First study in Qatar to reveal high Legionella counts in cooling towers

Legionella spp. is transmitted from water to humans by aerosol-generating devices, including cooling towers [CTs]. There have not been published reports about Legionella in these systems in Qatar. Ten CTs in Qatar University were sampled on a monthly basis. Bacteria were recovered from 90 water samples by filtration and concentration. Legionella DNA copy number [CN] was assessed by quantitative RT-PCR. Legionella DNA was detected in 100% of the samples. The bacterial counts ranged from 0.006 to 199.56 CFU/mL, and critical counts were found in 51 [56.7 %] samples. Moreover, 7 [7.8%] samples showed a count of more than 100 CFU/mL. The highest counts were found in the months of May and June. These results suggest that this organism is found in high number in tested CTs, presenting a potential health risk to the local population

Prevalence of parainfluenza and influenza viruses amongst children with upper respiratory tract infection

The objective of this study was to determine the prevalence of Parainfluenza and Influenza causing upper respiratory tract infections and to evaluate shell vial culture assay and direct immunofluorescence assay. A retrospective study during the period between November 1997 and May 1998. A total of 350 nasopharyngeal aspirates were obtained from children suffering from respiratory tract infections. Nasopharyngeal aspirates were investigated for the presence of Parainfluenza 1, 2 and 3, Influenza A and B using shell vial culture assay, conventional culture assay and direct immunofluorescence assay. Parainfluenza 1 were identified in 3%, Parainfluenza 2 in 5% and Parainfluenza 3 in 6%. Influenza A were identified in 4% and Influenza B in 2%. Parainfluenza 1, 2 and 3 were isolated in children less than 5 years old. Most of Parainfluenza cases were associated with other upper respiratory infections. Shell vial assay showed a sensitivity of 90-93% and specificity of 99-100% for detecting Parainfluenza 1, 2 and 3. These results emphasize that shell vial assay is important for the diagnosis of Parainfluenza and Influenza, although direct immunofluorescence assay is the superior diagnositic assay