Browsing by Subject "transmission"
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Item COVID-19 in India: Are Biological and Environmental Factors Helping to Stem the Incidence and Severity?(JKL International, 2020-05-09) Chakrabarti, Sankha Shubhra; Kaur, Upinder; Banerjee, Anindita; Ganguly, Upsana; Banerjee, Tuhina; Saha, Sarama; Parashar, Gaurav; Prasad, Suvarna; Chakrabarti, Suddhachitta; Mittal, Amit; Agrawal, Bimal Kumar; Rawal, Ravindra Kumar; Zhao, Robert Chunhua; Gambhir, Indrajeet Singh; Khanna, Rahul; Shetty, Ashok K.; Jin, Kunlin; Chakrabarti, SasankaThe ongoing Corona virus (COVID-19) pandemic has witnessed global political responses of unimaginable proportions. Many nations have implemented lockdowns that involve mandating citizens not to leave their residences for non-essential work. The Indian government has taken appropriate and commendable steps to curtail the community spread of COVID-19. While this may be extremely beneficial, this perspective discusses the other reasons why COVID-19 may have a lesser impact on India. We analyze the current pattern of SARS-CoV-2 transmission, testing, and mortality in India with an emphasis on the importance of mortality as a marker of the clinical relevance of COVID-19 disease. We also analyze the environmental and biological factors which may lessen the impact of COVID-19 in India. The importance of cross-immunity, innate immune responses, ACE polymorphism, and viral genetic mutations are discussed.Item Epidemiologic Assessment of a Targeted Tuberulosis Screening and Treatment Program Based on Geographic and Molecular Clustering(2005-08-01) Moonan, Patrick KevinMoonan, Patrick K., Epidemiologic Assessment of a Targeted Tuberculosis Screening and Treatment Program Based on Geographic and Molecular Clustering. Doctor of Public Health (Disease Prevention and Control), August 2005, 93 pp., 12 tables, 7 illustrations, bibliography, 148 tables. One of the primary goals of the tuberculosis elimination strategy is to interrupt the transmission of mycobacterium tuberculosis (TB). The most effective way to accomplish this goal is to identify and treat individuals who have active tuberculosis. However, even in highly effected tuberculosis control programs, M. tuberculosis continues to be transmitted to others, largely because most transmission occurs before diagnosis and initiation of therapy. Under the current recommendations, testing should be targeted at specific high-risk populations. While a strategy of targeted testing and treatment of persons most likely to develop tuberculosis is attractive, it is uncertain how best to accomplish this goal. This is the first study to assess the use of geographic and molecular surveillance in guiding a targeted tuberculosis screening and treatment of active tuberculosis and latent tuberculosis infection that monitors potential transmission in a defined high risk geographic area. The results of this geographically targeted program demonstrate significant yield for discovering active cases, latent tuberculosis infection, and recent transmission (TST converters). In this setting, geographically targeted screening identified as many as 19.8 tuberculosis cases per 1,000 persons screened and as many as 292.4 latent tuberculosis infections per 1,000 persons screened. Additionally, successful treatment of these individuals reduced the number of both cases and latent infection identified. Over a three-year period the case detection rate, latent infection detection rate, and TST conversion rate was reduced by 335%, 171% and 285% respectively.Item Geospatial and Molecular Clustering of Mycobacterium tuberculosis, Tarrant County, TX, 1993-2000(2002-05-01) Moonan, Patrick Kevin; Bayona, Manuel; Quituga, Teresa N.; Oppong, JosephMolecularly clustered cases are assumed to be the result of recent transmission of those in the cluster. An intervention that targets clustered cases with recent transmission, such as identifying contacts of active cases, could be effective as a programmatic control measure. The purpose of this study is to identify areas of recent transmission, whereby determining the contribution of geospatial and molecular clustering to the local tuberculosis morbidity. Tuberculosis cases due to recent transmission have important implications for tuberculosis control programs. They suggest that current methods of case-finding, investigations of susceptible contacts, and the provision of preventive therapy are ineffective in interrupting some transmission. This study utilized molecular strain characteristics and GIS technology to uncover geographical links to on-going transmission, where tradition public health surveillance methods are failing. Risk behaviors such as illicit drug use, crack-cocaine use, jail experience, and sexual relations with a prostitute were strongly associated with on-going transmission. Place factors, specifically where patients reside, was also found to be significantly associated for certain zip codes in Tarrant County. Cases in urban zip codes 76102 [OR=3.954; 95% CI=1.803, 8.671] and 76105 [OR=3.135; CI=1.254, 7.835] were strongly associated to infection with a clustered strain when compared to the rest of the county. The use of Geographical Informational Systems (GIS) technology and molecular strain typing provides a proactive approach that may be used to initiate traditional surveillance investigations. As an application utility, this project will be used to develop more effective means of tuberculosis control within Tarrant County.Item Transmission and Establishment of Helicobacter pylori Infection in Childhood(2013-08-01) Cervantes, Diana; David SterlingTransmission of Helicobacter pylori infection is thought to occur predominately during childhood in both developed and developing countries. Various bacterial, host and environmental factors influence H. pylori transmission and establishment of infection. The most likely routes of H. pylori transmission include gastro-oral, fecal-oral and oral-oral. Therefore, conditions such as close, personal contact with a child’s infected mother and siblings may favor H. pylori transmission. The immunological response mounted against H. pylori infection by a child, possibly modulated by age and passive immunity, may alter the establishment of infection. The current research, utilizing data from The Pasitos Cohort Study, aimed to estimate the effect that H. pylori infected mothers, H. pylori infected siblings and breastfeeding may have in the acquisition and establishment of H. pylori infection in children. The Pasitos Cohort Study, a birth cohort established on the U.S.-Mexico border, recruited pregnant women from El Paso, Texas and Juarez, Mexico to identify risk factors for H. pylori infection during childhood. Assessment of active H. pylori infection for 615 children (472 index children and 143 younger siblings) was performed from April 1998 until December 2005 accounting for an average of 3.8 years of follow-up for the index child and an average of 2.5 years of follow-up for younger siblings of the index. The Pasitos Cohort Study provides advantages such as longitudinal assessment of H. pylori status for determination of directionality of H. pylori infection in familial transmission. In addition, differentiation between infection acquisition, short-term and long-term establishment of infection was attempted. The current study found that infected older siblings in the household were positively associated with both the acquisition and long-term infection establishment of H. pylori in younger siblings. Mothers and breastfeeding may also be positively associated with H. pylori outcomes but due to highly uncertain results obtained, further studies are need to assess their association with infection acquisition, short-term infection and long-term infection in children.Item Transmissions of Mycobacterium tuberculosis in Dallas and Tarrant Counties: The Use of RFLP to Evaluate MTB Control Programs(2001-05-01) Kosterman, Edward Donald; Weiss, Stephen E.; Gratton, TerranceKOSTERMAN, EDWARD DONALD; MASTERS OF PUBLIC HEALTH; MAY 19, 2001 TRANSMISSION OF Mycobacterium tuberculosis IN DALLAS AND TARRANT COUNTIES: THE USE OF RFLP ANALYSIS TO EVALUATE MTB CONTROL PROGRAMS; 108 PAGES; 3 TABLES; 39 REFERENCES Dallas and Tarrant Counties are adjacent, similar counties in North Central Texas. Each county manages MTB patients under similar contracts with the Texas Department of Health. In Dallas county culture positive patients MTB are treated with Selective Directly Observed Therapy. Patients with culture positive MTB in Tarrant county are treated with Universal Directly Observed Therapy. RFLP IS6110-based RFLP analysis revealed that more strains were clustered in Dallas county than Tarrant county. Significantly more drug resistant isolates and drug resistant isolates in clusters were observed in Dallas county. These results suggest that DNA typing methods may be used to assess the efficacy of MTB control programs in areas where traditional epidemiological analysis may be ineffective.