Biomphalaria Arabica Research Articles

Development of species-specific primers for identification of Biomphalaria arabica, the intermediate host of Schistosoma mansoni in Saudi Arabia

Schistosoma mansoni is mediated through the intermediate host Biomphalaria arabica which lives in Saudi Arabia. Molecular characterization and identification of this intermediate host are important for epidemiological studies of schistosomiasis. The present work aimed to determine the molecular variations among the populations of B. arabica found in Southern part of Saudi Arabia, and to develop species-specific primers for identification of these snails as a first step in the development of multiplex PCR for simultaneously identifying the snails and diagnosing its infections in a single step. Five populations of Saudi B. arabica snails were collected from freshwater bodies. Three populations were collected from Asser and two populations were collected from AL-Baha. Genomic DNA was extracted from snails and was amplified using five different RAPD–PCR primers. The banding patterns of amplified materials by primers P1 and P5 were identical in all populations. However, the rest primers displayed intra-specific differences among populations with variable degrees. Largest sizes of RAPD–PCR products were cloned into TA cloning vector as a preparatory step for DNA sequence analysis. After sequencing, similarity searches of obtained DNA sequences revealed that there are no similar sequences submitted to genebank data bases and its associated banks. The results obtained will be helpful in the development of simultaneous identification of B. arabica snails and diagnosis of S. mansoni infection within it in a single step by an implementation of multiplex PCR.

Snail abundance in freshwater canals in the eastern province of Saudi Arabia and acute toxicity studies of copper sulphate in Biomphalaria arabica and Lymnaea auricularia

The present study aimed to investigate the distribution of three species of freshwater snails, namely; Biomphalaria Arabica ; Planorbidae, Lymnaea auricularia ; Lymnaeidae and Melanoides tuberculatus ; Thiaridae in two different parallel canals (the concrete irrigation and the earthen drainage canals) in the eastern province of Saudi Arabia and the effect of copper sulphate pentahydrate (CuSO 4 .5H 2 O) on mortality of the first two species after 24 h of exposure. The physico-chemical properties of the water especially, temperature and pH were determined as important factors for snail distribution. The results show that the water temperature and the pH of the two canals were almost the same. The range of water temperature was 25.8 to 28.3°C, while the water pH was 6.6 to 6.8. The two canals were occupied by three species of aquatic snails viz. B. arabica , L. auricularia and M. tuberculatus . The bioassay of CuSO 4 .5H 2 O on only two snail species showed 24 h–LC 50 as 5.7 ppm for B. arabicus and 7.8 ppm for L. auricularia. This result reveals that CuSO 4 .5H 2 O was highly effective in snail eradication. On the basis of the present study, it is recommended that some further studies on the canals including all environmental factors should be investigated for their role in aquatic snail distribution. However, the chronic effect of lower lethal dose of CuSO 4 .5H 2 O on the snails mortality and their effects on developmental stages should be investigated, and some local plant extract should also be tried for their potency on snail mortality. Key words : Biomphalaria, Lymnea, Melanoides , distribution, freshwater snails, copper sulphate, Saudi Arabia.

Biochemical characterization of Biomphalaria arabica, the molluscan intermediate host for Schistosomes in Saudi Arabia

Schistosomiasis is the most important human helminth infection in terms of morbidity and mortality. The present study provides a comparative analysis on Biomphalaria arabica, the intermediate hosts of Schistosoma mansoni from two different areas having different prevalence level of Schistosomiasis in Saudi Arabia. B. arabica snails were collected from Riyadh and Hofuf district, and the levels of various enzymes like aspartate and alanine aminotransferase (AST, ALT), Lactate dehydrogenate (LDH), acid and alkaline phosphatase (ACP,ALP), α amylase and lipases were measured in the tissue homogenate of snails, to confirm the relationship between the biochemical and endemic of the disease. Also amino acid profile of B. arabica was determined using amino acid analyzer. The result showed higher levels of AST and LDH in the sample of B. arabica from Hofuf as compared to Riyadh while ALT, ACP, ALK, α amylase and lipase enzymes were found lower in samples from Hofuf as compare to Riyadh. The amino acid profile shows that Riyadh samples have remarkably higher levels of most of the measured amino acids. The present study confirms that biochemical profile of B. arabica is critically important for the success of schistosome life cycle and that snail host definitely plays a part in prevalence of the disease. Keywords: Biomphalaria arabica, Schistosoma mansoni, Schistosomiasis, Saudi Arabia, Human helminthes infection.

Biochemical Characterization of Biomphalaria arabica , the Molluscan Intermediate Host for Schistosomes in Saudi Arabia

Schistosomiasis is the most important human helminth infection in terms of morbidity and mortality. The present study provides a comparative analysis on Biomphalaria arabica , the intermediate hosts of Schistosoma mansoni from two different areas having different prevalence level of Schistosomiasis in Saudi Arabia. B. arabica snails were collected from Riyadh and Hofuf district, and the levels of various enzymes like aspartate and alanine aminotransferase (AST, ALT), Lactate dehydrogenate (LDH), acid and alkaline phosphatase (ACP,ALP), α amylase and lipases were measured in the tissue homogenate of snails, to confirm the relationship between the biochemical and endemic of the disease. Also amino acid profile of B. arabica was determined using amino acid analyzer. The result showed higher levels of AST and LDH in the sample of B. arabica from Hofuf as compared to Riyadh while ALT, ACP, ALK, α amylase and lipase enzymes were found lower in samples from Hofuf as compare to Riyadh. The amino acid profile shows that Riyadh samples have remarkably higher levels of most of the measured amino acids. The present study confirms that biochemical profile of B. arabica is critically important for the success of schistosome life cycle and that snail host definitely plays a part in prevalence of the disease.

Fingerprint of Biomphalaria arabica, the intermediate host of Schistosoma mansoni in Saudi Arabia, using RAPD-PCR

In the time schistosomisis control programs are implemented in many countries, schistosomiasis continues to spread throughout the world. Among these control strategies is the vector control. Within this context, analysis of the genetic variability of the intermediate host snails is important because it allows identification of specific sequences of the genome of this mollusk related to determine their fingerprint. We investigated Biomphalaria arabica, which is found in Saudi Arabia, the intermediate host of Schistosoma mansoni infection. Genetic fingerprint was studied by RAPD-PCR using our own different random primers as well as published primers. The electrophoretic patterns resulting from amplification showed specific polymorphic markers of B. arabica. This information will be helpful in the identification of the snails and demonstrating that RAPD-PCR is an appropriate and efficient methodological approach for establishment of genetic barcode development.

Susceptibility of Biomphalaria spp. to infection with Schistosoma mansoni in sympatric and allopatric combinations with observations on the genetic variability between snails

This investigation was carried out to study the susceptibility of Saudi Biomphalaria arabica to Egyptian Schistosoma mansoni in comparison with the susceptibility of Egyptian Biomphalaria alexandrina to the same parasite. This was in order to know the possibility that the parasite might be able to spread into Saudi Arabia and to determine the genetic variability between Egyptian B. alexandrina and Saudi Biomphalaria arabica snails. Lab bred Egyptian B. alexandrina and Saudi B. arabica snails were exposed individually to 10 freshly hatched Egyptian S. mansoni miracidia/snail. The mortality rate, infection rate, prepatent period, duration of cercarial shedding and cercariae production per snail were recorded in both the sympatric couple (Egyptian B. alexandrina and Egyptian S. mansoni) and in the allopatric combination (Saudi B. arabica and Egyptian S. mansoni). The results revealed that, the survival rate of snails exposed to Egyptian S. mansoni miracidia at 34th day post-exposure (at first cercarial shedding) was higher in B. arabica than in B. alexandrina. After shedding, the mortality rate was higher in the B. arabica, compared to B. alexandrina. The infection rate was higher in B. arabica than B. alexandrina; the mean of prepatent period was shorter in the B. arabica than in the B. alexandrina. However, the duration of cercarial shedding was longer in the Egyptian snails and the cercarial production per snail was higher in B. alexandrina snails than in B. arabica. To study the genetic variability between B. alexandrina and B. arabica, RAPD-PCR on the genomic DNA of snails was done. RAPD-PCR revealed significant variation between the two snail species. In conclusion, the results suggest that B. arabica can play a role in the transmission of Egyptian S. mansoni in Saudi Arabia and therefore this parasite might be able to spread into the Kingdom. In addition, the RAPD-PCR results demonstrated genetic variability between the two species which may be related to the differences in susceptibility of both Saudi and Egyptian Biomphalaria snails to Egyptian S. mansoni infection.

Effect of salinity and drought on the survival of Biomphalaria arabica, the intermediate host of Schistosoma mansoni in Saudi Arabia

The effect of salinity and drought as two important abiotic factors on the survival of Biomphalaria arabica, the intermediate host of Schistosoma mansoni in Saudi Arabia was studied in the laboratory. Saudi B. arabica snails were collected from freshwater bodies in Abha, Asser district, Saudi Arabia. Snails were exposed to ten concentrations of Sodium Chloride as follow: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10‰. In addition, snails were exposed to a series of Sodium Chloride concentrations lie between the concentration that produced 100% mortality and the concentration lies previous to it. In drought experiments, the snails were exposed to complete dryness for 12, 24, 36 and 48 hours and the snails in moist soil were examined daily for fifteen days. The results revealed that B. arabica snails remain alive to 5‰ NaCl concentration and 100% mortality occurred at 7.2‰ of NaCl concentration. On the other hand, the ability of the snails to resist the complete dryness appeared to be limited, since 100% mortality was achieved after 36 hours in absence of lettuce leaves and after 48 hours in the presence of lettuce leaves . The snails in moist soil provided with fresh lettuce leaves remain surv ive to 15 days without any death. In the case of snails in the moist soil without fresh lettuce leaves, the survival was unaffected until 10 th day post-exposure, while further increases in exposure period resulted in reductions in survival up to 50% for snails exposed for 15 days. The present investigation declared that B. arabica has a great resistance to salinity increase and this may be explain why B. arabica has a great abundance in KSA. However, the ability of B. arabica snail to resist the dryness app eared to be limited.

Measurement of Selected Enzymatic Activities in Solanum nigrum-Treated Biomphalaria arabica Snails

Measurement of Selected Enzymatic Activities in Solanum nigrum-Treated Biomphalaria arabica Snails

Miracidia of an Egyptian strain of Schistosoma mansoni differentiate between sympatric snail species.

The host-finding behavior of miracidia of 2 strains of Schistosoma mansoni from Egypt and Brazil was studied by recording their responses to snail-conditioned water (SCW) from the Egyptian sympatric snails, Biomphalaria alexandrina, Physa acuta, Lymnaea cailliudi, and Balinus truncatus, as well as from Biomphalaria arabica and Biomphalaria glabrata. Miracidia of the Egyptian strain significantly preferred SCW from their compatible hosts B. alexandrina and B. arabica and showed no or a weak response to SCW from the other sympatric species, whereas miracidia of the Brazilian strain did not differentiate between SCW from different snail species.

Ecological and molecular studies on emerging schistosomiasis mansoni in Dhofar Governorate, Sultanate of Oman.

The recent detection of some cases of autochtonous schistosomiasis mansoni in Dhofar, Oman, prompted a search for the transmission sites. The five field surveys we conducted from November 2000 to February 2002 provided ecological data on schistosomiasis in Dhofar. Twenty-eight water bodies situated within 8-160 km from Salalah, the largest city of Dhofar and at altitudes of up to 900 m, were surveyed for freshwater snails. Biomphalaria arabica was found in 15 of them. Three sites (Tibraq, Siginitti and Arazat) had Schistosoma infected snails, the first snails shedding cercariae of this parasite ever collected in Oman. The parasite from Dhofar was analysed by Random Amplified Polymorphic DNA comparisons using 11 primers and 167 polymorphic fragments and had 87-88% similarity with Schistosoma mansoni from Guadeloupe, but only 37-38% similarity with S. rodhaini from Burundi. Thus, it is a strain of S. mansoni. During the November 2000 survey, the prosobranch snail Melanoides tuberculata was associated with B. arabica in 10 of the 13 B. arabica sites. Cercariae from other species of Digenea emerged from five of the B. arabica sites, including the three named above. This paper presents the first finding of S. mansoni in the Dhofar Governorate and represents an initial study of the biology of S. mansoni transmission. This parasite and its cycle need further biological and molecular characterization, and the clarification of its epidemiological status in Dhofar Governorate is an urgent task.

Quantitative RT-PCR Analysis of Polyubiquitin Gene Expression in Biomphalaria arabica after Exposure to Heat Stress and Cadmium

Quantitative RT-PCR Analysis of Polyubiquitin Gene Expression in Biomphalaria arabica after Exposure to Heat Stress and Cadmium

Schistosomiasis control in Saudi Arabia with special reference to the period 1983–1988

Schistosomiasis control operations carried out between 1983 and 1988 are described, together with information of the impact of schistosomiasis. The prevalence of schistosomiasis has declined from 9.5% in 1983 to 1.8% in 1988 (P less than 0.05). Bulinus truncatus, B. beccarii, and B. reticulatus wrighti are the intermediate hosts of S. haematobium in Saudi Arabia and are distributed unevenly in the different regions. Biomphalaria arabica is the intermediate host of S. mansoni and is found wherever the disease is endemic. The influx of expatriate workers from countries where schistosomiasis is endemic, inaccessible water sources, the constant movement of large numbers of bedouins in some regions, and manpower shortages in some regions are considered to be the main obstacles for schistosomiasis control programmes in Saudi Arabia.

Susceptibility of Snails, Biomphalaria arabica , from Various Parts of Saudi Arabia to Strains of Schistosoma mansoni from the Yemen Arab Republic and Egypt

Susceptibility of Snails, <i>Biomphalaria arabica</i> , from Various Parts of Saudi Arabia to Strains of <i>Schistosoma mansoni</i> from the Yemen Arab Republic and Egypt

The resistance of snail intermediate hosts of schistosomiasis in Saudi Arabia to desiccation

This investigation was conducted to study the ability of snail intermediate hosts of schistosomiasis in Saudi Arabia (Biomphalaria arabica and Bulinus truncatus) to survive desiccation under experimental conditions simulating field situations. The snails were more tolerant of desiccation when their habitats were gradually subjected to drying than when immediately removed from water habitats and placed on wet mud. Bulinus truncatus was more resistant to desiccation than Biomphalaria arabica, because of its mud burrowing ability. The ability of snails to aestivate is discussed in relation to the epidemiology of schistosomiasis.

Freshwater snails of Oman, South Eastern Arabia

A systematic account is given of the extant freshwater snail fauna of Oman, based on recent collections made in Dhofar and in the northern mountainous areas. Also included are certain species found in brackish coastal localities. A total of 8 freshwater species is regarded as belonging to the fauna of normal freshwater; 7 have been found alive (Thiara scabra, Melanoides tuberculata, Lymnaea natalensis, Gyraulus piscinarum, Biomphalaria arabica, Bulinus wrighti and Indoplanorbis exustus) and one is known only as shells (Paludestrina glaucovirens). This report of G. piscinarum is the first for Oman and may be the first reliable identification for Arabia. Three taxa from brackish water, Gangetia miliacea, Iravadia quadrasi and Melanoides sp., are new for the fauna of Oman and of the whole Arabian peninsula. The finding of G. miliacea provides the first instance of any member of the Stenothyridae living west of the Gulf of Oman and identified from whole snails rather than empty shells. I. quadrasi is the first member of its genus to be found alive west of the Gulf of Oman.

Schistosomiasis in Saudi Arabia.

Both intestinal and urinary schistosomiasis occur widely in Saudi Arabia. The rate of snail infection with schistosome cercariae was highest in Gizan. The intermediate host for Schistosoma mansoni is Biomphalaria arabica and for S. haematobium, Bulinus beccarii (and possibly Physa acuta, which was recorded for the first time in the central region of Saudi Arabia). The examination of different types of water bodies did not show any apparent overlap between the different snail vectors of Schistosoma.

Studies on schistosomiasis in Saudi Arabia.

During studies on schistosomiasis in Saudi Arabia, urine and stool samples from inhabitants of various areas (mostly rural) were examined, and 97 aquatic habitats in 46 localities were searched for snails. The results indicate the occurrence of both urinary and intestinal schistosomiasis in most parts of the country, with a patchy distribution and varying infection rates. The snail intermediate host of Schistosoma mansoni was found to be Biomphalaria arabica. For S. haematobium three species of snails, namely, Bulinus truncatus and B. beccarii in the west and B. reticulatus wrighti in the northeast, may transmit the infection; the susceptibility of the two former species has been confirmed in the laboratory. The limitation in the size of snail habitats--which consist of wells, small canals, cisterns, small swamps, interrupted streams, and ponds--creates a special type of transmission which can be defined as "oasis transmission," making control of the disease both simple and practical.