Petros Beyene (PhD)Enaro Desalegn2018-07-242023-11-092018-07-242023-11-091993-06http://etd.aau.edu.et/handle/123456789/9917A case - control study was calTied out to establish the etiologic agents causing acute respiratory infections in infants in Addis Ababa using the immunofluorescence technique. Special attention was given to viruses and Chlamydia trachomatis. The influence of the level of education, passive smoking, breast feeding, and meteorological factors in association with viral infection in acute respiratory infections was investigated using the questionnaire data. Nasopharyngeal aspirates of 225 cases and 178 control infants were studied for the presence of respiratory syncytial virus, parainfluenza virus, influenza virus types A and B, adenovirus and Chlamydia trachomatis between January, 1992 and December, 1992. The overall viral and chlamydial detection rate was 48.9%. The total viral detection rate was 32.9%, out of which respiratory syncytial virus accounted for 31.1 %. Chlamydia trachomatis was detected in 16%. In control infants 2.8% of viral detection was observed. Five control infants had detectable viral antigens but no control infants had detectable Chlamydia trachoma tis antigens. Infants having acute respiratory infection showed significantly higher rates of viral detection than healthy control infants (Chi-Square Yates cOlTected = 52.64, p<O.OOI). Viral detection demonstrated higher rates than that of Chlamydia trachomatis (Chi-Square with Yates corrected = 54, p<O.OOl). Mixed infections of virus and Chlamydia trachoma tis was evident in 6.2%. The rate of viral detection showed an inverse relationship with increasing age. -viiiThose infants aged up to 2 months demonstrated higher frequencies of viral detection compared to the 3-12 months of age . Slightly higher frequencies of viral detection were observed in females than in males, and males were more affected than females by chlamydial infections. In acute upper respiratory infections a similar frequency of viral detection rates were observed in comparison with that of the pnellIDonia cases . Respiratory syncytial virus was the most prevalent etiologic agent detected, and Chlamydia trachomatis was the second most important etiologic agent. The socio-economic factors thought to contribute to viral infections have not been established; however, meteorological factors tended to be associated with the prevalence of viral infections. This is an original study that establishes the importance of viral and chlamydial etiology of acute respiratory infections in infants in Ethiopia.enVIRAL and ChlamydialEtiology of Acute Respiratory InfectionThesis