Showing papers by "Mahmudur Rahman published in 2015"

An Outbreak of Chikungunya in Rural Bangladesh, 2011.

Abstract: Background The first identified Chikungunya outbreak occurred in Bangladesh in 2008. In late October 2011, a local health official from Dohar Sub-district, Dhaka District, reported an outbreak of undiagnosed fever and joint pain. We investigated the outbreak to confirm the etiology, describe the clinical presentation, and identify associated vectors.

Highly Pathogenic Avian Influenza A(H5N1) Virus Infection among Workers at Live Bird Markets, Bangladesh, 2009-2010

Abstract: The risk for influenza A(H5N1) virus infection is unclear among poultry workers in countries where the virus is endemic. To assess H5N1 seroprevalence and seroconversion among workers at live bird markets (LBMs) in Bangladesh, we followed a cohort of workers from 12 LBMs with existing avian influenza surveillance. Serum samples from workers were tested for H5N1 antibodies at the end of the study or when LBM samples first had H5N1 virus–positive test results. Of 404 workers, 9 (2%) were seropositive at baseline. Of 284 workers who completed the study and were seronegative at baseline, 6 (2%) seroconverted (7 cases/100 poultry worker–years). Workers who frequently fed poultry, cleaned feces from pens, cleaned food/water containers, and did not wash hands after touching sick poultry had a 7.6 times higher risk for infection compared with workers who infrequently performed these behaviors. Despite frequent exposure to H5N1 virus, LBM workers showed evidence of only sporadic infection.

Raw Sap Consumption Habits and Its Association with Knowledge of Nipah Virus in Two Endemic Districts in Bangladesh

Abstract: Human Nipah virus (NiV) infection in Bangladesh is a fatal disease that can be transmitted from bats to humans who drink contaminated raw date palm sap collected overnight during the cold season. Our study aimed to understand date palm sap consumption habits of rural residents and factors associated with consumption. In November-December 2012 the field team interviewed adult respondents from randomly selected villages from Rajbari and Kushtia Districts in Bangladesh. We calculated the proportion of people who consumed raw sap and had heard about a disease from raw sap consumption. We assessed the factors associated with raw sap consumption by calculating prevalence ratios (PR) adjusted for village level clustering effects. Among the 1,777 respondents interviewed, half (50%) reported drinking raw sap during the previous sap collection season and 37% consumed raw sap at least once per month. Few respondents (5%) heard about NiV. Thirty-seven percent of respondents reported hearing about a disease transmitted through raw sap consumption, inclusive of a 10% who related it with milder illness like diarrhea, vomiting or indigestion rather than NiV. Respondents who harvested date palm trees in their household were more likely to drink sap than those who did not own date palm trees (79% vs. 65% PR 1.2, 95% CI 1.1-1.3, p<0.001). When sap was available, respondents who heard about a disease from raw sap consumption were just as likely to drink it as those who did not hear about a disease (69% vs. 67%, PR 1.0, 95% CI 0.9-1.1, p = 0.512). Respondents' knowledge of NiV was low. They might not have properly understood the risk of NiV, and were likely to drink sap when it was available. Implementing strategies to increase awareness about the risks of NiV and protect sap from bats might reduce the risk of NiV transmission.

To catch a fake: Curbing deceptive Yelp ratings and venues

Abstract: The popularity and influence of reviews, make sites like Yelp ideal targets for malicious behaviors. We present Marco, a novel system that exploits the unique combination of social, spatial and temporal signals gleaned from Yelp, to detect venues whose ratings are impacted by fraudulent reviews. Marco increases the cost and complexity of attacks, by imposing a tradeoff on fraudsters, between their ability to impact venue ratings and their ability to remain undetected. We contribute a new dataset to the community, which consists of both ground truth and gold standard data. We show that Marco significantly outperforms state-of-the-art approaches, by achieving 94% accuracy in classifying reviews as fraudulent or genuine, and 95.8% accuracy in classifying venues as deceptive or legitimate. Marco successfully flagged 244 deceptive venues from our large dataset with 7,435 venues, 270,121 reviews and 195,417 users. Furthermore, we use Marco to evaluate the impact of Yelp events, organized for elite reviewers, on the hosting venues. We collect data from 149 Yelp elite events throughout the US. We show that two weeks after an event, twice as many hosting venues experience a significant rating boost rather than a negative impact.

Immunogenicity of three doses of bivalent, trivalent, or type 1 monovalent oral poliovirus vaccines with a 2 week interval between doses in Bangladesh: an open-label, non-inferiority, randomised, controlled trial

Abstract: Summary Background The provision of several doses of monovalent type 1 oral poliovirus vaccine (mOPV1) and bivalent OPV1 and 3 (bOPV) vaccines through campaigns is essential to stop the circulation of remaining wild polioviruses. Our study aimed to assess the shortening of intervals between campaigns with bOPV and mOPV1 and to assess the immunogenicity of bOPV in routine immunisation schedules. Methods We did an open-label, non-inferiority, five-arm, randomised controlled trial in Bangladesh. We recruited healthy infants aged 6 weeks at 42 immunisation clinics and randomly assigned them (with blocks of 15, three per group) to receive a short three-dose schedule of bOPV (bOPV short) or mOPV1 (mOPV1 short) with the first dose given at age 6 weeks, the second at age 8 weeks, and the third at age 10 weeks; or to a standard three-dose schedule of bOPV (bOPV standard) or mOPV1 (mOPV1 standard) or trivalent OPV (tOPV standard) with the first dose given at age 6 weeks, the second at 10 weeks, and the third at age 14 weeks. The primary outcome was the proportion of infants with antibody seroconversion for type 1, type 2, and type 3 polioviruses. The primary, modified intention-to-treat analysis included all patients who had testable serum samples before and after receiving at least one OPV dose. We used a 10% margin to establish non-inferiority for bOPV groups versus mOPV1 groups in seroconversion for type 1 poliovirus, and for bOPV1 short versus bOPV1 standard for types 1 and 3. This trial is registered at ClinicalTrials.gov, number NCT01633216, and is closed to new participants. Findings Between May 13, 2012, and Jan 21, 2013, we randomly assigned 1000 infants to our study groups. 927 completed all study visits and were included in the primary analysis. Seroconversion for type-1 poliovirus was recorded in 183 (98%, 95% CI 95–100) of 186 infants given bOPV short, 179 (97%, 94–99) of 184 given bOPV standard, 180 (96%, 92–98) of 188 given mOPV short, 178 (99%, 97–100) of 179 given mOPV1 standard, and 175 (92%, 87–96) of 190 given tOPV standard. Seroconversion for type 2 was noted in 16 infants (9%, 5–14) on bOPV short, 29 (16%, 11–22) on bOPV standard, 19 (10%, 7–15) on mOPV short, 33 (18%, 13–25) on mOPV1 standard, and 182 (96%, 92–98) on tOPV standard. Seroconversion for type 3 was noted in 175 infants (94%, 90–97) on bOPV short, 176 (96%, 92–98) on bOPV standard, 18 (10%, 6–15) on mOPV short, 25 (14%, 10–20) on mOPV1 standard, and 167 (88%, 83–92) on tOPV standard. The short schedules for mOPV1 and bOPV elicited a non-inferior antibody response compared with the bOPV standard schedule. 104 adverse events were reported in 100 infants during follow up. 36 of these events needed admission to hospital (32 were pneumonia, two were vomiting or feeding disorders, one was septicaemia, and one was diarrhoea with severe malnutrition). One of the infants admitted to hospital for pneumonia died 5 days after admission. No adverse event was attributed to the vaccines. Interpretation Our trial showed that three doses of mOPV1 or bOPV with a short schedule of 2 week intervals between doses induces an immune response similar to that obtained with the standard schedule of giving doses at 4 week intervals. These findings support the use of these vaccines in campaigns done at short intervals to rapidly increase population immunity against polioviruses to control outbreaks or prevent transmission in high-risk areas. Funding Centers for Disease Control and Prevention and UNICEF.

Exposure-Based Screening for Nipah Virus Encephalitis, Bangladesh

Abstract: We measured the performance of exposure screening questions to identify Nipah virus encephalitis in hospitalized encephalitis patients during the 2012–13 Nipah virus season in Bangladesh. The sensitivity (93%), specificity (82%), positive predictive value (37%), and negative predictive value (99%) results suggested that screening questions could more quickly identify persons with Nipah virus encephalitis.

Liveness verifications for citizen journalism videos

Abstract: Citizen journalism videos increasingly complement or even replace the professional news coverage through direct reporting by event witnesses. This raises questions of the integrity and credibility of such videos. We introduce Vamos, the first user transparent video "liveness" verification solution based on video motion, that can be integrated into any mobile video capture application without requiring special user training. Vamos' algorithm not only accommodates the full range of camera movements, but also supports videos of arbitrary length. We develop strong attacks both by utilizing fully automated attackers and by employing trained human experts for creating fraudulent videos to thwart mobile video verification systems.We introduce the concept of video motion categories to annotate the camera and user motion characteristics of arbitrary videos. We share motion annotations of YouTube citizen journalism videos and of free-form video samples that we collected through a user study. We observe that the performance of Vamos differs across video motion categories. We report the expected performance of Vamos on the real citizen journalism video chunks, by projecting on the distribution of categories. Even though Vamos is based on motion, we observe a surprising and seemingly counter-intuitive resilience against attacks performed on relatively "static" video chunks, which turn out to contain hard-to-imitate involuntary movements. We show that the accuracy of Vamos on the task of verifying whole length videos exceeds 93% against the new attacks.

Data Verifications for Online Social Networks

Abstract: OF THE DISSERTATION DATA VERIFICATIONS FOR ONLINE SOCIAL NETWORKS by Mahmudur Rahman Florida International University, 2015 Miami, Florida Professor Bogdan Carbunar, Major Professor Social networks are popular platforms that simplify user interaction and encourage collaboration. They collect large amounts of media from their users, often reported from mobile devices. The value and impact of social media makes it however an attractive attack target. In this thesis, we focus on the following social media vulnerabilities. First, review centered social networks such as Yelp and Google Play have been shown to be the targets of significant search rank and malware proliferation attacks. Detecting fraudulent behaviors is thus paramount to prevent not only public opinion bias, but also to curb the distribution of malware. Second, the increasing use of mobile visual data in news networks, authentication and banking applications, raises questions of its integrity and credibility. Third, through proofof-concept implementations, we show that data reported from wearable personal trackers is vulnerable to a wide range of security and privacy attacks, while off-theshelves security solutions do not port gracefully to the constraints introduced by trackers. In this thesis we propose novel solutions to address these problems. First, we introduce Marco, a system that leverages the wealth of spatial, temporal and network information gleaned from Yelp, to detect venues whose ratings are impacted by fraudulent reviews. Second, we propose FairPlay, a system that correlates review activities, linguistic and behavioral signals gleaned from longitudinal app data, to