Comparative inhibitory action of 4 standard bacteriophages on the larvicidal activity of certain mosquito pathogenic bacteria against culex pipiens larvae

Four bacteriophages [CP-51, CP-54, Yousten-4 and Yousten-14] were assayed against 7 entemopathogenic bacterial strains. The two CP ones, indicating variability of the host range of the tested phages was suggested to be related to the environmental characteristics of the tested strains. On testing the susceptibility of 5 bacterial strains to the phage Yousten-4 at different cultural ages, a correlation was found between incubation time and level of bacterial susceptibility to the tested phage. This observation was explained to be due to the number of vegetative cells and/or sporulation

field survey of bacteriophage contamination of mosquito breeding places, inhibiting bacterial insecticide

Twelve geographically different mosquito breeding places were described and sampled for the detection of naturally existed bacteriophage viruses which could transduct and lysate 5 entomopathogenic bacteria. The surveyed places are classified into seepage, sewage, and irrigation breeding water. Bacterial free filtrates of the collected samples were assayed against the tested bacteria in vitro and against 3rd instar Culex pipiens larvae as well. Nine out of the twelve places could demonstrate the presence of phages. Bacillus thuringiensis H-14 was found susceptible to phage[s] present in polluted and irrigated water of 5 locations, while B. thuringiensis Berliner was susceptible to only a specific phage of one breeding place [pollutes, sewage water]. With regard to Bacillus sphaericus strains 1593 and 114, bacteriophages of sewage and irrigated water could lysate them and these phages are characterized by being of a moderate host range, except one phage which showed high specificity with strain 114 and was detected in a polluted sewage water sample collected from Daqahlia Governorate. The detected phages proved to lysate both B. thuringiensis H-14 and B. sphaericus 1593 on their larvicidal action through a series of bioassay experiment, almost all results indicate the presence of a significant inhibitory activity

Isolation, purification and ultrastructure of bacteriophages from natural mosquito breeding places in Egypt

Two bacteriophages were isolated from field collected samples representing two different mosquito breeding places. The phage AB-1 [isolated from Abheit Village, Fayoum Governorate "seepage water"] and the phage GA-2 [isolated from El-Gabal El-Asfer, Qalyoubia Governorate "sewage drain water"] were purified. Both bacteriophages were ultrastructurally described with respect to their morphology, dimensions, phases of bacterial attack and lysogeny. No major differences were observed between both isolated phages in relation to specificity, however, they were isolated from two different types of breeding places and two different geographic areas as well. This study may assume a wide host range of the isolated phages and reflect how bacterial insecticides used for mosquito larval control could be inhibited by such bacteriophage

Distribution and host relationship of ticks [ixodoidea] infesting domestic animals and rodents in Sinai peninsula

Geographical distribution of ticks infesting farm animals in Sinai Peninsula revealed the presence of 12 tick species; namely, Hyalomma dromedarii, H. impeltatum, H. ananatolicum, H. anexcavatum, H. marginatum rufipes, H. M. turanicum, H. schulzei, Rhipicephalus sanguineus, R. turanicus, Boophilus annulatus, Ornithodoros erraticus and Argas persicus. The distribution map of those species is given. The areas of Sinai could be arranged as regards the number of tick species in the following descending order: Beer Lehfin and St. Catherine [9 spp.], Kosaimah and Nuweibah [8 spp.], Arish and Godirate [7 spp.], Firan [6 spp.], Beer El-Abd, Zowaid, Rafah, Quntara, Wadi- Hadra and El-Tur [5 spp.], Abu Redis, and Hammam Pharon [4 spp.]

Leishmania infection sought in rodents in north Sinai, Egypt

Zoonotic cutaneous leishmaniasis [ZCL] is endemic in certain foci in North Sinai. In the present study, eight species of commensal and wild rodents were trapped from seven areas. Suggestive ZCL lesions were seen on R. rattus, R. norvegicus, G. pyramidum, G. andersoni, G. gerbillus and Meriones sacramenti. Positive Giemsa stained smears were identified in G. pyramidum. The results were discussed. It was concluded that the ZCL transmission cycle is identified regarding the three factors; animal reservoirs, sand fly vector and man

Water soluble toxins of bacillus thuringiensis serotype H-14 demonstrating lethal action on culex pipiens larvae

The lethal action of Bacillus thuringiensis on mosquito larvae was studied, in relation to the exotoxin proteins secreted during the vegetative growth. The water soluble protein fractions [exotoxins] were separated through gel filtration and polyacrylamide gel electrophoresis and bioassayed against 3 rd instar larvae of culex pipiens. Five fractions were detected in 72 hr bacterial cultures. Results of bioassays indicate toxicity of 3 protein subfarctions of M. Wts [31.000, 32.700 and 36.700 dalton]. Other types of detectedd proteins were found non -toxic. Based on the achieved results the exotoxins may be considered in larvicids formulations of Bacillus thuringiensis H -14

Larvicidal activity of bacillus thuringiensis serotype H-14 on certain Egyptian mosquito species

Laboratory experiments were carried out to screen the susceptibility of five Egyptian mosquito species to the toxic effect of a standard formulation of B. thuringiensis H-14 [IPS82 Lot 91509] prepared by Pasteur Institute. Tests were carried out under laboratory conditions using the method described by [De Barjac 1978]. The obtained results indicated that all tested mosquito species were susceptible to the toxic agents of this formulation. However, degree of susceptibility varied according to mosquito species. The highest rate of mortality was found among the larvae of Aedes capius PaIlas followed by Culex Pipiens, Culex antennatus, Anopheles multicolor and Anopheles phareonisis