected from lakes, rivers, wetlands, irrigation ditches.. The medically important snail species found infected by cercaria are L. natalensis, B. pfeifferi and B. globosus. Biomphalaria pfefferi was the predominant species and highly infected by cercariae. Higher infection rate was observed in snails collected in Farmland (16.59%) and Grassland (36.6%).

Observations on the field transmission dynamics of Schistosoma mansoni and S. mattheei in southern Natal, South Africa

Parasitology ◽  
1985 ◽  
Vol 91 (2) ◽  
pp. 281-290 ◽  
Author(s):  
Fiona A. Donnelly ◽  
C. C. Appleton
Keyword(s):  
South Africa ◽  
Schistosoma Mansoni ◽  
Transmission Dynamics ◽  
Small Rivers ◽  
Seasonal Patterns ◽  
Infection Rates ◽  
Intermediate Hosts ◽  
Low Oxygen ◽  
Transmission Season ◽  
Extensive Growth

Cercarial transmission of Schistosoma mansoni and S. mattheei was monitored in two small rivers near Durban, South Africa. The seasonal patterns recorded corresponded to those already documented for these parasites. Tn the case of S. mansoni, however, this was interrupted at the height of the transmission season. The reason for this was believed to be very low oxygen concentrations in the snail habitat due to unusually extensive growth of the plant Ludwigia stolonifera over the water. The failure of the spring rains, which would normally have flushed the system is seen as contributing to this phenomenon. Infection rates in the snail intermediate hosts were low ( > 10%). A preponderance of male worms of both schistosome species was noted.

scholarly journals The Role of Spatial Analysis in Detecting the Consequence of the Factory Sites : Case Study of Assalaya Factory-Sudan

2018 ◽  
Vol 31 ◽  
pp. 12004
Author(s):  
Amar Sharaf Eldin Khair ◽  
Purwanto ◽  
Henna RyaSunoko ◽  
Omer Adam Abdullah
Keyword(s):  
Spatial Analysis ◽  
Analysis Data ◽  
Geographical Information ◽  
Nile River ◽  
Digital Elevation ◽  
White Nile ◽  
Elevation Model ◽  
Factory Site

Spatial analysis is considered as one of the most important science for identifying the most appropriate site for industrialization and also to alleviate the environmental ramifications caused by factories. This study aims at analyzing the Assalaya sugarcane factory site by the use of spatial analysis to determine whether it has ramification on the White Nile River. The methodology employed for this study is Global Position System (GPS) to identify the coordinate system of the study phenomena and other relative factors. The study will also make use Geographical Information System (GIS) to implement the spatial analysis. Satellite data (LandsatDem-Digital Elevation Model) will be considered for the study area and factory in identifying the consequences by analyzing the location of the factory through several features such as hydrological, contour line and geological analysis. Data analysis reveals that the factory site is inappropriate and according to observation on the ground it has consequences on the White Nile River. Based on the finding, the study recommended some suggestions to avoid the aftermath of any factory in general. We have to take advantage of this new technological method to aid in selecting most apt locations for industries that will create an ambient environment.

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