Prevention of typhoid fever in Nepal with the Vi capsular polysaccharide of Salmonella typhi. A preliminary report

We conducted a pilot study followed by a large clinical trial in Nepal of the use of the capsular polysaccharide of Salmonella typhi (Vi) as a vaccine to prevent typhoid fever. In the pilot study, involving 274 Nepalese, there were no significant side effects of the Vi vaccine; about 75 percent responded with a rise in serum antibodies of fourfold or more. In the clinical trial, residents of five villages were given intramuscular injections of either Vi or, as a control, pneumococcus vaccine dispensed in coded, randomly arranged, single-dose syringes. There were 6907 participants, of whom 6438 were members of the target population (5 to 44 years of age); each was visited every two days. Those with temperatures of 37.8 degrees C or higher for three consecutive days were examined and asked to give blood for culture. Typhoid was diagnosed as either blood culture-positive or clinically suspected on the basis of bradycardia, splenomegaly, and fever, with a negative blood culture. Seventeen months after vaccination, the codes were broken for the 71 patients meeting the criteria for either culture-positive or clinically suspected typhoid. The attack rate of typhoid was 16.2 per 1000 among the controls and 4.1 per 1000 among those immunized with Vi (P less than 0.00001). The efficacy of Vi was 72 percent in the culture-positive cases, 80 percent in the clinically suspected cases, and 75 percent in the two groups combined. These data provide evidence that Vi antibodies confer protection against typhoid. Surveillance continues to determine the duration of Vi-induced immunity.

Optical coherence tomographic assessment of macular thickness and morphological patterns in diabetic macular edema: Prognosis after modified grid photocoagulation

Introduction: The topographic mapping is useful for monitoring patients for the development of macular edema and following the resolution of edema after laser treatment. Objectives: To evaluate the usefulness of optical coherence tomography (OCT) for mapping of macula after laser therapy in clinically significant macular edema (CSME). Materials and methods: A prospective study was carried out enrolling 60 eyes of 35 patients with the diagnosis of CSME. OCT was performed at first visit and every successive follow up visit. The retinal thickness was measured automatically using OCT retinal mapping software. Statistics: Correlation between vision status and central macular thickness (CMT) was done using the Spearman’s correlation test. The analysis of variance (ANOVA) and independent t-test were used for comparison of groups. Results: The OCT revealed sponge like thickening pattern (ST) in 67.4 % followed by cystoid macular edema (CME) in 19.6 %. Best corrected visual acuity (BCVA) improved in 89.1 % after 6 months of treatment. There was high correlation between vision status and CMT (P =<0.001). The mean values of baseline CMT were 301.68 (±134.738), 434.83 (±180.758), 518.67 (±275.184), 327 (±108.393) and 334.85 (±158.91) microns for the OCT patterns of ST, CME, sub-foveal detachment (SFD), vitreo-macular interface abnormality (VMIA) and average CMT respectively (p=0.042). Conclusion: OCT is a useful tool for evaluating CSME. It can show the various morphological variants of CSME while the BCVA and CMT are fairly different. DOI: http://dx.doi.org/10.3126/nepjoph.v4i1.5864 NEPJOPH 2012; 4(1): 128-133