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

Effect of different temperatures on viability of seven encysted metacercariae recovered from freshwater fishes in Qualyobia, Egypt

Encysted metacercariae [EMC] from seven trematod-zoonotic parasites were exposed to different temperature mechanisms. Boiling of the infected fishes was sufficient to kill the EMC, frying of fishes for five minutes was quite sufficient to inhibit the viability of EMC, but frying for 10 minutes killed all EMC. Grilling of infected Tilapia zillii was sufficient to kill EMC after 10 minutes; however five minutes were sufficient only to kill EMC in Clarias gariepinus. Regarding chilling at 5°C, T. zillii EMC showed variation in response. Complete loss of viability of Prohemistomatidae EMC was achieved after 14 days, for Haplorchidae after 11 days, for Diplostomatidae after 12 days, while Clinostomatidae EMC required 15 days. For Cl. gariepinus, Bagrus bajad and Chrysichthys auratus achieved results were similar to those for T. zillii but with fewer days of withstanding chilling. The EMC infecting Tilapia lost their viability by freezing at -5 °C and -10 °C for Prohemistomatidae after 48 and 40 hours, for Diplostomatidae after 24 and 16 hours and for Clinostomatidae cysts after 48 and 32 hours respectively. In infected Clarias gariepinus, Bagrus bajad and Chrysichthys auratus the EMC lost their viability by fireezing at -5 °C and -10 °C for periods shorter than those of Tilapia sp

Metacercariae recovered from fresh-water fishes in the vicinity of Qualkyobia Governorate, Egypt

A total of 410 Tilapia zillii, 70 Clarias gariepinus, 30 Bagrus bajad and 15 Chlrysichthys auratus fishes were collected from different water bodies in Qualyobia Governorate. Microscopic examination of samples showed infection in muscles and head region [gills and branchial cavity] with encysted metacercariae in 91.7% of T. zillii, 82.85% of Cl. gariepinus, 70% of B. bajad and 86.66% of Ch. auratus. The highest distribution of metacercarial infection among the T. zillii was in the muscles of posterior third and tail followed by the middle third, anterior third and head region [gills and branchial cavity] while the highest distribution of metacercarial infection among Cl. gariepinus was in the middle third muscles followed by the posterior third, anterior third and lastly in the head region. The highest metacercarial infection among B. bajad and Ch. auratus fish was in the posterior third muscles and branchial cavity respectively. The taxonomic morphology of the encysted metacercariae and the excysted ones was given