Chlorination has been most widely practiced method of disinfection for potable waters since the turn of century and principal means by which the microbial quality of water is maintained in Iraq. Khabur river is the main source of our drinking water in Zahko-Duhok city, here chlorine in form of hypochlorous at concentration 2 ppm are most used. In this paper we have attempted to compare sensitivity of microorganisms toward chlorine and also we have tried to determination of chlorine resistance bacteria to antibiotics. Results from our experiment suggest that bacteria isolated from post chlorinated water samples are more resistant to chlorine disinfection than prechlorinated water samples. the isolated organisms are Staphylococcus aureus, Micrococcus varians and Aeromonas hydrophila fully resistant to chlorine at this concentration and the most resistant bacterium of all isolates is Staphylococci. Although the strains were sensitive to abroad spectrum of antibiotics but the strains show resistant to the most important clinical antibiotics. Suggestion that either the synthesis of unique proteins or aggregation of the bacteria as mechanisms of resistance to inactivation. This study will help us to suggest relevant changes in purification processes for supply of better quality of drinking water to our Municipal Corporation.

Background: As the COVID-19 pandemic evolves, many pediatricians and infants’ parents have been left with renewed questions about the consequences of infection on children and steps to be taken if their child has symptoms of, or tests positive for, COVID-19. Methods & Results: Literature reviews and recent studies revealed that children are better than adults at combating SARS –CoV‑2. There was conflicting evidence on age-related differences in ACE2 expression in the nose and lungs. However, measurements of SARS-CoV-2 viral load’ have shown no clear difference. Strikingly, cross-reactive antibodies from previous exposure to coronavirus common cold do not offer any special protection in both children and adults. The kid’s immune response against SARS‑ CoV-2 infection is initiated with low immunological tone to prevent overactive immunity and is characterized by rapid lung damage repair in contrast to stormy waves in adults. Conclusion: One of the few silver linings of the COVID-19 pandemic is that children are relatively spared and wining with their immunity.