THE USE OF NESTED-PCR TO DETECT THE PRESENCE OF PLASMODIUM IN ANOPHELES ARABIENSIS IN JAZAN REGION, SAUDI ARABIA.

The present study was carried out in 26 viJlages at two Governates (Al-Khobah, and Haroob) in Jazan Region in Southwest Saudi Arabia to identify and detect the presence of Plasmodium in Anopheles arabiensis using nested-PCR technique. An. Arabiensis was identified by PCR and it was the predominant Anopheles mosquito in all the collection sites. A total of 257 An. Arabiensis females were collected and two samples from two villages (Almuatan and Alsabkha) out of 107 (1.87%) female mosquitoes from Haroob Governorate were found positive for the sporozoites of Plasmodium falciparum. Similarly, 3 out of 150 (2%) female mosquito samples from Um-alkhameir, AL-Khobah Governorate, were also found positive. Around fourfold increase of the sporozoite rate (from 0.61 to 2.0%) in An. arabiensis in Al-Khobah Governorate has been observed compared to the previous study of 2007-2008. The wide spread of An. arabiensis in Jazan region with >90% of the malaria cases caused by P. falciparum, along with infectivity rate ranges between 1.87 to 2.0% for P. falciparum in Al-Khobah and Haroob Governorates, suggests that P. falciparumn is the most predominant malaria parasite and An. Arabiensis is a very efficient malaria vector in the region. It also suggests more in-depth researches on the ecology, behavior, and control of An. Arabiensis to promote area-specific control programs.

STUDIES ON AEDES AEGYPTI RESISTANCE TO SOME INSECTICIDES IN THE JAZAN DISTRICT, SAUDI ARABIA.

The present study provided information on the susceptibility status of the adult and larvae of Aedes aegypti mosquitoes in Jazan region of Saudi Arabia. Bioassay tests were performed on adults and larvae by using WHO recommended concentrations and test kits. Adults of Ae. aegypti mosquitoes were exposed to test papers impregnated with Lambda-cyhalothrin (0.05%), Cyfluthrin (0.15%), Deltamethrin (0.05%), Permethrin (0.75%), Fenitrothion (1%), Bendiocarb (0.1%) and DDT (4%) insecticides. Ae. aegypti mosquitoes were found to be susceptible only to Cyfluthrin; (mortality rate was 100%), whereas variable resistances were observed from the rest of the other insecticides tested (mortality rates ranged between 93.6 and 17%). Larvae were subjected to different concentrations of Diflubenzuron, Methoprene (IGRs) and Temephos (Organophosphate). Adult emergence inhibition (IE50 & IE95) values for the IGRs and the (LC50 & LC95) for Temephos were determined by log-probit regression analysis. Ae. aegypti larvae were resistant to Temephos (LC50 61.8-LC95 35600.1 mg/l) and showed high susceptibility to Methoprene than Diflubenzuron (IE50 0.49-IE95 10.9 mg/l) and (IE50 0.86 and IE95 93.8 mg/l), respectively. Larvae were more susceptible to Methoprene than Diflubenzuron by 1.8 folds.

A TRAINING PROGRAM ON DENGUE FEVER AMONG SECONDARY SCHOOL STUDENTS, JAZAN, SAUDI ARABIA.

Dengue fever (DE) is commonest rapidly spreading Aedes-bome viral fever worldwide. In the last decade several confirmed dengue cases were reported in Jazan Province. The study assessed the knowledge, attitudes and preventive practices of dengue fever among the secondary schools students in Ja.zan. A cross-sectional study was conducted among students of six secondary schools in Jazan. Multistage stratified random sample method was used and seven hundred forty two (742) were taken as respondents in study. The data on the socio-demographic characteristics of the respondents about their knowledge, attitude and practice towards DF were collected by using a pre-structured and self-administered questionnaire. The results showed a poor DF knowledge arpong the students, regarding attitudes towards DF, prevention and control, the majority of the participants' had good attitudes and believed that DF could be controlled and prevented (93.2%), DF control was the responsibility of government and community (83.1%) and they themselves have an important role to play in DF prevention (78.5%).The most common practice to prevent mosquito breeding were found to be the disposing of water from breeding containers (85.5%) and covering of water containers (68.6%). A significant association between the practice of DE preventive and control measures and sex of the participants' was (P

Demonstration of side coupling to cladding modes through zinc oxide nanorods grown on multimode optical fiber.

A novel concept is introduced that utilizes the scattering properties of zinc oxide nanorods to control light guidance and leakage inside optical fibers coated with nanorods. The effect of the hydrothermal growth conditions of the nanorods on light scattering and coupling to optical fiber are experimentally investigated. At optimum conditions, 5% of the incident light is side coupled to the cladding modes. This coupling scheme could be used in different applications such as distributed sensors and light combing. Implementation of the nanorods on fiber provides low cost and controllable nonlithography-based solutions for free space to fiber coupling. Higher coupling efficiencies can be achieved with further optimization.

Group velocity inversion in AlGaAs nanowires.

We investigated the dispersion characteristics of submicron sized AlGaAs waveguides. Numerical simulations shows that the tight confinement of the optical waves in such nanowires leads to strong variations of the dispersion characteristics compared to classic, weakly guided waveguides of the same material system. We found numerically that the investigated structure has negative GVD for the TE mode provided the waveguide width is between 670 nm and 280 nm. Experimental data obtained from 300 mum - 1 mm long wires confirms the numerical results.

Silicosis among grindstone cutters in the north of Nigeria.

Many of the grindstones used in Nigerian homes are quarried from sandstone in a small group of villages near Kano in the extreme north of the country. Of an unselected group of 126 stonecutters from two of these villages 49 were found to have radiographic evidence of silicosis, with progressive massive fibrosis in 17. Those with silicosis had worked longer in the quarries than 77 whose radiographs showed no evidence of silicosis. Sixty-three per cent of the silicotics had respiratory symptoms, the commonest being breathlessness on moderate exertion. Cough was the earliest symptom in 42%. Only 35% had abnormal physical signs in the cardiorespiratory system, 18% had clearly reduced ventilatory capacity, and airways obstruction was evident in 16%. The prevalence of silicosis in these open-cast sandstone quarriers is unexpectedly high. This is probably explained by the intensity of exposure and the particular kind of sandstone being worked. Reduction of dust exposure in these quarries raises severe practical problems, but the inhabitants of this drought-ridden area can scarcely be expected to abandon their traditional livelihood.