Chemical and biological assessment for Egyptian surface freshwater environment with reference to human activities

The Egyptian freshwater was assessed in the River Nile, branches, main canals and certain drainages in eight Governorates, over eight successive seasons starting from spring 2008. Chemical assessment was made through ten parameters and the biological one was made through macro-invertebrates information. Results showed that means of Cd, Pb, Cu, Hg, Mn, Fe, Ni, Na, K and Ca varied in watercourses seasonally within somewhat narrow ranges, which may exceed the level of concern but with some elevations in branches, Rayahs and canals during certain seasons. Sites showed chemical levels over the permissible one or those gain total points

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

Biological and biochemical studies on Biomphalaria Alexandrina snails showing overgrowth and their infection with Schistosoma mansoni

The growth, egg-laying capacity, susceptibility to infection with Schistosoma mansoni and some biochemical parameters were-determined for Biomphalaria alexandrina snails which showing overgrowth compared to those of the same age having normal growth. During the period of 14 weeks, the growth rate of snails with overgrowth was significantly higher than those with the normal size. At the first week of observation the mean shell diameter of overgrowth snails was 5.75 +/- 0.8 mm and reaching 9.03 +/- 0.6 mm by the end of the 14[th] week, compared to 2.9 +/- 0.6 mm and 7.2 +/- 0.7mm for snails with normal size. The rate of increasing growth [relative to snails with the normal size] in the overgrowth snails was comparatively very high during the 1[st] week [ranged between 64.5% and 98.3%]. It was found that B. alexandrina snails with overgrowth laid higher number of eggs than those with the normal size. Their onset of egg-laying was at the first week of observation [1.42 eggs/snail/week] until reaching to the highest peak at the 15[th] week [18.7egg/snail/week]. Comparing with snails of the same age and normal size, the egg-laying started at the 5[th] week with a very low number of eggs [0.5 eggs/snail /week], reaching to 4.3 eggs/snail/week at the 15[th] week. There was a very highly significant reduction [p< 0.001] in the infection rate of snails with overgrowth [ranged between 5.0% and 8.3%] compared to those of snails with normal size [ranged between 52.4% and 52.9%]. The hemolymph glucose concentration of B. alexandrina with overgrowth was significantly [P<0.05] and highly significant [p<0.01 and p<0.001] higher than those of the corresponding snails with the normal size in Set I [snails from egg-masses of individual snails], Set II [snails from individual egg-masses] and Set III [snails from groups of egg-masses of groups of snails]. The total protein concentrations in hemolymph of snails which showing overgrowth were increased than those of normal size of Sets I and II, but urea concentrations were decreased in Sets I and III

Efficacy of temperature, and two commonly used molluscicides and fertilizers on fasciola gigantica eggs

This study .evaluated the effect of temperature, molluscicides [Copper sulphate and Niclosamide], fertilizers [Superphosphate and Ammonium sulphate] on the hatchability of Fasciola gigantica eggs. The results showed that hatchability decreased to 4% when eggs were incubated in bile secretion at 37°C for 5 days and to 1.4% for 10 days, but few eggs incubated in water at 37°C hatched. Bile secretion at 37°C was a poor medium for in-vitro egg preservation. But, hatching occurred only when eggs were transferred to water at 26°C. Temperature fluctuation from 26-4°C or from 32- 4°C had an inhibitory effect on embryos development [35.2% and 32.3%, respectively] as compared to controls [60% and 63.9%, respectively]. The incubation period [19 and 17 days] was higher than controls [14 and 12 days, respectively]. The LC50 and LC9o of Copper sulphate and Niclosamide against Biomphalaria alexandrina and Lymnaea natalenesis had no toxic effect on Fasciola eggs. The higher concentrations of Copper sulphate [30ppm] and Niclosamide [Ippm] slightly lower eggs hatchability rate than controls. The rate decreased by increasing the exposure time from 3 to 6 hours with both molluscicides. Ammonium sulphate had a lethal effect on eggs, but Superphosphate had some inhibitory effect on egg development, which increased by increasing Superphosphate concentration or with the prolongation of the exposure time

Laboratory studies on the effect of magnetic technologies on some biological parameters of biomphalaria Alexandrina in Egypt

The effect of magnetic water on some biological parameters of B. Alexandrina was investigated. The growth rate, egg laying capacity, hatchability of deposited eggs, development of the newly hatched snails and the mortality rate of the treated snails [maintained in magnetic water for 12 weeks] were determined and compared with control ones maintained in normal water. The mean length of the diameter of treated snails after 12 weeks exposure to magnetic water [6.8 +/- 0.93] was slightly greater than the control group [6.4 +/- 0.8]. Also, a highly significant increase in number of eggs and egg-masses of treated snails [8.06 +/- 6.55 and 1.14 +/- 0.8, respectively] as compared with controls [2.5 +/- 1.2 and 0.33 +/- 0.14, respectively]. Hatchability rate of treated eggs in magnetic water for a period of 5 days was higher [63.4%] than the control group which recorded 28.2%. However, a highly significant reduction in the survival rate of newly hatched snails [22.5%] maintained in magnetic water for another 7 days after hatching as compared with the control [61.5%]. Also a highly significant reduction in the survival rate of adults in magnetic water for 12 weeks which recorded 40% in contrast with the control ones, recorded 88%, [P<0.001]. There was slight decrease in the calcium content of the shells of treated snails [25.44% of wt.] as compared to controls [29.58% of wt.]. The haermaphrodite gland acini of snails in magnetic water for 12 weeks were most frequently in final stages of oogensis and spermato-genesis. There were a significant increase in the mean number of 2ry oocytes and mature ova in acini of treated snails comparing with the control group [P<0.05]

Food composition and feeding habits of some fresh water fishes in various water systems at Abbassa, Egypt, with special reference to snails transmitting diseases

Study of feeding habits of freshwater fishes collected from ponds at World Fish Center [ICLARM] showed that the African catfish, Clarias gariepinus and Forskal catfish, Bagras bayad had the highest proportion of full stomachs [31-58% and 44-45% respectively]. In cichlid fishes, the rate of full stomachs was much lower, being 0.0-12.5% and showed higher incidence of empty stomachs that varied from 37.5% for Oreochromis niloticus to 78.3% for Sarotherodon galilaeus. Food items were analyzed by the percentage of point assessment [P%], abundance [N%] and frequency of occurrence [F%]. Results of the three methods of analyses [Index of relative importance. I.R.I] emphasized the importance of plants [1214.7] as a major food resource in the stomach of Nile tilapia, O. niloticus followed by shell fragments [628.5], whereas, snail soft bodies were the main food category in the diet of hybrid tilapia O. niloticus x O. aureus [2539.3]. Shell fragments [652] and snail soft bodies [296.9] were the 1st in relative importance as foods of O. aurea. In case of S. galillae, shell fragments [338] came 2nd in I.R.I. after plants [559]. Present investigation shows that shell fragments were represented by 11.1% and 15.1% in the diet of African catfish, C. gariepinus by [N%] and [P%] methods, however, they came as the second food item in its diet by I.R.I [1237.3]. According to F% method, both shell fragments and Crustacea were present in the diet of C. gariepinus in considerable proportions each of 47.4%. Shell fragments were represented by low proportions in the diet of B. bayad 3.9, 2.1 and 22.2 by N%, P% and F% respectively

Corralation between snails and fish in fish ponds of world fish center [ICLARM] with spicial refernce to snail vectors of schistosomiasis and fascioliasis

The abundance of snail species in earthen fish ponds, irrigation and drainage canals at World Fish Center [ICLARM] in a descending order was Bellamya unicolor [50.89%] > Physa acuta [18.94%] > Cleopatra bulimoides [7.6%] > Lanistes carinatus [6.73%] > Bulinus truncatus [5.19%] > Melanoides tuberculata [4.83%] > Lymnaea natalensis [3.14%] > Gabbiella senaarensis [0.9%] > Biomphalaria alexandrina [0.55%] > Lymnaea truncatula [0.4%] > Planorbis planorbis and Succinea cleopatra [0.33%] > Ferrissia isseli [0.18%]. The dead snails constituted about 5.19% of all the collected specimens. There was a dramatic decrease in the total number of pulmonates in fish ponds, which contained only Tilapia sp., and a very small number of cat fish, whereas the numbers of Prosobranchia snails were much higher in these ponds. In fish Ponds, which accommodated a variety of fish species, the most dominant snail was B. unicolor, followed by L. carinatus. However, pulmonate snails were absent in these ponds. B. Truncatus was the only snail species found in concrete tank, which contained only young tilapias with a very small size [5-8 cm in standard length]. In irrigation canals, the number of snails and diversity was much higher than those in fish ponds. Out of 191 snails collected from inlet irrigation canal, 71 were dead, but in the outside irrigation canals, 7 out of 564 snails were dead. P. acuta was absent in all examined fish ponds, but it was alive and occurred in a high number [497 snails] in the outside irrigation canals. The number of snails collected from Bahnasawy drain was remarkably low [128 snails]; however, the diversity of snails was much higher compared with those in fish ponds and irrigation canals. Snail populations were stable with constant recruitment of young to adult snails for all the studied species

Molluscicidal effect of fungicide herbicide and plant extract on some biological and physiological parameters of Biomphalaria alexandrina

It was found that the exposure of B. alexandrina to LC25 of fungicide [Isoprothiolane], herbicide [Anilofos] and plant extract [Euphorbia lactea] led to a highly significantly elevation in the number of abnormal egg masses laid by treated snails in comparison with the control ones. The LC25 caused reduction in infection rate of B. alexandrina. It caused reduction in number of cercariae per snail during the patent period and reduction in the period of cercarial shedding. The results showed that adenosine triphosphatase [ATPase] activity of tissue of snails was significantly increased in response to tested substances. The activity level of lactate dehydrogenase [LDH], pyruvate kinase [PK] and phosphoenolpyruvate carboxy kinase [PEPCK] was significantly reduced in response to the treatment. This reduction did not reflect on both D. lactate and pyruvate concentrations

Effect of various foods on Biomphalaria alexandria and Bulinus truncatus and their susceptibility to Schistosome miracidia

The tested foods are tropical fish food [tetramine], rat food, blue green algae, dried lettuce leaves and a mixture of all these foods. The results indicated that feeding of B. alexandrina on a mixture of foods increased their growth and survival rates and their susceptibility to S. mansoni. Tetramine elevated the egg laying capacity of snails compared to other tested foods. The hatchability of eggs of B. alexandrina fed on algae for a period of 16 weeks showed the highest rate followed by snails fed on a mixture of foods and then tetramine. B. truncates maintained on a mixture of foods for 16 weeks, exhibited an increase in their growth, egg laying, survival rates and recorded the highest infection rate with S. haematobium than other foods. Among the used foods, the hatchability of eggs of B. truncates fed on tetramine for 16 weeks was the highest one