Schistosoma mansoni and fascioliasis are worldwide parasitic diseases infecting 83 and 17 million people respectively causing significant morbidity and mortality. The present work was carried out to evaluate the molluscicidal activities of the ethanolic extract of three plant species namely Euphorbia aphylla, Ziziphus spina-christi and Enterolobium contortisiliquum against Biomophalaria alexandrina and Lymnaea cailliaudi (natalensis), the snails intermediate hosts of Schistosoma mansoni and Fasciola respectively. The highest molluscicidal activity was recorded for Euphorbia aphylla on both snails’ species. The least activity was recorded for Enterolobium contortisiliquum which gave negative results against both snail species up to1000 ppm. The LC50 and LC90 of the ethanolic extract of Euphorbia aphylla against Biomophalaria alexandrina snails were 87.6 ppm and142.5ppm respectively while the LC50 and LC90 of Euphorbia aphylla against Lymnaea cailliaudi snails were 0.66 ppm and 0.88 ppm respectively. The LC50 and LC90 of Ziziphus spinachristi ethanolic extract against Lymnaea cailliaudi snails were 311ppm and 500 ppm respectively. However it showed no molluscicidal activity againist B. alexandrina snails up to 1000 ppm. The histopathological changes in hermaphrodite gland of B. alexandrina and Lymnaea cailliaudi snails 2 weeks post exposure to LC25 of the ethanolic extract Euphorbia aphylla and the histopathological effect of LC25 of the ethanolic extract Ziziphus spina- christi on Lymnaea cailliaudi snails were studied. Degenerative changes in hermaphrodite acini and their contents of ova and sperms were observed. The purification of active compounds present in Euphorbia aphylla and Ziziphus spina- christi plants may offers an alternative tool for the control of snails’ intermediate hosts of Schistosoma mansoni and Fasciola. Further investigations for Enterolobium contortisiliquum may increase its potential use as plant molluscicide are recommended

Schistosoma mansoni and fascioliasis are worldwide parasitic diseases infecting 83 and 17 million people respectively causing significant morbidity and mortality. The present work was carried out to evaluate the molluscicidal activities of the ethanolic extract of three plant species namely Euphorbia aphylla, Ziziphus spina-christi and Enterolobium contortisiliquum against Biomophalaria alexandrina and Lymnaea cailliaudi (natalensis), the snails intermediate hosts of Schistosoma mansoni and Fasciola respectively. The highest molluscicidal activity was recorded for Euphorbia aphylla on both snails’ species. The least activity was recorded for Enterolobium contortisiliquum which gave negative results against both snail species up to1000 ppm. The LC50 and LC90 of the ethanolic extract of Euphorbia aphylla against Biomophalaria alexandrina snails were 87.6 ppm and142.5ppm respectively while the LC50 and LC90 of Euphorbia aphylla against Lymnaea cailliaudi snails were 0.66 ppm and 0.88 ppm respectively. The LC50 and LC90 of Ziziphus spinachristi ethanolic extract against Lymnaea cailliaudi snails were 311ppm and 500 ppm respectively. However it showed no molluscicidal activity againist B. alexandrina snails up to 1000 ppm. The histopathological changes in hermaphrodite gland of B. alexandrina and Lymnaea cailliaudi snails 2 weeks post exposure to LC25 of the ethanolic extract Euphorbia aphylla and the histopathological effect of LC25 of the ethanolic extract Ziziphus spina- christi on Lymnaea cailliaudi snails were studied. Degenerative changes in hermaphrodite acini and their contents of ova and sperms were observed. The purification of active compounds present in Euphorbia aphylla and Ziziphus spina- christi plants may offers an alternative tool for the control of snails’ intermediate hosts of Schistosoma mansoni and Fasciola. Further investigations for Enterolobium contortisiliquum may increase its potential use as plant molluscicide are recommended

Background: External ophthalmomyiasis refers to superficial infestation that involves the lids and conjunctiva in man by fly larvae (maggots of the order Diptera). Ophthalmomyiasis is often a benign self-limiting disease. Oestrus ovis (O. ovis) is the most common cause affecting mainly persons in rural areas such as shepherds and farmers. Numerous cases of external ophthalmomyiasis due to this fly were reported from Africa, Middle East, Australia, North America, Southern Europe and Egypt. Objective: The aim of this study is to describe the morphological characteristics of O. ovis 1st stage larvae using light microscopy (LM) and scanning electron microscopy (SEM) and to correlate between these larval structures and their pathogenesis. Material and methods: A 24 years-old - man presented with severe symptoms of conjunctivitis. On examination, 5 small sized larvae were observed in the bulbar conjunctiva. They were picked up, described and documented photographically by LM and SEM. Results: The larvae were identified as O. ovis 1st stage larvae. They showed characteristic mouth parts, surrounded by crown shaped spines. More distinctive features revealed by SEM were mirror image papillae on the ventral side and rows of currycomb-shaped spines on the body segments. Conclusion: This study highlighted particular diagnostic structures of the anterior and posterior ends of O. ovis 1st stage larvae that may aid in larval identification, and explain their mechanism of pathogenesis. Most important is the early diagnosis and treatment. KEY WORDS: Oestrus ovis, Myiasis, Ophthalmomyiasis, Egypt.

Background: External ophthalmomyiasis refers to superficial infestation that involves the lids and conjunctiva in man by fly larvae (maggots of the order Diptera). Ophthalmomyiasis is often a benign self-limiting disease. Oestrus ovis (O. ovis) is the most common cause affecting mainly persons in rural areas such as shepherds and farmers. Numerous cases of external ophthalmomyiasis due to this fly were reported from Africa, Middle East, Australia, North America, Southern Europe and Egypt. Objective: The aim of this study is to describe the morphological characteristics of O. ovis 1st stage larvae using light microscopy (LM) and scanning electron microscopy (SEM) and to correlate between these larval structures and their pathogenesis. Material and methods: A 24 years-old - man presented with severe symptoms of conjunctivitis. On examination, 5 small sized larvae were observed in the bulbar conjunctiva. They were picked up, described and documented photographically by LM and SEM. Results: The larvae were identified as O. ovis 1st stage larvae. They showed characteristic mouth parts, surrounded by crown shaped spines. More distinctive features revealed by SEM were mirror image papillae on the ventral side and rows of currycomb-shaped spines on the body segments. Conclusion: This study highlighted particular diagnostic structures of the anterior and posterior ends of O. ovis 1st stage larvae that may aid in larval identification, and explain their mechanism of pathogenesis. Most important is the early diagnosis and treatment. KEY WORDS: Oestrus ovis, Myiasis, Ophthalmomyiasis, Egypt.

Background: External ophthalmomyiasis refers to superficial infestation that involves the lids and conjunctiva in man by fly larvae (maggots of the order Diptera). Ophthalmomyiasis is often a benign self-limiting disease. Oestrus ovis (O. ovis) is the most common cause affecting mainly persons in rural areas such as shepherds and farmers. Numerous cases of external ophthalmomyiasis due to this fly were reported from Africa, Middle East, Australia, North America, Southern Europe and Egypt. Objective: The aim of this study is to describe the morphological characteristics of O. ovis 1st stage larvae using light microscopy (LM) and scanning electron microscopy (SEM) and to correlate between these larval structures and their pathogenesis. Material and methods: A 24 years-old - man presented with severe symptoms of conjunctivitis. On examination, 5 small sized larvae were observed in the bulbar conjunctiva. They were picked up, described and documented photographically by LM and SEM. Results: The larvae were identified as O. ovis 1st stage larvae. They showed characteristic mouth parts, surrounded by crown shaped spines. More distinctive features revealed by SEM were mirror image papillae on the ventral side and rows of currycomb-shaped spines on the body segments. Conclusion: This study highlighted particular diagnostic structures of the anterior and posterior ends of O. ovis 1st stage larvae that may aid in larval identification, and explain their mechanism of pathogenesis. Most important is the early diagnosis and treatment. KEY WORDS: Oestrus ovis, Myiasis, Ophthalmomyiasis, Egypt.

Background: External ophthalmomyiasis refers to superficial infestation that involves the lids and conjunctiva in man by fly larvae (maggots of the order Diptera). Ophthalmomyiasis is often a benign self-limiting disease. Oestrus ovis (O. ovis) is the most common cause affecting mainly persons in rural areas such as shepherds and farmers. Numerous cases of external ophthalmomyiasis due to this fly were reported from Africa, Middle East, Australia, North America, Southern Europe and Egypt. Objective: The aim of this study is to describe the morphological characteristics of O. ovis 1st stage larvae using light microscopy (LM) and scanning electron microscopy (SEM) and to correlate between these larval structures and their pathogenesis. Material and methods: A 24 years-old - man presented with severe symptoms of conjunctivitis. On examination, 5 small sized larvae were observed in the bulbar conjunctiva. They were picked up, described and documented photographically by LM and SEM. Results: The larvae were identified as O. ovis 1st stage larvae. They showed characteristic mouth parts, surrounded by crown shaped spines. More distinctive features revealed by SEM were mirror image papillae on the ventral side and rows of currycomb-shaped spines on the body segments. Conclusion: This study highlighted particular diagnostic structures of the anterior and posterior ends of O. ovis 1st stage larvae that may aid in larval identification, and explain their mechanism of pathogenesis. Most important is the early diagnosis and treatment. KEY WORDS: Oestrus ovis, Myiasis, Ophthalmomyiasis, Egypt.