We aimed to generate a valid reliable Arabic version of MOS social support survey (MOS-SSS). We did a cross sectional study in medical students of Faculty of Medicine in Khartoum, Sudan. We did a clustered random sampling in 500 students of which 487 were suitable for analysis. We followed the standard translation process for translating the MOS-SSS. We accomplished factor analysis to assess construct validity, and generated item-scales correlations to evaluate the convergent and discriminant validity. We extracted the Cronbach’s α and Spearman Brown coefficient of spit half method to determine internal consistency. We measured stability by correlation between the scores of the MOS survey taken at two different occasions with ten days apart in 252 participants. All items correlated highly (0.788 or greater) with their hypothesized scales. All items in subscales correlated higher by two standard errors with their own scale than with any other scale. Principle component analysis with varimax rotation was conducted on the 19 items and examination of scree plot graphically suggested 4 predominant factors that account for 72 % of variance. It showed high loadings, ranging from 0.720 to 0.84 for items of emotional support, 0.699–0.845 for tangible support, 0.518–0.823 for affectionate support, and 0.740–0.816 for positive social interaction. Cronbach’s alpha for overall MOS scale and subscales indicated high internal consistency. The test–retest correlation showed weak correlation between the test and retest (ranges from 0.04 to 0.104). The Arabic MOS-SSS had high validity and internal consistency.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-2960-4) contains supplementary material, which is available to authorized users.

The diurnal flight activity of Simulium griseicolle Becker was determined at Shambat, Khartoum, by means of a suction trap and a vehicle-mounted trap; and the biting activity by means of a chicken-baited trap. Only incidental observations of mammal-biting activity were made. The three trapping methods indicated two peaks of activity, one in the morning and the other late in the afternoon. Fly activity was lowest in the early afternoon when temperature and light intensity were highest, wind speed was moderate and relative humidity was least. Females outnumbered males in all the catches, except in the early morning when more males were sometimes recorded.