Potential for Transmission of Schistosomiasis in Kayonza District

Introduction: Schistosomiasis; also known as bilharzia or snail fever; is a tropical parasitic disease caused by a trematode platyhelminthes called Schistosoma check for this species in other resources sp. Schistosoma species are transmitted by cercariae penetrating the skin when a person is bathing; washing clothes; fishing or engaged in agricultural activities; involving contact with fresh water that has fecal or urinary contamination; and contains the parasites' snail host. The present study aimed to survey freshwater snails in Kayonza District (Rwanda) especially Lake Muhazi and surrounding water bodies; stream and swamps to assess the potential for transmission of two species of Schistosoma: S. mansoni check for this species in other resources and S. haematobium check for this species in other resources. Methods: Six sites were selected to assess the potential for transmission of schistosomiasis. The intermediate hosts of schistosomes; namely the snails Biomphalaria check for this species in other resources ; Bulinus check for this species in other resources sp. and Lymnaea check for this species in other resources sp.; were collected and brought to the laboratory and investigated to see if trematode cercaria responsible for the disease were present. Results: Snails dissected were not only infected with trematode cercaria but also with annelids and flatworms (Platyhelminths). Cercaria found therein were of two types: furcocercous; probably responsible for schistosomiasis; and gymnocephalous cercaria for fasciolasis: an infection of cattle; goats and sheep. Conclusion: Biomphalaria sp were the major hosts for schistosome cercaria; and most snails collected of this species were infected. Moreover; they were found in large number from all sites. Lymnaea sp; hosts snails for Fasciola cercaria check for this species in other resources ; were also found in a considerable number compared to the low number of Bulinus sp in the region. District and national authorities may wish to further investigate this infestation and identify potential interventions to disrupt the disease transmission

study on biological control of six fresh water snails of medical and veterinary importance

This study evaluated the molluscicidal effect of Commiphora molmol oil extract [Myrrh], on control of six fresh water snails [Lymnaea natalensis, Bilinus truncatus, Biomphalaria alexandrina, Physa acuta, Melania tuberculata and Cleopatra bulimoides]. Also, the extract effect on the egg masses of L. natalensis, B. truncatus, B. alexandrina and Ph. acuta was evaluated. Snails and egg masses were exposed at 16-20°C to various concentrations [conc.]- LD[50] after 24 hours exposure were 264/132, 283/195, 230/252, 200/224, 241/246 and 241/246 ppm for young/adult of L natalensis, B. truncatus, B. alexandrina, Ph. acuta, M. tuberculata and C. bulimoides respectively. LD[100] after 24 hours exposure were 400/400 for L. natalensis, B. truncatus, B. alexandrina, M. tuberculata and C. bulimoides, and 300/300 for Ph. acuta. Also, complete mortality [100%] was achieved for the egg masses of L. natalensis, B. truncatus, B. alexandrina and Ph. acuta at concentrations of 300, 200, 300 and 400 ppm respectively. Lower concentrations gave the same results after longer exposure. LD[100] of C. molmol oil extract [Myrrh] had a rapid lethal effect on the six snail species and their egg masses in high conc, of 300 and 400 ppm. Commiphora molmol is a promising plant to be included with the candidate plant molluscicides. The oil extract of this plant showed a remarkable molluscicidal activity against used snail species

Helobdella nilae and Alboglossiphonia conjugata leeches as biological agents for snails control

The efficacy of leeches, as biological agents, in control of snail intermediate hosts of schistosomiasis [Bulinus truncatus, Biomphalaria alexandrina] and fascioliasis [Lymnaea natalensis] as well as their effect on the non-target snails Physa acuta, Melanioides tuberculata and Cleopatra bulimoides was evaluated. Two glossiphoniid snail leeches, Helobdella nilae and Alboglossiphonia conjugata were used. They destroyed egg masses and young snails more rapidly than adult ones. H. nilae showed a stronger destructive effect than A. conjugata. In a descending order, it preferred L. natalensis followed by B. truncatus, B. alexandrina, Ph. acuta, M. tuberculata and lastly C. bulimoides. But, A. conjugata preferred L. natalensis followed by B. truncatus, Ph. acuta, M. tuberculata, B. alexandrina and lastly C. bulimoides. The detailed diagnostic morphology and biology of the two leeches were given

Biological and biochemical studies in Bullinus truncatus snails collected from Saudi Arabia

In Saudi Arabia three species of snails namely, Bulinus truncatus, B. beccarii and B. wrighti, have been incriminated as intermediate hosts for Schistosoma haematobium. The present work was conducted on Saudi Arabian B. truncatus snails, [growth, survival rate and fecundity] in addition to comparison of some enzymatic activities between B. trunctus [control and infected with S. heamatobium] snails from Egypt and Saudi Arabia. Under laboratory constant temperature 24 +/- 1°C and after 20 weeks, the results show that the growth of Saudi Arabian Bulinus snails can be differentiated into two groups: the 1[st] one [70%] of the tested snails showed a total growth of 600% and 2[nd] one [30%] with a growth rate of 327.8%. The snails egg laying started at the 10[th] and 20[th] weeks without differences in their sizes [3.6 +/- 0.86 and 3.85 +/- 0.82] for these two groups respectively. A considerable survival rate was recorded for the 1[st] group after 20 weeks [68%] with mean life span 10.8 +/- 6.7 weeks. A convenient number of eggs were laid by survived snails with a net reproductive rate [Ro] of 129.12. In Egyptian and Saudi Arabian B. truncatus snails, the activities of enzymes, aspartate aminotransferase [AST], alanine aminotransferase [ALT] and alkaline phosphatase [AlkP] were significantly [P<0.0001] altered in the tissue homogenate of infected snails compared to control ones, in contrast acid phosphatase [AcP] was increased in infected snails than control ones, Both snail strains were classified as oxyphilic, poorly adapted to anaerobic conditions with the AST/ALT ratio higher than 2 in both control and infected ones

association between fresh water snails, macrophytes and water quality in different water courses in Egypt

The pattern of association between freshwater snails and macrophytes in relation to some water quality parameters were studied in 258 sites representing the Nile River. main branches, canals and drainages in Menia. Giza. Helwan, Cairo. Qalyubiya, Esmailia. Behaira and Damietta Governorates during May 2008 - March 2009. The survey study collects 15 aquatic plant species and 13 snail species. Statistical analysis showed high significant correlation between snails and plants [r = 0.462]. The examined sites were divided into four categories, sites with plant only [20%], sites with snails only [7%], sites free from both plants and snails [9%] and the biggest category which include sites with both plants and snails [64%]. Results showed that free sites characterized by the highest concentrations of cadmium, lead, mercury, sodium and potassium. Plant sites were characterized with the highest concentration of dissolved oxygen. Snail sites characterized with highest concentration in calcium. Sites in which snails associated with plants were characterized with higher ranges of chemicals, dissolved oxygen and conductivity than that observed in sites with snails only and this indicates the helpful role of plants for increasing snail tolerance to unfavorable conditions

Impact of Echinoparyphium recurvatum against schistosoma haematobium, on some physiological parameters of bulinus truncatus snails

The effects of single and double infection of Bulinus. truncatus with Schistosoma haematobium and/or Echinostorna recurvatum on free amino acid and some enzymes activity were hereby studied. The results indicated a disruption in the snail metabolism due to exposure to S. haematobium and E. recurvatuin miracidia and this effect was more pronounced in case of double exposure to the two parasites. The results obtained also revealed results showed that the infection rate of B. truncatus snails with E. recurvatum was higher than that by S. haematobium. Moreover, E recurvatum exerted a negative that free amino acids showed variation in their concentrations and percentages of TFAA in tissue of infected snails with two parasites as compared to control snails. Aspartic, Glutamic, Glyc ine, Threonine, Alanine, Methio-nine, Cystine, Tyrosine, Phenylalanine, Lysine and Luecine were increased in the tissue, but Serine, Histidine, Arginine, Proline, Valine and Isolucecine were decreased. The glucose, lipid and cholesterol level in the haemolymph of infected snails was increased, while the protein and glycogen content decreased in soft tissues. A significant elevation in the levels of Aspartate aminotransferase [ASAT] and alanine aminotransferase [ALAT] enzymes was recorded in heamolymph and tissues of exposed snail than unexposed. There were significant increases in the levels of acid and alkaline phosphatases enzymes in exposed snails

Identification of the Boudicca and Sinbad retrotransposons in the genome of the human blood fluke Schistosoma haematobium

Schistosomes have a comparatively large genome, estimated for Schistosoma mansoni to be about 270 megabase pairs (haploid genome). Recent findings have shown that mobile genetic elements constitute significant proportions of the genomes of S. mansoni and S. japonicum. Much less information is available on the genome of the third major human schistosome, S. haematobium. In order to investigate the possible evolutionary origins of the S. mansoni long terminal repeat retrotransposons Boudicca and Sinbad, several genomes were searched by Southern blot for the presence of these retrotransposons. These included three species of schistosomes, S. mansoni, S. japonicum, and S. haematobium, and three related platyhelminth genomes, the liver flukes Fasciola hepatica and Fascioloides magna and the planarian, Dugesia dorotocephala. In addition, Homo sapiens and three snail host genomes, Biomphalaria glabrata, Oncomelania hupensis, and Bulinus truncatus, were examined for possible indications of a horizontal origin for these retrotransposons. Southern hybridization analysis indicated that both Boudicca and Sinbad were present in the genome of S. haematobium. Furthermore, low stringency Southern hybridization analyses suggested that a Boudicca-like retrotransposon was present in the genome of B. truncatus, the snail host of S. haematobium.

Field trials of low dose Bayluscide on snail hosts of schistosome and selected non-target organisms in sahelian Cameroon

More than 85 percent of all cases of schistosomiasis in Cameroon occur in the northern sahelian half of the country representing 20 percent of the population. Several workers have advocated the integrated approach to schistosomiasis control, including snail control, but the death and decay of aquatic organisms, and fish kill that often follows Bayluscide application at the dose of 1g/m³ decrease its acceptability. The present study was designed to assess the effect of lower Bayluscide doses on snail host and non-target fish, frog, the tadpole kill. Bayluscide was applied to study ponds at concentrations of 0, 0.25, 0.5, and 1 g/m³ (ppm). Pre and post application assessment of snails hosts of schistosomes, fish, frog, and tadpole kill were carried out. All 0.25, 0.5, and 1 g/m³ Bayluscide concentrations reduced snail population significantly. Bayluscide concentration of 0.50 g/m³ applied in two rounds of 0.25 g/m³ resulted in high snail mortality and low lethality to fish, frogs, and tadpoles. Further studies are needed to assess the cost-effectiveness of Bayluscide in the control of schistosomiasis following the simplified approach.

Molluscicidal activities of aqueous extract of the sea anemone parasicyonis actinostoloides against vector snails Bulinus truncatus and Lymnaea natalensis

The aqueous extract of the sea anemone Parasicyonis actinostoloides showed molluscicidal effect against vector snails of Schistosoma haematobium and Fasciola gigantica after 24 hours of exposure. LC 50 and LC 90 values for P. actinostoloides were 40 and 78.6 ppm for B. truncatus and 46.6 and 86.5 ppm for L. natalensis respectively. The effect of continuously exposure of B. truncatus and L. natalensis to sublethal aqueous extract concentrations [LC 0, LC 10 and LC 25] on survival rate, egg production and on infectivity of miracidia to infection with S. haematobium and F. gigantica were studied. The data showed that no B. truncatus survived more than 42, 32 and 27 days after exposure with a mean life span of 18.5, 13.3 and 11.1 days respectively. The death rate of B. truncatus with LC 0 was highly significant as compared to treatment with LC 10 and LC 25 [p<0.01]. L. natalensis were more susceptible to the effect of aqueous extract than B. truncatus. LC 0, LC 10 and LC 25 extract killed all L. natalensis through 32, 27 and 22 days. The mean life span of those exposed to LC 0 was 12.37 days, high significant when compared with treated LC 10 and LC 25 ones [p<0.01]. The cumulative mortality rates of B. truncatus and L. natalensis in controls during the experimental study [52 days] was 60% and 75%, respectively. Egg production of B. truncatus and L. natalensis was not affected by sublethal concentrations. Control snails layed significantly higher no. of eggs than treated ones. B. truncatus stopped egg laying 17 days after exposure to LC 25. those treated with LC 10 and LC 0 ceased to deposit eggs after 22 and 27 days respectively. The percent reduction in egg laying capacity of B. truncatus treated with LC 0, LC 10 and LC 25 compared to controls was 77.1%, 93.2% and 92.8% respectively [p<0.01]. Similar reduction in egg production of treated L. natalensis compared to controls occurred, the percent reduction in egg production of snails treated with LC 0, LC 10 and LC 25 in relation to controls was 78.4%, 92.4% and 94.7% respectively. Sublethal concentrations of aqueous extract of P. actinostoloides affected hatchability of B. truncatus and L. natalensis eggs. The data showed that eggs of B. truncatus and L. natalensis can hatch in all tested concentrations but with different rates. The eggs' hatchability in snails exposed to LC 0, LC 10 and LC 25 extract at 5 days old was 44%, 38% and 30% in B. truncatus respectively. In L. natalensis eggs, the corresponding rates were lower 28%, 24% and 18% respectively. The infection of B. truncatus and L. natalensis with S. haematobium and F. gigantica miracidia was greatly reduced by the sublethal concentrations of aqueous extract of P. actinostoloides. The reduction of infection rate increased with the increased of sublethal concentrations. in B. truncatus the reduction was 43.2%, 57.6% and 76.6% compared to controls and in L. natalensis was 56.3%, 70.2% and 77.4%, respectively

Molluscicidal effect of three monoterpenes oils on schistosomiasis and fascioliasis vector snails in Egypt

Thymol, Linalool and Eugenol showed considerable molluscicidal effect against Biomphalaria alexandrina, Bulinus trancatus and Lymneae natalensis. The thymol was the potent one at least LC 50 and LC 90 followed by euganol then linalool. L. natalensis were mole sensitive to these compounds followed by B. truncatus and then B. alexandrina. The LC 50 and LC 90 of thymol were 22 and 34 ppm against B. alexandrina, 20 and 30 ppm for B. truncatus and 1 8 and 29 ppm for L. natalensis. These values were higher with Eugenol, 28 and 48 ppm for B. alexnadrina, 24 and 44 ppm for B. truncatus and 22 and 40 ppm for L. natalensis. Linalool showed highest values of LC 50 and LC 90 against B. alexandrina, 34 and 56 ppm, against B. truncatus 30 and 52 ppm and for L. natalensis 28 and 48 ppm, respectively. Maintaining of B. alexandrina at LC 10 of Thymol for one week induced an inhibitory effect in the level of some enzymes [AchE, SDH]. It led to increase in the activity of other enzymes [ACP, ALP and G-6-PD]. Acetylcholine-sterase activity [AchE] of treated B. alexandrina was significantly reduced by 45.9% when compared to control. The results showed a significant decrease in succinate dehydrogenase activity [SDH] by 46.4% together with a concomitant increase in glucose-6-phosphate dehydrogenase activity level [G-6-PD] by 47.5% in comparison with control. The activities of acid phosphatase and alkaline phosphatase enzymes were found to be higher in the treated snails than in control ones. The percentage increases were 47.2% and 73.2% respectively. The results also showed an elevation in the hemolymph glucose content of treated snails by 51.9% while the tissue glycogen content was reduced by 48.1%. The infection of B. alexandrina with S. mansoni miracidia was greatly reduced by thymol LC 10 [sublethal dose]. The infection rate reduction was 43.1%. The treated snails' prepatent period was prolonged [34.2 +/- 3.3 days] compared to control [28.4 +/- 1.2 days]. A highly significant reduction of total cercarial production per snail occurred in experimental snails as compared to control

Electrophoretic patterns of protein fractionations in hemolymph and tissues of Biomphalaria Alexandrina and bulinus truncatus during course of schistosome infection

Electrophoresis of plasma protein of B. alexandrina [uninfected and infected with S. mansoni] showed that the major dominant bands had molecular weights of 20,44,96,139 and 205KD in both types of snails. The 1day and 1 week post miracidia1 exposure [PME] groups were characterized by band 54 KD. All groups except a day PMA were characterized by a common band of MW 65 KD. Three days PME group had three bands of 123 KD, 150 and 177 KD, not found in other groups. The highest similarity index in 2 weeks PME and 5 weeks PME groups [during cercaria1 shedding] was 0.667 the lowest one was in 3-dys PME [0.5]. the 3-days PME had a unique band of MW 177.04 KD, not found in other groups. Similar electrophoretic pattern of B. alexandrina protein was seen. The major dominant bands had molecular weights of 14, 21, 80 and 140KD in both non-infected and infected snails. The 1day PME had a band of 48.483 KD, 3days PME had band of 87.985 KD, one-week PME group characterized by two band 61.761 KD and 70.33 KD. The two-weeks PME had a band 91.111 KD. While, the 5week PME [during cercaria1 production] was the only group that shared the common band of MW 115 KD with controls. The highest similarity index in 5 weeks PME [during cercaria1 shedding] group was 0.545 and the lowest one was in 1 week and 2 weeks PME [0.43]. The electrophoresis of plasma protein of B. truncates [uninfected and infected with S. haematobium] showed that the major dominant bands had molecular weights of 20, 30, 65, 80, 106, 117 and 170 KD in both type of snails. The 1 day PME group was characterized by three band of MWs 26.539, 51.891 and 91.509 KD. All experimental groups, except 5 weeks PME [during cercaria1 shedding] and control, had a common band of MW 45KD. Three days PME group had a characteristic band of 113.72 KD which was not found in any other group. The highest similarity index was in one week PME group was 0.857 and the lowest one in 1 days PME [0.5]. In B. truncatus tissue protein, the major dominant band by electro- phoretic pattern had molecular weights of 20, 45, 54, 80, 97, and 171KD in both type of snails. A day PME had of 73.544KD and a week PME had a band of MW 60.813 KD. Two and 5weeks PME groups had 2 bands of MWs 27 and 62 KD .All experimental groups had a characteristic band not found in control of MW 141 KD. The highest similarity index in 3-days PME was 0.8 and the lowest one was in 5 weeks PME during cercaria1 shedding [0.545].

Molluscicidal activity of certain sudanese medicinal plants used in folk-medicene

In view of the promising potential of plant molluscicides, 10 plants indigenous to Sudan and of common use in Sudanese folk-medicine, were screened for their molluscicidal activity, using two local snail vectors, Bulinus truncates and Biomphalaria pfeifferi. At different concentrations up to 500 ppm., seven plant samples were found to be lethal to both of the snail species. The pet. ether/CHCH 3 [1:1] extracts of 6 plants were lethal as molluscicidal agents while only two plants showed 100% mortality to the snails as methanol extracts. The two most active plants that killed both snail hosts [

Applied study using leaves extract of Neirum ole and er L. to control the snail of Bulinus truncatus L. the intermediate host of Schistosomiasis in Iraq

The effects of Nerium ole and er leaves extracts were used in attempt to control the Bulinus truncatus snail which is the intermediate host of Schistosomiasis in Iraq. The powder of N.ole and er leaves was dissolved in water [50 mgl/1]. The study was carried out in a river that contains this snail in Al-Rasheed district about 25 Km south of Baghdad. Three stations were chosen for this study, the distance between each station is 500m. The first station was the control station; the water of second station was treated with the leaf extracts. The study showed high effects of N.ole and er extracts to control B. truncates. The effect in the third station were less than that f the second station because of dilution of the extract during its flow in the river. The effect of this extract was represented by mortality, the snails attempt to escape from the exposure media, disorders and troubles of behaviour in the submerge activity throughout the exposure [96hr]. The effect of the N.ole and er extracts was limited for the treated area only. This study showed the ability to use the N.ole and er extracts to control the snail B. truncatus.

Spot light survey on fresh-water snails of medical importance in Al Fayoum governorate, Egypt

In a survey carried out during summer and autumn of 2004, for snails of medical importance, nine species were recovered. They were Biomphalaria alexandrina, B. glabrata, B. pfeifferi, Bulinus truncatus, B. forskalii, Lymnaea natalensis, Bellamya [=Vivipara] unicolor, Physa acuta and Hydrobia mesaensis. Parasitological examination revealed that B. alexandrina, B. glabrata and L. natalensis harboured immature stages of their concerned trematode parasites. Moreover, P. acuta harboured the immature stage of the nematode parasite Parastrongylus cantonensis

Effect of water plants and non-target snails on the infectivity of bulinus truncatus with schistosoma haematobium

The application of the water plant [Ceratophyllum demersum, Eichhornia crassipes and Lemna gibba] and/or non-target snails [Planorbis planorbis, Physa acuta and Melanoides tuberculata] gave a significant degree of reduction in the infection rate of B. truncatus subjected to S. haematobium miracidia. The data also indicated a reduction in mean total number of cercarial production/snail. However, no significant difference was detected in the prepatent period and duration of cercarial shedding of the parasite when compared with the control group. So, the results revealed that the snails exhibited a competitive ability against B. truncatus. Both survival rate and egg production of B. truncatus were greatly reduced when existed in mixed cultures with non-target snails and the magnitude of this reduction increased by increasing the number of the non-target snails

Epidemiology of Schistosoma mansoni infection and its relationship to snail distribution in a village at the Nile Bank south to Cairo

The relationship between epidemiology of S.mansoni infection and snail distribution at a village, related to Guiza Governorate and lies south to Cairo, was investigated. A systematic random sample of houses was selected. All inhabitants of the houses were invited to share in the study. The Number examined was 704. Urine and stools were examined using Nucleopore filtration and standard Kato-Katz techniques, respectively. Snail collection was done from 35 sites along the water bodies related to the village. Snails collected were examined by cercariae shedding under light. Snail differentiation was done. The results showed that the prevalence of Schistosoma mansoni human infection was 25.1% and GMEC was 2.4 +/- 5.5. Schistosoma haematobium infection was zero percent. Biomphlaria alexandrina snail infection rate was 3.7% with density equal 0.5 +/- 1.3. Bulinus truncatus snail infection rate was zero percent. The pattern of S. mansoni human infection was closely related to snail distribution and infection. Presence of a hybrid species of B.alexandrina and B.glabrata may explain the epidemiological pattern found in the studied village