Essam Shaalan | Aswan University (original) (raw)
Papers by Essam Shaalan
Mosquitoes are well-known vectors of disease and threaten the health of millions of people annual... more Mosquitoes are well-known vectors of disease and threaten the health of millions of people annually. While synthetic insecticides have been relied on to combat these diseases, insecticide resistance and environmental concerns have directed attention towards novel and more targeted mosquitocides derived from botanicals. Research on the activity of botanical derivatives has focused on mosquito larvae and adults with little attention given to their potential as oviposition deterrents against gravid female mosquitoes. This review explores the influence of chemical and biological factors on deterrence and examines issues relating to environmental persistence and non-target effects. With very few discoveries of new insecticide pathways, the answer to effective mosquito control may well reside within other ancient plantbased organisms that have co-resided and evolved with this ubiquitous pest.
A laboratory evaluation of three slow-release formulations (SRFs) of spinosad tablets, sumilarv g... more A laboratory evaluation of three slow-release formulations (SRFs) of spinosad tablets, sumilarv granules and du-dim tablets was carried out in 20 liters plastic containers. The tested formulations were applied according to recommended doses to evaluate their efficacy and longevity against Ae. aegypti. The results revealed that the tested SRFs achieved complete inhibition of adult stages emergence of Ae. aegypti in the first four weeks and gave continuous effective with 50-100% for 98, 86 and 78 days post-treatment by using spinosad tablets, sumilarv granules and du-dim tablets respectively. The highest larval mortality was observed for spinosad followed by sumilarv and du-dim, it gave 1.3 folds than sumilarv and 1.1 folds with du-dium, whereas sumilarv and du-dium were more effective on pupal mortality than spinosad. On the other hand, morphological abnormalities were observed in larval and pupal stages of Ae. aegypti as delayed effects by tested formulations. This study highlighted that these SRFs could be used as potential larvicidal compounds in mosquito control programs as a single treatment and provide satisfactory results and continuous control against the dengue vector Ae. aegypti for several weeks.
Mosquitoes are undesirable arthropods transmitting many diseases not only in Saudi Arabia but als... more Mosquitoes are undesirable arthropods transmitting many diseases not only in Saudi Arabia but also worldwide. Identifying mosquito species relied for long time on both larval and adult characters whilst little or no attention was given to eggs. Electron microscopic studies of mosquito eggs are important as it is not only characterizing the external morphology of the eggs never seen by stereoscopic microscopes but also facilitates mosquito species identification. Accordingly, morphology and morphometric of Culex pipiens eggs collected from Al-Ahsa oasis, eastern Saudi Arabia were examined by scanning electron microscopy (SEM) for the first time in Saudi Arabia in the present work. Mosquito egg rafts were collected from breeding sites in Al-Ahsa by using of special long aquatic net. A portion of the rafts was reared for identification whilst the other portion was preserved in glutaraldehyde and prepared for SEM examination. Eggs appeared to be conical in shape with two ends, the anterior one that is represented with the micropyle is more tapered than the posterior end. The morphometrics gave many characteristics for the eggs such as length, width, proportion of length /width and so on. Eggs morphology and morphometrics were then compared to that of other Culex eggs. Our findings using SEM of the eggshell confirmed that the present mosquito species is Cx. pipiens. Scanning electron micrographs of any mosquito species eggs are valuable in correlating its fine structure that cannot be easily seen by light microscope and can assist in species separation. Thus, identifying medically important mosquito species is crucial in both mosquito and disease control.
International journal of mosquito research, 2019
The mosquito fauna of Yemen is poorly studied and no modern taxonomic keys to mosquitoes of this ... more The mosquito fauna of Yemen is poorly studied and no modern taxonomic keys to mosquitoes of this country are found. This investigation was conducted to provide baseline data about mosquito vectors prevailing in Sana'a, northwest of Yemen. Immature stages of mosquitoes breeding in different aquatic habitats were collected seasonally from nine locations in Sana'a. Results indicated that 2054 mosquito larvae were collected by dipping method during 2015-2016, representing six culicine mosquito species belonging to 3 genera whilst no anopheline mosquito larvae were found. Depending on morphological keys of the fourth instar larvae, such mosquito species were identified as Culiseta longiareolata (980 larvae = 47.71%), Culex pipiens (559 larvae = 27.22%), Culex mattinglyi (252 larvae = 12.27%) Culex laticinctus (207 larvae = 10.08%), Culex (lutzia) tigripes (34 larvae = 1.67 %), and Aedes aegypti (22 larvae = 1.07%). Both Cs. longiareolata and Cx. pipiens were the most predominant species that found in all locations whilst both Ae. aegypti and Cx. (lutzia) tigripes were found in only one location, Sana'a city and Al-Haymah Ad Dakhiliyah respectively. Out of the six mosquito species, five (Cs. longiareolata, Cx. pipiens, Culex laticinctus, Culex mattinglyi and Ae. aegypti) are important vectors of diseases and 2 (Cx. (lutzia) tigripes and Cs. longiareolata) are predaceous in their larval stages. Additionally, both the dengue vector, Ae. aegypti, and the predaceous mosquito, Cx. (lutzia) tigripes, were detected for the first time in Sana'a city. Present findings highlighting the importance of regular mosquito surveillance in recording new species as well as identifying mosquito vectors and their preferable breeding sites. Hence, a satisfactory mosquito control program can be raised. Future extensive surveys, studies of cytogenetic and molecular analysis in addition to predation potential of predaceous mosquito larvae are recommended.
Mosquitoes are well-known vectors of disease and threaten the health of millions of people annual... more Mosquitoes are well-known vectors of disease and threaten the health of millions of people annually. While synthetic insecticides have been relied on to combat these diseases, insecticide resistance and environmental concerns have directed attention towards novel and more targeted mosquitocides derived from botanicals. Research on the activity of botanical derivatives has focused on mosquito larvae and adults with little attention given to their potential as oviposition deterrents against gravid female mosquitoes. This review explores the influence of chemical and biological factors on deterrence and examines issues relating to environmental persistence and non-target effects. With very few discoveries of new insecticide pathways, the answer to effective mosquito control may well reside within other ancient plantbased organisms that have co-resided and evolved with this ubiquitous pest.
A laboratory evaluation of three slow-release formulations (SRFs) of spinosad tablets, sumilarv g... more A laboratory evaluation of three slow-release formulations (SRFs) of spinosad tablets, sumilarv granules and du-dim tablets was carried out in 20 liters plastic containers. The tested formulations were applied according to recommended doses to evaluate their efficacy and longevity against Ae. aegypti. The results revealed that the tested SRFs achieved complete inhibition of adult stages emergence of Ae. aegypti in the first four weeks and gave continuous effective with 50-100% for 98, 86 and 78 days post-treatment by using spinosad tablets, sumilarv granules and du-dim tablets respectively. The highest larval mortality was observed for spinosad followed by sumilarv and du-dim, it gave 1.3 folds than sumilarv and 1.1 folds with du-dium, whereas sumilarv and du-dium were more effective on pupal mortality than spinosad. On the other hand, morphological abnormalities were observed in larval and pupal stages of Ae. aegypti as delayed effects by tested formulations. This study highlighted that these SRFs could be used as potential larvicidal compounds in mosquito control programs as a single treatment and provide satisfactory results and continuous control against the dengue vector Ae. aegypti for several weeks.
Mosquitoes are undesirable arthropods transmitting many diseases not only in Saudi Arabia but als... more Mosquitoes are undesirable arthropods transmitting many diseases not only in Saudi Arabia but also worldwide. Identifying mosquito species relied for long time on both larval and adult characters whilst little or no attention was given to eggs. Electron microscopic studies of mosquito eggs are important as it is not only characterizing the external morphology of the eggs never seen by stereoscopic microscopes but also facilitates mosquito species identification. Accordingly, morphology and morphometric of Culex pipiens eggs collected from Al-Ahsa oasis, eastern Saudi Arabia were examined by scanning electron microscopy (SEM) for the first time in Saudi Arabia in the present work. Mosquito egg rafts were collected from breeding sites in Al-Ahsa by using of special long aquatic net. A portion of the rafts was reared for identification whilst the other portion was preserved in glutaraldehyde and prepared for SEM examination. Eggs appeared to be conical in shape with two ends, the anterior one that is represented with the micropyle is more tapered than the posterior end. The morphometrics gave many characteristics for the eggs such as length, width, proportion of length /width and so on. Eggs morphology and morphometrics were then compared to that of other Culex eggs. Our findings using SEM of the eggshell confirmed that the present mosquito species is Cx. pipiens. Scanning electron micrographs of any mosquito species eggs are valuable in correlating its fine structure that cannot be easily seen by light microscope and can assist in species separation. Thus, identifying medically important mosquito species is crucial in both mosquito and disease control.
International journal of mosquito research, 2019
The mosquito fauna of Yemen is poorly studied and no modern taxonomic keys to mosquitoes of this ... more The mosquito fauna of Yemen is poorly studied and no modern taxonomic keys to mosquitoes of this country are found. This investigation was conducted to provide baseline data about mosquito vectors prevailing in Sana'a, northwest of Yemen. Immature stages of mosquitoes breeding in different aquatic habitats were collected seasonally from nine locations in Sana'a. Results indicated that 2054 mosquito larvae were collected by dipping method during 2015-2016, representing six culicine mosquito species belonging to 3 genera whilst no anopheline mosquito larvae were found. Depending on morphological keys of the fourth instar larvae, such mosquito species were identified as Culiseta longiareolata (980 larvae = 47.71%), Culex pipiens (559 larvae = 27.22%), Culex mattinglyi (252 larvae = 12.27%) Culex laticinctus (207 larvae = 10.08%), Culex (lutzia) tigripes (34 larvae = 1.67 %), and Aedes aegypti (22 larvae = 1.07%). Both Cs. longiareolata and Cx. pipiens were the most predominant species that found in all locations whilst both Ae. aegypti and Cx. (lutzia) tigripes were found in only one location, Sana'a city and Al-Haymah Ad Dakhiliyah respectively. Out of the six mosquito species, five (Cs. longiareolata, Cx. pipiens, Culex laticinctus, Culex mattinglyi and Ae. aegypti) are important vectors of diseases and 2 (Cx. (lutzia) tigripes and Cs. longiareolata) are predaceous in their larval stages. Additionally, both the dengue vector, Ae. aegypti, and the predaceous mosquito, Cx. (lutzia) tigripes, were detected for the first time in Sana'a city. Present findings highlighting the importance of regular mosquito surveillance in recording new species as well as identifying mosquito vectors and their preferable breeding sites. Hence, a satisfactory mosquito control program can be raised. Future extensive surveys, studies of cytogenetic and molecular analysis in addition to predation potential of predaceous mosquito larvae are recommended.